One of the most common questions people ask about heat pumps is:
“Should I leave my heat pump on all the time?”
The answer is not a simple yes or no.
A better answer is: Heat pumps work best when they run steadily at low temperatures, but that does not mean every room needs to be kept warm 24 hours a day.
The advice to “leave it on all the time” came from real, genuine experience, but it is often oversimplified. With modern heat pumps, smart controls, zoning and responsive heat emitters, the best approach now for the user is usually more flexible.
Why people say heat pumps should stay on
Heat pumps are different from boilers.
A boiler can produce high-temperature water quickly. It can heat radiators in short bursts, switch off, then fire up again when needed.
Heat pumps work more efficiently when they deliver heat steadily at lower flow temperatures. The lower the water temperature your heating system needs, the less hard the heat pump has to work.
This is why heat pumps are often paired with:
- underfloor heating;
- larger or correctly sized radiators;
- smart controls;
- weather compensation;
- well-insulated homes.
If a heat pump is asked to heat a cold home very quickly, it may need to raise its flow temperature. That can reduce efficiency because the system has to work harder.
So the advice to “leave it on” came from a sensible idea: avoid big temperature swings and avoid forcing the heat pump to recover too aggressively.
Why “always on” can be misleading
The problem is that “leave it on all the time” can sound like: “Heat every room to the same temperature all day and night.” That is rarely necessary, efficient or comfortable.
There is a big difference between letting a heat pump run steadily at low output and keeping the whole home at a comfortable temperature 24/7.
The first supports efficiency. The second however can waste energy, especially in rooms that are not being used.
A better principle is to keep the system stable, but use sensible schedules and zoned or room-by-room control.
Comfort temperatures vs setback temperatures
Instead of thinking only in terms of “on” or “off”, it is better to think about comfort temperatures and setback temperatures.
A comfort temperature is the temperature you want when a room is being used.
A setback temperature is a lower background temperature used when a room is empty, overnight, or not needed for several hour. Let’s also remember, that different rooms have different functions and different temperatures are required.
For example:
- a living room may need to be around 20–22°C in the evening, to feel comfortable sitting in
- people often find bedrooms are more comfortable for sleeping in slightly cooler temperatures at 16-19°C
- bathrooms may need warmth for short periods
- a home office may only need heating during working hours
- a spare room may only need a low background temperature.
Zoned and scheduled control allows this approach and avoids letting the house become too cold, while also avoiding unnecessary heating.
Should you turn a heat pump off overnight?
In many cases, a small overnight setback is better than turning the whole system fully off.
If the home cools too much, the heat pump may have to work harder in the morning to bring it back up to temperature. With an air source heat pump, this can sometimes happen when outdoor temperatures are at their lowest, which may reduce efficiency.
However, keeping every room at the same warm temperature all night can also waste energy.
So the best approach is more reasonable, turn rooms down, rather than fully off.
For example, bedrooms may be kept cooler for sleeping, while living areas can be set back until the morning or evening. The system remains under control, but it is not heating unused spaces unnecessarily.
What about underfloor heating?
The type of underfloor heating makes a big difference.
Traditional screed underfloor heating has high thermal mass. This means the pipes heat a thick floor slab, which then slowly releases heat into the room. It can be very comfortable once warm, but it can take hours to respond. Users also report it can be uncomfortably warm and hard to cool down, relying on opening of windows, leading to wasted energy.
Because of this, screed underfloor heating is often run continuously at a low level. Turning it fully off can lead to long warm-up times and make the heat pump run less efficiently, or leave the user feeling uncomfortable waiting for the warmth.
Low thermal mass overlay underfloor heating behaves differently.
Wunda’s Rapid Response® overfloor system is designed to transfer heat into the room more quickly than traditional screed systems, as fast as radiators. Instead of heating a heavy slab for hours, it sits beneath the floor finish and directs warmth into the room quickly. Leading to better control along with all the comfort, sustainable and eco-friendly benefits of water based under floor heating. This approach allows the user to be more efficient with their energy use and more precise with their ‘comfort’ windows in their schedules.
That makes scheduling and zoning more practical and useful. Rooms can be heated toa comfort level closer to when they are actually needed, rather than being kept warm all day just in case.
Does zoning help?
Yes, when it is designed properly.
Zoning means dividing the home into separate heating areas, such as living rooms, bedrooms, bathrooms and home offices. Each zone can then be controlled independently.
This matters because not every room needs the same temperature at the same time.
A single thermostat may be simple, but it cannot know whether the bathroom is cold, the living room is comfortable, or the bedroom is too warm. Zoning gives each room or area more appropriate control.
However, zoning must be designed around how heat pumps operate.
Poorly designed zoning can cause problems, especially if only one very small zone is calling for heat and the heat pump cannot reduce its output. This can lead to short cycling, where the heat pump switches on and off too often.
A good system avoids this through correct sizing, smart controls, enough system volume, and a heat pump that can modulate its output. In some cases, a further practical option could be to have an ‘open zone’ such as a bathroom, hallway, or towel rail; to help a maintain the heat pump’s minimum flow and prevent short cycling.
Does heat leak from warm rooms into cooler rooms?
Some heat will always move from warmer rooms to cooler rooms, that is normal.
Heat can transfer through internal walls, gaps around doors, floors, ceilings and open doorways. But in most homes, this definitely does not mean zoning is pointless.
Closed doors reduce air movement and sensible zone layouts help. The goal is not to make unused rooms freezing cold, but to keep them at a lower background temperature when they are not needed.
Heat leakage is real, but with sensible use, it does not cancel out the benefit of zoning.
Air source vs ground source heat pumps
Air source heat pumps draw heat from the outside air. Their efficiency can fall when outdoor temperatures are very low. This is one reason large overnight temperature drops can be less effective with air source systems.
Ground source and water source (less commonly used) heat pumps draw heat from more seasonally stable sources. Ground and water temperatures fluctuate less than outdoor air, so these systems can be less affected by seasonal changes and cold night-time air temperatures.
That does not mean they should be used carelessly, but it does mean the best operating strategy can vary depending on the type of heat pump and the heating system it is connected to.
Should I leave my heat pump on if I am leaving for work, going out for the day, or even a few days on holiday?
When you leave the house, think in terms of setback, not simply on or off. As a general rule, the longer you are away, the lower the setback can usually be. A small reduction may suit a normal workday, while a deeper setback may make sense for a weekend away.
The key is to allow enough warm-up time before you return, especially with slower screed underfloor heating. You also do not want the home to become too cold, as this can have health implications and may increase the risk of damp, mould and poor indoor comfort.
If you are going on holiday for a few weeks in summer, the house will usually stay warmer naturally, so the heat pump is unlikely to be doing much heating anyway. If you are away in winter, a low setback of around 13–15°C may be suitable for many homes, helping reduce unnecessary heating while avoiding the property becoming too cold.
The aim is to reduce unnecessary heating while keeping the property protected and easy for the heat pump to bring back up to temperature.
So, should you leave your heat pump on all the time?
For most homes, the best answer is: Do not treat your heat pump like a boiler, but do not assume every room needs full heating all day either.
In practice:
- avoid deep temperature drops in cold weather;
- use gentle setbacks rather than switching everything fully off;
- keep flow temperatures as low as practical;
- use zoning to reduce heat in unused rooms;
- allow enough warm-up time;
- use smart controls and weather compensation where possible;
- make sure the system is correctly sized and commissioned.
The aim is steady, efficient heating — not wasteful constant heating.
Final takeaway
You do not need to think of heat pump operation as a choice between always on and completely off.
The best approach is usually somewhere in the middle. Heat pumps work best when they run steadily at low flow temperatures, but modern systems can still be used flexibly. With good design, smart controls, sensible zoning and responsive heat emitters, you can heat the rooms you need, when you need them, without forcing the system into inefficient operation.
So, should you leave your heat pump on all the time? Not necessarily. You should run it reasonably and sensibly: avoid big temperature swings, use reasonable setbacks, control zones and rooms individually, and keep the system operating at the lowest practical flow temperature.
That is how you get the best balance of comfort, control and efficiency.