Do not turn the thermostat up fully
Setting 5 does not make the room warm faster. The valve just stays open longer until a higher temperature is reached. Set the level you want straight away.
Guide · As of 2026
Saving on heating costs: less gas, same comfort
In most households, heating is the biggest energy cost. Even small changes to temperature, airing and heating settings reduce gas consumption. Here you can find out what really helps, how to compare your consumption with the heating benchmark (Heizspiegel) and what the CO2 price means for you in 2026.
- Room temperature
- Airing
- Hydraulic balancing
- Heizspiegel
- CO2 price
The right room temperature
As a rule of thumb, each degree less reduces heating energy consumption by about 6%. According to co2online, in a 130 m² detached house with gas heating, that is about 1,000 kWh and about €120 a year.
| Room | Recommendation | Thermostat setting (approx.) |
|---|---|---|
| Living room | 19–20 °C | just below 3 |
| Children's room and study | 19–20 °C | just below 3 |
| Kitchen | 19 °C | just below 3 |
| Bathroom | 21 °C | just above 3 |
| Bedroom | 17 °C | just above 2 |
| Hallway | 16 °C | 2 |
Guide values according to co2online. On standard thermostatic valves, setting 3 is about 20 °C. There are usually about 4 °C between two settings.
Heating correctly every day
Open windows wide instead of tilting them
Air your home briefly several times a day with the window wide open (Stoßlüften); co2online recommends three to four times. It is best to open windows on opposite sides. Turn the thermostats down while you do this. Windows that are tilted open all the time cool down the walls and waste heat.
Keep radiators clear
Furniture, long curtains or covers in front of the radiator hold the heat back. The room warms up more slowly, and the thermostat does not control the temperature correctly.
Turn down instead of off
Lower the temperature at night and when you are away. But do not let rooms cool down completely. Cold walls attract moisture, and heating them up again uses a lot of energy.
Programmable thermostats
They lower the temperature automatically at set times, for example at night or when nobody is at home. This is more convenient than adjusting each radiator by hand.
Keep the heat in the room
Close the shutters and curtains in the evening. Keep doors between warm and cool rooms closed.
Having your heating checked and adjusted
These steps mainly concern owners. If you are a tenant, speak to your landlord if radiators do not get properly warm.
- 01
Bleed the radiators
If a radiator gurgles or does not get warm at the top, there is air in the system. Bleed it with a radiator key and then check the water pressure on the heating system.
- 02
Have the heating serviced
Have your heating serviced regularly by a specialist company, ideally before the heating season. Settings such as the heating curve and the pump are also checked.
- 03
Have hydraulic balancing done
In hydraulic balancing (hydraulischer Abgleich), a specialist company sets how much heating water each radiator gets. Then all rooms warm up evenly. The consumer advice centre (Verbraucherzentrale) mentions possible savings of about 15% of heating costs. In individual cases, the savings can be much lower.
- 04
Check the pump and flow temperature
Old, unregulated heating pumps often run harder than necessary. A high-efficiency pump saves electricity. Also have someone check whether the flow temperature (Vorlauftemperatur) can be lowered.
Compare your gas consumption with the Heizspiegel
The Heizspiegel 2026 from co2online shows whether your consumption is low, medium, elevated or too high. Divide the building's annual consumption in kWh by the floor area of the whole building. You can find both values in the heating cost statement (Heizkostenabrechnung).
| Floor area of the building | low | medium | elevated |
|---|---|---|---|
| 80–150 m² | up to 65 | up to 127 | up to 220 |
| 150–250 m² | up to 67 | up to 123 | up to 197 |
| 250–500 m² | up to 64 | up to 120 | up to 194 |
| over 500 m² | up to 60 | up to 119 | up to 188 |
Natural gas, kWh per m² per year, billing year 2025, space heating and hot water. Higher values count as too high. If hot water is heated with an instantaneous water heater (Durchlauferhitzer) or a hot water tank (Boiler), add 24 kWh per m². Source: co2online, Heizspiegel 2026.
What the CO2 price means in 2026
A CO2 price is charged on natural gas, heating oil and other fossil fuels under the Fuel Emissions Trading Act (Brennstoffemissionshandelsgesetz, BEHG). For 2026, there is a price range of €55 to €65 per tonne of CO2. Since 2026, the certificates have been auctioned. The supplier passes the costs on to you through the gas price.
By our calculation, this is about 1.0 to 1.2 ct net per kilowatt hour of gas, or about 1.2 to 1.4 ct with 19% VAT (Umsatzsteuer). This is based on the legal emission factor for natural gas, converted to the kilowatt hours shown on your gas bill (calorific value, Brennwert). The consumer advice centre calculates with 201 g CO2 per kWh of net calorific value (Heizwert) and therefore arrives at slightly higher amounts. With 15,000 kWh a year, the CO2 price comes to about €180 to €210 gross by our calculation.
From 2028, the CO2 price for buildings and transport is to be set by supply and demand in the European emissions trading system. How high it will be then is not yet known.
Every kilowatt hour you save also saves the CO2 price. The less gas you use, the less future price increases will affect you.
For tenants: heating cost statement and CO2 costs
With central heating, the landlord bills the heating costs once a year. 50 to 70% of the costs are divided according to your consumption, and the rest according to floor area. So if you save, your share goes down.
If remotely readable meters or heat cost allocators (Heizkostenverteiler) are installed, the landlord must give you consumption information every month. It shows your consumption in the previous month and comparisons with earlier months. This way you can see early whether your behaviour is having an effect.
Since 2023, the CO2 costs have been divided between tenant and landlord. The worse the building's energy performance, the bigger the landlord's share, up to 95%. With central heating, the landlord must deduct their share in the statement. If this is missing, you may reduce the heating costs by 3%. If you have your own gas contract, for example for gas heating in your own flat (Gasetagenheizung), you must calculate the landlord's share yourself and claim it.
If you have questions about the statement, the Verbraucherzentrale or a tenants' association (Mieterverein) can help. With your own gas contract, you can choose the supplier yourself. If you would like to check your tariff, we compare the tariffs of the suppliers we work with.
Replacing your heating: what applies since July 2026
The Building Energy Act (Gebäudeenergiegesetz, GEG) has been replaced by the Building Modernisation Act (Gebäudemodernisierungsgesetz). The main new rules have applied since 29 July 2026. The requirement that a new heating system must run on at least 65% renewable energy no longer applies. Gas and oil heating systems may still be installed.
If you install a new gas or oil heating system in an existing building, from 2029 you must gradually use a minimum share of climate-friendly fuels, for example biomethane: 10% from 2029, 15% from 2030, 30% from 2035 and 60% from 2040 (the “Bio-Treppe”, or bio staircase). From 2045, heating fuels must be completely climate-neutral. An additional quota for gas suppliers, which will also affect existing heating systems from 2028, is to be set out in a separate law.
If you are planning to replace your heating, get advice first from an energy adviser or a specialist company. Also expect rising CO2 costs and check the current funding.
Checklist for the heating season
- Check the room temperature: living areas 19 to 20 °C, bedroom cooler.
- Set the thermostats to the level you want, not to 5.
- Air your home with windows wide open several times a day, and turn the thermostats down while you do.
- Clear the space around radiators and bleed them if needed.
- Book a service and, if it has not been done yet, hydraulic balancing.
- Compare your gas consumption with the Heizspiegel.
- Write down your meter reading regularly to see changes early.
- Check your monthly instalment (Abschlag) so that you do not face a large back payment with the annual bill.
Frequently asked questions
How much does one degree lower room temperature save?
As a rule of thumb, about 6% of heating energy. According to co2online, in a 130 m² detached house with gas heating, that is about 1,000 kWh and about €120 a year.
Is it cheaper to switch the heating off completely during the day?
Usually not. If rooms cool down a lot, heating them up again uses a lot of energy, and moisture can form on cold walls. It is better to lower the temperature when you are away.
How much does the CO2 price cost me?
For 2026, roughly expect 1.2 to 1.4 ct per kWh of gas including VAT. With 10,000 kWh a year, that is about €120 to €140. The exact amount depends on the certificate price your supplier pays.
How can I tell whether my gas consumption is too high?
Divide the building's annual consumption by the floor area of the whole building and compare the result with the Heizspiegel. If the value is in the “elevated” column or above, it is worth having your heating checked and getting energy advice.
Do I have to replace my gas heating now?
The Building Modernisation Act does not ban gas heating systems that work. However, there may be replacement duties for very old boilers. If in doubt, have this checked by a chimney sweep (Schornsteinfeger) or a specialist company.
Related topics
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Learn moreGas consumption calculator
How much gas does a flat or house of your size need? The calculator estimates the annual consumption using the values of the Heizspiegel 2026 (heating benchmark) and assesses your own consumption.
Open the calculatorGas: m³ to kWh
Your gas meter measures cubic metres, but your bill is calculated in kilowatt hours. With the calorific value (Brennwert) and conversion factor (Zustandszahl) from your bill, you can convert the consumption yourself.
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Learn moreEnergy terms A–Z
Abschlag, Arbeitspreis, MaLo-ID, Netzentgelt or Zustandszahl: the key German terms on electricity and gas bills and in contracts, explained briefly and clearly.
Learn moreSources
- co2online: Heating correctly – the 10 best tips
- co2online: Heizspiegel 2026 (flyer, billing year 2025)
- Verbraucherzentrale: Hydraulic balancing
- Gesetze im Internet: § 10 BEHG (prices 2026)
- Gesetze im Internet: EBeV 2030, Annex 2 (emission factor for natural gas)
- Verbraucherzentrale: How much the CO2 price adds to your heating costs
- Verbraucherzentrale: Checking heating cost statements
- Bundesregierung: The new Building Modernisation Act
Get personal advice
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