That ‘Money Saving’ Radiator Trick Might Actually Raise Your Heating Bill

If you believe that the best way to save money on the bills is to switch off the radiators in rooms, you’re probably wrong! This only makes sense because if the rooms are not used, there is no point in heating them. However, there is growing evidence from heating experts that not only is turning off the radiators not the best solution, but it can have the opposite effect. In fact, it can cause the system to work harder and increase the bills.

To understand the reason behind the above phenomenon, it is important to understand the way the system heats the house.

How modern heating systems distribute heat

Modern home heating systems are made in such a way that they function at their best when there is a constant flow of heat in all the radiators in the home. Modern systems, such as condensing boilers and heat pumps, use warm water to circulate heat in all parts of the home in order to maintain constant temperature levels.

According to heating engineers cited by the home energy education platform Heat Geek, modern systems achieve their highest efficiency when all radiators allow at least some heat to pass through them. This continuous circulation allows boilers or heat pumps to operate at lower water temperatures and maintain steady heating cycles. Research outlined in the Heat Geek technical guide shows that when radiators are left partially open, the system can run smoothly without repeatedly switching on and off, helping conserve energy.

When radiators in several rooms are turned off completely, the heating system experiences a pressure and temperature imbalance across the circuit. As explained in an energy analysis published on Energy Surprises, boilers and heat pumps are calibrated to operate under a certain heat load, and shutting off radiators reduces that load in ways that disrupt normal operation.

Why turning off radiators can increase energy use

When radiators are closed in unused rooms, it is expected that the heating system will simply provide less heat in total. But in fact, it behaves in a more complicated way. The boiler or heat pump will try to keep the target temperature in the other parts of the house and simply increase the temperature of the water or lengthen the heating cycles.

Heating specialists writing for Heat Geek explain that this response can lead to higher fuel or electricity consumption than maintaining a low heat throughout the house. The system must work harder to achieve comfortable temperatures in occupied rooms because heat distribution has become uneven.

Frequent start-and-stop cycles can also reduce efficiency. Each time a boiler restarts, it must raise water temperature again before delivering heat to radiators. According to the Energy Surprises heating analysis, this repeated cycling wastes energy compared with steady operation, where all radiators receive moderate heat flow.

In simple terms, a heating system works best when it distributes warmth evenly rather than concentrating all heating demand in a few rooms.

Damp and condensation risks

A complete shutdown of radiators can also pose structural and health hazards in the home. Rooms that are not being heated may become much colder than adjacent areas. This temperature differential can cause moisture to accumulate on the walls, windows, and ceilings.

Poorly heated rooms, especially those with limited sunlight or ventilation, are more likely to develop damp patches and mold growth, as per the experts at The Radiator Centre. Condensation forms when warm, humid air from the rest of the house enters a colder room and deposits moisture on cooler surfaces.

This moisture can damage paint over time and reduce indoor air quality. Mold spores can spread through ventilation systems or doorways, creating additional maintenance challenges for homeowners.

The role of setback temperatures

A more balanced approach recommended by experts in the field of energy is called ‘setback heating.’ Rather than turning off the heating in unused rooms, it is recommended that the temperature in these rooms be lowered but remain steady.



Heat Geek suggests setting thermostatic radiator valves to about 12-16 degrees Celsius for rarely occupied rooms. This lower temperature provides enough warmth to prevent condensation while still reducing energy use compared with fully heating the room.

Allowing some heat to circulate also helps the heating system maintain its natural balance. Boilers or heat pumps can continue operating steadily at lower temperatures rather than compensating for sudden changes in demand. Isn’t that helpful?

Maintenance and airflow also matter

Efficient heating depends on more than just thermostat settings. Regular radiator maintenance can also improve system performance. Consumer advice from Citizens Advice recommends bleeding radiators periodically to remove trapped air, allowing hot water to circulate properly and preventing cold spots that force boilers to work harder.

Temperature control devices also help maintain efficiency. Consumer guidance from Which? suggests that programmable thermostats allow homeowners to automate setback temperatures across different rooms, which reduces the risk of overheating or accidental energy waste.

Ventilation plays an equally important role in preventing damp conditions. Guidance from the Health and Safety Executive notes that periodic ventilation, such as briefly opening windows or using extractor fans, helps remove excess humidity from indoor air.

A small habit with big consequences

Draught-proofing by turning off radiators in unoccupied rooms is one of the most obvious ways to save money on heating bills, but, according to heating experts, the truth is not so straightforward. In fact, modern heating systems are designed to function in balance in all radiators, and turning off the heating in certain rooms can cause an imbalance.

In fact, the most effective way for householders to reduce their bills, prevent damp, and improve efficiency may be to use every radiator slightly rather than turning them off altogether.