Primary fossil energy use: the core value of your energy label
Behind every label letter sits a single figure: the primary fossil energy use, expressed in kWh per m² per year. Since 2021 that figure determines whether your home gets an A or a G. The lower, the better. On this page we break the term down — because «primary» and «fossil» each mean something very specific.
What does «primary» mean?
Primary energy use counts the energy needed at the source, not only what passes through your meter. Energy is lost when electricity is generated and transported: in the power station and in the grid. To get one kWh into your socket, more energy was needed at the source.
The calculation method accounts for this with a conversion factor per energy carrier. The result: gas and electricity become fairly comparable. A home with a heat pump (electric) and a home with a gas boiler are measured against the same yardstick.
What does «fossil» mean?
Only the fossil share counts towards the value. Energy you generate renewably yourself, or draw from the environment, does not count as fossil. That explains why certain measures have such a strong effect:
- Solar panels generate renewable electricity — which lowers the fossil share directly.
- A heat pump draws heat from the air or the ground; that ambient heat is renewable.
- A solar water heater does the same for your hot water.
Insulation works via a different route: it lowers the energy demand itself, so that less (fossil) energy is needed in the first place.
Why per square metre?
Because a large house simply needs more energy than a small flat. By dividing by the usable floor area, you compare efficiency rather than size. That way a detached villa and a terraced house can both achieve an A.
Please note: this is a calculated value for the building, using standard occupant behaviour and a standard climate year. So it is not your actual consumption — and that is why your energy bill says nothing about your label class. See NTA 8800.
From figure to label class
Once the value is known, the label class follows from it: from A++++ to G. The threshold values are not the same for every home — they depend on the shape and compactness of the building. So there is no universal «figure for label A»; during the inspection the advisor calculates which value your home achieves and which class that falls into.
What lowers the figure?
| Measure | Effect on primary fossil energy use |
|---|---|
| Roof, wall or floor insulation | Less heat demand, so less fossil energy needed |
| HR++ glazing | Limits heat loss through the windows |
| Solar panels | Renewable generation lowers the fossil share directly |
| (Hybrid) heat pump | Uses renewable ambient heat instead of gas |
| Ventilation with heat recovery | Recovers heat from the extracted air |
Which measure pays off most for your home depends on the current situation — insulation only really pays off if the envelope is poor now. Read more in improving your energy label or request a tailored advice report.
Frequently asked questions
What is primary fossil energy use?
It is the amount of fossil energy a building needs per square metre per year, expressed in kWh/m2 per year. Since 2021 this figure determines the energy label class: the lower the value, the higher the label.
Why is it called primary energy use?
Because it counts the energy needed at the source, not only what arrives at your home. Energy is lost when electricity is generated and transported. Primary energy use includes that loss, so that gas and electricity can be compared fairly.
Do solar panels lower my primary fossil energy use?
Yes. Solar panels generate renewable energy, which does not count as fossil. As a result the primary fossil energy use drops and the label often rises by one or more classes. The advisor records the capacity in kWp and how the panels are positioned.
Is primary fossil energy use the same as my energy consumption?
No. It is a calculated value for the building, using standard occupant behaviour and a standard climate year. Your actual consumption depends on how you heat and shower. That is why an economical occupant in a poorly insulated house can have a low bill and still a low label.
Which value do I need for label A?
That differs per property type: the threshold values per label class depend on the shape and compactness of the home. So there is no single figure that applies to every home. During the inspection the advisor calculates which value your home achieves and which class that falls into.
More in the knowledge base
- NTA 8800: the calculation method behind the label
- Energy label A to G: what do the label classes mean?
- EP-online: the official register of energy labels
- Solar panels and the energy label
- Improving your energy label: which measures pay off?
Curious which value your home achieves?
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. You will hear straight away which measures pay off most for your home. BRL 9500-MWA-W certified, member of AVEPA, registered directly in EP-online.