Energy certificate and class: what A–G means
By Lumi · Updated: Jun 16, 2026, 12:00 AM
The energy class shows a flat's energy efficiency and affects heating costs and value. How to read the energy certificate as a buyer.
Important: A poor energy class (E–G) means higher heating costs and a possible energy renovation down the line.
An energy certificate rates a building's energy efficiency on an A–G scale. It affects heating costs, comfort and, increasingly, resale.
What the class tells you
A is the most efficient, G the weakest. The class is based on calculated energy use (the E-value), not just the actual bill. New buildings are typically A–B, older ones often D–F.
Why it matters
A poor class usually means higher heating costs and a possible energy renovation. A good class can support value and loan terms.
Where to get the certificate
The energy certificate is usually in the listing or available from the seller or manager. Lumi links to the official energy-certificate registry; check the flat's own class from the certificate.
Frequently asked questions
- Is the energy certificate mandatory when selling?
- As a rule yes — an energy certificate must be presented when selling a home.
- What is the E-value?
- A calculated energy-efficiency figure that determines the A–G class.
- Can the class be improved?
- Yes, with an energy renovation (insulation, windows, heating), but it requires investment.
Sources
See also
This guide is general information, not personal advice. Verify figures and rules from official sources.