A central heating thermostat is the main “decision-maker” for your boiler. It senses the temperature in your home and tells the boiler when to turn on or off to maintain your chosen setting. Used properly, it prevents overheating, reduces wasted gas, and keeps rooms consistently comfortable.
Upgrading from a basic manual control to a programmable thermostat — or using one correctly — typically cuts heating bills by 10–15%. For an average UK home, that’s around £80–£150 per year, without changing the boiler itself.
Why Thermostats Make Such a Big Difference
The biggest energy waste in UK homes isn’t cold rooms — it’s heating rooms more than needed, for longer than needed. A thermostat fixes that by matching heat output to real demand.
Energy Savings
Lowering the temperature when you’re asleep or out is where savings stack up. As a rule of thumb, reducing the thermostat by 1°C can cut gas use by around 10%. Modern thermostats also hold temperatures much more tightly, avoiding the wide swings common with older manual dials.
Comfort
Instead of rooms cycling between too hot and too cold, a thermostat maintains steady warmth. Programmable models can also pre-warm the house before you get home, so comfort improves even as energy use drops.
Convenience
Once set up, there’s no need for daily adjustments. Combined with radiator valves, you can fine-tune rooms — for example, keeping bedrooms cooler while living areas stay warmer.
Health and Safety
Most thermostats include frost protection, keeping temperatures above 5–7°C to protect pipes. They also help avoid prolonged cold conditions linked to damp and mould, which tend to develop when rooms stay below 14–18°C.
Where Your Thermostat Should Be Placed
Placement matters more than many people realise.
The best location is usually a hallway or living room, mounted on an internal wall:
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Away from radiators or direct sunlight
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Not near draughts or doors
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With free airflow around it
A poorly positioned thermostat can cause the boiler to run longer than needed or shut off too early.
How to Use a Central Heating Thermostat (Step by Step)
Power and Mode
Ensure the thermostat is switched on and set to heating mode. Some models also have an “off” or “manual” setting — avoid leaving it there by mistake.
Set the Temperature
Start with 18–20°C for living areas. When the room temperature drops below this, the thermostat signals the boiler to fire. Once the set temperature is reached, the boiler switches off automatically.
Use Programme Mode (If Available)
Programmable thermostats allow multiple on/off periods each day. Typical setups use:
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A morning heating period
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An evening heating period
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Lower temperatures in between
Confirm each setting so the schedule runs automatically.
Boost or Override
Temporary changes let you raise or lower the temperature for a short time. The system then reverts back to the schedule, preventing accidental all-day heating.
Frost Mode
The * symbol or frost setting keeps the property protected when unoccupied, usually maintaining 5–7°C.
Quick Test
Set the thermostat to 20°C and listen for the boiler firing. When the room reaches temperature, the boiler should shut down smoothly. Pairing the thermostat with a programmer ensures heating only runs within chosen time blocks.
Example Heating Schedule: 9–5 Office Workers
The goal here is simple: heat only when you’re home, with short warm-up periods and gentle setbacks.
This approach usually limits heating to 4–6 hours per day and can save £100+ per year compared to constant heating.
| Time | Weekday Temp | Weekend Temp | Why It Works |
|---|---|---|---|
| 6:30–8:30 | 20°C | 20°C | Morning warm-up |
| 8:30–5:00 | 15°C | 19°C | Away / light use |
| 5:00–10:00 | 21°C | 21°C | Evening comfort |
| 10:00–6:30 | 16°C | 16°C | Night setback |
Example Heating Schedule: Working From Home
When you’re home all day, comfort matters — but constant high temperatures aren’t necessary.
This schedule provides background warmth with short peaks, typically saving £50–£100 per year versus running at a fixed temperature.
| Time | Temperature | Reason |
|---|---|---|
| 6:30–8:00 | 19°C | Morning routine |
| 8:00–5:00 | 18–19°C | Low-activity work hours |
| 5:00–10:00 | 20–21°C | Evening use |
| 10:00–6:30 | 16°C | Overnight setback |
Fine-Tuning for Better Results
Small tweaks make a big difference:
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Adjust settings by ±1°C based on insulation and weather
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Use radiator valves to balance rooms (living rooms warmer, bedrooms cooler)
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Keep doors closed to prevent heat drifting into unused spaces
Smart thermostats can automate some of this using geolocation, but even basic programmable models deliver strong savings when used well.
The Boilers2Go Takeaway
A thermostat isn’t just a switch — it’s the control centre for your entire heating system.
Set correctly, it reduces waste, improves comfort, and protects your home, all without touching the boiler itself. Whether you use a simple programmable stat or a smart upgrade later, how you schedule and set temperatures matters more than the brand on the wall.
If your heating feels inefficient or unpredictable, reviewing thermostat settings is often the fastest win.
I’m Penny North, a home energy heating expert. My mission is to demystify new boilers and complex heating systems to help you achieve a warm, cosy home with lower energy bills and a smaller environmental footprint.