Heating bills for 2025 are landing in letterboxes now, and for many households they are higher than a year ago. According to the new Heizspiegel from co2online, the German Tenants’ Association (Deutscher Mieterbund) and the Bauherren-Schutzbund, published on 22 September, natural gas costs rose by up to 15 per cent in billing year 2025 and wood pellets by up to 24 per cent. The reasons: higher energy prices and a colder winter.
What heating costs, and what 2026 may bring
For a 70 m² flat in a block of flats, the Heizspiegel gives these annual costs:
| Energy source | 2025 (change on 2024) | 2026 forecast |
|---|---|---|
| Natural gas | €1,170 (+14%) | €1,120 (−4%) |
| Heating oil | €1,030 (±0%) | €1,275 (+24%) |
| District heating | €1,295 (+6%) | €1,310 (+1%) |
| Heat pump | €715 (+5%) | €735 (+3%) |
| Wood pellets | €735 (+20%) | €860 (+17%) |
For gas, the authors expect a slight fall in 2026 because the gas storage levy has been dropped. That is no all-clear: rising wholesale prices could push gas up again in late 2026 or 2027. We think that scenario is realistic, though not certain. Over the long term co2online expects gas and oil heating to more than double in cost by 2045, because of rising CO₂ costs, higher grid fees and the “Bio-Treppe” (a rising biofuel blending requirement). “The era of cheap fossil heating energy has been over since the energy crisis four years ago at the latest,” says co2online managing director Tanja Loitz.
Checking your statement in four steps
The landlord’s deadline. The statement must reach you by the end of the twelfth month after the billing period ends, which for 2025 means 31 December 2026. If it is late, tenants generally do not have to pay any extra, according to the Berliner MieterGemeinschaft, though a credit must still be paid out. The exceptions are narrow.
Comparison. co2online.de/heizspiegel offers a free HeizCheck that compares your consumption with similar buildings. If you are well above average, ask your landlord why.
Receipts. Tenants may inspect invoices, contracts and meter-reading records, usually at the landlord’s office. Objections can be raised until the end of the twelfth month after the statement arrives and must give specific grounds. A bare “objection” (Widerspruch) is not enough.
Back payment. If you suspect errors, you can pay “under reservation” (unter Vorbehalt) and note it on the transfer. The statement then does not count as accepted.
Help is available from local tenants’ associations (Mieterverein), in Munich for example the Mieterverein München; the Mieterbund points to its local groups. It is also calling for legal protection against excessive heating costs. “Fossil heating in particular is increasingly becoming a cost risk,” says its federal director Florian Becker.
Savings are possible almost everywhere: according to the Heizspiegel, about 90 per cent of households can still cut costs, by roughly €465 a year per flat on average. Heating and airing correctly and using less hot water can save up to 10 per cent.
Sources: co2online (Heizspiegel 2026), Deutscher Mieterbund, Berliner MieterGemeinschaft
