Thermostat mistakes to avoid this winter to cut your heating bill

Energy tariffs keep swinging up and down, the weather is increasingly unpredictable, and that little plastic box on the wall quietly controls hundreds of pounds’ worth of heating each year. Used properly, it can take a sizeable bite out of your costs. Used poorly, it drains money hour after hour.

Why your thermostat habits matter more this winter

In both the UK and the US, energy suppliers continue to point out that space heating is typically the largest part of household energy use. Even so, many of us still lean on “common sense” tips picked up from family, neighbours, or online posts - and plenty of that advice is simply inaccurate.

Unnecessary degrees on the thermostat rarely feel warmer, but they always cost more.

Most heating systems respond in a steady, predictable way. They do not race to warm the house just because you spin the dial to its highest number. They also respond to the home itself - insulation levels, draughts, solar gain, and even furniture placement such as where the sofa sits. When you treat the thermostat like a volume control, you often get higher bills rather than better comfort.

Thermostat mistake 1: Cranking it up to heat the house faster

A very common misconception this winter is that a higher thermostat setting makes your home warm up sooner. It doesn’t. The thermostat sets a target temperature for your boiler or heat pump - it is not a “faster/slower” control.

If you’re comfortable at 20°C (68°F) but set 25°C (77°F), the heating generally runs at the same output, just for longer. You’re more likely to overshoot, the rooms can feel stuffy, and you end up paying for heat you didn’t actually need.

Set the temperature you actually want. Not the temperature you think will “kick-start” the system.

The main caveat is very old thermostats that are badly calibrated and tend to undershoot. Even then, a small nudge usually works better than a large jump.

Thermostat mistake 2: Keeping a fixed temperature all day

Keeping one temperature from morning until night may feel straightforward, but it often wastes money unnecessarily. If the house is empty for long stretches, there’s rarely any point heating every room as though someone is sitting in it.

In a decently insulated property, letting the temperature drop by a few degrees while you’re out or asleep typically pays off. Homes cool gradually, and bringing a slightly cooler space back up later is often cheaper than maintaining a higher set point all day.

When constant temperature can make sense

There are situations where a near-constant temperature is more sensible. Some buildings - for example, older stone properties with very thick walls, or homes with underfloor heating and heat pumps - change temperature more slowly. In these cases, large setbacks can be unhelpful because the system then has difficulty “catching up”.

For those homes, smaller changes - about 1 to 2°C - can be more effective than big overnight or daytime drops. If you’re uncertain, pay attention to how quickly the house cools and how long it takes to warm again.

Thermostat mistake 3: Turning the heating off completely when you leave

At the opposite extreme, some people turn the heating off the second they go out, hoping to “beat” the bill. In genuinely cold winter weather, that approach can backfire.

If a property falls to a very low temperature, it can take far longer to reheat. Your system may run flat out - sometimes for hours - just to restore rooms to a liveable level. That spike in demand can swallow a lot of the savings you expected.

There can be knock-on effects as well. Cold spaces with little air movement are more prone to condensation on walls and windows. Over time, that moisture can encourage mould, spoil paint finishes, and even affect parts of the structure.

Instead of “on or off”, think “warmer when you are there, cooler when you are not”.

A modest setback - roughly 3 to 4°C lower while you sleep or when you’re at work - usually offers a better compromise between saving money, staying comfortable, and protecting the building.

Thermostat mistake 4: Putting the thermostat in the wrong place

Even the best thermostat will give poor results if it’s sited badly. Many are still placed in hallways near a front door, radiator, or window simply because that was easiest for an installer decades ago.

If the device is warmed by direct sunshine, influenced by a nearby heat source, or chilled by a draught, it will misread the home’s true temperature. The result is predictable: the heating switches off too early or runs longer than it should.

Where a thermostat should go

• On an internal wall and out of direct sunlight.
• Well away from radiators, fireplaces, and heat-producing appliances.
• Roughly 1.2–1.5 m (4–5 ft) above the floor, in the area where people actually spend time.
• Not tucked behind curtains, furniture, or bookcases that restrict airflow.

A placement-related error of 1–2°C may seem minor, but over the course of a full winter it can show up clearly in what you pay.

Thermostat mistake 5: Ignoring smart features you already paid for

“Smart” thermostats are now common in millions of homes, yet many people use them as little more than expensive on/off switches. The features that often justify the cost can remain untouched.

Programming schedules and using presence detection usually brings more savings than constantly fiddling with the dial by hand.

Smart features that genuinely help

Feature	What it does	Benefit in winter
Scheduling	Sets different temperatures for day, night and weekends.	Prevents overheating while you sleep or work.
Geolocation / presence	Adjusts heat when everyone leaves or comes home.	Reduces waste during unexpected absences.
Learning algorithms	Observes your routines and adapts automatically.	Gradually fine-tunes comfort and consumption.
Consumption tracking	Shows how much energy each setting uses.	Makes the cost of each extra degree visible.

Even simple scheduling - cooler overnight and warmer in the early evening - can noticeably reduce heating use without making the house feel chilly.

Thermostat mistake 6: Treating every room the same

Different rooms have different needs. A lounge where people sit for long periods generally needs more warmth than a hallway, landing, or a spare room used a handful of times each month.

As a broad guide, many energy agencies recommend around 19–20°C (66–68°F) for main living areas and 16–18°C (61–64°F) for bedrooms. Bathrooms may be slightly warmer while in use, particularly for young children or older adults who tend to feel the cold more.

Thermostatic radiator valves, zoning, or separate thermostats make it easier to tailor temperatures room by room. Even something as basic as keeping the door shut on a cooler bedroom can help the rest of the home stay at the intended level.

Good practices that turn your thermostat into a savings tool

Reliable savings usually come from small, repeatable habits rather than occasional dramatic changes. This winter, a few tactics consistently stand out.

• Dial down slightly: Dropping your set point by 1°C can reduce heating use by roughly 5–7% over the season.
• Set realistic comfort bands: Keep living spaces around 19–20°C, and choose a jumper or blanket rather than pushing to 23–24°C.
• Use time blocks: Warmer at breakfast time and in the evening, cooler overnight and during working hours outside the home.
• Combine with insulation: Draught-proofing around doors and windows means the thermostat calls for less heat to achieve the same comfort.
• Service the system: A well-maintained boiler, warm-air furnace or heat pump runs more efficiently and spreads heat more evenly.

The thermostat is only one part of the picture; insulation, habits and heating maintenance quietly shape the final bill.

How much money can a well‑managed thermostat actually save?

The exact figure varies with your home’s size, current energy prices, and whether you use a boiler, heat pump, or something else. Even so, guidance from utilities and energy agencies tends to show the same general scale.

In a typical medium-sized home, reducing the thermostat by 1–2°C over the heating season can amount to the equivalent of a few hundred pounds or dollars. Adding scheduled settings on top can deliver another worthwhile cut, particularly for households that are out for long periods.

The biggest improvements usually appear when several adjustments are combined - sensible target temperatures, smart schedules, better zoning, and straightforward draught-proofing. A useful side benefit is that comfort can improve too, because heating becomes steadier and you avoid the “too hot then too cold” cycle.

Going further: using your thermostat as a planning tool

Beyond day-to-day control, your thermostat can help you learn how your home performs. If you note how quickly rooms cool once heating turns off, you can spot likely insulation gaps or air leaks. A room that loses several degrees within an hour is clearly shedding heat faster than the rest of the property.

That sort of insight can inform future spending: perhaps replacing window seals will deliver more than a boiler upgrade, or maybe topping up loft insulation should happen before changing radiators. Smart thermostats that record temperature trends make this easier, but regular manual checks can still build a useful picture.

Extra strategies to stabilise comfort and bills

Thermostat settings tend to work best alongside a few everyday routines. Drawing curtains at night, keeping internal doors closed between warmer and cooler zones, and bleeding radiators before the coldest weather arrives can all help the system run more smoothly.

Some households also try to “heat the person, not the space”: extra layers, thick socks, sofa throws, or small heated pads used for short periods. Done sensibly, these options can make slightly lower thermostat settings feel perfectly comfortable.

When it’s used with intention, the thermostat stops being a panic-button on icy days and becomes a quiet background controller that keeps comfort and spending aligned through the winter months.