Heating cost billing
Pipe heat under VDI 2077: when the heating cost statement misses heat beyond the radiator
19 September 2026MEVIO editorial team9-minute read
Key points at a glance
- Pipe heat is heat that uninsulated heating pipes give off inside the flats — it is not recorded by any heat cost allocator.
- The result: flats along the riser pipe are heated “for free”, while the others pay for that consumption too.
- § 7 Abs. 1 Satz 3 of the Heating Costs Ordinance (Heizkostenverordnung, HeizkostenV) allows a correction in accordance with the generally accepted rules of technology — the supplementary sheet on pipe heat (Beiblatt Rohrwärme) to the VDI 2077 guideline of the Association of German Engineers (VDI).
- This requires predominantly uninsulated, exposed pipes and a recording rate below 34%.
- The best solution is still to insulate the pipes.
In many older buildings, the heating pipes run openly through the flats — as a vertical riser pipe in the bathroom, kitchen or hallway, often without any insulation. In winter these pipes get hot and give off heat to the room. For the residents, this is pleasant. For the heating cost statement, it is a problem: the heat is used but not measured.
What pipe heat is
Heat cost allocators are mounted on the radiator and only record the heat it gives off. Whatever the pipe gives off on the way there escapes them. In well-insulated buildings, this share is small. In buildings with uninsulated riser pipes or single-pipe heating systems, however, it can make up a large part of the total heating energy.
The heat cost allocators only record what the radiators give off. The heat from the pipe reaches the flat but does not appear as consumption in the statement.
The result is a distorted statement. A flat through which a warm riser pipe runs can leave its radiators almost turned off and still stay warm. It shows hardly any consumption and pays correspondingly little in consumption costs. These costs are then borne by the other users — precisely those who get their heat from the radiators.
What the Heating Costs Ordinance allows
Since the 2009 amendment, the HeizkostenV has contained a specific rule for this case. It is not an obligation but opens up an option: consumption may be determined in accordance with the generally accepted rules of technology if two conditions are met.
Legal basis · § 7 Abs. 1 Satz 3 HeizkostenV
In buildings in which the exposed pipes of the heat distribution system are predominantly uninsulated and in which, as a result, a substantial share of the heat consumption is not recorded, the users’ heat consumption may be determined in accordance with generally accepted rules of technology.
In practice, the accepted rule is the supplementary sheet to the VDI 2077 guideline, which deals specifically with heat given off by pipes. It describes when a “substantial share” exists and how the unrecorded heat is taken into account in the calculation.
The word exposed is important. In 2017, the Federal Court of Justice (Bundesgerichtshof, BGH), Germany’s highest civil court, clarified that this means visibly laid pipes. Pipes under plaster or in the screed do not justify a pipe heat correction, even if they give off heat.
When a correction may be considered
Whether pipe heat substantially distorts the statement can be measured. The key figure is the recording rate: the share of heating energy that is actually measured at the radiators. If it is below 34 per cent, a large part of the heat is being used without passing the measuring devices.
- Uninsulated pipespredominantlyThe exposed pipes of the heat distribution system are predominantly uninsulated — a requirement of the ordinance.
- Recording ratebelow 34%Less than a third of the heating energy is measured at the radiators.
- Uneven consumptionconspicuousConsumption varies widely, and a noticeable share of the flats shows hardly any measurable consumption.
Criterion 1 follows from § 7 Abs. 1 Satz 3 HeizkostenV, criteria 2 and 3 from the supplementary sheet on pipe heat to VDI 2077.
A low recording rate alone is not enough. The supplementary sheet also requires that consumption in the building is distributed in a conspicuously uneven way and that a noticeable share of the flats shows hardly any measurable consumption — typical signs of flats that are being heated via the pipe.
How the balance method works
The method compares the heat that goes into the building with the heat measured at the radiators. From the difference, the part that reaches the flats as pipe heat is calculated. This part is allocated to the flats as additional, notional consumption units according to the heated floor space.
- Heat into the buildingDetermine the heating energy from the fuel or the heat meter.
- Recorded heatConvert the readings of the heat cost allocators into heat.
- Balance the differenceSeparate the pipe heat in the flats from the other losses.
- Allocate the pipe heatAdd it as additional units by heated floor space.
Without correction
recorded 30 per cent, not recorded 70 per cent
With pipe heat
recorded 30 per cent, pipe heat 13 per cent, other 57 per cent
“Other” mainly covers losses outside the flats, for example in the basement. The values are a simplified example; in practice they result from the building’s energy balance.
Legal basis · § 7 Abs. 1 Satz 4 HeizkostenV
The consumption of the individual users determined in this way is taken into account as recorded heat consumption — so it is included in the allocation of the consumption costs just like measured consumption.
What changes for the users
The correction does not change the costs of the building, only how they are distributed. Flats that were previously heated via the pipe are allocated a share of this heat. Flats that heat via their radiators pay less.
Flat A — heats almost entirely via the riser pipe
Flat B — heats via the radiators
With the correction, Flat A pays €339 more, because a share of the heat from the riser pipe is now attributed to it. Flat B pays €339 less. The costs of the building stay the same.
Assumptions: 10,000 recorded units in the building; the pipe heat corresponds to 4,333 additional units, allocated by floor space (433 per flat).
In the example, Flat A’s bill rises from €880 to €1,219, while Flat B’s falls from €3,120 to €2,781. The statement thus once again better reflects who actually used how much heat.
Alternatives and recommendations
- Insulate the pipesThe permanent solution: insulated pipes give off hardly any heat, the recording rate rises and a correction becomes unnecessary. At the same time, energy consumption falls.
- Review the allocation keyA higher floor-space share, such as 50/50, softens the distortion. A change is only possible within the limits of § 6 Abs. 4 HeizkostenV and at the start of a billing period.
- Get reliable dataThe balance requires reliable figures on the heat supplied — ideally from a heat meter at the boiler or at the transfer station.
- Communicate transparentlyA pipe heat correction noticeably changes the cost distribution. Owners and tenants should be told in advance why and by which method the calculation is made.
How basic and consumption costs are allocated in general is explained in our article The 70/30 rule in heating cost billing.
Suspect pipe heat in your building?
Send us your latest heating cost statement. We will look at the recording rate and the distribution of consumption and tell you whether a review under VDI 2077 makes sense.
This article is intended as general guidance and does not replace legal advice in individual cases. Last updated: September 2026.
Frequently asked questions
Pipe heat — brief answers
What is pipe heat?
Pipe heat is the heat that uninsulated heating pipes give off inside the flats — above all riser pipes and distribution pipes in older buildings. It helps to heat the rooms, but it is not recorded by the heat cost allocators on the radiators.
Why is pipe heat a problem for billing?
Because it is unevenly distributed. Flats through which a warm riser pipe runs are heated as well, without any consumption being counted. The consumption costs are then spread across the other users. The statement no longer correctly reflects the heat actually used.
Is it mandatory to take pipe heat into account?
No, it is a discretionary provision. Under § 7 Abs. 1 Satz 3 of the Heating Costs Ordinance (Heizkostenverordnung, HeizkostenV), consumption may be determined in accordance with the generally accepted rules of technology if the exposed pipes are predominantly uninsulated and a substantial part of the consumption is therefore not recorded. The supplementary sheet on pipe heat (Beiblatt Rohrwärme) to the VDI 2077 guideline is regarded as such an accepted rule.
When is there a “substantial share” of unrecorded heat?
The supplementary sheet to VDI 2077 sets out test criteria for this. The main factor is the recording rate — the share of the total heating energy that is measured at the radiators. If it is below 34 per cent and, at the same time, consumption is distributed in a conspicuously uneven way, a pipe heat correction may be considered.
Does this also apply to pipes inside the wall?
No. The ordinance refers to exposed pipes. According to the case law of the Federal Court of Justice (Bundesgerichtshof, BGH), pipes that run under plaster or in the screed are not exposed; the rule does not apply to them.
Who bears the costs of the pipe heat calculation?
The costs of the calculation and allocation are part of the costs of consumption metering and billing and can in principle be passed on to the users (§ 7 Abs. 2 HeizkostenV). This requires that applying the pipe heat correction is permissible.
Are there alternatives to the pipe heat correction?
Yes. The most sustainable solution is to insulate exposed pipes — then the problem does not arise in the first place. In addition, a higher floor-space share in the allocation key can soften the effects, provided that a change of the key is permissible.