NTA 8800: the calculation method behind the energy label
NTA 8800 is the legal calculation method used in the Netherlands to determine the energy performance of buildings. Since 1 January 2021 it has been the basis of every energy label: the method decides whether your home gets an A or a G. On this page we explain what the method calculates, which data counts — and why your own energy bill plays no part in it.
What does NTA 8800 mean?
NTA stands for Nederlandse Technische Afspraak (Dutch Technical Agreement). The full title is «Energy performance of buildings — Determination method». So it is not a label or a certificate, but the calculation rulebook: it sets out in detail how to calculate the energy performance of a building, so that every advisor arrives at the same result for the same home. The method applies to homes and commercial buildings, and to both new and existing buildings.
What does NTA 8800 calculate?
The core result is the primary fossil energy use, expressed in kWh per m² per year. That figure shows how much fossil energy a building needs per square metre. The lower the figure, the better the label class — from A++++ to G.
Besides that figure, the method also calculates the other energy performance indicators, such as the energy demand and the share of renewable energy. For new build these are known as the BENG indicators; for an existing home, the primary fossil energy use is the figure that determines your label.
Which data counts?
During the inspection the advisor records the actual situation of the property. Broadly speaking:
| Component | What is assessed |
|---|---|
| Building envelope | Insulation of roof, walls and floor, and the type of glazing (single, double, HR++) |
| Floor area & shape | Usable floor area and the ratio between envelope and volume |
| Heating | Type of generator (boiler, heat pump, district heating), efficiency and heat emission |
| Hot water | How the hot water is produced and which appliance does it |
| Ventilation | Natural, mechanical, or with heat recovery (WTW) |
| Renewable energy | Solar panels (kWp), solar water heater, and how they are positioned |
Important: NTA 8800 assesses the building, not the occupant. The method calculates with a standard climate year and standard occupant behaviour. This makes homes fairly comparable with one another — and that is why your energy bill says nothing about the label class.
Default values or evidence: why it matters
If the advisor cannot establish or prove something, the method requires the use of a default (forfaitaire) value: a safe standard value that is deliberately unfavourable. If there is evidence — a construction drawing, an invoice, a photo of the insulation or a product declaration — the actual value may be used.
That difference is bigger than people think. A concrete example are the BCRG quality declarations. The BCRG manages the official register of quality and equivalence declarations for the energy label calculation. With such a declaration, the advisor may use the actual tested values of a specific boiler — for auxiliary energy and hot water — instead of the less favourable default values. That can be exactly the difference between two label classes. This is why we look those declarations up for you as standard.
What did NTA 8800 replace?
Before 2021 the energy label for existing homes was determined with the Energie-Index, and new build with the EPC system. NTA 8800 replaced both and brought them under one method. An important consequence: labels from before and after 2021 are not directly comparable. A home that had a B under the old method may get a C under NTA 8800 without anything having changed to the house. An old label does remain valid until its expiry date — see provisional and definitive energy label.
The method itself does not stand still: it is updated periodically. You can read what changes in 2026 in our article NTA 8800 method 2026: what is changing?
Who may apply NTA 8800?
Not everyone. A valid energy label according to NTA 8800 may only be issued by a BRL 9500-certified EPA advisor, working with certified calculation software and registering the result in EP-online, the official register of the RVO. Online calculators can give an indication, but never produce a legally valid label.
Frequently asked questions
What does NTA 8800 mean?
NTA 8800 stands for Nederlandse Technische Afspraak 8800, or Dutch Technical Agreement 8800, with the full title Energy performance of buildings - Determination method. It is the calculation method that defines how the energy performance of a building is determined, and therefore the basis of the energy label.
Since when does NTA 8800 apply?
Since 1 January 2021. From that date every new energy label is calculated according to NTA 8800. The method replaced the old Energie-Index for existing buildings and the EPC system for new build.
Why does my energy label not match my energy bill?
Because NTA 8800 assesses the building, not your consumption. The method calculates with standardised use: a fixed climate year and standard occupant behaviour. This makes homes fairly comparable with each other. So if you heat sparingly in a poorly insulated house, you have a low bill and still a low label.
What is the difference between NTA 8800 and the old Energie-Index?
The Energie-Index gave a figure without a unit. NTA 8800 calculates primary fossil energy use in kWh per square metre per year, looks in more detail at installations and ventilation, and always requires an on-site inspection. Labels from before and after 2021 are therefore not directly comparable.
Who may issue an energy label according to NTA 8800?
Only a BRL 9500-certified EPA advisor, using certified calculation software. The advisor inspects the property, enters the data and registers the result in EP-online. So you cannot make an NTA 8800 calculation valid yourself.
More in the knowledge base
- Energy label A to G: what do the label classes mean?
- Provisional and definitive energy label: the difference
- NTA 8800 method 2026: what is changing?
- Improving your energy label: which measures pay off?
- What does an energy label cost?
Request an energy label under NTA 8800?
At Hollands Duurzaam you pay from €220 for an official energy label including free improvement advice — a fixed all-in price, with no travel costs in our service area. We look up the right quality declarations as standard, so your label does not come out unnecessarily low. BRL 9500-MWA-W certified, member of AVEPA, registered directly in EP-online.