In brief: Every building needs an energy certificate when sold, rented, or — from 2026 — when renewing a lease. The consumption certificate is cheaper, the demand certificate more informative. For buildings with up to 4 units (built before 1977, without energy modernization), the demand certificate is mandatory.
Legal Basis
The energy certificate requirement originated in the Energy Saving Ordinance (EnEV) and was continued by the Building Energy Act (GEG) in 2020. With the Building Modernisation Act (GModG), which has replaced the GEG since July 29, 2026, the requirements are further expanded — the new energy certificate rules phase in from January 1, 2027.
Basic rule: A valid energy certificate must be presented for every sale, new rental, and — new under the GModG (from 2027) — also for lease renewals. It must be listed in the property ad and shown unprompted at the latest during viewing.
The Consumption Certificate
How It Works
The consumption certificate is based on actual energy use over the last three years. Consumption data is taken from heating cost statements and climate-adjusted — meaning corrected for an average weather year.
Cost
Starting from around 100 euros. Inexpensive because only limited data needs to be collected.
Limitations
The consumption certificate reflects occupant behavior, not building condition. A frugal tenant can mask poor values, while a generous heater can make good building fabric look bad. Vacancy also significantly distorts results.
The Demand Certificate
How It Works
The demand certificate is based on an engineering calculation of building physics: wall construction, window quality, roof structure, heating system, hot water generation, and other parameters are assessed according to standard procedures (DIN V 18599).
Cost
Starting from around 350 euros. The higher price reflects the significantly greater effort — an on-site inspection is usually required.
When Is It Mandatory?
The demand certificate is legally required for residential buildings with up to 4 units built before 1977 that have not been modernized to at least the 1977 Thermal Insulation Ordinance level. For all other buildings, there is freedom of choice.
Comparison at a Glance
Consumption Certificate
Demand Certificate
New Energy Efficiency Classes A to G
Under the GModG, from January 1, 2027 the previous A+ to H scale is replaced by an EU-wide system with classes A to G. Class A will represent zero-emission buildings, class G the worst-performing buildings in the national stock.
The new scale aims to improve comparability across the EU and set clear renovation targets. The EU Building Directive (EPBD) requires the worst-performing buildings (class G) to reach at least class F by 2030 (non-residential) or 2033 (residential).
Extended Requirements Under the GModG
Previously, an energy certificate was only required for sales and new rentals. The GModG extends this obligation to two additional occasions:
Lease Renewal
When extending existing leases, a valid energy certificate must also be presented. This particularly affects commercial tenancies with renewal options.
Major Renovations
When more than 25% of the building envelope is renewed (e.g., facade insulation, roof renovation, window replacement), a current energy certificate is required. This ensures the energy rating reflects the post-renovation condition.
Validity: 10 Years
An energy certificate is valid for 10 years from the date of issue — regardless of whether it is a consumption or demand certificate. Existing certificates with the old scale (A+ to H) remain valid for their full term. After expiration, a new certificate must be issued according to the regulations in force at that time.
When Is a Voluntary Demand Certificate Worth It?
Even when the consumption certificate would be permitted, there are good reasons to voluntarily choose the demand certificate:
Selling Advantage
Buyers trust the demand certificate more because it shows objective building condition. A good demand value can positively influence the sale price — especially for energy-retrofitted buildings.
Renovation Planning
The demand certificate specifically shows where the greatest heat losses occur — exterior walls, roof, windows, or heating. This is the ideal basis for a prioritized renovation strategy.
Objective Assessment
If a building has been vacant for a longer period or used unusually (e.g., low heating demand due to work-related absence), the consumption certificate is not meaningful. The demand certificate then provides the more reliable picture.
Tip: Energy Certificate as Part of an iSFP
If you are commissioning energy consulting with an individual renovation roadmap (iSFP) anyway, the demand energy certificate can be created alongside it — often without significant additional effort. This way you get both: strategic renovation planning and a legally valid energy certificate. Additionally, the energy consultation itself is subsidized up to 50% by BAFA (max. 650 euros for one-/two-family homes).
Note: As of July 2026. The GModG took effect on July 29, 2026; the new energy certificate rules (EU scale A–G, extended mandatory details and disclosure occasions) phase in from January 1, 2027. This article does not replace individual consulting.
Need an Energy Certificate? We Can Help.
Whether consumption certificate, demand certificate, or a complete renovation roadmap — we advise you on which option is right for your building.