Mandatory Hydronic Balancing 2026: Who Has to Comply, and When?

Hydronic balancing is a legal requirement only for a narrowly defined group of buildings: it becomes mandatory exclusively for buildings with six or more residential units, once a new water-based heating system is installed or set up there on or after 1 October 2024. For single- and two-family homes, as well as smaller existing systems, it remains voluntary, though it is a precondition for heating subsidies.

This exact distinction causes most of the confusion in practice, because guidance pieces often lump the legal requirement, the funding condition and the general recommendation together. For portfolios with a mix of building sizes, it pays to get a clear view of where a statutory obligation actually starts and where only an economic recommendation remains.

Four factors determine whether and how a building is affected:

Mandatory, Funding-Linked, or Optional: Three Scenarios Under Section 60c and BEG

Three legally distinct scenarios determine whether hydronic balancing is mandatory, whether it is simply a precondition for funding, or whether it remains purely an economic recommendation. Which one applies depends on the size of the building and on whether a new heat generator is currently being installed.

For most existing-building portfolios, the real work isn't spotting the obligation itself; it's checking every single building against this matrix before a boiler replacement is due.

Section 60c GModG (Formerly GEG): From What Building Size Does the Obligation Apply?

The statutory obligation to carry out hydronic balancing applies exclusively to owners of buildings with at least six apartments or comparable usage units, where a heating system using water as the heat carrier is newly installed or set up. It applies regardless of fuel type: whether a gas boiler or a heat pump goes in makes no difference, and the obligation has been in force since 1 October 2024 (Section 60c GEG/GModG).

On 29 July 2026, the legislator replaced the Buildings Energy Act (GEG) with the Buildings Modernization Act (GModG). Nothing substantive changed for hydronic balancing as a result: Section 60c was carried over unchanged and is now referred to as "Section 60c GModG" (as Haufe explains regarding the legislative transition). Anyone who still knows the old paragraph reference from the GEG era will find the same rule under the new law's name.

What matters for existing-building portfolios: the obligation isn't tied to building size alone, it's tied to the new installation or setup of the heat generator. A building with eight residential units whose boiler has been running unchanged for years currently faces no ongoing retrofit obligation. The earlier EnSimiMaV deadlines for existing systems, dated 2023 or 2024 depending on building size, have already expired and been replaced by the new-installation rule in Section 60c.

Why BEG Funding Doesn't Come Without Hydronic Balancing

For BEG heating subsidies under KfW Program 458, hydronic balancing can't be sidestepped: the only accepted proof is Method B, submitted via the official VdZ confirmation form, and without it KfW pays out no grant at all (KfW's information sheet on Grant 458).

This funding condition applies regardless of whether the Section 60c obligation even kicks in. A single-family home installing a new heat pump carries no statutory balancing obligation, yet this funding condition still applies: anyone applying for the grant effectively makes the balancing mandatory for themselves.

Since the BEG reform of 21 July 2026, this funding condition itself hasn't changed, but the size of the grants has. The base subsidy for a heating system replacement stays at 30 percent, the climate speed bonus dropped from 20 to 16 percent, and the income bonus was restructured into three tiers reaching up to 40 percent (details on the reform from ThermoSchmiede). Combined, that allows for funding of up to 80 percent. On eligible costs of 28,000 euros for the first residential unit, that works out to a grant of roughly 22,400 euros, provided hydronic balancing under Method B has been completed.

For existing buildings with up to five residential units, which sit below the Section 60c threshold, BAFA's "Heating Optimization" program is also worth considering: 15 percent of eligible costs, plus 5 additional percentage points with an iSFP certificate. For buildings with six or more units, this separate funding option no longer applies, because a statutory obligation generally isn't eligible for its own funding.

Boiler Replacement and New Heat Generators: When Does Balancing Become Mandatory?

Balancing becomes mandatory the moment a new water-based heat generator is installed or set up in a building with six or more residential units, whether an old boiler is being replaced or a system is being installed for the first time. The trigger is the boiler replacement itself, not a fixed calendar date.

The balancing is documented by the specialist company carrying out the work. It confirms in writing the building's heat load, the configured output of the heat generator, and the other values listed in Section 60c, paragraph 4, communicates these to the responsible owner, and must provide them to tenants without delay upon request.

The party obligated remains the building owner, not an operator commissioned by them. That sets Section 60c apart from other operator obligations under the GModG, such as the heating inspection under Section 60b, where a contracting company can take on that responsibility (according to a legal analysis of Section 60c).

Multi-Family Buildings With 6+ Units and Condominium Associations: What the Obligation Means

From six residential units upward, the obligation applies to every new installation of a heating system, and in condominium associations with a central heating system, that turns into a question of common property. The homeowners' association has to resolve on the balancing by simple majority before a specialist company can carry it out (as a guide for landlords and condominium management companies describes it).

Because the underlying obligation is a matter of public law, each individual owner arguably has a claim to having the measure carried out as part of proper management. For management companies overseeing larger portfolios, that means: as soon as a heat generator is renewed in a building with six or more units, the resolution on balancing sensibly belongs in the same meeting as the resolution on the heating system replacement itself.

Voice from practice: VDIV Deutschland has pointed out that many property management companies could barely meet the time-bound predecessor obligations from EnSimiMaV, because quotes from specialist companies were often simply unavailable due to the skilled-labor shortage. The same capacity question applies to new-installation cases under Section 60c: anyone planning a boiler replacement does well to line up the specialist company for the balancing at the same time.

For portfolios that have already completed the one-time mandatory balancing, the question that remains is how well the configured values hold up during ongoing operation. Our article on heating monitoring in multi-family buildings shows how deviations from the originally set controller values can be spotted early.

Proof, Method A vs. B, and the Consequences of Non-Compliance

The only proof accepted for Section 60c is Method B: the room-by-room heat load calculation under DIN EN 12831, following the ZVSHK/VdZ technical guideline. The simpler Method A, which works with estimated reference values instead of a room-by-room calculation, does not satisfy the statutory obligation and remains reserved for voluntary optimization or the heating inspection under Section 60b.

By law, the written proof must contain several pieces of information (Section 60c, paragraph 4 GModG):

The owner receives this proof from the company that carried out the work and must provide it to tenants without delay upon request. If the balancing isn't carried out at all, or is carried out late, that can be treated as an administrative offense in cases of intent or recklessness.

Good to know: For the fine attached to a missed mandatory balancing, the majority of expert sources, including a legal essay in the NZM as well as Haufe and Haus & Grund Rheinland-Pfalz, cite a range of up to 5,000 euros under Section 108, paragraph 1, number 7, in conjunction with paragraph 2, number 3a GModG. One individual source cites a figure of up to 50,000 euros instead; that number should be treated as an outlier rather than the norm.

An explicitly named exemption for Section 60c, for instance for listed buildings or technical hardship cases, isn't found in the provision itself. That sets it apart from Section 60b, where a contracting arrangement with an external energy supply company is explicitly exempted from the operator obligation. Under Section 60c, the owner remains responsible in every case, regardless of who later operates the system.

After the Mandatory Balancing: How to Hold On to 5 to 15 Percent in Savings

A professionally executed hydronic balancing typically cuts heating costs by 5 to 15 percent and can improve the seasonal performance factor of heat pumps by roughly 0.3 to 0.5 points (based on practical figures from heating trade professionals). Skip the balancing, and a flow temperature that's just 2 to 3 degrees too high can cut the seasonal performance factor by up to 10 to 15 percent.

The one-time balancing isn't a finished task; it's the starting point for ongoing operation. Controller settings documented at handover drift over months due to occupant behavior, weather, and minor technical deviations, without anyone noticing in day-to-day operation.

That's exactly where continuous operational optimization comes in. With KUGU EOS (Energie-Optimierungssystem), the state established after balancing can be readjusted automatically and continuously, based on actual consumption data rather than a one-time calculation. KUGU VIS (Visuelles-Informationssystem), through its VIS Anlagendiagnose feature, makes visible where imbalances between residential units or heating circuits creep back into existing systems, long before they show up in the next billing cycle.

For portfolios that are just now rolling out the mandatory balancing across multiple buildings, or planning the next boiler replacement, it's worth looking beyond the statutory minimum. Our article on heating optimization in existing buildings shows which additional levers unlock further savings potential beyond balancing, and our piece on plant diagnostics for existing heating systems describes how technical faults can be caught early.

From a Compliance Deadline to an Ongoing Operating Strategy

For management companies with mixed portfolios, there's a practical consequence that rarely gets spelled out: within a single portfolio, several legal situations can apply at the same time, depending on when each building last received a new heat generator. A building with eight units and a ten-year-old boiler currently faces no retrofit obligation, while the neighboring building with seven units falls under Section 60c the moment its next boiler is replaced.

Knowing these differences in advance lets you factor hydronic balancing into every heating replacement plan from the outset, avoiding extra work down the line. The same logic applies to funding applications regardless of building size: without proof under Method B, the grant doesn't materialize, whether the statutory obligation applies or not.

The practical next step is to review every building in the portfolio: count the residential units, check the date of the last boiler replacement, and line up the specialist company for balancing early for any upcoming replacement. Where the mandatory balancing has already been completed, ongoing operation determines whether the configured values still hold up months later.

Frequently Asked Questions About Hydronic Balancing and the Obligation

As the owner of a single-family home, do I have to get hydronic balancing done?

No, single- and two-family homes carry no statutory obligation under Section 60c. However, as soon as BEG funding is applied for through KfW Program 458, proof under Method B becomes a mandatory precondition for payout. Without a funding application, balancing remains a voluntary, economically worthwhile measure.

How high is the fine for a missed hydronic balancing?

Up to 5,000 euros is the fine range cited by the majority of expert sources when the mandatory balancing under Section 60c is not carried out, or carried out too late, intentionally or recklessly. This is based on Section 108, paragraph 1, number 7, in conjunction with paragraph 2, number 3a GModG. One isolated source cites a higher figure, which counts as an outlier rather than the norm.

Is the simplified Method A sufficient for BEG funding?

No, for any BEG heating subsidy under KfW Program 458, only proof under Method B, submitted via the official VdZ confirmation form, is accepted. Method A, which relies on estimated reference values, is not accepted by KfW as proof for funding purposes. Without this specific proof, no payout is made.

Does hydronic balancing have to be repeated with every new boiler?

Yes, in buildings with six or more residential units, every new installation or setup of a water-based heat generator triggers the Section 60c obligation again. A balancing carried out previously doesn't exempt the building from the obligation at the next boiler replacement. What matters is always the condition of the newly installed system.

Who decides on hydronic balancing in a condominium association?

The homeowners' association decides on carrying it out by simple majority, since the central heating system counts as common property. Where the statutory obligation under Section 60c applies, each owner arguably has a claim to implementation as part of proper management. The resolution should be passed together with the decision on the heat generator itself.