Frequently asked questions
Is a heat pump suitable for a UK home?
Heat pumps can work efficiently in new and old homes. The more energy saving features you have in your home the better, e.g. underfloor heating instead of radiators.
A hybrid system which consists of a heat pump and also a gas condensing boiler can also offer a high supply of energy efficiency.
How quiet is a heat pump?
Vaillant heat pumps are among the quietest on the market. To showcase how quiet our heat pumps are, we have created the “Vaillant Soundbox” which simulates the sound of a heat pump within a suburban environment.
The low noise level allows the outdoor unit of a Vaillant heat pump to be installed without trouble even in housing estates with strict noise restrictions.
Is an underfloor heating system an essential for the integration of a heat pump?
No, it is not essential, but we do recommend having underfloor heating. The reason why we recommend to have it is because it helps with the efficiency of a heat pump by making the flow temperature of your system as low as possible.
Nevertheless, there shouldn’t be a problem with combining a heat pump with radiators – however, we recommend that you consult with your architect or installer for the best possible option.
What does "flow temperature" mean?
The flow temperature is the temperature in which the water is supplied from the heat source (a heat pump or a boiler) into the pipework. Radiators work with an average flow temperature of 50°C whilst underfloor heating only needs 35°C. The lower the flow temperature, the more efficient the heating system is. A flow temperature of 45°C or below will result in a very efficient system.
If your home is well insulated, this will also improve the flow temperature of your heating system. Buildings with poor insulation require more energy to heat up to the desired temperature, resulting in higher energy bills.
How much space do I need to be able to install a heat pump?
Inside your property, you will need enough space for a hot water cylinder, and depending on the system a small buffer tank (a buffer tank is not required for all systems).
Outside the property depends on the heat pump you choose. With an air source heat pump like the aroTHERM you need a small section of garden close the building wall. When selecting the site to place the air to water heat pump, you need to consider your neighbours and ensure the heat pump does not exceed 42dB (decibels) from their closet window or door. Your installer or architect will advise you on this.
If you are looking ground source heat pump such as the flexoTHERM, inside you will need space for the flexoTHERM heat pump, outside you will see a small ‘drain’ cover which will be the top of your collector which will be underground.
What is COP and SCOP?
COP (coefficient of performance) and SCOP (seasonal coefficient of performance) are the major ratios indicating the efficiency of a heat pump. They are calculated based on the thermal energy generated by the heat pump divided by the electric power used for the pump operation.
For instance, if a heat pump provides 12 kW output and consumes 3 kW current to do so, the COP will be 12 / 3 = 4. The COP results from a highly simplified calculation with assumed values. This ratio is used to compare the efficiency of different heat pumps. The higher the COP is, the lower the consumption of electric power used for the heat pump.
The SCOP follows the same principle. However, it considers the entire year with all existing temperature variations. Therefore, it can only be calculated retrospectively. An installed heat pump will show a different SCOP for every year – depending on the usage pattern and the weather conditions. A mild winter, for example, will result in a significantly better SCOP than a long and hard winter with many cold days and temperatures below 0°C.
Which heat pump types are available?
Heat pumps are distinguished based on the type of heat source they use.
Air source heat pumps use the heat from the ambient air. There are two versions; air-to-water and air-to-air. Air-to-water transfers the absorbed heat to radiators or an underfloor heating and will also provide hot water. Air-to-air heat pumps transfer the heat to a fan installation that serves to heat the house.
Ground source heat pumps use the environmental heat stored in the ground. They can only be used in combination with a water-based heat distribution system (radiators or underfloor heating) and therefore are called brine-to-water heat pumps.
Water-to-water heat pumps use the heat contained in the groundwater. Water source heat pump systems are ideal for homeowners that have a suitable water source onsite, such as a lake, river or stream.
Will a heat pump save me money?
Whilst heat pumps have a higher upfront cost than traditional boilers, they have a great energy efficiency rating, and can therefore significantly reduce energy costs long term. Heat pumps also typically have double the life expectancy of a boiler, helping to balance the upfront cost.
The Government's Boiler Upgrade Scheme (BUS) provides funding in the form of a grant of up to £7,500. BUS operates in the form of a grant voucher which is provided to the installer after installation and commissioning, with the expected amount deducted from the homeowners upfront cost. To find out more, click here.