Should I Leave My Heat Pump On All Summer?

For most UK homes, the answer is straightforward: yes, it's usually best to leave your heat pump switched on right through the summer.

A lot of homeowners assume they'll save money by flicking the system off at the mains once the weather warms up. In reality, that habit rarely makes a meaningful dent in electricity bills, and it can create inconvenience that far outweighs any saving. A heat pump doesn't sit there continually heating your home just because it's powered on. Through the summer, the heating side of the system normally stays idle unless there's an actual demand for heat. If your heat pump also produces domestic hot water, it simply heats the cylinder when needed and drops back to standby the rest of the time.

Why is it usually best to leave a heat pump on?

Modern air source heat pumps are built to run all year, not just through the colder months. Leaving the system powered lets it produce domestic hot water whenever it's needed, carry out automatic pump exercise or maintenance cycles that keep components from seizing up, retain your schedules and controller settings rather than resetting them, and stay ready in case outdoor temperatures suddenly drop. When your home doesn't need heating, the heat pump typically spends most of its time quietly in standby, only waking up to heat your hot water.

So what should you actually do with the heating?

You don't need to switch the whole system off at the wall. It's usually better to turn the heating schedule off through your controller if it allows that, reduce or disable heating demand at the room thermostat instead, and leave domestic hot water enabled if you still want hot water on tap. This lets the system keep operating efficiently in the background without wasting energy heating a home that doesn't need it.

What if your heat pump can also cool?

If your system has active cooling built in, you'll need to leave it switched on to actually use that feature during warmer weather. Many modern air-to-water heat pumps can provide cooling through underfloor heating, fan coil units, or specially designed radiators, but only where the system has been properly designed for it and includes the right controls, such as dew point protection. If you're not sure whether your system falls into that category, our heat pump cooling overview is a good place to start, and our article on Can a Heat Pump Cool Every Room in the House? walks through what's actually needed for whole-home cooling. If you're wondering whether your existing pipework could carry chilled water without a full re-pipe, that's covered in Can You Use Existing Pipework for Heat Pump Cooling?

Should you ever turn it off completely?

For most homeowners, there's very little reason to switch a heat pump off entirely. These systems are designed to remain powered throughout the year, automatically producing hot water when required and standing ready the moment heating is needed again. Many also include built-in frost protection: if outdoor temperatures fall unexpectedly, the heat pump can automatically circulate water or briefly run to protect its components from freezing. That feature isn't a substitute for correct system design or antifreeze protection where it's genuinely required, but it's another reason manufacturers generally recommend leaving the system powered on rather than isolating it.

If you're going away for an extended period, most modern controllers include a holiday mode, or let you temporarily reduce your hot water schedule instead. That's almost always a better option than switching the entire system off at the mains, since it avoids the settings resets and restart delays that full power-downs can cause. Unless a manufacturer or a qualified engineer has specifically told you otherwise, leaving your heat pump switched on year-round is normally the simplest, safest, and most efficient approach.

Does leaving it on actually cost much?

Most modern heat pumps draw very little electricity while they're sitting in standby waiting to produce hot water. During summer, the real driver of your electricity bill is heating your hot water, not the heat pump idling in the background. If your electricity use seems unusually high over the warmer months, the more likely culprits are an immersion heater running more than it needs to, hot water settings that need adjusting, incorrect controller programming, a circulation pump running continuously when it shouldn't be, or a fault quietly preventing the system from operating efficiently. These are generally straightforward to pin down once the system's settings and controls have been properly checked, which is exactly the kind of thing a Controller Configuration Review is designed to catch.

The bottom line

For most homeowners, the simplest and most efficient approach is to leave the heat pump switched on right through summer. Disable the heating schedule if it's no longer needed, keep using the system for domestic hot water, and take advantage of cooling if your installation supports it. If your heat pump seems to be running constantly, drawing far more electricity than expected, or behaving unusually during the warmer months, it's worth investigating properly before assuming the heat pump itself is at fault.

Need help with your heat pump?

If your heat pump isn't behaving as expected, our Fix My Heat Pump service provides independent remote support to help identify faults, poor settings, and installation issues without unnecessary guesswork. If you're planning a new installation or want to check whether a proposed system has been designed correctly, our Pre-Installation Heat Pump Review provides an independent assessment before any work begins.

"Whether you're looking to add cooling to your existing heat pump or you're planning a new installation and want cooling designed in from the start, we can carry out an independent cooling assessment and provide a design tailored to your home. Find out more about our heat pump cooling assessment."