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Leaving the heating on overnight seems wasteful in times when we’re trying to save electricity. If your heating runs all night, there are a few drawbacks.
That’s why you should switch off the heating overnight rather than leave it on
To ensure you get the best possible night’s sleep, the room temperature should be between 16 and 18 degrees Celsius. This means you definitely need to turn the heating down at night compared to during the day. Leaving the heating on full blast overnight therefore makes little sense. Experts such as Andreas Luczak, Professor of Sustainable Energy Technologies at Kiel University of Applied Sciences, even advise switching the heating off completely overnight.
- Firstly, bear in mind: The energy requirements of your living spaces depend on the temperature difference between indoors and outdoors.
- You’ll save energy as soon as you lower the temperature inside your home. Whether you simply reduce the heating output or switch it off completely doesn’t matter at first. However, if you switch your heating off completely overnight, you’ll achieve a greater and faster drop in temperature. This leads to greater energy savings – lower heating output means greater savings.
- The common belief that you then have to use more energy the following morning to reheat the rooms is fundamentally correct. However, Luczak says: “This additional requirement is smaller than the heating energy saved whilst the system is switched off.” This means that even if you have to use more energy in the morning to bring your rooms up to temperature, you will have saved enough during the night.
- Concerns about mould growth when the temperature drops below 16 degrees Celsius are also generally justified. Cool walls and ceilings can cause moisture to condense and seep in. However, you can counteract this process by ventilating properly in winter. “It is more energy-efficient to prevent mould through proper ventilation than by maintaining unnecessarily high room temperatures,” says Luczak.
Night-time temperature reduction: should you leave the heating on overnight in some cases?
- A night-time temperature reduction is advisable if you do not wish to switch off your heating completely at night. The energy savings depend on factors such as the building’s insulation, the masonry and the outside temperature.
- In a well-insulated home, your rooms can retain heat for quite a long time. If the temperature is lowered, it takes longer for the rooms to cool down. The savings here are smaller than in unrenovated buildings, but they are still significant.
- If you live in an unrenovated old building or if your home is simply poorly insulated, turning the heating down at night makes even more sense. These types of buildings cool down quickly, but can be warmed up again just as quickly. You will certainly save money if you reduce the temperature overnight. If you switch off your heating completely, the energy savings here are greatest.
- Even with underfloor heating systems and heat pumps, lowering the temperature at night leads to significant energy savings, as the same principle applies here: the additional energy required to heat the room up again in the morning is less than the energy saved whilst the system is switched off.
- In the case of milder night-time outdoor temperatures, you can also make use of night-time temperature reduction or night-time shutdown. A modest saving effect remains.
