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Ventilation - introduction The indoor climate in our apartments is a crucial part of our daily living experience. It not only determines whether a space feels comfortable but also influences our health and well-being. A good indoor climate is the result of a combination of various factors. It's a balance between heat, humidity, fresh air, CO₂, light, and sound. A good ventilation system is essential to maintain a healthy and comfortable indoor climate. Good ventilation prevents: accumulation of CO₂, moisture, dust particles and all kinds of contaminants, which reduces complaints such as headaches, allergies, shortness of breath and fatigue; mold and moisture problems in bathrooms, kitchens and bedrooms; a musty, stuffy air and keeps the temperature and humidity stable. Too much? However, a ventilation system can also lead to excessive ventilation. This is called overventilation, resulting in unnecessary heat loss and drafts. Modern ventilation systems, especially when combined with heat recovery (HRV) , ensure that fresh air is supplied without significant heat loss, keeping energy costs low and maintaining a comfortable climate in the home. In this article we specifically discuss the possibilities of improving the ventilation system. The ventilation system - the current situation Fresh ventilation air is now supplied naturally. Metal sub-ducts —ventilation ducts ("suskasten") that channel air from outside to inside—are incorporated into the facade of each apartment. These ventilation ducts actually form an open connection to the outside air and do not contain any insulation, sound insulation or smart control. As a result, they can transmit a lot of cold air into the home in winter and heat in summer. This creates a less stable indoor climate and increases unnecessary energy consumption. The exhaust air is extracted mechanically through shared ducts on the roof ( ventilation type C ). This system is constantly running and consumes a lot of energy. The natural supply of fresh ventilation air can lead to heat loss in winter and the supply of overly warm outside air in summer. Because the grille has to be opened and closed manually, there is a risk of insufficient ventilation or over-ventilation and draught. Both the HU students and Steeds advies believe that an adjustment to the current situation is desirable in order to improve living comfort and save energy. We see 3 possible improvements Possibility 1. Ventilation type C+ ventilation type C is retained, only it is controlled by CO² sensors The existing system C will be retained, but expanded with CO₂ sensors. These sensors measure the air quality in each room and automatically control the ventilation. Operation the supply of fresh air remains natural, through the existing ventilation grids and window or wall grilles; The discharge is done mechanically and now only when necessary, based on the measured CO₂ and moisture content. Advantages energy saving: the system only runs when necessary, reducing heat loss and power consumption; healthy indoor climate: automatic control ensures constant air quality and prevents mold and moisture problems. Manual operation of the grilles will be maintained in this scenario. The existing ventilation boxes can be retained. These empty ventilation boxes can technically be filled with insulating material, but this will significantly reduce the ventilation capacity and may even be lost entirely. Possibility 2. Ventilation system C+   Ventilation system C+, expanded with self-regulating grilles (ZR) In this variant, the C+ system is combined with self-regulating grilles (ZR). These automatically adjust the air supply to changes in wind pressure or outside temperature. Operation A ZR grille operates mechanically thanks to an ingenious self-regulating valve. This valve automatically responds to changes in wind pressure and ensures that the incoming air volume remains constant as the wind increases. It works by using a flexible valve or spring mechanism that partially closes at higher pressure, preventing excessive cold air from entering and preventing drafts, noise, or energy loss. When the wind pressure decreases, the valve opens again, ensuring sufficient ventilation even at low air pressure. No electrical components or motor are required; operation is entirely via the air pressure and the design of the grille itself. Advantages constant ventilation and more comfort, even in changing weather conditions; A ZR grille has excellent thermal performance and contributes to the building's insulation. This is achieved through its design, which usually consists of aluminum profiles with a double or triple seal. This limits heat loss through the grille. In combination with demand-controlled extraction (CO₂ and moisture), the efficiency can be approximately 75% higher than with standard grilles. Points of interest Self-regulating grilles require periodic maintenance to remain functioning properly (inspection, cleaning, lubrication). They are more expensive to maintain than manual grilles, but offer greater comfort and stability. Existing soundproofing cabinets can be partially reused in this scenario, provided they are adapted for the installation of self-regulating and possibly sound-dampening grilles; It is important to note that even the quietest ventilation grilles can still produce some noise under certain conditions, especially in strong winds or due to pressure differences. #3. Ventilation system D   balanced ventilation In this system, both the supply and exhaust of air are mechanically controlled. The system requires the installation of a network of air ducts. Installing this in existing buildings is complex and expensive. Therefore, in practice, it is only used in new-build homes. Therefore, this possibility will be disregarded here. Costs, subsidy and financing Subsidies can be requested through the SVVE (for homeowners' associations) for energy-saving measures, including CO2-controlled ventilation systems and balanced ventilation with heat recovery. The subsidy is a percentage of the construction costs for one insulation measure: 15% of the costs, maximum €600 per apartment; for two or more insulation measures: 30% of the costs, maximum €1,200 per apartment. The CO2-controlled ventilation can also be further financed by a loan from the National Heat Fund. Read all about saving, borrowing and subsidies here . Sources & references Utrecht University of Applied Sciences, V entilation Research , 2024 SVVE (2024), Subsidy for energy-saving measures at homeowners' associations National Heat Fund (2024), Financing for collective sustainability Do you have any questions, ideas or would you like to share your experiences? Email us at duurzaamkleiburg1@gmail.com . Together we'll chart a path toward a future-proof Kleiburg.

Making Kleiburg phase 1 more sustainable will cost. As a homeowners' association, we have to make choices: how far do we want to go and how will we pay for it? Energy savings and improved living comfort are the benefits, but the investments are substantial. The main options are: saving , borrowing , and, where possible, utilizing subsidies . Subsidies cover on average 15–30% of the costs. The remainder must come from our own resources and/or loans. This article lists the options and their advantages and disadvantages. How do we pay for the sustainability of the apartment building? Reducing energy consumption and improving living comfort requires investment. The amount depends on the measures chosen. As with any investment, the question is: what does it cost and what is the return? Financing can be done in three ways Save; To borrow; Make use of subsidies. Because subsidies never cover all costs, it is important to first look at savings and borrowing. Save or borrow? We can finance large expenses in various ways: Save until we have enough cash; Accelerated savings through monthly contributions to be significantly increased; One-off contributions to the VvE reserve fund; Borrowing through a joint VvE loan. Advantages and disadvantages side by side To borrow If, as a homeowners' association, we choose to (partially) finance the sustainability plans of our building (only the common areas) with a loan, this can only be done with a resolution of the AGM (general members' meeting) with a qualified majority. Borrowing, option 1: from the National Heat Fund The National Heat Fund and the Homeowners' Association Energy Saving Loan - The Heat Fund, commissioned by the National Government, offers loans for more than 30 energy measures. The following applies: No closing costs; Members pay interest and principal through the monthly contribution; The interest rate is more favorable and remains fixed for the entire term (10–30 years). In July 2025: 3.29% (10 years) to 3.71% (30 years); Money goes into a construction fund; invoices are paid from it; Early repayment up to 20% per year without penalty. The Heat Fund does impose requirements on the quality and effectiveness of the sustainability measures to be implemented. And also: Have a customized VvE energy advice drawn up and update or create a current multi-year maintenance plan (MJOP); Possible restrictions on rented apartments, shops or commercial spaces. Everything can be found here: https://warmtefonds.nl/vve The research results pages will indicate for each proposed measure whether it meets the conditions for the VvE Energy Saving Loan. The National Heat Fund and the VvE Member Loan - an additional option for owners (who also occupy the apartment) with a low income. If the VvE finances the sustainability improvements with the VvE Energy Saving Loan, the contribution you must pay to the VvE will increase. If this is difficult for you due to a low income, you can apply for a Member Loan as a member of that VvE. This is: intended for owners who occupy their apartments themselves. interest-free and only needs to be repaid when the apartment is sold. However, maximum income limits apply to this loan. Owner -occupiers must apply for this loan themselves. For more information, see here . Borrowing, option 2: from the Future-proof maintenance fund for homeowners' associations This route is an alternative for possible measures that are not financed by the Heat Fund; The interest rate is higher: in autumn 2025 around 5.8% for 20 years; Advantages and disadvantages need to be further investigated. Subsidies - RVO The central government offers subsidies through the RVO (Netherlands Enterprise Agency) for: Research and advice  : up to 50% reimbursement, max. € 40,000  ; Construction supervision  : 50% reimbursement, max. € 20,000  - Construction supervision means that a construction supervisor monitors the quality of the project management and the construction itself ; The   Sustainability Measures  : fixed amounts per m² or per piece; For one measure: an average of 15% of the costs; For two or more measures: average 30% of the costs; Please note: some packages such as ZEP (very energy efficient package) impose additional requirements that are not profitable for Kleiburg. The percentages mentioned are from the Ministry of the Interior and Kingdom Relations (BZK). Read all about it at here . Several committee members also attended the webinar below . We highly recommend listening, provided you can set aside an hour for it. Subsidy - the Municipality of Amsterdam Amsterdam offers several subsidy options for sustainability, but Kleiburg does not meet the requirements in most cases: These include that the measures will ensure that all homes in the building achieve at least 3 label steps . Because a number of improvements have already been made during the renovation in 2013 , it is practically impossible for us to meet this condition. Of possible interest to us is the subsidy for sustainability planning for homeowners' associations . This subsidy is awarded for having a number of construction technical studies carried out, such as asbestos research, thermal bridge calculations, flora and fauna research; activities related to obtaining permits, applying for subsidies, construction cost estimates; preparation and guidance of the decision-making process.   For the Amsterdam City Council's planning subsidy, a contractor is required to develop a plan in advance that addresses the above components. Again, it's not possible to apply for the subsidy in installments. Next step In our publications on possible measures for Kleiburg, the committee will indicate for each measure whether it is eligible for a subsidy and/or loan; On this basis, the VvE can make choices that suit our financial situation and ambitions. Do you have any questions, ideas or would you like to share your experiences? Email us at duurzaamkleiburg1@gmail.com . Together we'll chart a path toward a future-proof Kleiburg.

Table of contents of insulation Introduction The roof The floors (undersides) of gallery walkways and balconies, including upstands Front and rear facade: wall and brackets Front and rear facades: window frames, glazing and air gaps Ground-floor floors Loose ends   ( this page) A couple of issues have not yet been addressed in the previous section: possibly insufficient insulation of the district heating pipe on the roof; insufficient insulation of the vertical riser pipes from the boiler room to the roof possibly insufficient insulation of the ceilings of the bicycle sheds; and the uninsulated expansion joint. These topics were not investigated by the students. The insulation of the bicycle shed ceilings is always mentioned, but not the expansion joint. 1. Possibly insufficient insulation of the district heating pipes on the roof The main district heating pipelines run outside on the roof and are approximately 125 meters long. This pipeline is likely installed in 2013. The pipes are insulated, however the question is whether the heat output/loss can be calculated in the current situation and what the gain would be if the pipes were to be better insulated. These questions were not addressed in the HU and Steeds studies . Our own research shows that: around 2013 for hot pipes in industry and district heating, CINI guidelines mainly recommend mineral wool (glass wool/rock wool), with thicknesses adjusted to temperature and diameter and often in one or two layers around the pipe (25–40 mm); it was common practice for external pipes to finish the rock wool pipe sections with aluminium or steel sheeting, or sometimes with a plastic outer sheath, for protection against weather and moisture; By current standards, heat loss is often considerable; therefore, additional insulation to approximately 60–100 mm in total would usually be cost-effective, especially with a long external pipe. When asked about this, Perplexity indicated that the improved insulation of this outside pipe would be placed in the compartment where the roof insulation is also located . 2. Insufficient insulation of the vertical riser pipes from the boiler room to the roof The vertical riser pipes (one supply and one return) for the hot water run vertically from the boiler room, through an unused space on the first floor, and then through the nine storage units in the bend of the building. They are currently fitted with an insulation layer of mineral wool (stone wool) with a thickness of approximately 4 cm. At the floor penetrations, no insulation has been applied. As a result, a significant amount of heat is absorbed by the concrete floors. This heat loss occurs throughout the entire year. The clearance between the pipe and the concrete floor is approximately 2 cm, which is too narrow to allow insulation with mineral wool. This issue has not been addressed in the studies carried out by Hogeschool Utrecht (HU) and Steeds Advies . Our own investigation indicates the following: the thickness of the existing insulation is based on older insulation guidelines and is thinner than what is currently considered economically optimal; the problem of the narrow pipe penetrations may be solvable by using Armaflex: a flexible, synthetic rubber insulation material that can be compressed by approximately 50–70% and then returns to its original thickness; the insufficient insulation could be improved by adding an extra layer of mineral wool (20–30 mm) on top of the existing layer, while applying a flexible intermediate layer of Armaflex in the penetration zones; this measure could reduce heat losses by approximately 25–35%. When asked about this, Perplexity indicated that improving the insulation of these internal pipes, together with the insulation of the pipes on the roof, could be grouped under the same category as roof insulation . 3. Possibly insufficient insulation of the bicycle shed ceilings The apartments above the bicycle shed already have lightly insulated floors. This floor can be further insulated by installing insulating ceiling panels in the bicycle sheds.   However, the existing piping and lighting fixtures will have to be relocated. The costs are always estimated at €45,474 excluding VAT. It is unclear whether this provision qualifies for subsidy. Despite the light insulation already mentioned, the thermal image indicates a poor connection of the insulation to the walls. It should be investigated whether this problem can be solved by better insulation of the connection to the wall. 4. The uninsulated expansion joint There is an uninsulated expansion joint vertically across the 10 residential floors between numbers 06-07. A vertical expansion joint in a building like Kleiburg serves to absorb structural deformations caused by temperature fluctuations, shrinkage, deflection, or other stresses within the building components. The expansion joints prevent cracking and structural damage by allowing movement between components. No insulation material has been applied to the expansion joint. House numbers 06 and 07 therefore experience radiating cold from the wall adjacent to the expansion joint. This problem is not discussed in either the HU or Steeds reports. Perplexity indicates that insulation can be applied, provided it is carried out with special expansion profiles or materials that do not hinder movement. Should be investigated: whether such a measure would be useful for Kleiburg; or whether the solution should be sought in insulation on the inside of the apartments concerned. Want to read something about insulation? Introduction The roof The floors (undersides) of gallery walkways and balconies, including upstands Front and rear facade: wall and brackets Front and rear facades: window frames, glazing and air gaps Ground-floor floors Loose ends   ( this page) Do you have any questions, ideas or would you like to share your experiences? Email us at duurzaamkleiburg1@gmail.com . Together we'll chart a path toward a future-proof Kleiburg.

Kleiburg is not only a large residential building but also part of the Bijlmer Museum, a municipally protected cityscape . This means that the cultural-historical value of the apartment building and its surroundings is protected. Exterior modifications, such as facades and window frames, are only permitted if they harmonize with the original character. This may have consequences for the sustainability improvements of phase 1 : some measures require additional consultation and permits. The flat Kleiburg was built in the early 1970s. The name refers to an old farmhouse in the Bijlmermeer neighborhood. In the 1980s, the Bijlmer neighborhood fell into disrepair. After the Bijlmer disaster of 1992, a major renovation of the neighborhood began. Housing association Rochdale wanted to demolish Kleiburg around 2008/2009, but local residents took action. The building was eventually sold to Consortium DeFlat for €1, on the condition that a sound renovation plan be developed. The exterior renovation began in September 2013. The homes were sold as empty shells for fixer-uppers. Phase 1 was completed in February 2014. In 2017, Kleiburg received international recognition: the project won the prestigious Mies van der Rohe Award and a Dutch Design Award . The protected cityscape Since May 2019, the Bijlmer Museum has been designated a protected cityscape by the municipality of Amsterdam. Kleiburg is part of this, along with the Gooioord, Groeneveen, Grubbehoeve, Kikkenstein, and Kruitberg flats. The elevated metro line, the greenery, the water, and the bridges are also part of this designation. The goal is to protect the cohesion and cultural-historical value. For Kleiburg, this means that the appearance cannot simply be altered. Limitations and consequences For Kleiburg phase 1, "protecting cohesion and cultural-historical value" may mean that we sometimes have to work together with phases 2, 3, and 4 on sustainability. Consider this: facades at the front and back; windows and frames; raising the roof for insulation. Permits In most cases, a permit is required for changes visible from the street or public space. Examples include: replacement of windows and frames; roof insulation on the outside; applying facade insulation. The municipality assesses whether changes are compatible with the character of the apartment building and the surrounding area. For advice, the homeowners' association can contact the Sustainable Heritage Desk (in Dutch: Loket Duurzaam Erfgoed) of the City of Amsterdam. Next step We will always indicate in the research results whether a measure might be restricted by the "protected cityscape" status. This way, it remains clear what is and isn't permitted. Do you have any questions, ideas or would you like to share your experiences? Email the committee at duurzaamkleiburg1@gmail.com . Together we'll chart a path toward a future-proof Kleiburg!

Intro Heating with infrared panels is a modern form of electric heating that provides direct radiant heat to objects and people in a room, similar to the heat of the sun. Infrared panels are particularly suitable as supplementary heating or for specific applications in well-insulated homes, but can also serve as primary heating with a good layout and sufficient insulation. [1] [2] [3] [4] Benefits of infrared panels Instantly pleasant warm feeling when switched on, without air circulation, so less spread of dust or allergens. [2] [5] [3] Simple and flexible installation without pipes or radiators, suitable for both residential and commercial spaces. [6] [4] Suitable for local heating, allowing only used zones (e.g. a workplace) to be heated particularly efficiently. [5] Modern and sleek appearance, often fitting into the interior. [3] [6] No noise, no outdoor unit and low maintenance compared to a heat pump or central heating boiler. [1] [3] Can be beneficial in combination with solar panels, because production and consumption are electric. [7] Disadvantages and points of interest Relatively high electricity consumption when used as main heating: in a well-insulated corner house this amounts to approximately 4,650 kWh per year for infrared panels (excluding tap water), more than twice the consumption of a standard electric heat pump. [1] Only surfaces and people within the radiation range are heated efficiently; corners and shaded areas may remain cold. [3] Higher purchase costs than electric panel heating, and a good installation plan is important for total comfort. [7] [3] Less suitable for poorly insulated homes due to direct heat loss through walls and windows. [3] [7] Aesthetics: Visibility of panels can be perceived as disturbing if they are not properly integrated. [3] Energy consumption and savings The consumption of a panel (550 watts) is 0.55 kWh per hour, which means a significant power demand when used frequently, especially if it serves as the main heating system. [8] In well-insulated houses, infrared can save approximately 10 to 40% energy compared to traditional heating, provided the system is used efficiently and selectively. [5] However, compared to an electric heat pump, the total annual consumption can be significantly higher: fully electric heat pump (2,700 kWh) versus infrared panels as main heating (4,650 kWh). [1] Applications in the home Ideal as additional heating, for example in the bathroom, home office or sitting area. [4] Can be the main heating source in smaller or highly insulated homes, provided panels are correctly positioned and sized. [4] [7] Flexible in use and quick to switch on/off, useful for people who only heat for a short time or in limited areas. [2] [4] [1] In summary: infrared panels are particularly interesting for targeted, fast, and localized heating, and are ideal for heavily insulated spaces or as supplementary heating. With primary heating, the total electricity costs are often considerably higher than with a heat pump, although the investment/installation can be simpler. [4] [1] [3] ⁂ 1. https://www.milieucentraal.nl/energie-besparen/duurzaam-verwarmen-en-koelen/infraroodpanelen-voor-verwarming/ 2. https://www.infraroodverwarming-info.nl/voordelen-en-nadelen/ 3. https://www.woonwijzerwinkel.nl/de-voor-en-nadelen-van-infrarood-verwarming/ 4. https://dutchheating.nl/kenniscentrum/alles-over-infrarood-panelen/ 5. https://www.bobex.be/nl-be/infraroodverwarming/nadelen/ 6. https://www.verwarminghandel.nl/blogs/blog/infrarood-verwarming-de-echte-voor-en-nadelen 7. https://www.infraroodverwarming-soest.nl/blogs/info/infrarood-panelen-test-consumentenbond/ 8. https://www.verwarminginfo.nl/infraroodverwarming 9. https://extrawarmte.nl/energiebesparing/de-warmtepomp-nadelen-tot-infrarood-panelen/ 10. https://www.infraroodverwarming-soest.nl/blogs/info/infrarood-verwarming-vs-cv-de-ultieme-vergelijking/ 11. https://greeniuz.nl/infrarood-verwarming/nadelen-infrarood-verwarming/ 12. https://weblog.independer.nl/energie/breng-warmtepomp-vergeleken-met-een-cv-ketel/ 13. https://www.verwarminghandel.nl/blogs/blog/beste-keus-infrarood-paneel-2025 14. https://infrarood-verwarming.nl/infrarood-verwarming-nadelen/ 15. https://extrawarmte.nl/energiebesparing/wat-is-het-verbruik-van-een-elektrische-kachel-vergeleken-met-infraroodverwarming/ 16. https://doe-duurzaam.nl/artikel/duurzaam-verwarmen-de-voordelen-van-infraroodpanelen/ 17. http://dcnduurzaam.nl/nadelen-infrarood-vloerverwarming/ 18. https://www.verwarminghandel.nl/collections/energieverbruik-kosten-infrarood-panelen 19. https://greeniuz.nl/actueel/moet-er-groen-licht-komen-voor-infrarood-panelen/ 20. https://www.infraroodpaneel.nl/kennisbank/infrarood-verwarming-vs-elektrische-verwarming/ Do you have any questions, ideas or would you like to share your experiences around DYI topics? Email us at duurzaamkleiburg1@gmail.com  . Together we'll chart a path toward a future-proof Kleiburg; Do-it-yourself  is about improvements in your own apartment, not about VvE measures. Sharing your experiences can really help others — and is very welcome!

Table of contents of insulation Introduction The roof The floors (undersides) of gallery walkways and balconies, including upstands Front and rear facade: wall and brackets Front and rear facades: window frames, glazing and air gaps Ground-floor floors   ( this page) Loose ends Current situation The ground floor is not insulated on the underside (in the crawl space); During the renovation in 2013, no hatches to a crawl space were installed; In 2018/2019, several apartments experienced sewer blockages. These were caused by a subsiding sewer pipe. To repair this, hatches to the crawl spaces were installed in several apartments. the crawl space is 1.10 meters high. Opportunities for improvement As a proposal, 2 options are explained: Option 1. PUR on the underside of the ground floor After research, it has been calculated that a 13 cm thick PUR foam on the underside of the ground floor will provide an Rc value of 3.5 m2/Kw. Option 2. Thermal cushions After research, it has been calculated that hanging thermal cushions on the underside of the ground floor will yield an Rc value of approximately 3.8 m2/Kw. For apartments without a hatch to the crawl space, a hatch could be installed in the terrace outside under the balconies of higher floors to prevent damage to underfloor heating and/or floor coverings. Costs, subsidy and National Heat Fund Costs Thermal cushions, including installation and base foil, cost an average of €38-€50 per m² (incl. VAT), with lower prices for larger areas, such as €45 per m² for 61-100 m². Subsidy Subsidies can be requested via the SVVE (for VvE's) for energy-saving measures, including insulation of the ground floor floors. The conditions are that the new insulation material has a minimum thermal resistance of 3.5 Rc; 70% of the entire floor of the building is insulated. the subsidy amounts to: for one insulation measure: €5.50 per m2; for two or more insulation measures: €11 per m2. To borrow The floor insulation can be further financed by a loan from the National Heat Fund. Read all about saving, borrowing and subsidies here .   Marginal note In some cases, applying floor or ground insulation increases the thermal bridge effect of the structure, resulting in an increased risk of moisture problems. This risk can be mitigated with thermal cushions combined with a good, continuous ground sheet. However, in very damp crawl spaces (regular flooding, leaks), thermal bridges and condensation can still occur, even with a properly installed system. Want to read more about insulation? Introduction The roof The floors (undersides) of gallery walkways and balconies, including upstands Front and rear facade: wall and brackets Front and rear facades: window frames, glazing and air gaps Ground-floor floors   ( this page) Loose ends Do you have any questions, ideas or would you like to share your experiences? Email us at duurzaamkleiburg1@gmail.com . Together we'll chart a path toward a future-proof Kleiburg.

Table of contents of insulation Introduction The roof The floors (undersides) of gallery walkways and balconies, including upstands (this page) Front and rear facade: wall and brackets Front and rear facades: window frames, glazing and air gaps Ground-floor floors Loose ends The floors/walkways of the galleries and balconies are also the roofs of the galleries and balconies of the floors below. Therefore, they are referred to as roofs in the report. These walkways are also considered roofs in the SVVE subsidy scheme. The floors (roofs) of the galleries and balconies Research by students from Utrecht University of Applied Sciences showed that the upper floors lose heat internally because there is only 15 mm of insulation between the interior floor and the exterior floor of the balcony and gallery, causing cold to seep into the floor through the balcony. This causes heat loss, higher heating costs, a greater chance of condensation and mould, and an uncomfortable indoor climate. The concrete roofs/floors of the galleries and balconies are not insulated at all. Therefore, insulation is most effective here (see insulation - introduction ). Roof insulation on those floors provides a concrete temperature difference for the homes below: in average Dutch flats, the indoor temperature can rise by 1.5 to 3°C with roof insulation while energy consumption remains the same. This means that homes under insulated galleries become noticeably more comfortable and warmer, especially in the winter months; In summer, the insulation helps keep the outside temperature out, keeping it cooler inside during hot days. Steeds Advies recommends applying roof insulation to the concrete walking surfaces of the galleries and balconies. The target insulation value is Rc = 6.5 m²K/W, in accordance with new construction requirements. To prevent moisture problems and extend the structure's lifespan, a vapor barrier is applied. In addition, the Triflex BIS insulation system is used, which not only provides high-quality thermal insulation but also offers a durable and waterproof finish. The uprisings The upstands are the raised concrete edges from the floor to the frame. The thermal image below shows that, in addition to the brackets (top), the upstands also form a significant thermal bridge. Gallery floor and upstand - the red and yellow shows the apartment heat leaking out The insulation of these upstands was not addressed in any of the reports. The research by the HU and Steeds Advies did note that the connection between the gallery and balcony floors and the window frames was poor, causing drafts. However, no solution was provided for this problem.   Our own research shows that the upstands can be insulated in addition to the insulation of the balcony and gallery floors: if the liquid Triflex sealant is pulled up from the gallery floor against the upstand and around the frames , the seams and cracks are made waterproof and airtight. Insulating the gallery floor itself provides greater energy savings than insulating the upstands, but including the upstands helps reduce cold airflow through gaps along sills and window frame feet, making the indoor climate more stable and limiting draughts. Costs Steeds Advies estimates the insulation costs at € 158,270, based on a m2 price of € 280. Our own research indicated that: for the Triflex BIS insulation €80-140 per m² for the floor; for the upstand insulation €40-80 per linear meter; These prices include installation and finishing but exclude VAT. Marginal note Due to the large difference in price quoted by Steeds Advies and the quoted research tool Perplexity , further inquiries were made as to the reason for this difference: Difference compared to the advisor’s estimate (€280/m²) Subsidy and National Heat Fund (Read all about saving, borrowing and subsidies here ). The above insulation is only eligible for subsidy if the total surface area of the floors/walkways is more than 70% of the total roof surface (= main roof + floors, balconies and galleries). The total floor area is roughly 25,472 m². According to a rough calculation, this is more than 70% of the total, and this measure is therefore eligible for a subsidy. The subsidy amounts to: for one insulation measure: €16.25 per m2. for two or more insulation measures: €32.50 per m2. For the limited surface area this amounts to 25,472 x € 16.25 = € 41,392.   The insulation can be further financed by a loan from the National Heat Fund.   Payback period for insulation with Triflex BIS (highest prices, excl. VAT, without/with subsidy) Marginal note By using high-quality insulation with a waterproof finish, the protection of sealant joints and concrete is significantly improved. This leads to fewer sealant replacements and reduced maintenance costs (in 2024, sealant replacements cost €45,900 excluding VAT). Want to read more about insulation? Introduction The roof The floors (undersides) of gallery walkways and balconies, including upstands   (this page) Front and rear facade: wall and brackets Front and rear facades: window frames, glazing and air gaps Ground-floor floors Loose ends Do you have any questions, ideas or would you like to share your experiences? Email us at duurzaamkleiburg1@gmail.com . Together we'll chart a path toward a future-proof Kleiburg.

Table of contents of insulation Introduction The roof The floors (undersides) of gallery walkways and balconies, including upstands Front and rear facade: wall and brackets Front and rear facades: window frames, glazing and air gaps ( this page) Ground-floor floors Loose ends Current situation The front and rear facades consist largely of HR++ glass, set in hardwood frames. The HR++ glass was installed in 2013. The frames According to Steeds Advies, the window frames are in poor condition. The basis for this opinion is unclear. Steeds did not inspect the window frames during the inspection. Both the student teams from Utrecht University of Applied Sciences and the 2019 and 2024 MJOPs consider the condition of the window frames to be adequate. It appears that a significant amount of heat is lost through the window frames and air gaps. It has also been observed that the connections to the ceiling, floor, and inner wall of the cavity wall ("inner cavity wall") leave much to be desired. The glazing The HR++ glass has a U-value of 1.1 and the frames have a U-value of 1.6. (See also Insulation - introduction ). The existing situation even meets the requirements of the Building Decree for new construction, which requires a maximum average Uw-value of 1.65 for all windows and doors combined. with HR++ glass with a U-value of 1.1 and frames with a U-value of 1.6, the total U value, depending on the glass surface and frame dimensions, averages 1.3 to 1.5 W/m²K, which meets the standard for new construction. HR++ glass typically provides good insulation for 25 to 30 years. After that, its insulation performance noticeably declines. Other cold bridges See Insulation - introduction for an explanation of thermal bridges. the upstands (raised concrete edge from floor to frame); the current ventilation grilles installed in the window frames (empty ventilation grilles); this is because an empty ventilation grille is an open flow channel without insulated walls or thermal breaks; therefore, heat is easily lost. Opportunities for improvement Opportunity for improvement for the window frames The HU students also mention installing so-called ClickOvers over the window frames. This is not so much for better insulation, but mainly to avoid the costs of the necessary periodic painting. ClickOvers? ClickOver is a renovation system for windows and doors in which a new plastic frame is clicked over the existing wooden frame, without demolishing the old frame. However, further study shows that after installation of the clickovers, the existing glazing no longer fits and therefore has to be replaced. Improvement option for cracks and upstands   Since the building is located within a protected cityscape , interventions on the outside of the window frames are limited. However, according to Steeds Advies, this problem can be solved indoors by applying seam and gap sealing to the existing window frames. are tackled effectively. Outside, insulating the upstands will provide some improvement in the poor connection between the frame and the floor of the balcony and gallery. This will reduce drafts and cold airflow along the floor. Because the insulation of the upstands forms a whole with the insulation of the balcony and gallery floors, this improvement opportunity is identified there further explained.   Opportunity for improvement in glazing   The HU team of full-time students suggests replacing the HR++ glass with triple glazing as an improvement. Triple glazing offers a (limited) improvement compared to the 10-year-old HR++ glass. Triple glazing reduces the total U-value from 1.4 to 1.0-1. See also Insulation - introduction . Notes on glazing triple glazing often does not fit in existing frames with HR++ glass due to its greater thickness; with HR++ glass that is only 10 years old, the additional energy savings with triple glazing are usually too small to recoup the early replacement costs within the technical lifespan of glass and frames (25 to 30 years); TNO is in the final phase of developing smart windows , also known as thermochromic windows, aimed at energy savings and climate-neutral living. The windows automatically regulate solar heat: in summer they block heat, while in winter they let it in. This happens without the user having to do anything; The thermochromic windows will initially be offered as new windows, but TNO is also working on retrofit solutions for existing buildings, for example as film for older glass . Glazing: costs, subsidies and National Heat Fund Costs: the costs of replacing HR++ glass with triple glazing are estimated by HU students (2024) at € 329,047. Subsidy: Subsidies for energy-saving measures, including the installation of triple-glazed windows, can be requested via the SVVE (for homeowners' associations). The subsidy is €25 per m2; in our building that is €63,812. Borrowing: the replacement of HR++ with triple glazing can be further financed by a loan from the National Heat Fund. Read all about saving, borrowing and subsidies here . Opportunity for improvement for the suskasten   Replace empty baffle boxes with insulated grilles. New insulated grilles effectively reduce thermal bridges and are ideal as replacements for empty baffle boxes in type C ventilation systems. You can read more about this in the article Ventilation at Kleiburg ; ZR grilles have an average U-value between 2.6-3.0 and manual grilles (AK+ or flap models) have an average of 2.5-3.5; AK+ also offers additional sound insulation of up to 37-40 dB. Want to read more about insulation? Introduction The roof The floors (undersides) of gallery walkways and balconies, including upstands Front and rear facade: wall and brackets Front and rear facades: window frames, glazing and air gaps   ( this page) Ground-floor floors Loose ends Do you have any questions, ideas or would you like to share your experiences? Email us at duurzaamkleiburg1@gmail.com . Together we'll chart a path toward a future-proof Kleiburg.

Table of contents Energy Introduction Power: solar panels and storage Heat: hydronic balancing (this page) Heat: Heat Recovery (WTW) Heat consumption: measuring is knowing The feasibility study by consultancy firm Steeds Advies BV does state that the current heating system is largely functioning properly; but also that heat loss and pressure differences in the pipes can lead to an uneven distribution of heat within the building. The current situation Kleiburg uses district heating, with a collective boiler, risers and radiators and/or underfloor heating per apartment. The difference in heating demand between the lower and upper floors compared to end-of-terrace and mid-terrace homes can be significant. This often leads to overloaded heating systems near the boiler and insufficient heating systems further away, leading to complaints such as: too cold corner houses; noise in pipes; and unnecessarily high return temperatures. Without proper regulation, excessive amounts of hot water often circulate through risers and corridors, even when relatively little heat is needed. This causes unnecessary heat to remain in the shafts and corridors. Opportunity for improvement Not recommended by Steeds Advies, but RVO and the National Heat Fund mention hydronic balancing as an energy-saving measure. What is hydronic balancing? Hydronic balancing is a way to adjust the heating system so that the water flows automatically adapt to the actual heat demand. For this purpose, dynamic balancing valves are installed in the risers and in each radiator/underfloor heating loop. These valves automatically limit the flow rate and compensate for pressure fluctuations. In an apartment building like Kleiburg with 10 risers, this ensures that: each riser and each radiator/loop gets its “own” maximum water flow; pressure differences between above and below are automatically compensated; an equal temperature difference between supply and return water can be achieved everywhere, so that the water in all apartments gives off the same heat. Dynamic valves are specifically suitable for apartments with block and district heating, precisely because residents operate their heating independently of each other and pressure fluctuations can therefore be large. In homeowners' associations (VvE) buildings, the flow is limited per riser and per radiator/heating loop. This reduces transport losses in the risers and ensures a more equitable heat distribution. Hydronic balancing reduces heat loss in pipes through lower flow rates, smaller total volume flows, and decreasing water temperatures in the network. Left: without hydronic balancing; Right: with hydronic balancing. Red = warm water coming in. Blue - cooled down water going out. What does it yield? In an apartment building like Kleiburg phase 1 (110 apartments, high-rise building, 1970s, block heating and heat network), dynamic adjustment can lead to 12-15% savings on total heat consumption, especially because the return water temperature decreases; dynamic valves absorb pressure fluctuations; boiler and pump run more quietly. Hydronic balancing extends maintenance intervals for boilers, pumps and heat exchangers by reducing stress and wear. Hydronic balancing can extend the actual lifespan of existing risers and reduce the occurrence of leaks and blockages caused by magnetite/sludge. The adjustment reduces the total volume flow and dampens pressure fluctuations → less erosion and less cavitation in bends, T-pieces and constrictions; allows the system to run more quietly (less “ramming” of pumps) → less mechanical stress on pipes, couplings and accessories; ensures a lower average temperature in return and often also in supply → less thermal load, which somewhat slows down the rate of corrosion at high temperatures. In addition, comfort improves: rooms heat up more evenly, extreme temperature differences disappear and flow noise in radiators is significantly reduced. Costs and payback period For a block of 110 apartments, the costs are roughly estimated at around €60,000–€110,000 and a payback period of 3 to 5 years. Why these bandwidths? Costs For an apartment building with 110 apartments, the costs depend on: number of radiators per home (and/or underfloor heating groups); whether or not to replace existing taps with dynamic valves; yes/no additional pressure differential regulators, pumps, adjustment work in the boiler house; accessibility, planning (e.g. working by grid/rise), and regional labor costs. However, if the Ferroli heat exchangers are simultaneously replaced with a 2026 model, 100% of the adjustment can be done centrally, eliminating the first two considerations. This reduces costs by 40 to 50%. Payback period (TPR) Higher savings with a heating network and poor current system: closer to 3 years; Longer TVT with good existing regulation or a lot of underfloor heating: up to 5 years. Subsidy and loan Subsidies for hydronic adjustment are provided through the SVVE scheme (for homeowners' associations) but only in combination with one or more energy-saving insulation measures and/or sustainable heating options; the subsidy amounts to €90 per apartment. The hydronic adjustment can also be further financed by a loan from the National Heat Fund. [Read all about saving, borrowing and subsidies here ] Marginal note Under certain conditions, it is possible to finance the replacement of heat exchangers simultaneously with hydronic balancing through the National Heat Fund. To qualify, the replacement must be recognized as an energy-saving measure and be stated as such in the quotation. In practice, this means that if replacing heat exchangers clearly contributes to improving heat output, energy efficiency, and comfort, and this is explicitly described as part of the measure in the quotation, it can be co-financed. However, this must be requested clearly and specifically in advance and approved by the Heat Fund. Read more about Energy? Introduction Power: solar panels and storage Heat: hydronic balancing (this page) Heat: Heat Recovery (WTW) Heat consumption: measuring is knowing Do you have any questions, ideas or would you like to share your experiences? Email us at duurzaamkleiburg1@gmail.com . Together we'll chart a path toward a future-proof Kleiburg.

Introduction Power: solar panels and storage Heat: hydronic balancing Heat: Heat Recovery (WTW) this page Heat consumption: measuring is knowing Summary In the current ventilation system at Kleiburg, a lot of heat is lost. Students from Hogeschool Utrecht investigated an innovative idea: use the warm air being exhausted from the apartments and, via a heat pump, pre-heat the return water of the district heating network. This would reduce the amount of heat that Vattenfall needs to supply and could lower energy bills. The calculations show that the concept is technically feasible and could yield significant savings, although it has not yet been applied anywhere. Relevance for Kleiburg phase 1 Our ventilation system runs day and night. That means warm air from inside the apartments is continuously blown outside, and cold air is drawn in. In the current system, heat recovery (WTW) is not used. Students from Hogeschool Utrecht have studied whether and how the wasted heat could be better utilized by connecting a heat pump to the ventilation system. How it works On the roof there are about 10 fans that exhaust the warm ventilation air from the apartments. This warm air (about 21 °C) can be captured and directed via a duct to a heat pump placed on the roof. The heat pump extracts heat from the air and transfers it to the return water from the district heating network, pre-heating it before Vattenfall reheats it to around 65 °C. According to the students’ calculations , about 40 % of the energy currently supplied by the heat network could be recovered from the ventilation air. This could lead to significant savings on heating costs. Heat pump In the calculations, the students assumed the use of a Rhoss Poker 290 heat pump with the eco-friendly refrigerant propane (R290). This pump can deliver water up to 75 °C, which matches the requirements of Kleiburg' s existing district heating system. Costs, subsidy and financing In the spring of 2024, the students provided this cost-benefit overview: The costs of the heat pump installation and the ductwork do not appear to be fully included in that overview, so the estimated payback period may be somewhat optimistic and will need to be recalculated. The heat pump is eligible for the ISDE subsidy of € 3 375. This subsidy has been included in the cost–benefit overview. The WTW installation can also be financed through a loan from the National Warmtefonds. ( read all about saving, borrowing and subsidies here ). Marginal notes The students calculated the energy gain at an outside temperature of 11.5 °C; They assumed a system with CO2-controlled ventilation, in which half of the air in the building is refreshed every hour; The heat pump uses additional electricity; therefore, it is recommended to combine the heat pump with solar panels and a CO2-controlled ventilation system , which in turn saves electricity. To our knowledge, this idea hasn't yet been implemented anywhere. We still need to seek further advice on the feasibility of implementing this idea. A permit is required for installing the heat pump on the roof. Due to protected cityscapes , a roof structure may not exceed 2 meters in height. The recommended Rhoss Poker 290 is 2.26 meters, but there are plenty of subsidized alternatives under 2 meters with the same specifications. Read more about Energy? Introduction Power: solar panels and storage Heat: hydronic balancing Heat: Heat Recovery (WTW) this page Heat consumption: measuring is knowing Do you have any questions, ideas or would you like to share your experiences? Email us at duurzaamkleiburg1@gmail.com . Together we'll chart a path toward a future-proof Kleiburg.

Introduction Power: solar panels and storage (this page) Heat: hydronic balancing Heat: Heat Recovery (WTW) Heat consumption: measuring is knowing Installation of solar panels (PV panels) Due to the deed of division (a.k.a. "splitsingsakte"), most of the roof is "reserved" for residents of the 10th floor. As a result, only a limited portion of the roof can be used for collective solar panels. Potential solar panel location (in red) Installing enough panels to supply all apartments with electricity is therefore not feasible. Moreover, for a large homeowners' association like ours, the wiring to all the individual meter boxes is too complex and expensive. And with the abolition of the net metering scheme, the return on such an investment is also insufficient. With regard to the possible number of solar panels on the available part of the roof, the studies show notable differences : Full-time team: 113 panels possible Part-time team: 50-70 panels, (depending on the direction) 32 panels (11,000 kWh per year, half of the collective consumption) In addition, both the HU student teams, as well as Steeds Advies, limited themselves to placing panels above the collective space of the bend , so only connecting to the meter in the bend. The possibility and effectiveness of solar panels above the collective space in the head has not been investigated. The use of solar panels for collective electricity consumption It might be interesting to install solar panels to power communal facilities. These could be placed on the roof sections above the stairwells at the top and bottom of the building. This energy demand is distributed in the common areas over: the elevators; lighting in common areas; and energy required for heating systems and ventilation. The ideal would be to install enough panels to meet as much of the power needs of the collective facilities as possible. The problem is however that on sunny days, more energy may be supplied by the PV panels than is consumed by the elevators, lights and heating systems at certain times; while more power is needed for lighting and elevators in the evenings and at night. It is important that this is prevented. Solutions to this problem would be keep the energy supply from the PV panels so low that it never exceeds the minimum energy consumption; the use of a battery so that energy can be stored in it. New developments: sodium-ion batteries Lithium-ion batteries are still the most common type. But sodium-ion batteries are now a promising alternative: cheaper; safer; and more resistant to temperature differences. Sodium-ion batteries stand out as a sustainable and environmentally friendly alternative thanks to the raw material they use (common salt), the absence of harmful or toxic components and easy recycling. Conclusion Installing solar panels remains a viable option for the shared building segment of the apartment building. However, because the research results in the three reports differ, and developments in areas such as sodium-ion batteries are not considered, further research is desirable and necessary. Costs, subsidy and National Heat Fund Costs Further advice is still needed regarding the number of panels and the desired battery capacity. Afterward, the costs and payback period can be estimated. Subsidy In combination with other sustainability measures, subsidies for installing solar panels are available through the SVVE; There are indirect and fiscal benefits for shared energy storage such as batteries through EIA (Energy Investment Deduction): Tax benefit of up to 40% on investments in batteries on the Energy List, ideal for homeowners' associations (VvE) solar energy storage. Both sodium and lithium-ion batteries are eligible. SDE++: For large-scale projects involving storage and sustainable generation (solar panels), a subsidy is provided for produced/stored energy. Suitable for shared facilities in apartments, but subsidy eligibility depends on the specific scale and cost structure. This will need to be further investigated in due course. Borrowing the remaining costs are eligible for a loan from the National Heat Fund. Read all about saving vs. borrowing and subsidies here . Want to read more about Energy? Introduction Power: solar panels and storage (this page) Heat: hydronic balancing Heat: Heat Recovery (WTW) Heat consumption: measuring is knowing Do you have any questions, ideas or would you like to share your experiences? Email us at duurzaamkleiburg1@gmail.com . Together we'll chart a path toward a future-proof Kleiburg.

Table of Contents Energy Introduction (this page) Power: solar panels and storage Heat: hydronic balancing Heat: Heat Recovery (WTW) Heat consumption: measuring is knowing Introduction The following topics will be covered: electricity: generation of power by installing solar panels for collective facilities; heat: savings on heating costs through hydronic balancing of the central heating systems; heat: save heating costs by recovering heat (WTW) from ventilation; heat: consumption awareness through registration and monitoring of consumption via the ista app. The pages on insulation and ventilation also discuss several options for saving energy. The current situation The energy consumption of Kleiburg phase 1 mainly consists of: heat via the heating network (from supplier Vattenfall); and electricity for the collective installations and common areas (from supplier Greenchoice). The VvE does not have a collective gas connection, and issues related to (stopping) gas are therefore individual for the owners. Energy: electricity, heat and natural gas   Heat Kleiburg uses district heating, with a collective boiler; risers; and radiators and/or underfloor heating per apartment. Electricity - consumption Kleiburg phase 1 has 2 electricity meters. a meter in the head / a.k.a. "kop" (use approx. 11,000 kWh per year) for: the small elevator; half of the gallery lighting; half of the fans on the roof (10 pieces); the rented storage areas; and the bell system; one meter in the bend / a.k.a. "knik" for: the heating system (with electric pumps and filters); the hydrophore; 2 large elevators and the stairwell; the other half of the gallery lighting; the other half of the fans (also 10 pieces); and the storage areas; use approximately 24,250 kWh per year. Electricity - elevators Because the elevators, in particular, consume a lot of electricity, research was conducted to determine whether savings could be achieved. Research showed that the elevators already have a standby mode, meaning they consume less energy even when stationary for a period of time, saving up to 60% (source: Mitsubishi). Further sustainability improvements to an elevator entail significant costs, so it is better to wait until the elevators are due for replacement (according to our MJOP). Electricity - lighting The stairwells and galleries are already illuminated with LED lamps. Want to read more about Energy? Introduction   (this page) Power: solar panels and storage Heat: hydronic balancing Heat: Heat Recovery (WTW) Heat consumption: measuring is knowing Do you have any questions, ideas or would you like to share your experiences? Email us at duurzaamkleiburg1@gmail.com . Together we'll chart a path toward a future-proof Kleiburg.