The ISDE subsidy in 2026: how do you apply for it for heat pumps and solar water heaters?
The ISDE subsidy (Investment Subsidy for Sustainable Energy and Energy Saving) offers Dutch businesses and private individuals a unique opportunity in 2026 to obtain financial support for sustainable energy investments. With amounts ranging from €500 to €5,800 for heat pumps and solar water heaters, this subsidy scheme is an essential instrument for the energy transition in the Netherlands. Applications are submitted via mijn.rvo.nl and must be filed within six months of the invoice date, with one important rule: once the budget runs out, that's it.
For the manufacturing industry, sustainability is playing an increasingly important role in operations and competitive positioning. Companies that invest in energy-saving technologies such as heat pumps and solar water heaters not only benefit from lower energy costs, but also strengthen their position in the market. The ISDE subsidy makes these investments more financially attractive and thereby supports the sustainable trends in the manufacturing industry that are essential for the future.
What is the ISDE subsidy and who is it intended for?
The ISDE subsidy is a government scheme that financially supports investments in sustainable energy technologies through a one-off payment after the investment has been realised. This subsidy scheme, managed by the Netherlands Enterprise Agency (RVO), focuses on stimulating energy saving and the production of renewable energy in the Netherlands.
The target group for the ISDE subsidy is broad and includes both private individuals and businesses of all sizes. For the manufacturing industry, this scheme offers particular opportunities for production sites, office buildings and warehouses where heat pumps and solar water heaters can contribute significantly to energy savings. The subsidy is available to owners of buildings completed before 2 January 2021, which means that many existing industrial sites qualify.
The subsidy programme stands out from other schemes through its focus on proven technologies with a clear energy-saving effect. Heat pumps and solar water heaters were chosen because these technologies are mature, widely applicable and have a significant impact on CO2 reduction. For companies in the manufacturing industry, this means that investments in these technologies not only deliver financial benefits, but also contribute to sustainability goals.
The ISDE subsidy differs from other subsidies such as the WBSO subsidy for R&D in that it focuses on implementing existing technologies rather than research and development. This makes the scheme more accessible for companies that want to invest directly in energy saving without setting up complex innovation projects.
An important aspect of the ISDE subsidy is the “budget runs out = gone” principle. This means that the available budget for 2026 is limited and that early applicants have the best chances. For the manufacturing industry, where investment decisions often take time, it is therefore crucial to plan in good time and to prepare the application procedure thoroughly.
The subsidy is paid out after the investment has been realised, which means that companies must first finance the investment themselves. This pre-financing aspect is important for cash flow planning, but the certainty of a subsidy award upon approval makes the investment more attractive than loans or other forms of financing.
Subsidy amounts for heat pumps: what can you expect?
The ISDE subsidy for heat pumps ranges between €1,000 and €5,800, depending on the type of heat pump, its capacity and the specific application in residential or non-residential buildings. These amounts are set on the basis of the expected energy savings and the payback period of the investment.
For air-to-water heat pumps, the most common variant in the manufacturing industry, the following subsidy amounts apply per kW of capacity. For smaller installations up to 5 kW, applicants receive €800 per kW, resulting in a subsidy of €1,000 to €4,000. For larger installations above 5 kW of capacity, €600 per kW is paid, with a maximum of €5,800 for very large systems.
Ground-to-water heat pumps, also known as geothermal heat pumps, qualify for higher subsidy amounts due to their higher investment costs and superior efficiency. These systems receive €1,200 per kW for installations up to 5 kW and €900 per kW for larger systems. The maximum subsidy amount, however, remains €5,800.
| Type of heat pump | Capacity | Subsidy per kW | Maximum amount | Suitable for |
|---|---|---|---|---|
| Air-to-water | 0-5 kW | €800 | €4,000 | Small business premises |
| Air-to-water | 5+ kW | €600 | €5,800 | Large commercial buildings |
| Ground-to-water | 0-5 kW | €1,200 | €5,800 | Office buildings |
| Ground-to-water | 5+ kW | €900 | €5,800 | Large production sites |
| Water-to-water | All capacities | €1,000 | €5,800 | Sites near water |
For companies in the manufacturing industry, air-to-water heat pumps are particularly attractive due to their lower installation costs and broad applicability. These systems can be used for space heating of office areas, changing rooms and social spaces within production sites. Larger systems can even contribute to process heat for industrial applications where relatively low temperatures are required.
It is important to realise that the subsidy amounts are tied to specific technical requirements. Heat pumps must meet minimum COP values (Coefficient of Performance) and installation must be carried out by certified companies. These requirements ensure that only high-quality installations receive a subsidy, which benefits the effectiveness of the programme.
For companies considering installing multiple heat pumps at different locations, it is possible to apply for a subsidy separately for each location. This offers opportunities for companies with multiple sites to make their entire property portfolio more sustainable with the support of the ISDE subsidy.
Subsidy amounts for solar water heaters: maximum reimbursements
The ISDE subsidy for solar water heaters ranges between €500 and €2,100, with the exact amount depending on the system's capacity and the type of collector installed. Solar water heaters are particularly attractive for companies with a constant hot water demand, such as canteens, shower facilities and certain production processes.
For standard flat plate collectors, a subsidy amount of €150 per square metre of collector surface applies. Systems with 4 to 8 square metres therefore receive between €600 and €1,200 in subsidy. Vacuum tube collectors, which are more efficient but also more expensive, qualify for €200 per square metre, resulting in subsidy amounts of €800 to €1,600 for comparable systems.
The maximum subsidy amount of €2,100 is reached with large installations of more than 10 square metres of collector surface. These large systems are particularly attractive for companies with substantial hot water needs, such as food companies or machine factories where cleaning and degreasing take place regularly.
For the manufacturing industry, solar water heaters offer opportunities primarily at companies where hot water is used for:
- Cleaning of machines and workpieces
- Degreasing and pre-treatment of materials
- Sanitary facilities for employees
- Canteen and catering facilities
- Process heat for certain production applications
| Type of collector | Surface (m²) | Subsidy per m² | Total subsidy amount | Application |
|---|---|---|---|---|
| Flat plate | 4-6 m² | €150 | €600-900 | Small business |
| Flat plate | 6-10 m² | €150 | €900-1,500 | Medium-sized business |
| Vacuum tube | 4-6 m² | €200 | €800-1,200 | Efficient small-scale installation |
| Vacuum tube | 6-10 m² | €200 | €1,200-2,000 | Large-scale application |
| All types | 10+ m² | Variable | Max. €2,100 | Industrial application |
An important advantage of solar water heaters for the manufacturing industry is their relatively short payback period, especially when combined with the ISDE subsidy. The constant hot water demand in many industrial applications ensures that the system is used throughout the year, which benefits profitability.
When planning a solar water heater installation, it is important to take the orientation and pitch of the roof into account. For optimal performance, collectors should preferably face south with a pitch between 30 and 45 degrees. Commercial buildings with flat roofs can often be configured optimally for solar water heater installations.
Combining solar water heaters with existing hot water preparation systems requires technical expertise. Professional installers can advise on the optimal system configuration and ensure that the installation meets all technical requirements for the subsidy to be granted.
Step-by-step application procedure via mijn.rvo.nl
The ISDE subsidy application is submitted entirely digitally via the mijn.rvo.nl portal and must be filed within six months of the invoice date, with a systematic approach being essential for a successful application. The procedure requires careful preparation and the gathering of all necessary documentation before starting the online application.
The digital application procedure is optimised for efficiency, but it does require applicants to prepare well. For companies in the manufacturing industry, where multiple people are often involved in investment decisions, it is advisable to make one person responsible for the entire application procedure.
- Preparation and gathering documentation
Start by collecting all necessary documents before beginning the online application. You will need: the installer's invoice (no older than 6 months), technical specifications of the heat pump or solar water heater, an installation certificate from a recognised installation company, and any additional technical documentation. For companies, an extract from the Chamber of Commerce (KvK) is also required. Make sure all documents are available in PDF format. - Creating an account on mijn.rvo.nl
Go to mijn.rvo.nl and create an account using DigiD (for private individuals) or eHerkenning (for businesses). For businesses, at least eHerkenning level 3 is required. The account must be created in the name of the owner of the building where the installation is placed. Check that all company details have been entered correctly, as incorrect details can lead to delays in processing. - Starting the ISDE subsidy application
Log in to your account and select “New application” followed by “ISDE subsidy”. Choose the correct subsidy component: heat pump or solar water heater. The digital wizard will guide you through all the steps and automatically checks whether you meet the basic requirements. Save your progress regularly, as the session may expire after a period of inactivity. - Entering building and installation details
Enter all the requested details about the building where the installation is placed. This includes address details, year of construction (must be before 2021), ownership situation and current energy systems. For heat pumps, you must specify the type, brand, model and capacity. For solar water heaters, the collector surface, type of collector and system capacity are required. Double-check all technical specifications against the invoice and installation documentation. - Uploading financial details and invoices
Upload the installation invoice, which must specify all costs including VAT. The invoice must be in the applicant's name and may not be older than 6 months at the time of application. Enter the invoice amount and invoice date correctly, as this determines the application deadline. For companies with VAT deduction, this must be clearly indicated. - Uploading technical documents
Upload the installation certificate from the recognised installation company. This certificate confirms that the installation meets all technical requirements and safety standards. Add any additional technical documentation, such as performance measurements or declarations of conformity. Make sure all documents are legible and relate to the correct installation. - Review and final submission
Check all entered data carefully before submitting the application. Pay particular attention to technical specifications, amounts and dates. Download a copy of your application for your own records. After submission, you will receive a confirmation with an application number. Keep this confirmation safe, as you will need the application number for any correspondence. - Follow-up and communication
RVO assesses the application within 8 weeks. During this period, you can track the status via your account on mijn.rvo.nl. Respond quickly to any requests for additional information from RVO. After approval, the subsidy is paid out within 4 weeks to the bank account number provided. Keep all correspondence for your records.
For companies, it is wise to schedule the application procedure as part of the investment project. The certainty of a subsidy award upon approval makes it possible to include the subsidy in the business case for the investment. This is particularly relevant for larger projects where the ISDE subsidy can cover a significant part of the investment.
Many errors in applications arise from haste or incomplete documentation. Take the time to carry out all steps carefully and check whether your installer can provide all the necessary certificates before having the installation carried out. A professional installer has experience with ISDE subsidy applications and can often help gather the correct documentation.
Conditions and requirements for granting the subsidy
The ISDE subsidy applies strict conditions concerning building age, technical specifications, professional installation and timeliness of application, to ensure the effective spending of public money and maximum energy savings. These conditions are non-negotiable and must be fully complied with for a successful subsidy application.
The most important basic condition is that the building where the installation is placed must have been completed before 2 January 2021. This requirement ensures that the subsidy is used for making existing buildings more sustainable rather than for new developments. For the manufacturing industry, this means that virtually all existing production sites, office buildings and warehouses qualify.
Technical conditions for heat pumps are specifically defined per system type. Air-to-water heat pumps must have a minimum COP (Coefficient of Performance) of 3.0 at an outdoor temperature of 7°C and a supply temperature of 35°C. Similar performance requirements apply to ground-to-water and water-to-water heat pumps, tailored to the specific technology. These requirements ensure that only efficient systems receive a subsidy.
For solar water heaters, technical requirements apply concerning collector efficiency and system certification. Collectors must be certified according to Solar Keymark standards and the complete system must comply with Dutch installation standards. The minimum collector surface area is 3 square metres to ensure a meaningful contribution to the hot water supply.
Professional installation is mandatory and must be carried out by a company certified for the specific technology. For heat pumps, a Certin WKO/BKO certificate or comparable qualification is required. Solar water heater installers must have Solar Energy Europe certification or the equivalent. This requirement ensures the quality of installation and correct commissioning of systems.
Ownership conditions specify that the applicant must be the owner of the building or the energy system. For companies with rented property, a subsidy application is possible if there is a lease agreement that permits investments in energy systems and the investment benefits the rented object. Ownership of the installation must be clearly established.
Timing conditions are crucial for a successful application. The subsidy application must be submitted within 6 months of the installation's invoice date. This deadline cannot be extended, so planning is essential. The “budget runs out = gone” principle means that early applicants within the subsidy year have the best chances of being awarded.
Additional conditions concern administrative obligations and the use of the installation. Applicants must be willing to provide data on the functioning of the installation for the evaluation of the subsidy programme. The installation must remain in use for its intended purpose for at least 5 years, and in the event of early sale or demolition, repayment of the subsidy may be demanded.
For companies, additional conditions apply concerning state aid and cumulation with other subsidies. The total aid intensity may not exceed 30% of the investment costs for medium-sized companies and 20% for large companies. Other subsidies must be reported with the application in order to correctly apply the cumulation rules.
Failure to comply with the conditions can lead to rejection of the application or recovery of subsidy already paid out. It is therefore essential to check all conditions carefully before the installation is realised and the application is submitted. Professional advice can help ensure compliance and minimise the risk of problems.
Budget and timing: why speed is essential
The ISDE subsidy budget for 2026 is limited and is awarded according to the “budget runs out = gone” principle, meaning that early applicants have significantly better chances than companies that wait until later in the subsidy year. This reality makes timing a crucial success factor for companies that want to benefit from this subsidy scheme.
The total ISDE budget for 2026 is around €200 million, divided over various categories, of which heat pumps and solar water heaters together receive approximately €80 million. At average subsidy amounts, this means there is room for around 40,000 to 50,000 applications. This may seem like a lot, but the growing interest in sustainable energy and the attractive subsidy amounts mean that the budget is often exhausted within a few months.
Historical data show that in previous years the ISDE budget was exhausted between March and June, depending on popularity and the available budget. For 2026, RVO expects an even faster depletion due to increased awareness of sustainability and rising energy costs that make investments in own energy generation more attractive.
For the manufacturing industry, this timing has a significant impact on investment planning. Companies are best advised to plan their sustainability investments for the first quarter of 2026 in order to retain optimal chances of obtaining a subsidy. This requires forward planning because installations take time and the application must be made within 6 months of the invoice date.
The monthly budget distribution is not even. January and February traditionally see lower application volumes due to the holidays and slow project start-ups. March to May are peak months when the budget is used up fastest. Companies that can submit their application in January or February therefore have the best chances of being awarded.
RVO publishes weekly updates on the remaining available budget via its website. This transparency helps applicants estimate whether a planned investment still has a chance of receiving a subsidy. For companies, it is wise to follow these updates and align investment decisions accordingly.
The impact of budget depletion goes beyond simply missing out on a subsidy. Suppliers and installers often experience a surge in demand when it becomes known that the budget is nearly exhausted. This can lead to longer waiting times, higher prices and possibly quality problems due to overloaded installers. Early planning prevents these problems.
For larger companies with multiple locations, it is possible to spread subsidy applications over the year by planning different project phases. This does require that each project individually meets the minimum investment requirements and technical conditions. The possibility of spreading offers strategic flexibility for large investment programmes.
Emergency planning is wise for companies that depend on a subsidy for their investment decision. Develop alternative financing scenarios in case the subsidy budget is unexpectedly depleted quickly. This prevents important sustainability investments from being postponed to the following year.
The combination of a limited budget and growing demand makes the ISDE subsidy a competitive process. Companies that are serious about sustainability investments are best advised to adopt a proactive attitude and realise their projects as early as possible in 2026. This approach not only maximises the chances of obtaining a subsidy, but also ensures the earliest possible moment at which energy savings can be realised.
The relationship between timing and success in the ISDE programme underlines the importance of professional project planning. Companies that take their energy transition seriously integrate subsidy deadlines into their strategic planning and ensure adequate resources to realise projects on time. This approach fits perfectly with the broader digital transformation in industry where planning and efficiency are central.
Frequently asked questions about applying for the ISDE subsidy
Can I apply for an ISDE subsidy for a heat pump in a commercial building built after 2021?
No, the ISDE subsidy is only available for buildings completed before 2 January 2021. This condition is intended to target the subsidy at making existing buildings more sustainable rather than new construction. Commercial buildings constructed after 2021 must comply with modern energy standards and therefore do not qualify for this subsidy scheme. For new construction, other incentive schemes are available, such as tax benefits or other specific subsidies for sustainable new construction.
What happens if I miss the 6-month application deadline?
If you exceed the 6-month period after the invoice date, you can no longer apply for an ISDE subsidy for that specific investment. This deadline is laid down by law and has no exceptions, not even in special circumstances. It is therefore crucial to start the application procedure immediately after installation. For future investments, you can still apply for a subsidy as normal, provided this is done within the applicable deadlines. Many companies therefore set a reminder when planning the investment to submit the subsidy application in good time.
Can I combine the ISDE subsidy with other energy subsidies?
Yes, combining with other subsidies is possible, but specific cumulation rules apply. For companies, the total aid intensity may not exceed 30% of the investment costs for medium-sized companies and 20% for large companies. Private individuals can combine the ISDE subsid