Heating and airing

Last checked: 18.10.2026

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How warm each room should be, how to air properly and avoid mould: save heating energy in your Berlin flat without feeling cold.

When it comes to housing, heat is the biggest item: according to the German Environment Agency (Umweltbundesamt, UBA), private households in Germany use around two thirds of their energy to heat rooms (as of 2024) [3]. In a rented flat in Berlin, you may not decide about the boiler in the basement – but you do decide how warm each room is and how you air it. Both save energy and protect against mould.

The right temperature for every room

The German Environment Agency recommends no more than 20 °C in living areas if possible, as long as it feels comfortable, 18 °C in the kitchen and 17 °C in the bedroom [1]. Every degree less saves heating energy [1]. If you are away for a few hours or asleep, about 18 °C is enough, and 15 °C if you are away for a few days [1].

But too cold is not good either: bedrooms should not drop below 16 °C if possible when the window is not open at night, and even rooms that are rarely used need some warmth [2].

Thermostat and radiators

The thermostatic valve keeps the room temperature constant; the middle setting – usually 3 – corresponds to about 20 °C [1]. Programmable thermostats lower the temperature at set times and can save around ten per cent of energy [1]; whether you are allowed to replace them in a rented flat is something to clarify with the property management beforehand.

Don't block radiators with furniture or cover them with curtains – otherwise the room may never reach the desired temperature [2]. If a radiator gurgles, it needs bleeding [1]; in a rented flat, report this to the property management if you can't do it yourself.

Airing properly

In a four-person household, breathing, showering, cooking and washing release about twelve litres of water into the air every day [1]. So: open the windows wide several times a day for a short, intensive burst of airing (Stoßlüften), ideally with a cross-draught through windows on opposite sides – in winter five to ten minutes are enough [1]. Turn the radiators off while you do so [1]. Windows left permanently tilted open achieve little and encourage mould around the window frames [1]. Always air the room when steam is produced: after cooking, after showering and when drying laundry [1]. A hygrometer shows you the humidity; in uninsulated or poorly insulated flats, it should generally stay below 50 per cent in winter [1]. Don't “heat” cool rooms with warm air from the other rooms – doing so carries moisture into them [2].

Stop draughts

A lot of energy is lost through leaky windows and doors; gaps can be sealed with foam sealing tape or rubber seals [1]. Take care with gas heaters that serve a single flat (Gasetagenheizung): many draw their combustion air directly from the room – check with the chimney sweep (Schornsteinfeger) or a heating contractor beforehand which kind of sealing is possible [1].

If your heating costs are still high

How to check your heating bill and what rights you have as a tenant is explained in the guide “Lowering heating costs in a rented flat”; for a new heating system in the building, “Replacing a heating system” will help. You will find independent energy advice in Berlin in the area “Housing and energy”.

Places and events

Energy advice for tenantsHousing and energy · 13 services

GuideLowering heating costs in a rented flat

GuideReplacing a heating system