How Can We Save?

In an uninsulated building it is generally worth turning the heating down for the time nobody is inside: according to the measurements quoted in the article, a 12-hour break can reduce energy use by 5–10 per cent in a brick house and by 10–15 per cent in a lightweight-structure building. In continuously occupied houses, however, the bigger saving comes not from switching on and off but from thermal insulation.

What did the press release claim?

The article was published by amiotthonunk.hu with data from experts at the insulation manufacturer Knauf Insulation. The title of the original piece cannot be identified; it has been readable on our blog since 2016. The main ideas:

• There is no single right answer. Whether intermittent or constant heating is cheaper is determined together by the structure and thickness of the walls, heat transmission, insulation, the difference between the outside and the desired inside temperature, and the length of the absence.
• With an uninsulated wall, heat escapes continuously. To hold a constant temperature the boiler then has to work almost non-stop – the greater the loss, the more energy it needs.
• Who benefits from turning it down? Primarily offices and properties where only 6–8 hours a day are spent, and which stand empty for 12–16 hours or at weekends. According to the Hungarian statistical office's figure at the time, 266,000 homes were used as offices, surgeries, shops or workshops.
• In an occupied house, insulation is the key. According to the manufacturer, modern thermal insulation 15–20 cm thick can allow savings of 40–50 per cent; according to the company's managing director, with 20 cm of rock wool the heating bill can be at least 40 per cent lower.
• Windows and insulation together. With the two, the building's heat loss can be cut by up to half, and every further centimetre of insulation can bring a 3–4 per cent saving. In an insulated house, therefore, the thermostat does not necessarily have to be set lower either.

The press release put the number of uninsulated family houses in Hungary at about 2.5 million – this is an estimate for the time of publication, not a current figure. The savings ratios come from an insulation manufacturer.

How does intermittent heating work with electric heating?

Turning the heating down brings the most if it covers exactly the time of absence and the room is warm again in time. With room-by-room electric heating you do not have to arrange this by hand:

• A time programme for each room. With a programmable thermostat, weekday absence, night and weekend can be set separately, so the heating switches back by itself.
• Setback, not a complete shutdown. Even for a longer absence it is worth keeping a lower temperature so that the walls and furnishings do not cool through completely and the reheating does not take long.
• The place of installation matters. Heating film mounted on the ceiling or wall warms the surfaces directly, so it is felt quickly; heating built in under a thicker floor covering reacts more slowly, and there it is worth setting the time programme earlier.

The options for control are presented on our thermostat page and in our article on intelligent heating control, and the electricity consumption of heating film on our consumption page. Where the most heat escapes in a family house is covered in our article We could get away with lower energy bills!