Getting the most from your heating controls

Most homes with central heating have a few dials and switches that decide when the heating runs and how warm it gets. Set well, they keep a home comfortable without heating rooms that nobody is using.

This page explains what each control does and what smart controls add. It draws on guidance from the Energy Saving Trust and the NHS, and covers boilers that run on gas, oil or LPG.

The basic set of controls

The Energy Saving Trust says a boiler central heating system should have at least three kinds of control.

A home with a hot water cylinder should also have a cylinder thermostat. A programmer for a combi boiler usually has one channel, for heating only. Two or three channels let a system time its hot water, or heat upstairs and downstairs separately.

Choosing a comfortable temperature

The Energy Saving Trust suggests setting the room thermostat to the lowest temperature that feels comfortable. For most people that is between 18°C and 21°C. The NHS suggests heating the rooms you use most, such as the living room and bedroom, to at least 18°C if you can.

The house warms to the set temperature whatever the weather outside. On a cold day it may simply take longer. So in winter it helps to set the heating to come on a little earlier, rather than turning the thermostat up.

Many programmable thermostats also have a setback temperature for nights and time away. The Energy Saving Trust gives 12°C to 15°C as an example. It says households with an older person, someone vulnerable to the cold, or someone at home all day may need a higher minimum. Comfort and health come first.

Room by room with radiator valves

A thermostatic radiator valve senses the air around it. As the room warms up, it lets less hot water into the radiator. The numbers on the dial mean different temperatures on different models, so a middle setting is a good place to start.

The Energy Saving Trust suggests keeping some background heat in rooms used less often, to help with condensation and mould. It also says radiator covers can trap warm air around the valve, so the room ends up cooler than intended.

What smart controls add

Smart controls do everything ordinary controls do, and they connect to the internet. People can change the heating from a phone while they are out. Some controls learn a household's habits. Some can use a phone's location to turn the heating down when everyone has left, and these features can be switched off.

Programmable radiator valves can link to a smart system, so each room becomes its own zone. Whether smart controls save money depends on how the heating is run now. The Energy Saving Trust notes that a learning thermostat can also warm a home earlier, which adds comfort but can use more energy.

Flow temperature and compensation

The boiler's own thermostat sets the flow temperature, which is how hot the water is when it goes to the radiators. If it is set higher than needed, turning it down can help the boiler run more efficiently. Set too low, the radiators may not warm the home on cold days.

With a hot water cylinder, the Energy Saving Trust says the flow temperature should be no lower than 65°C. That lets the cylinder reach 60°C, which helps to stop bacteria growing. Weather compensation and load compensation adjust the flow temperature automatically. The Energy Saving Trust says a smart thermostat is probably the easiest way to add compensation to an existing system.

Getting controls fitted

For a particular model, ask the installer or check the maker's manual. The Energy Saving Trust suggests quotes from at least three installers. It suggests looking for a TrustMark scheme member, registered with Gas Safe Register for a gas boiler or with OFTEC for an oil boiler.

Useful links