Expert Air Source Heat Pump Installation

There is an ongoing debate over which system is the most efficient. An air source heat pump relies on the outside air temperature, which can be much cooler than the ground temperature, which is relatively stable in comparison. As a result, a ground source heat pump tends to be more efficient in all outside temperature situations. However, they are significantly more expensive to install and, as a result, are less popular than air source heat pumps.

A heat pump is at its best when it is circulating low temperature water around the heating system in a “steady state” mode. The heat pump is best run from a weather compensation system and allowed to run at all times as dictated by the external weather temperature and the internal room temperature. Because of the low temperature of the heating system water it is not best suited to be operated intermittently like a boiler. A boiler is typically turned on for a couple of hours in the morning, switched off all day and then turned back on at night for 5 or 6 hours. 

The high temperatures produced by a boiler enable it to heat a house more rapidly than a heat pump. Therefore, the heat pump should be operated in a "steady state" mode to avoid the need to quickly heat the house from a low starting temperature.

The servicing requirements of a heat pump are not as onerous as a boiler however, there are disagreements as to whether the homeowner can undertake this or a service engineer is required.  

With a Ground Source heat pump the requirements are more of a check than an activity, the closed loop collection system needs to be checked for the correct levels and efficacy as the fluid also serves as an anti-freeze. The heating system water pressure needs to be maintained and, if the installation has a mains pressure unvented hot water storage cylinder, the servicing requirements of that needs to be considered.

An air source heat pump requires the external unit to be kept free of leaves and debris. Any filters within also need to be cleaned or replaced as specified by the manufacturer. Similar to a ground source heat pump, any unvented, mains water pressure cylinder needs to be serviced according to the manufacturer’s instructions.

The running costs of a heat pump will vary from house type to house type. A well-insulated house built to new building regulation standards will generally be less expensive to run than a gas or oil fi red boiler system providing the heating system flow temperatures are kept relatively low, ideally around 40ºC.

A heat pump will be less efficient and more costly to run when it is generating higher temperatures. This can happen if the house isn’t well insulated if the radiators are not properly sized for lower temperatures, or when higher temperatures are needed to produce hot water.

The short answer is yes. This is called a hybrid heat pump and typically consists of gas boiler and air to water heat pump outdoor unit. It works using an outdoor heat pump with an existing or new boiler to provide heating and hot water to the home.

Unlike a standalone heat pump, remedial changes such as resized radiators and fabric improvements are less likely to be required to ensure performance. The hybrid heat pump may utilise the existing system and fabric improvements can be installed over a longer period.

The heat pump can effectively heat the house for most months. However, during colder temperatures, the boiler will assist the heat pump in reaching the desired temperature. Additionally, a combi boiler can supply hot water while the heat pump warms the property.

The installation cost of a heat pump will differ from house to house and from size and type of heat pump chosen. As a rule of thumb, an air to water heat pump will cost between £3,500 to £10,000 to install and a ground source heat pump could be anything up to and around £20k. This though is very dependent on the site and as to whether the existing heating system can be used and the position of the equipment etc.

Remember the following information:

There are grants available to help with investment, sometimes at the local and regional levels. Additionally, there is The Boiler Upgrade Scheme, a government incentive that can assist with the upfront cost of upgrading your heating system with our air-to-water and ground-source heat pumps. Moreover, there is currently no VAT on heat pumps, further reducing the cost.

An air source heat pump has an outdoor unit that contains a fan to induce the external air into the unit and consequently, they are noisier than a ground source heat pump. Generally, there are few complaints about the noise from a heat pump and when compared with the normal ambient external noise are quite acceptable.