What to expect when living with a heat pump

One of the most noticeable differences when you have a heat pump is that you will usually leave the system active, so it runs 24 hours per day, seven days per week. This is quite a big change compared to using a traditional boiler, where most consumers usually programme the heating for when they are at home in the morning and evening.

The reason is simply that heat pumps are more efficient when they run for longer periods at lower temperatures, allowing them to replace heating as and when it’s lost. The benefit is that your house stays at a constant and steady temperature within 1°C of the temperature set on your thermostat.

You might wonder what running it constantly means for your energy bills! Fortunately, having a heat pump operate all day at a constant temperature is often the most cost-effective way to use your heat pump and shouldn’t cost you more than your current system (and could even cost less over the year). A well-designed heat pump system will generate about 3kW of useful heat for every 1kW of electricity used – that means it is about 300% efficient. By contrast, modern gas boilers are about 90% efficient.

Your heat pump installer will carefully design your system to your needs. As part of this detailed design process, your radiators will be checked (and some might be changed) to ensure that they can provide all the heat required for your property at lower water temperatures. Often, radiators may not be piping hot like with a gas boiler, due to heat pumps using ambient heat living with your new central heating system may be slightly different to what you’re used to.

A major benefit of running your heat pump 24/7 is that you get a consistent, even temperature throughout your home, all day long. Rather than the spikes and falls in heat that you get with running a traditional system periodically during the day, a well-insulated home with a heat pump should stay roughly the same temperature (you can of course change this – see below). That’s especially appealing when you’re at home on the weekends or are working from home.

This also means that the temperature throughout your house will be fairly steady, no matter the time of the day. And if you prefer it cooler at night, you can simply programme a lower room temperature. Another benefit of constant temperatures throughout the house is reduced thermal movements (the expansion and contraction of material caused by changes in temperature) that may otherwise cause dust to move around.

What heat pumps aren’t designed to do is to offer a sudden boost of high energy output (as is possible with a fossil fuel boiler). But if the system is set up correctly, you won’t need this since the internal temperature is maintained.

If you want to use your heat pump as effectively and efficiently as possible, then simply leave it on and it will automatically provide heat when the property requires it. A weather compensator built into the heat pump monitors the required internal temperature and the outdoor temperature, then provides the correct water temperature to your radiators or underfloor heating system. As the weather gets colder, the heat pump will increase the water temperature to compensate for the higher heat loss, and the system will keep you toasty.
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You might have heard that heat pumps don’t perform as well as gas boilers when it comes to heating water for your shower, bath or taps. This is not true –modern heat pumps with the latest generation of refrigerants can produce very hot water (60°C – 70°C). However, some older-style heat pumps are unable to work at these temperatures and only heat the stored water in your cylinder to around 50°C. In these cases, you would simply add less cold water to the sink, shower or bath.

Most people won’t notice the difference anyway. Dermatologists say that a temperature of around 37°C – 41°C is ideal for bathing (much hotter, and it can damage your skin and hair) and to protect against scalding.

If you store hot water at a lower temperature in either a traditional or heat pump system, it is important to periodically raise the temperature of the cylinder above 60°C. This is because certain bacteria, including legionella, can grow at a lower temperature. Don’t fear, your heat pump installer will activate the pasteurisation cycle to automatically heat and disinfect the cylinder at regular intervals.

One of the attractions of heat pumps is how little maintenance they usually require. As with traditional heating systems, you will require an engineer to do an annual inspection and ensure that the system is running efficiently. However, the machinery itself is relatively simple and requires very little upkeep. From time to time, you might need to check the outdoor unit is unobstructed by leaves so that air can move freely around it, and you may wish to check the system filter, but otherwise you can leave it to work by itself.