Air source heat pumps are the simplest and cheapest systems to install. They ate stand alone units which can be placed inside or outside your premises.

The UK has a relatively moderate winter climate with average winter temperatures of around 5°C allowing excellent levels of efficiency and performance to be achieved throughout the year. Seasonal co-efficients of performance comparable with ground source heat pumps are achievable, without the additional cost of expensive ground loop systems having to be installed.

There are various different models available and there are options for either outdoor or indoor installation, given that in some instances, it may not be desirable for the heat pump to be installed in the garden. In these circumstances,indoor air source heat pumps offer a practical alternative and can be installed for example in a garage, basement or utility room. The heat pump is connected to the outside air via air ducts

Heat can be distributed using either:
• Air-to-water systems These distribute heat via your wet central heating system. Heat pumps work much more efficiently at a lower temperature than a standard boiler and so they are suited to underfloor heating systems. Radiators can be used but these need to be oversized to compensate for the lower temperature.
• Air-to-air systems These produce warm air which is circulated by fans to heat your home. They are unlikely to provide you with hot water as well.

Air source heat pumps are between three and four times more efficient than a conventional boiler. All you pay for is the electricity to run the pump.

Heat pump efficiencies are expressed in terms of a Coefficient of Performance (COP) which is the amount of heat the heat pump produces compared to the total amount of electricity needed to run it. The higher the COP, the less electrical energy is required to deliver a given amount of heat: a high COP shows good performance, and a low COP indicates lesser performance. For example, a COP of 3 effectively means that for every unit of electricity used to pump heat, 3 units of heat are produced.

Detailed specifications are provided for each of the pumps on this site and there is the ability to compare models and their performance to see what is best suited to your application.

Is an air source heat pump suitable for my home?

To tell if an air source heat pump is right for you, there are a few key questions to consider:
• Do you have somewhere to put it? You'll need space outside your house where the heat pump can be fitted to a wall or placed on the ground and where it will get a good flow of air. A sunny wall is ideal. Alternatively there are certain models that are designed for indoor installation.
• Is your home well insulated?Heat pumps work best when producing heat at a lower temperature than traditional boilers, and therefore your home will need to be well insulated and draught proofed for the heating system to be effective.
• What fuel will you be replacing?Heat pumps have the potential to reduce running costs compared with oil, direct electric, LPG or coal, and can provide substantial carbon savings over the lifetime of the installation. Heat pumps are not however generally recommended for homes where mains gas is available
• What type of heating system will you use?Air source heat pumps generally perform better with underfloor heating systems or warm air heating than radiator-based systems because of the lower water temperatures required.
• Is the system intended for a new development?Combining the installation with other building work can reduce the cost of installing the system as you are only then concerned with the marginal extra cost of the pump and ancillary apparatus.

Costs for installing a typical system suitable for a detached home range from about £5,000 to £9,000 including installation.

Savings - Running costs will however vary depending on a number of factors - including the size of your home and how well insulated it is. It is however important that the controls are appropriate for the installation and the customer understands how to use them properly.