How to ensure a good E-value?

A good E-value (E-luku) depends on the building’s intended-use category. Different E-value limits have been defined for the different intended-use categories, and on the basis of these, buildings are placed in different energy efficiency classes. Energy efficiency classes are on a scale of A-G, where buildings in energy class A are the best in their intended-use category and those in energy class G the worst. For blocks of flats, for example, a value of 75 or below can be considered a good E-value, placing the building in energy class A. When the aim is to improve a building’s E-value and achieve a good E-value, it is advisable to turn to an energy consultant. To prepare an energy performance certificate (energiatodistus), an energy consultant must hold the qualification of an energy certificate assessor.

Good E-value by intended-use category

There are intended-use categories 1-9 for buildings, and a good E-value is reached at different values in the different intended-use categories. Here, a good E-value, i.e. a good energy efficiency figure, has been taken to mean an E-value that places the building in energy class A for its own intended-use category. The energy efficiency class limit for small residential buildings also depends on the building’s heated net floor area, and if you wish, you can read more about it in the energy certificate for a detached house -article.

Intended-use category		Energy class A limit / good E-value
Description	Category	kWhE/(m² year)
Small residential buildings 50–150 m²	1a	110 – 0.2 × Anetto
Small residential buildings over 150, 600 m² or under	1b	83 – 0.02 × Anetto
Small residential buildings over 600 m²	1c	70
Terraced houses and blocks of flats with 2 storeys	1d	80
Blocks of flats with more than 2 storeys	2	75
Office buildings and health centres	3	80
Commercial buildings, e.g. department stores	4	90
Accommodation buildings, e.g. hotels	5	90
Educational buildings and day care centres	6	90
Sports halls, excluding e.g. ice rinks	7	90
Hospitals	8	150
Other buildings, e.g. warehouses	9	90

Energy class A is reached in the different building types as shown in the table above. If needed, you can read in more detail how the energy efficiency figure itself is determined in the E-value calculation examples article.

Ways to improve the E-value

Achieving a good E-value is best done with the help of an energy consultant, regardless of the building’s intended use. Below we have collected some ways to improve the E-value:

• Ground source heat

• Exhaust air heat pump

• Air-to-water heat pump

• Air-to-air heat pump

• Solar panels

• Solar thermal collectors

• More energy-efficient windows

• Additional insulation of external walls

• Additional insulation of the roof structure

• Additional insulation of the base floor

• Constant-pressure valve for domestic water

When aiming for a good E-value, in addition to the actual systems, attention must be paid to the way the energy certificate is drawn up and the E-value calculation is made. The same building always gets a better energy class and E-value when the calculations are made with values taken precisely from the design plans rather than with table values. Table values are alternative calculation values that often include a safety margin relative to reality, which is why using them worsens the calculated energy efficiency.