Heat Pumps and UK Climate: Everything You Need to Know

Are Heat Pumps Effective in the UK's Climate?

The climate in the UK can be characterised by mild summers and cool, damp winters. This can pose some challenges for home heating. Air source heat pumps can operate effectively in these conditions, as long as they are well installed. A heat pump can extract heat down to -15°C, so even the coldest parts of the country will be fine, although the efficiency is lowered in extremely cold conditions (Heat Geek). Heat pumps have worked in colder Nordic countries for many years.  

Do Heat Pumps Become Less Efficient Due to UK Temperature Swings?

The UK can have quite volatile rises and falls in temperature and these sudden fluctuations can lead to increased ‘cycling’ of the heat pump. This means it will turn itself on and off again and the compressor within a heat pump uses the most amount of energy when it is starting up, so this can reduce efficiency. If you are in a part of the country that is particularly prone to these fluctuations, then the design of the system can overcome this. Adding volume to the system can help maintain steady temperatures, in some cases it might need a buffer (Energy Saving Trust).

Does the UK Climate Mean Radiator and Pipe Upgrades are Necessary?

Heat pumps operate at a lower flow temperature compared to traditional gas boilers and therefore the home mayhave been designed with higher flow temperatures in mind, hence smaller radiators. The lower flow temperature of a heat pump means an emitter with a larger surface area is required. Properly sized or larger radiators, and ideally underfloor heating, are highly recommended, especially in older UK properties with poorer insulation (Vaillant UK).

The pipework for houses built in the UK during the late 1970’s, 1980’s and the early 1990’s was commonly microbore. This is because it was more flexible and easier to use (and cheaper) when piping the house. Pipes of these sizes restrict flow rate, which is bad for a heat pump. So in some instances it is important to change these pipes in order to make the system run efficinently. Again, in some cases it might be best to use a buffer, as 10mm pipes can still transfer the necessary heat energy to the radiators for homes with a lower heat loss.

Are Heat Pumps Cost-Effective with UK Energy Prices?

The UK imposes higher levies on electricity, compared to many other European countries, as a hangover from times when the UK burned a lot of coal to generate the electricity. However, time of us tariffs can help to mitigate these prices, by utilising cheaper rates at off-peak periods.

You can also pair heat pumps with solar and batteries. Read our article on pairing solar with a heat pump, and this article to understand using a battery to make the most of time of use tariffs to lower your bills.  

How Reliable are Heat Pumps in the UK's Weather?

In modern heat pump installations, the unit will include defrost cycles, which will handle the ice accumulation around the unit. Regular professional maintenance ensures the reliability and longevity of these systems in the higher humidity climate of the UK (Daikin UK).

When the heat pump defrosts frequently to remove ice, it temporarily operates at reduced efficiency, consuming slightly more electricity. Heat pump manufacturers typically incorporate intelligent defrost cycles to minimise efficiency losses. The system enters a defrost cycle, which temporarily reverses its operation in order to transfer heat from the indoor central heating system back to the outdoor unit, which in turn melts the ice. This method can briefly reduces indoor comfort and overall system efficiency, as it removes heat already provided to the home, but the cycle doesn’t take long and, thus, the impact is minimal.

Viessmann is a manufacturer that takes a unique approach to the defrost cycle. Their innovative design incorporates a dedicated defrost tank in some models, housed within the indoor unit itself. Instead of extracting heat from your home's heating system during defrosting, Viessmann uses stored energy from this internal buffer, minimising any disruption to heating performance. This not only maintains consistent indoor temperatures but also significantly enhances efficiency, making Viessmann heat pumps particularly suited to handling the demands of the UK’s variable winter climate. However, it does make the indoor unit quite large in the home, so there is a trade-off for the innovation.

How about damp in the home? 

The way a heat pump works, by heating the home low and steady, rather than heat it up and then letting in cool will help avoid damp in the home. Rather than heating the rooms quickly at a high temperature and then turning off the heating and allowing the room to cool. A constant temperature above 14 degrees will help keep damp out of the home.

What Warranties Are Offered for Heat Pumps in the UK?

Many manufacturers, such as Vaillant, Ideal, Viessmann and Daikin offer warranties of between 2 to 7 years, the length of which is normally determined by whether the installer is an accredited installer of that manufacturer their models of heat pump. Often longer warranties will be baked into the price in some way, as the manufacturer clearly prefers shorter warranties and can offer installers better terms for these shorter periods.

Do Heat Pumps Require a Buffer Tank?

While buffer tanks are not mandatory, in fact we advise against them in scenarios where they will not add any benefit and will likely reduce the efficiency, buffer tanks are quite widely used in the UK and can help retrofit installations where the pipework might be 10mm or the customer wants to have multiple zones in the property. They de-couple the primary heating circuit from the heat pump to the rest of the system. The heat pump to the buffer becomes its own circuit ensuring a stable flow rate and volume, so that different zones after can be controlled with TRVs and actuators if that is the wish of the customer (not always recommended for the best efficiency). They help manage the rapid weather changes by maintaining system stability, preventing frequent cycling, and ensuring even heating distribution across the home.

UK Heat Pump Manufacturers – Spotlight on Ideal Heating

Ideal Heating is a leading UK-based manufacturer who are known to produce reliable, high-quality boilers and heat pumps, which are specifically designed for UK homes and climate conditions. Ideal Heating's heat pumps offer very impressive performance, with 7-year warranty coverage through dwellow, and excellent customer support nationwide, which makes them a popular choice among homeowners in the UK (Ideal Heating). Read our review of the Ideal Logic Air here.

Conclusion

Air to water heat pumps are very capable of running efficiently in the UK. Our climate just means that the design of the system is crucially important to ensure it maximises energy efficiency, while keeping the home as comfortable as possible. Use our online tool to get a fast and easy quote for a new heat pump.