What the Energy Label Means: From A to G Explained

An energy label is often the first thing an advisor or investor looks up when assessing the condition of a building. The letter is easy to read and quick to compare — but it reflects a calculated consumption, not a measured one, and it carries an expiry date that far from everyone keeps an eye on. The difference between a C and an F can have real consequences for operating economics, financing, and the price a buyer is willing to pay.

That makes it worth understanding what a building’s energy label actually expresses, what it is built on, and how far you can lean on it in a concrete assessment. This is a walkthrough of the A-to-G scale, of the label’s validity, and of how it comes into play when a property is to be sold or let.

The scale from A to G

The energy labelling of buildings uses a scale from A to G, where A is the lowest energy use and G the highest. The A end is subdivided into several tiers — typically A2020, A2015 and A2010 — reflecting the tightened requirements in different vintages of the building code. The further down the alphabet, the more energy the building is expected to use for heating, hot water, ventilation and cooling per square metre per year.

A few practical anchors:

• A labels signal new construction or comprehensive renovation to more recent energy requirements.
• B and C are typical of newer or well-renovated buildings with a reasonable building envelope.
• D and E cover a large share of the existing Danish building stock — older buildings with scattered improvements.
• F and G indicate substantial energy use and, as a rule, a significant backlog on insulation, windows or heat supply.

Rule of thumb: a one-letter step roughly corresponds to a noticeable jump in the expected heating bill — but it is a calculated expectation, not a guarantee of actual consumption.

It is important to remember that the label describes the building, not the occupant’s behaviour. Two identical buildings with the same label can have wildly different real bills depending on how they are used.

What the label is based on — and what it is not

An energy label is prepared by a certified energy consultant who inspects the building and records the building envelope, installations, heat supply and the like. On that basis, a standardised energy consumption is calculated under fixed assumptions for climate and use. The point of the standardisation is that two buildings can be compared on equal terms — regardless of whether one is occupied by a family of five and the other by a single person.

That also means the label has its limitations:

• It is a calculated figure, not a reading from the meter.
• It is based on an inspection at a given point in time — subsequent changes (new windows, a heat pump, added insulation) are not reflected until the label is renewed.
• The quality depends on how thoroughly the building was inspected and how accurate the recorded data is.

The energy label is typically delivered together with a set of proposed energy improvements, each with a stated saving and payback period. That part is often more useful to a buyer or developer than the letter itself, because it points to where operating savings can actually be found. When you combine the label with the building’s other register data — for example areas and construction year from BBR (the Buildings & Dwellings Register) — you get a fuller picture than the letter alone. The pitfalls in those figures are worth knowing; we have collected them in the walkthrough of the typical errors in BBR data and how to spot them.

Validity — how long does a label last?

An energy label is not valid forever. Its validity is time-limited, and an expired label has effectively no value in a sale or letting — it has to be renewed. The exact validity period depends on the type of label and on the rules that applied when it was issued, so it should always be verified on the specific label rather than assumed.

The practical move is to look the label up in the public energy label register, where you can see:

• which label the building currently holds,
• when it was issued,
• and when it expires.

A lookup in the register takes only a moment and quickly reveals whether you are looking at a current label or one that should long since have been renewed. It is one of the first checks in an initial screening, and it sits naturally alongside the rest of the register review you carry out before committing — see also our site due diligence checklist.

The energy label at sale and letting

When a building is sold or let, a valid energy label is generally required, and it must be made available to the buyer or tenant. The rules are designed to make energy use transparent, so that whoever takes over the building can consider the expected operating costs in advance. The specific requirements and exemptions should always be checked against the current legislation or with the municipality, but the principle is firm: the label has to be in place, and it has to be valid.

For professional players, the significance reaches beyond mere formality:

• Investors and developers use the label as an early indicator of backlog and renovation needs — a low label can mean CAPEX that has to be priced in.
• Asset managers and administrators use the label level to prioritise energy measures across a portfolio.
• Insurers and lenders increasingly look at energy condition as part of the risk and financing assessment.

The letter alone rarely decides a deal, but it shifts expectations — and with them the negotiation. How it actually feeds through to price we have treated separately in the article on how the energy label affects a property’s value.

From a single building to a portfolio

An energy label on a single building is manageable. But when you have to consider many properties at once — a portfolio, an acquisition target area, a municipality you want to enter — the manual lookups become heavy going. This is where the label really becomes a data point rather than a document: something you can filter, sort and compare across many addresses.

That exercise is at the core of a data-driven decision basis, where energy condition sits alongside planning status, areas and transaction data. We have described the overall approach in the article on data-driven property work, from energy label and ESG to a decision basis, and the procedure for the portfolio itself in the guide to how to screen a property portfolio on energy label and building data.

How Arcili makes the manual exercise faster

Most of what is described here — look the label up, check its validity, cross-reference it with areas and construction year, assess the backlog — is manual work, one register at a time. In the Ejendomme (Properties) module, the energy label sits together with BBR data, planning status and economics on the same property, so a lookup that would otherwise require several sources is gathered in one place. It does not replace an energy consultant’s assessment, but it removes the initial sorting, so you can more quickly see which buildings are worth a closer look.

Want to see what it looks like on your own properties? Read more about Arcili or book a walkthrough.