Should you turn underfloor heating off in summer? Summer shutdown and autumn switch-on

Every autumn, installers get the same calls: a room that will not warm up, a manifold actuator that will not open, a pump that hums but does not turn. Many of these faults start in summer, when the heating sits unused for months. A little care in May and a simple check in September or October avoid most of them.

This guide covers whether to leave water or electric underfloor heating on over summer, which settings to use, why parts stick, and a step-by-step autumn switch-on checklist for homeowners and installers.

Does underfloor heating use energy in summer if I leave it on?

Very little, if it is set up properly. A room thermostat only calls for heat when the room is below its set temperature, and on a warm day it will not call at all. When no zone calls for heat, the wiring centre should switch off both the boiler or heat pump and the underfloor heating pump. BEAMA's controls guidance asks for exactly that interlock.

So leaving the system powered with sensible settings costs almost nothing, and it keeps the thermostats' clocks, schedules and frost protection running. The exception is a system without proper controls, such as an old dial thermostat with no interlock, where the pump may keep running. If that sounds like yours, see our guide to UFH zoning and wiring centres.

Should I turn it off, lower it or use frost mode?

Lower it or use frost mode for most homes. Full isolation is only needed for work on the system or long empty periods with frost protection elsewhere.

Option	How	Best for
Leave settings as they are	Nothing to do. Warm rooms will not call for heat.	Homes where cool summer evenings still need some heat
Lower the setpoints	Drop each thermostat a few degrees, for example to 18°C	Most homes over summer
Frost protection	Set thermostats to frost mode. Heatmiser default is 12°C, adjustable 7 to 17°C	Holidays and empty homes
Holiday function	Set the dates on the thermostat or app	Trips away, with automatic return to normal
Isolate at the mains	Switch off at the fused spur after turning thermostats off	Servicing or work on the system

On a networked system, such as Heatmiser neoStats with a neoHub, you can change every zone from the app in one go and switch them back in autumn just as easily.

Why do underfloor heating valves and pumps stick after summer?

Because parts that do not move for months can stick. Two parts are most at risk.

• Manifold valve pins. Each thermal actuator sits on a spring-loaded valve pin. If the pin sticks down, the loop stays shut even when the actuator opens. Remove the actuator and check the pin springs back freely. A light silicone spray and gentle movement often frees it. If it will not move, the valve insert needs replacing.
• Circulating pump. A pump left still for months can seize, and it may hum without turning. A seized pump needs a heating engineer, and any electrical work on it needs a qualified electrician.

The simplest prevention is to keep things moving. Every few weeks in summer, turn each thermostat up for a short spell so its actuator opens, the pump runs and water flows through every loop. On a cool evening the heat will be welcome anyway. Our guide to actuator, zone valve and wiring centre faults covers diagnosis in more depth.

Should I drain underfloor heating for summer?

No. There is no need to drain a water system in a home that is lived in, and draining lets air into the loops that then has to be purged out. If a property will stand empty through a cold winter, keeping frost protection on is the normal approach. Take advice from the installer before draining, and check the system manufacturer's instructions.

What about electric underfloor heating in summer?

Electric underfloor heating is not harmed by being off for months, because there are no pumps or valves to stick. Many people keep a bathroom floor running all year for comfort, which is fine with the right settings.

• Use floor sensing. Set the thermostat to read the floor probe, so it warms the floor rather than heating the room air on a warm day.
• Set a floor limit. The Heatmiser neoStat-e floor limit can be set from 20 to 45°C, 28°C out of the box.
• Use a timer. Heat the floor around the times you use the room, not all day.

Do heat pumps need anything different in summer?

Usually not. With weather compensation, the heat pump lowers the flow temperature as the outside temperature rises. In the Energy Saving Trust's worked example, the curve reaches 20°C flow at 20°C outside, so little or no heat goes to the floor in warm weather. The heat pump keeps making hot water as normal. Check the maker's manual for any summer or heating-off setting, and leave anti-frost functions on.

How do I switch underfloor heating back on in autumn?

Start early and go gradually. A screed floor responds in hours, not minutes, so switch on as soon as the forecast turns rather than waiting for the first cold snap. Then work through this checklist.

1. Check the pressure. Look at the boiler or system gauge and the manifold gauge if fitted. If it has dropped below the figure your installer or boiler manual gives, top up through the filling loop.
2. Check power and controls. Wiring centre lights on, thermostats awake, batteries replaced in wireless thermostats, clocks right after the change of hour.
3. Restore the settings. Put each thermostat back to its comfort temperature or schedule. On a heat pump, check the heating mode is back on.
4. Raise the temperature in steps. Increase each setpoint by about 1°C at a time, holding each step for a day.
5. Watch the manifold. Each actuator should open soon after a call for heat, and each loop's flow meter should show flow.
6. Feel the loops. Flow and return pipes for each open loop should warm up. A cold loop points to a stuck pin, air or a closed flow meter.
7. Listen for air. Gurgling or a cold loop after the pump has run usually means air. Purge it at the manifold. See our guide to bleeding air from UFH loops.
8. Look for leaks. Check manifold connections and the pump pack for drips after the first few days of running.

Once rooms are comfortable, leave the settings alone until spring. On a screed floor, keep any night setback to about 2°C. Bigger drops take a lot of energy to recover and may not be felt until the next morning.

If a room still will not warm after these checks, our guide to underfloor heating not getting warm runs through 12 causes and fixes.

Frequently asked questions

Should I turn my underfloor heating off in summer?

You do not need to. Lower the thermostats or use frost mode, and the system will stay off on warm days. Switching off at the mains is fine too, but run each zone briefly every few weeks.

What should I set underfloor heating to in summer?

A few degrees below your winter setting, for example 18°C, so it only comes on in a cold spell. Use frost protection when you are away. Heatmiser neoStat frost protection is 12°C by default.

Why is my underfloor heating not working after the summer?

The usual causes are stuck manifold valve pins, a seized pump, low system pressure, air in the loops or thermostat batteries and clocks. Work through the autumn checklist above.

How long does underfloor heating take to come back on in autumn?

A screed floor takes hours to respond, so switch on early. Raise the setpoint about 1°C a day until the rooms are comfortable.

Can I leave a bathroom underfloor heating on in summer?

Yes. Use floor sensing with a floor limit and a timer, so the floor warms when you use the room without overheating it.

Does leaving underfloor heating on in summer waste energy?

Not if the thermostats and wiring centre are working. With no call for heat, the wiring centre should switch off the pump and the boiler or heat pump.

Sources: BEAMA guidance on controls for water UFH, Heatmiser neoStat datasheet, Energy Saving Trust weather compensation guidance, Cambridgeshire County Council cold weather advice (18°C)