Frequently Asked Questions

A heat pump is a device which moves thermal energy from one space to another via the refrigeration cycle. When heating a home, energy is extracted from the air outside and transferred into the heated space. When cooling (as in air conditioning) the opposite happens - energy is removed from the air in the room and dumped outside.

Modern air source heat pumps work effectively in cold climates - down to minus 25 degrees Celsius. This is because the natural boiling point of the refrigerant in the system is much lower still, at around minus 50 degrees. The refrigeration cycle works by controlling the pressure and therefore the boiling point of the refrigerant, which is when heat is absorbed from the air around it.

The rated efficiency of a heat pump, known as the SCOP (Seasonal Coefficient of Performance) can typically be 300-500%. This means that for every 1kW of electrical power consumed it can produce 3-5kW of heat. The 'free' energy is absorbed into the refrigerant from the air at the point of evaporation.

This is the same process which results in your skin getting a 'cold burn' from spraying it with an aerosol can - the liquid from the container immediately boils when no longer under pressure, absorbing energy from the air and surfaces it comes into contact with.

While this of course depends on how the system is used, we can get an idea of the running costs from the SCOP (efficiency). With a SCOP of 4.0, the heat pump will produce 4kW of heat for every 1kW of electricity consumed.  At an electricity price of 32p per kWh, that's 8p per kWh of heat, which makes it cheaper to run than a modern gas boiler - and of course a quarter of the cost of a plug-in electric heater.

In short, no. The indoor heat emitter units have an adjustable fan speed, and at the low setting are almost silent.

The outdoor units are also very quiet with the latest inverter compressor technology. These systems are designed specifically to be comfortable to live with, and shouldn't be confused with similar-looking heat pumps used in other settings - for example, chiller units outside shops and pubs.

In our experience over 15 years fitting air to air heat pumps, they have proven to be exceptionally reliable. With only a few moving parts and no water circuit & associated components, a properly installed and maintained heat pump should give many years of trouble-free service.