Energy report for a building permit – a plain-language guide for detached house builders

The permit paperwork for your detached house project is almost complete, and then a message arrives from the building control authority: the building permit application needs an energy report. What is it, who is allowed to prepare it, what does it cost and how long does it take to get one? In this article we go through, from the detached house builder’s perspective, at which stage of the permit process the energy report is needed, what it includes and what you need to supply yourself – in plain language, without formulas. The guide is for you if you are building or commissioning a detached house, whether it is a prefabricated house package or a house built on site from scratch.

Why does building control ask for an energy report?

An energy report is a set of documents that demonstrates, before construction even begins, that the new house meets the energy efficiency requirements of the law. The authority is not asking for it out of spite: the report is building control’s way of making sure that the planned house complies with the regulations before a single footing has been poured. For a detached house, the core of the report is the E-value calculation and the energy certificate based on it. At the permit stage everything is based on plans: the calculations are made from the drawings and equipment choices, and no site visit is needed. In this article we stay within the permit process – if you want to dig deeper into the contents of the report, read the builder’s guide: energy report.

Rakennuslupa or rakentamislupa – which Finnish term is correct?

Both mean the same permit, but since the start of 2025 the law recognises only one of them. The new Building Act (751/2023) entered into force on 1 January 2025, and in it the old term for a building permit, rakennuslupa, was replaced by rakentamislupa. In plain language, the law says this to a detached house builder: constructing a residential building always requires a building permit regardless of its size, and a permit is also needed for example for drilling a geothermal energy well and for a renovation project that has a significant effect on the building’s energy efficiency – we cover the latter in more detail in the article energy renovation. The current text of the act is available on Finlex. In everyday speech and on many municipal forms the old word rakennuslupa lives on, and it makes no difference which word you use – it is the same permit. In the title of this article, too, we use the familiar term building permit, but your permit decision will probably say rakentamislupa.

At which stage of the permit process is the energy report needed?

The energy report travels with the project from the drawing board all the way to the final inspection. This is how it proceeds:

Stage	What happens to the energy report
Design	The energy report is drawn up during the design phase. It pays to have the E-value calculation prepared already at the draft stage, while the heating system, windows and insulation can still be changed at low cost.
Permit application	Building control may ask for the energy report as an attachment to the application. At this stage the energy certificate included in the report shows the house's estimated energy performance.
Construction	If the implementation deviates from the plans – for example the heating system or the windows change – the changes are entered in the report.
Commissioning	If the implementation changed or the details became more precise, the report and the certificate are updated before commissioning to reflect the completed building. A building is considered commissioned once it has been approved at the final inspection.

From the start of 2026 the energy report is no longer an automatic attachment to every permit application: the only mandatory attachments are the main drawings and certain other documents, and building control requests the energy report based on the nature and scope of the project. The energy efficiency requirements for a new detached house must nevertheless always be met and the energy report drawn up during the design phase – so the request is not a sign of a problem but a normal part of the permit process.

In practice the best moment to order the energy report is when the main drawings are nearly finished and the heating system, ventilation unit and windows have been chosen. The calculation can then be done in one go with the right data, and the report is ready and waiting when building control asks for it.

What does the energy report for a detached house include?

The energy report for a detached house typically includes the following parts – here each is explained in a single sentence:

E-value calculation: the E-value is the house’s calculated energy performance figure, which must stay below a limit value that depends on the size of the house.
Energy certificate: the document in which the E-value and the energy class are presented in an official format – at the permit stage it describes the planned house.
Heat loss equalisation calculation: a calculation demonstrating that the heat losses of the building envelope, air leakage and ventilation stay within the permitted limits as a whole.
Specific fan power of the ventilation: a check that the ventilation system does not use too much electricity relative to the amount of air it moves.
Summer-time room temperature assessment: a calculated check that the interior does not heat up harmfully in summer – small residential buildings such as detached houses are, however, exempt from this requirement.

The whole may sound technical, but you do not need to calculate anything yourself: the assessor compiles all the parts into a single package that you can attach to your permit application as it is.

More good news for the detached house builder is that the new obligations applied from the start of 2026, the climate report and the building product list, do not apply to a separate small house, that is, an ordinary detached house. And if you want to influence your future energy class before the calculation, read our article how to get a good E-value.

What input data is needed from you?

The assessor needs the house’s design data for the calculation. A checklist for the detached house builder:

the main drawings, that is, the floor plans, elevations and sections
the structure types, that is, the wall, roof and base floor structures with insulation thicknesses, or the U-values provided by your designer
the details of the windows and external doors
the model of the ventilation unit, or a plan showing the annual efficiency of its heat recovery
the heating system and the domestic hot water solution
any on-site energy generation, such as solar panels, and any fireplace.

A house package builder usually gets all of this from the house supplier with a single request; when building on site from scratch, the principal designer compiles them. A single missing detail will not derail the project – if needed, we ask your designer for it directly. If some choice is still open, the calculation can be made with the planned option and updated once the final choice is confirmed.

Who may prepare the energy report for a detached house?

The energy certificate included in the energy report may only be prepared by a person whose qualification has been verified and who is entered in the national register of assessors. The qualification requires a degree in a technical field or work experience replacing it, plus a passed assessor examination, and it is verified by bodies designated by the Ministry of the Environment, currently FISE Oy. In practice it therefore makes sense to order the whole energy report from a qualified assessor as a single package. All qualified assessors can be found through the public assessor search of the energy certificate register, so you can check an assessor’s background before ordering if you wish. Read more in the articles energy certificate assessor and high-quality energy certificate.

How much does the energy report for a new detached house cost and how quickly can you get it?

The energy report for a new detached house is one of the smallest expense items in the permit process: from us it costs less than two hundred euros, and you can always see the up-to-date price in our price list. The price is clearly lower than for the energy certificate of an existing house, because the calculation for a new build is made from the plans and no separate observation visit on site is needed. Delivery is fast once the input data is in place – we give you the exact schedule with the quote. For the overall timeline the most important thing is to move early: when the calculation is done already at the design stage, the energy report never becomes the bottleneck of your permit application.

Remember the commissioning stage too

The permit-stage energy report is not the project’s final word. If the implementation deviates from the permit-stage plans, the report and the energy certificate are updated before commissioning to reflect the completed house. The final certificate is prepared with an electronic signature in the energy certificate register, and it is valid for up to ten years – so the same certificate also serves you later if you sell or rent out the house. The smartest move is to agree already when ordering that the same assessor also handles the commissioning-stage update.

How to order an energy report for a building permit

Ordering is straightforward:

Send us the main drawings and the structure, window, ventilation and heating solutions that are already known.
You receive a quote and a delivery schedule.
We deliver the energy report documents ready for building control – and update them for commissioning if the plans change along the way.

Submit a request for a quote and you will receive a quote for an energy report with fast delivery. If your project is still at the draft stage, order the E-value calculation already during the design phase – then you still have time to choose the solutions that will give your house a good energy class. You can find all our services on a single page.

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