Use Your Thermostat Properly and Cut Heating Costs

The small control box on the wall can determine whether you need a thick jumper in January – or only feel a chill when you see your heating bill. Using your thermostat incorrectly means literally burning money. The positive news is that a few straightforward changes can substantially reduce consumption without turning your home into an icebox.

Turning the thermostat up to heat faster is an expensive misconception

During winter, many people instinctively set the temperature much higher in the belief that the home will warm up more quickly. It sounds plausible, but it is simply untrue.

A thermostat controls the target temperature rather than the speed of the heating system. Whether you select 20 or 25 degrees, the boiler or heat pump runs at the same output until it reaches the chosen temperature.

“Setting it to 25 degrees when 20 degrees is enough does not heat the room faster – it merely heats for longer and costs considerably more.”

A typical situation is this: it is minus three degrees outside and the home has become cold. Impatiently, many people turn the heating right up, go into the kitchen to make a coffee, forget about it, then later wonder why the room feels oppressively hot. This is precisely how an extra 10 to 20 per cent of energy use can arise, with no benefit at all to comfort.

Keeping the same temperature all day: convenient, but costly

Another common habit is leaving the heating at one constant temperature from morning until evening, regardless of whether anyone is at home. Although convenient, this approach is excessive in most cases.

If the home is empty for hours during the day, the living room does not need to stay at 21 degrees. Reducing the setting by just two or three degrees noticeably lowers heating demand, as less heat escapes through the walls, windows and roof.

Useful guidance for many households:

• during the day when people are at home: around 19–21 degrees in living areas
• during working hours or a longer absence: reduce to roughly 16–18 degrees
• overnight: lower living areas to 16–18 degrees as well

Modern thermostats can make these changes automatically through a timed programme. Anyone who permanently keeps the setting high pays more – often without noticing, because every small “convenience” accumulates over the months.

Switching the heating off completely is not a good solution either

At the other extreme are people who turn their heating off altogether while away or overnight to save as much as possible. It may sound radically efficient, but it creates problems of its own.

When a home cools down too much, the heating system needs more energy later to bring the walls, floors and furniture back up to temperature. Keeping rooms too cold for extended periods also increases the risk of damp and mould.

“A moderate setback is better than switching everything off completely – it protects the building fabric and keeps the indoor climate stable.”

In poorly insulated buildings especially, leaving the heating permanently off can result in clammy walls. The cost of correcting this later can quickly consume the apparent saving.

Incorrect placement: when a thermostat can be fooled

Many thermostats are installed wherever the electrician happened to find an available space, which is not always the ideal location. Yet their position has a major effect on how accurately the device judges the real room temperature.

Common problem areas on the wall

• Directly above a radiator: The thermostat is more likely to measure rising warm air than the air in the rest of the room.
• In sunlight: A single patch of sunshine can raise the detected temperature substantially, causing the heating to switch off too early.
• In a draught or on a cold external wall: The air is measured as cooler there, so the thermostat calls for more heat and the room overheats.

The best location is an internal wall, approximately 1.5 metres above the floor and away from radiators, windows and direct sunlight. Anyone renovating or refurbishing should plan for this position from the outset, as it affects energy use for many years.

A smart thermostat used unintelligently

“Smart” thermostats are appearing in an increasing number of homes, offering a wide range of functions through an app or on the unit itself. However, many people use only the basic “warmer/cooler” setting and therefore miss substantial saving potential.

Making full use of digital thermostat tools

Modern devices can do far more than display a number:

• Weekly programmes: Different temperatures for weekdays, weekends, night-time periods and holidays.
• Occupancy detection: Some models automatically lower the temperature when nobody is home.
• Consumption logs: App-based charts show when the heating works hardest, providing a useful starting point for optimisation.
• Remote control: Warm the home shortly before arriving back using a smartphone, rather than heating it all day.

“Anyone who only sets the target temperature often uses not even half of a connected thermostat’s capabilities.”

Carefully calibrated programming is particularly worthwhile when combined with heat pumps or underfloor heating, as these systems respond slowly and benefit from consistent operating periods.

One temperature for every room? Rarely sensible

The body does not require the same warmth in every room. Applying a single setting throughout the home wastes potential savings.

Practical guideline temperatures include:

• Living room, kitchen and home office: around 19–21 degrees
• Bedroom: 16–18 degrees is usually sufficient; many people sleep better in slightly cooler conditions
• Bathroom: 22–23 degrees feels pleasant for short periods, while the setting can be reduced in between
• Storage areas and hallways: 15–17 degrees is often enough, provided pipes cannot freeze

Individual radiator thermostat valves or zone-based controls make it easy to reflect these differences. Rooms used infrequently offer particularly good savings potential without reducing everyday comfort.

How much can realistically be saved

Even modest adjustments to the target temperature can have a clear effect. Energy studies repeatedly point to a useful rule of thumb: lowering the temperature by one degree saves roughly seven per cent of heating energy, although this naturally depends on the building and heating system.

Measure	Typical saving
Lower the temperature by 1 °C	approx. 5–7 % less heating energy
Use night-time setback consistently	an additional 5–10 % possible
Set up smart timed programmes	up to 15–20 % overall compared with continuous operation

For a detached house with annual heating costs of, for example, €1,500, this can save several hundred euros without anyone having to feel cold.

Even the best thermostat cannot compensate for neglected heating maintenance

The most effective control unit is of little use if the heat generator itself operates inefficiently. An old, poorly adjusted or dirty system consumes energy regardless of how cleverly it is controlled.

This includes:

• regular servicing of the boiler or heat pump
• bleeding radiators so water can circulate freely
• hydraulic balancing to ensure every room receives an even supply
• checking the flow temperature, which can often be reduced slightly

“The thermostat and heating system work as a team: only when both are well matched will the final bill add up.”

How to start with simple thermostat changes

Anyone who does not want to change everything at once can begin gradually. A brief check over a weekend is useful:

• Measure the current temperatures in the most important rooms rather than relying solely on the thermostat scale.
• Check whether the temperature is genuinely reduced during absences in the day and overnight.
• For smart devices, open the app, review the timed programmes and adapt them to daily routines where needed.
• Trial a one-degree reduction and see whether comfort actually changes.

After a few days, many people notice hardly any difference in how their home feels, but do notice one later when they look at the bill. This fine-tuning is especially worthwhile when energy prices are high.

Why mindful use pays off in the long term

A thermostat used well delivers not only lower costs but also steadier room temperatures. Large fluctuations place strain on both the building fabric and personal wellbeing. Consistently heated rooms help prevent stress cracks in walls and reduce the risk of damp corners.

In addition, anyone who saves heating energy automatically lowers their own CO₂ emissions. In many countries, schemes also provide financial support for switching to intelligent control technology. Once configured, most settings run by themselves, with only occasional adjustments needed – for instance when working hours change or when travelling for longer periods.