Energy class A–G: what the letters actually mean

The energy class in a Swedish energy performance certificate is set by the building's primary energy number expressed as a share of the energy requirement applying to new construction. A building that just meets the new-build requirement gets class C. Better than that gives B or A, worse gives D through G. The scale is therefore relative to a requirement level — not an absolute measurement of consumption in kilowatt hours.

The full scale

Energy class	Primary energy number as a percentage of the new-build requirement
A	Up to 50 %
B	Over 50 % up to and including 75 %
C	Over 75 % up to and including 100 %
D	Over 100 % up to and including 135 %
E	Over 135 % up to and including 180 %
F	Over 180 % up to and including 235 %
G	Over 235 %

Two conclusions follow directly from the table.

C is not mediocre — C is the requirement level for a new building. A building in class C therefore meets what is demanded of new construction today, which in an older portfolio is unusually good rather than middling.

The steps are not equal. From A to B the distance is 25 percentage points; from F to G it is unbounded upwards. An improvement from G to F can therefore be a larger energy saving in kilowatt hours than one from B to A, even though both are a single step.

Primary energy number, not consumption

Since 2019 a building's energy performance has been expressed as a primary energy number. The figure starts from the energy delivered to the building and weights it by energy carrier, rather than simply summing kilowatt hours. Two buildings with identical measured consumption can therefore receive different primary energy numbers if one is heated by district heating and the other by electricity.

That is the most common source of confusion when someone compares an old certificate with a new one: the numbers are not directly comparable, because the measure changed.

What is a normal energy class for a 1970s apartment building?

There is no official normal value per year of construction, and we will not invent one. What you can do instead is read the reference values contained in the certificate itself: it includes comparison figures showing how the building relates to similar buildings and to the new-build requirement. Those values are calculated on real data for that building type, unlike second-hand rules of thumb. If you have several buildings in the portfolio, the most useful comparison is anyway the internal one — same building type, same location, same heating.

Why the class is sometimes hard to read by machine

A detail worth knowing if you work with certificates in volume: in many certificates the energy class is coloured graphics, not text. The letter sits inside an arrow or a bar embedded as an image in the PDF.

It shows immediately when you try to extract it automatically. In our own evaluation on a small sample of certificates, plain text extraction read 0 of 4 classes correctly, while image reading gave 4 of 4 — and a straight calculation of the primary energy number divided by the requirement value also gave 4 of 4. The sample is too small to be statistics, but the direction is unambiguous, and the latter method has a property worth more than the hit rate: it can be checked afterwards, because both the number and the requirement value appear as text in the certificate.

That is the route energy certificate handling in Emphyx takes — calculate the class from the numbers where the numbers exist, rather than guess at an image.

What the class is used for

• In the listing on sale and letting — see energy certificates when selling.
• As prioritisation support across the portfolio: which buildings are worst placed, and which of those have recommendations that are reasonable to act on. See the recommendations.
• As a starting point in financing, where lenders increasingly ask for energy performance.

What the class is not: a measure of indoor climate, of moisture status or of maintenance need. A building can be class B and at the same time hold a failed ventilation inspection report — see reading a ventilation report. They measure different things.