Your boiler, thermostat, timer and radiator controls each have a different job. Using them together can keep your home comfortable without heating it more than necessary.
Know Your Controls
A typical gas central-heating system may have:
- a boiler
- a room thermostat
- a timer or programmer
- thermostatic radiator valves (TRVs)
- boiler temperature controls
Some homes also have smart controls or separate heating zones.
First, find out which controls you have and what each one does.
What Does the Timer Do?
Your timer or programmer controls when the heating operates.
So, set it around when you normally need your home warm.
For example, you might want heating:
Morning → before and while you get ready
Daytime → only if somebody is home and needs it
Evening → while rooms are occupied
Your own schedule will be different.
The important point is to avoid routinely heating the home for long periods when nobody needs it.
Also, check the timer after the clocks change or after a power cut if your control does not update automatically.
What Does the Thermostat Do?
The room thermostat controls temperature.
You choose the temperature you want. Then, the heating responds according to the room temperature and how the system is designed.
Turning the thermostat much higher does not normally make the home heat up faster.
Instead, it asks the heating system to keep going until the room reaches a higher temperature.
So, choose a temperature that keeps you comfortable rather than automatically turning the thermostat to maximum.
Find a Comfortable Temperature
There is no need to make every home or every room exactly the same temperature.
Your needs can depend on:
- who lives in the home
- age and health
- the room
- activity
- clothing
- the weather
- how the property holds heat
So, use your thermostat to find a suitable comfortable temperature.
Then, make small changes rather than constantly moving between very high and very low settings.
Should You Leave Heating On All Day?
Not necessarily.
Your home loses heat while it is warmer than outside.
So, keeping an empty home warm all day can mean replacing heat that continues to escape.
Instead, use your timer and thermostat to match heating to when you need it.
However, every home is different. Some take much longer to warm up than others.
So, adjust the schedule to suit your property rather than following a fixed rule.
Don’t Start Heating Too Early
Heating needs some time to warm your home.
However, that does not mean it needs to start hours before you get up or return home.
Experiment with the start time.
If the home is already comfortably warm long before you need it, try starting the heating a little later.
Likewise, if it is still cold when you need it, start slightly earlier.
The aim is:
Comfortable when needed — not hot long before.
What Do TRVs Do?
Thermostatic radiator valves, or TRVs, help control individual rooms.
They are normally fitted to radiators.
As the air around the valve approaches the selected temperature, the TRV reduces the flow of hot water through the radiator.
So, a TRV can help prevent a room becoming warmer than needed.
Use Different Rooms Differently
Not every room needs the same amount of heat.
For example, you may want:
Living room → warmer while occupied
Bedroom → cooler
Spare room → lower heating when rarely used
TRVs can help you do this.
However, avoid allowing parts of the home to become excessively cold where that could contribute to damp or condensation.
Don’t Use the TRV Like an On/Off Switch
A high TRV setting does not normally make a radiator heat the room faster.
Instead, it allows the room to reach a higher temperature before the valve reduces the flow.
So, choose a suitable setting and let the valve do its job.
Also, avoid covering the TRV with curtains or furniture where this prevents it from sensing the room temperature properly.
What Does Boiler Flow Temperature Mean?
If you have a boiler and radiators, the boiler heats water and sends it around the heating system.
The temperature of this water is called the flow temperature.
This is different from your room thermostat.
So:
Room thermostat → desired room temperature
Boiler flow temperature → temperature of water sent around the heating system
They perform different jobs.
Can You Lower Flow Temperature?
Modern condensing boilers can often operate more efficiently when the heating-water temperature is lower.
However, the best setting depends on the heating system and the home.
If the flow temperature is too low, your radiators may not provide enough heat during colder weather.
So, don’t simply copy somebody else’s setting.
Instead, follow suitable guidance for your boiler and system.
Also, be careful not to confuse central-heating flow temperature with stored hot-water temperature.
They are not the same thing.
Learn more: Your Hot Water System →
Combi Boilers
If you have a combi boiler, you may have separate controls for:
- radiator heating
- hot water
So, reducing the radiator flow temperature does not necessarily mean reducing the temperature of the water from your taps.
However, boiler controls vary.
Therefore, check the instructions for your model before changing settings you do not understand.
Boilers With Hot-Water Cylinders
If your boiler heats a hot-water cylinder, be more careful.
The system needs to provide suitable temperatures for stored hot water as well as space heating.
So, advice intended for a combi boiler should not automatically be applied to a boiler-and-cylinder system.
If you are unsure which system you have:
Learn more: Your Hot Water System →
What Is Boiler Pressure?
Many sealed central-heating systems have a pressure gauge.
This shows the pressure of the water inside the heating circuit.
If the pressure becomes too low or too high, the boiler may not work properly.
However, the correct pressure depends on the boiler and system.
So, use the maker’s instructions rather than relying on one figure for every boiler.
Learn more: Boiler Pressure and Radiators →
What If a Radiator Is Cold?
One cold radiator does not automatically mean the boiler is faulty.
Possible reasons include:
- the TRV setting
- a closed valve
- air in the radiator
- system balancing
- circulation problems
- another heating-system fault
First, check the normal user controls.
Then, if the problem remains, investigate the radiator rather than repeatedly changing the boiler settings.
Learn more: Boiler Pressure and Radiators →
What About Smart Controls?
Smart thermostats can make heating easier to schedule and control.
Depending on the system, they may offer:
- phone control
- heating schedules
- separate zones
- occupancy features
- energy information
However, a smart thermostat does not save energy simply because it is smart.
The benefit comes from using the extra control to avoid unnecessary heating.
So, don’t replace working controls just because a newer product has more features.
Ask whether those features would actually help you control your heating better.
Check Your Settings as Seasons Change
A schedule that works in January may make little sense in April.
So, review your heating as the weather changes.
You may be able to:
- shorten heating periods
- start heating later
- stop it earlier
- reduce heating in some rooms
- turn space heating off when it is no longer needed
Small adjustments can prevent an old winter schedule continuing long after the weather has changed.
Five Controls to Check
If you want to improve the way your heating works, start with these:
- Timer — when does the heating run?
- Thermostat — what room temperature are you asking for?
- TRVs — which rooms are you heating?
- Flow temperature — how hot is the heating water?
- Hot-water controls — are they separate from the heating?
You do not need to change everything.
First, understand what each control does.
Then, change only what needs changing.
Key Points
The timer controls when you heat.
The thermostat controls how warm the home becomes.
TRVs help control individual rooms.
Meanwhile, boiler flow temperature affects the water circulating through the heating system.
So, use each control for its intended job.
Most importantly, don’t turn everything to maximum and hope for the best.
Set the heating around when, where and how much warmth you actually need.
Important Information
Energility provides general information to help you understand energy, household and business costs, services and ways to save money. It is not financial, legal, tax, technical or professional advice.
Prices, tariffs, grants, government schemes, regulations and other information can change. Costs, savings and calculator results are estimates and your actual results may be different.
Before making an important financial decision, signing a contract or carrying out significant work, check the latest information and consider getting advice from a suitably qualified professional where needed.
Energility may receive a commission or other benefit from some links or services. Where this applies, we aim to make it clear. This does not increase the price you pay unless stated otherwise.
Next: Boiler Pressure and Radiators →
Energility
Learn. Compare. Save.