How do I use my heating controls to save money?

The savings figures are wide because they measure different things. Turning a thermostat down by one degree Celsius could save as much as 10 per cent on heating bills, according to official Northern Ireland guidance². Reducing room temperatures by 1°C is put at up to 10 per cent of the annual fuel bill by the UK and Ireland Fuel Distributors Association³. One local authority puts a 1°C reduction at up to 25 per cent of heating bills and associated carbon⁴. Ofgem's load control guidance models much smaller effects for electric heating in a large, high-usage house, at 2 to 6 per cent of the heating bill depending on how much control is applied⁵.

What heating controls do, and why they matter for bills

Heating controls help control when the heating system operates and the temperature in each room⁷. That is the whole mechanism: a boiler or heat pump left to run against no time limit and no room limit heats a house to whatever the radiators can reach, for as long as it is switched on. A programmer sets the hours, a room thermostat sets the target temperature, and thermostatic radiator valves set the ceiling for individual rooms.

The bill effect comes from the overlap between those three. Official guidance notes that using a high efficiency condensing boiler with heating controls could save a substantial amount of money over a year⁸. Low carbon heating could save money on heating bills depending on what system it replaces⁹. Underfloor heating adds its own layer: zoning allows the temperature of individual rooms to be controlled, and smart, programmable thermostats can keep a home heated on a schedule to help minimise bills¹⁰.

For a household's energy independence, controls are the one lever that works on every heat source. They do not remove dependence on the grid, a gas supplier or imported fuel, and they do not generate anything. What they do is cut the waste that comes from heating an empty house or an unused room, which is the part of the bill a household actually decides.

How much you can save: from 10% to 25%, and why the figures differ

The headline numbers come from different bodies measuring different things, and the gap between them is real rather than a contradiction.

The Ofgem modelling is the most conservative and the most specific: for a large house on electric heating using around £300 a month, low control gives a 2 per cent heating bill saving, £6 a month; medium control 4 per cent, £12 a month; high control 6 per cent, £18 a month⁵. That is a modelled case, not a promise, and it shows how much the answer depends on the fuel, the size of the house and how much control is actually fitted.

The 25 per cent figure is the outlier and the most optimistic. The 10 per cent figures are the ones repeated across official and independent guidance. A household should treat the range as evidence that the direction is reliable and the size is not.

Thermostats, TRVs and programmers: what each control does

Independent guidance sets out the minimum core for a central heating system: a programmer for time control, at least one room thermostat, and thermostatic radiator valves¹¹. A fuller set adds a cylinder thermostat where the system has a hot water cylinder⁷. Cadent describes a full set of heating controls as a programmer, thermostatic radiator valves and a room thermostat¹².

• Programmer or timer: controls when the heating comes on and off¹¹.
• Room thermostat: sets the target temperature for the home or a zone.
• TRVs: give better control over individual room temperatures¹³, and are recommended on individual radiators so the temperature can be adjusted by room usage, turning them down in unused rooms¹⁴.
• Cylinder thermostat: recommended where the system has a hot water cylinder¹⁵.
• Zone controls: heat different rooms at different times of day automatically through separate programmable heating circuits¹¹.

On a heat pump the advice changes shape. Testing of an air source heat pump at Salford Energy House found that trimming scenarios produced space heating energy savings of between 6 and 8 per cent, but the same bulletin states that a whole house setback period should be programmed using the heat pump controller rather than smart TRVs on all radiators⁶. TRVs still balance rooms; they are not the tool for a whole house setback.

Smart controls: what automatic optimisation changes

Smart heating controls are connected to the internet and offer more functionality than conventional controls¹¹. In practice that means remote control: most link to a phone, and heating can be controlled by smartphone, tablet or laptop, or by telling a smart speaker what is wanted¹⁶. They can remotely turn heating on and off and adjust temperature¹⁴, and they automatically optimise heating settings to save money and energy¹⁴.

The more substantive change is compensation. Load and weather compensation adjust the boiler flow temperature to maximise boiler efficiency, and a smart thermostat is probably the easiest way to add compensation to an existing system¹⁶. That is a different mechanism from scheduling: it lowers the temperature the boiler runs at rather than the hours it runs.

Smart controls also pair with other kit. Fitting a smart tank monitor and smart heating controls optimises fuel use and reduces waste¹⁷. Modern storage heaters generally come with improved heating controls, including an automatic charge control, thermostat and programmer, compared with older units¹⁸, and digital electric storage heaters can be given a programmer or timer to set specific times for heating to come on and off¹⁹.

Setting temperatures and schedules to match when you are home

The pattern most guidance converges on is simple: heat the house for the hours it is occupied, and let it fall back when it is not. Set the heating to come on just before getting up and switch off after going to bed, and in very cold weather extend the time rather than turning the thermostat up²². Turning the heating down by one or two degrees when people are over saves money on energy bills²³.

On the off-all-day question, leaving heating on 24/7 typically uses more fuel, and the most energy-efficient approach is to programme the heating system so it comes on when needed most²⁴. For heat pumps, using a setback temperature, a slightly lower setting during off peak hours, can save energy without reducing comfort²⁵.

Zone controls do the room-by-room version of the same thing, heating different rooms at different times of day automatically through separate programmable circuits¹¹. That is where TRVs and zoning overlap: TRVs cap a room, zoning decides when that room's circuit runs at all.

Pairing controls with your heating system, including heat pumps

Controls have to match the heat source, and the requirements differ by system.

Heat pumps can work with radiators or underfloor heating, and some types can work without either⁹. They run on electricity, which is where bill savings can arise²⁶. Official guidance for dwellings calls for weather compensation or internal temperature control, and a timer or programmer for space heating²⁷. Ground source heat pumps can be synced up with smart heating controls to create a system that benefits the household most²⁸, and their controls should allow pre-programming of switch-on and switch-off times, which matters for cheaper electricity on heat pump or time-of-use tariffs²⁹. Heat pumps support automated controls that optimise performance²¹, and can provide both space and water heating, which significantly lowers fuel bills³⁰.

Hybrid systems take a different approach: a hybrid uses intelligent controls to determine the most efficient way to heat a home³¹, and heat pump and hybrid controls can be fitted to different heat sources and boiler types such as regular or combination boilers³².

For storage heaters, the controls are built in: improved heating controls including an automatic charge control, thermostat and programmer¹⁸, with a programmer or timer setting the on and off times¹⁹.

Where controls fall short

Controls reduce waste; they do not change the physics of a poorly insulated home, and they do not make a household independent of the grid, a supplier or a fuel it has to buy. The savings figures above are percentages of a bill that controls can only trim, and the Ofgem modelling shows how modest the effect can be in a large electrically heated house at 2 to 6 per cent⁵.

There is also a limit to how far a thermostat can be turned down before comfort suffers, and the guidance is explicit that in cold weather the answer is more time, not a higher setting²². On heat pumps, the interaction between TRVs and setback matters: whole house setback belongs at the controller, not on every radiator⁶.

What remains is the part a household controls directly: the hours, the room temperatures and the flow temperature. Those are the settings that decide how much of the energy bought is actually used to heat occupied rooms.