How much can heating controls save?

The important qualifier is the starting point. Those headline figures describe a home that had no controls at all, not a home with a thermostat that is simply being used badly. Where controls already exist, the saving comes from the setting rather than the hardware: turning the thermostat down by one degree Celsius is put at as much as 10 per cent off heating bills⁴, and turning down radiators in unused rooms at around £50 a year⁵.

What follows is what the published figures cover, where they come from, what a full set actually consists of, and how far controls take a household towards energy independence, which is to say not very far on their own.

£110 a year: the headline figure and what it assumes

The £110 figure comes from Cadent Gas and applies to installing and using a full set of heating controls where the system previously had no controls¹. That condition does most of the work. A household with a programmer, a room thermostat and thermostatic radiator valves is not starting from the position the figure describes, and cannot expect to bank £110 by adding a smart display to what is already there.

The Energy Saving Trust gives the same measure as £100 a year in Great Britain and £110 in Northern Ireland². Its separate guidance on EPC ratings states that using heating controls will help the average semi-detached house save £100 each year in GB and £110 in NI, which ties the figure to a house type as well as a nation⁷. The Northern Ireland figure is higher, and the difference is not explained in the published material; it is simply the number given for that jurisdiction.

Confused.com quotes a smart thermostat and controls package at up to £110 a year³, which lands on the same number by a different route. These are estimates for typical homes, not guarantees, and they assume the controls are actually used rather than installed and left on a default schedule.

Savings as a percentage: up to 20%, and the 40% claim examined

Percentage claims for controls are where the numbers get loose, and it is worth separating what each one measures.

Turning the thermostat down by one degree Celsius is put at as much as 10 per cent off heating bills by NI Direct⁴, and at up to 10 per cent by its companion energy efficiency page⁸. East Herts Council gives a higher figure for the same action, stating that reducing the thermostat by 1 degree could save up to 25 per cent of heating bills and associated carbon⁹. The two figures disagree and are not reconciled: the 10 per cent figure appears in two separate official sources, the 25 per cent in one.

A 40 per cent reduction from controls alone is not supported by any figure here. The largest percentage in the material belongs to a different measure entirely: heat pumps, where fuel bills can be reduced by a massive 50 per cent¹⁰. That is a change of heat source, not a control upgrade, and it is not comparable.

Ofgem's load control consumer protection guidance gives worked examples for electric heating in a large house on high usage, around £300 a month, showing a 2 per cent heating bill saving and £6 a month at low control, 4 per cent and £12 at medium, and 6 per cent and £18 at high¹¹. Those are smaller than the thermostat figures because they describe load control rather than temperature reduction, and they show how much the answer depends on what is being controlled and what fuel is being used.

What a full set of controls means, and why the starting point matters

A full set is not one device. It is a programmer or timer, a room thermostat, thermostatic radiator valves on the radiators, and increasingly zoning that allows different areas to run to different schedules. Ofgem's ECO4 guidance describes time and temperature zone controls as enabling independent programming of temperature and heating times in at least two different areas or zones of a premises¹². That is the formal definition of what most people mean by zoning.

The starting point matters because each element adds a different kind of saving. A timer stops the heating running when nobody is home. A room thermostat caps the temperature. Thermostatic radiator valves stop individual rooms overheating. Zoning does the same at the level of a floor or wing. Age UK's guidance explains that an all day or once setting means the heating will switch on at the first On setting programmed and then stay on until the last Off setting of the day, which is the behaviour a better schedule is meant to avoid¹³.

The Energy Saving Trust makes a sequencing point that bears on this page directly: it is important to get heating controls right before trying to change the flow temperature¹⁴. Controls are the prerequisite for the other settings, not an alternative to them.

Smart controls and the £75 figure: how the estimates differ

Smart thermostat savings are quoted across a wide band, and the differences are worth setting out plainly.

The Energy Saving Trust estimate cited by the CPA is around £75 per year with a smart thermostat¹⁷. Confused.com quotes up to £110 a year for a smart thermostat and controls package³. Nesta puts a customer's outlay for a smart thermostat at as little as £100¹⁸. Which? gives around £100 to £250 for a smart thermostat⁶, and Uswitch gives £100 to £200 for most smart thermostats, noting that add-ons such as installation push the total higher¹⁹.

The gap between £75 and £110 is not explained by the sources, and both are estimates for typical use. Smart Energy GB is direct about the limits: a smart thermostat could save money, but savings aren't guaranteed²⁰. It lists the variables as the home, heating habits, existing controls, energy prices and how the thermostat's features are used²⁰.

There is also a maker claim in circulation. Uswitch reports that tado° thermostats, according to the manufacturer, can help users save up to 31 per cent on energy bills¹⁹. That is a manufacturer's figure for its own product, not an independent measurement, and it sits well above the £75 to £110 cash estimates.

Where the savings actually come from

The cash comes from three places: less time running, lower temperature, and fewer rooms heated.

Less time running is the timer and the schedule. Lower temperature is the thermostat setting, and the one degree reduction is the single most repeated figure in the material, at as much as 10 per cent⁴ or up to 25 per cent⁹ depending on the source. Fewer rooms heated is the radiator valve and the zone, at around £50 a year for turning down radiators in rooms not in use⁵.

BEAMA's work on control upgrades sets out the technical basis. Its savings estimates for thermostatic radiator valves, load compensation and weather compensation are based on tests, with details published on the BEAMA website²¹, and it references the temperature control classes I, IV, V and VI described there²¹. Its fuel bill savings work draws gas prices from Ofgem²². That matters because it means the savings figures move with the price of gas, not only with the hardware.

For comparison, mechanical ventilation with heat recovery is put at reducing household heating costs by 10 to 30 per cent²³, and solar assisted heat pump savings depend on how much hot water is used and what system currently heats it²⁴. Both are larger measures with larger costs, and both show that controls sit at the small, cheap end of the range.

Controls as part of household energy independence

Controls give a household command over when heat is produced and how warm each room gets. Home Energy Scotland states that heating controls help control when the heating system operates and the temperature in each room²⁵. The Energy Saving Trust advises learning how to control the heating in the house²⁶, and notes that smart heating controls automatically optimise heating settings to save money and energy²⁷. Planning guidance for self-build homes goes further, recommending smart systems that control lighting, heating and cooling based on occupancy and time of day²⁸.

What that buys is real but bounded. A household with good controls decides its own schedule and its own temperatures, and can cut the waste that comes from heating an empty house or an unused room. It cannot decide the price of the gas, the carbon intensity of the electricity, or whether the boiler itself is efficient. The £100 to £110 figures are savings against a bill set by others.

The dependence that remains is the fuel and the grid. A hybrid heating system still uses a smart controller like a thermostat to set the temperature²⁹, and a heat pump installation still draws on the same controls logic. Controls are the layer that makes every other measure work properly, which is why the Energy Saving Trust puts them before flow temperature changes¹⁴, and why they belong early in a plan rather than at the end. For the wider sequence, see where to start energy improvements and payback periods compared.

Compatibility, meters and what to check before buying

Controls are made for particular systems. Ideal Heating states that it provides thermostats, timers and accessories for the full range of Ideal boilers and heat pumps³⁰, which is a maker's compatibility claim for its own products and says nothing about other makes. For any other boiler, whether it accepts weather compensation or load compensation, and how zoning is wired, are installer questions.

A smart meter is not required. The Energy Saving Trust states that smart meters are different to smart heating controls and that one can be used without the other²⁷. The Welsh Government adds that while the two are independent, combining them can enhance the ability to manage a home's heating and energy use remotely³¹. A smart meter measures and reports consumption; a smart thermostat schedules and sets temperature. They are separate purchases that happen to work well together.

On funding, the picture differs by nation. Home Energy Scotland lists heating controls at £150 as a loan and £450 as a grant as a secondary improvement¹⁵. Cornwall Council's eligible works for home improvement loans include cylinder thermostats, heating controls for wet central heating or warm air systems, and zoning controls³². Legislation lists hot water system controls among energy-saving materials³³. For the general route into grants, see finding grants before you start.