Air source heat pumps allow you to heat your home with just electricity. That’s right; no more gas or oil, and you could even use 100% renewable electricity to power the system.
This guide will tell you everything you need to know about air-to-water heat pumps, commonly known as air source heat pumps. We will share our recommendations of which ones are the best, and will tell you how to get started in getting one installed.
Why get an air-to-water heat pump?
Air-to-water heat pumps are the renewable heating solution for most urban home owners. Rural home-owners may also consider ground or water source heat pumps – learn more here. But why get a heat pump?
- Low-cost heating; installation costs are a lot more than traditional boilers, but running costs are much lower. Heat pumps deliver 3-4 kilowatts of heat energy for every 1 kilowatt of electricity used, making them super-efficient. If you heat your home using off-peak electricity you can cut bills by 40%.
- Longer lasting; many have 25-year warranties. This means they have double the life of your traditional boiler.
- Cooling and heating capabilities; as well as heating these units can be used to extract heat. During a hot summer that can be very helpful!
- Government incentives; the government helps fund the installation cost of heat pumps through the Renewable Heat Incentive (RHI). This grant is paid out over 7 years and allows you to recoup your installation cost.
- Cut carbon emissions; 15% of an average person’s carbon emissions come from heating their home. Use 100% renewable energy to power your heat pump and you could slash your carbon footprint!
How does an air-to-water heat pump work?
Heat pumps transfer heat by circulating a substance called a refrigerant, as used in our fridges. Air from outside your property is sucked up and pressurized, and is used to heat a refrigerant, which then heats water, which can be used in the house. Hence air-to-water heat pumps.
The heat from ambient air, close to the house, is essentially condensed using electricity. These systems therefore deliver three times as much heat energy as the electricity used, known as the Coefficient of performance (COP). This is why you would use a heat pump instead of other electric heating solutions, and why heat pumps can still deliver effective heating with external temperatures of -25°C. Thermal stores are used within these systems to ensure no loss of heat, but also to increase the heat of hot water used in the property through exchange units.
How does a heat pump affect existing heating infrastructure?
There are two components of the system. A fan to pull in the air and heat the refrigerant and a thermal store. The fan sits outside, and does create a little noise, but most with a well performing heat pump do not have sound issues. The thermal store can become another floor standing kitchen unit, may be placed in a cupboard (to replace a water tank) or some manufacturers provide a unit the same size as a combi boiler to put on the wall.
You can get monobloc systems that heat water on demand, resulting in only a larger fan unit being used outside (and no thermal store), but these are best used for very efficient homes. Low and high temperature systems can also be selected. Low temperature systems deliver heat at around 55°C, and are largely more efficient, but are likely to need replacement of radiators, which need a larger surface area. High temperature systems can deliver at 80°C, requiring no radiator replacement.
Heat pumps require a fairly energy efficient home without too much heat loss. If your home has an energy efficiency rating below C, it’s likely to be better to improve energy efficiency first. Learn more here.
Best air-to-water heat pumps?
We have read blogs, looked at reviews and have had our community comment on the heat pumps they’ve used. This has helped us arrive at the best air source (air-to-water) heat pumps to recommend.
Alongside the manufacturer finding the right installer is incredibly important. We have found across the board that poorly installed products perform very badly and attract incredibly bad reviews. So take some tips on choosing the right installer below.
1. Mitsubishi Ecodan
Purchase price: £5,000 – £7,000
Benefits: Sound, reliability, maintenance, aesthetic, controls, range.
Downfalls: Internal thermal store size, reviews.
They’ve been delivering electrical devices for over a century, so they know what they’re doing. This is why they are beating many on cost and have developed some very nice looking products, with good reliability and low cost maintenance, for all sizes of property. What we particularly like are the advanced control systems that allow you to connect to solar panels, whilst optimising heat pump usage during low cost energy tariffs.
The only downfall we can see is the lack of a wall mounted thermal store and that there isn’t a high temperature system, with all heat pumps delivering water at 55°C. There have also been a few rough reviews online, which we attribute mainly to poor installation.
2. Samsung EHS
Purchase price: £3,000 – £6,000
Benefits: Size, cost, reliability, controls, range
Downfalls: Aesthetic, limited range.
Samsung has extremely compact outdoor units, that claim to be 40% smaller than competitors, and they major on a unique refrigerant that is super environmentally friendly and efficient. On top of all of this they provide a low cost solution, but do have a limited range of external products with only 16kw output and no low noise solutions. Connectivity on their products is great though, so you can control them remotely, can optimise upon energy tariffs and sync with solar solutions.
We feel the big downfall of this product is the way it looks. It does have nice internal units though and one good wall mounted one. It also has very few negative reviews we can find, with only positive ones relating to suppliers.
3. Nibe F2040
Purchase price: £6,000 – £8,500
Benefits: Reliability, efficiency, controls, range, maintenance, aesthetic.
Downfalls: Cost, flexibility of internal units.
Nibe is a lesser known brand, which has built it’s reputation in Poland, Czech Republic and Scandinavia. Their products are some of the most energy-efficient on the market and they have a great range, which variable outputs of heat up to 65°C, allowing a smaller demand on replacing radiators. They have great controls, including an app that flags issues, and like most Scandanavian products are well made and require little maintenance.
Our only criticism is the lack of a wall mounted internal unit, and potentially the high initial outlay. They do have some negative reviews but they are mostly installer related and are countered by may positives.
Purchase price: £5,500 – £9,000
Benefits: Reliability, efficiency, range, aesthetics, maintenance.
Viessman is a German manufacturer that focuses on delivering efficiency in its range, which is extensive. Delivering heat up to 65°C makes this again a super deliverer. Internal units are also flexible and extensive. Not much is posted on the controls of their units, but there is a flexible range of thermal stores. We think their range is pretty aesthetically appealing as well.
5. Daikin Altherma
Purchase price: £6,000 – £8,000
Benefits: Heat output, range, maintenance.
Downfalls: Aesthetic, reviews.
Daikin, a Japenese firm, is a leading global supplier of air conditioning units. It has a long history of providing climate control technology. They are the only unit we can find that delivers heat at 80°C in their High Temperature heat pump, meaning these units can be installed in less efficient houses, using existing heating infrastructure. They have a very good range and espouse low maintenance requirements.
The aesthetics of their units we don’t find that attractive, and unfortunately we’ve found some very negative reviews of their product support. Saying this they are recommended time and time again from blogs from leading review sites in the heating world.
Finding a good installer
You can choose to either follow a manufacturer when you are sourcing an installer or seek the installer first. The analysis of our reviews finds that manufacturers don’t necessarily screen their installers sufficiently, so when seeking a quote through that channel do also check on reviews of particular installers.
You can also simply choose an installer. We have a list on our renewable heating page, which have all been recommended by our community.
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