How Heat Pumps Work

Air Source Heat Pumps
An air source heat pump needs to be installed outside of the building. They look like large air conditioner units and so are often placed out of view – ie to the rear of a building. They can be installed in sheds.

Ground Source Heat Pumps
Ground source heat pumps need to have piping buried in the ground. This can be done either horizontally or vertically. A well insulated domestic house would require a horizontal ground loop buried between 1.5m – 2m deep in a 40m – 100m long trench. Not many properties have that much space available. The alternative, a vertical installation of the piping, requires a bore hole of 50m – 100m depth. Creating this require a specialist boring rig which makes these installations more expensive. The pump itself is a square box similar in size to a fridge freezer.

Water Source Heat Pumps
If you have a handy stream, the piping can be laid in the water.

Frequently Asked Questions About Heat Pumps

1. How do I get the most out of investing in a heat pump?
Heat pumps work most efficiently in combination with low temperature heat distribution systems, such as under floor heating, where they only have to raise the water temperature to perhaps 30°C to 35°C.

2. Does the Air Source Heat Pump work in Winter?
They work all the year round even in temperatures as low as minus 15°C but their efficiency depends on the external air temperature. A lower external air temperature gives lower efficiency.

3. Can I produce all my space heating with this technology?
Heat pumps can supply space heating and domestic hot water (DHW) but the efficiency falls at hot water delivery temperatures above 45°C to 50°C. Therefore an alternative form of heating may be needed to ‘top up’ the hot water cylinder.

4. Will it work with my wet central heating system ?
Heat pumps are less well suited to traditional heating systems in which hot water is pumped around radiators as these require hotter water (up to 80°C) which cannot be achieved using a heat pump alone. The size of the radiators may also need to be increased. Heat pumps do work well with underfloor heating systems, however.

5. Do I need to add extra insulation to the building ?
The answer to this question will almost always be YES.
Poorly insulated buildings will require a larger pump which significantly increases the capital cost.

Costs & Grants for Heat Pumps

Air Source Heat Pumps
A 7 kW system may cost around £3000.00 plus installation costs, and should be able to supply 70% of space and water heating for a modern well insulated home.

For installations from 31st March 2013 to 31st March 2014, the Renewable Heat Premium Payment will refund £1,300 of the installation costs.

Ground Source Heat Pumps
A typical 8 kW GSHP system costs between £6,400.00 – £9,600.00, excluding the cost of the internal heat distribution system. An under floor heating system is the best solution although it is also possible to use specially designed low temperature radiators. An average house would be looking at a total outlay of £10,000.00 – £13,000.00.

For installations from 31st March 2013 to 31st March 2014, the Renewable Heat Premium Payment will refund £2,300 of the installation costs. Ground Source Heat Pumps installed since 15th July 2009 will also be eligible for the Renewable Heat Incentive (RHI), due to come into force in Spring 2014.

Water Source Heat Pumps
Installation costs vary.

For installations from 31st March 2013 to 31st March 2014, the Renewable Heat Premium Payment will refund £2,300 of the installation costs. Water Source Heat Pumps installed since 15th July 2009 will also be eligible for the Renewable Heat Incentive (RHI), due to come into force in Spring 2014.

Benefits & Rewards of Using Heat Pumps

Save up to 75% on electricity bills

Heat pumps use electricity to generate heat. For every 1 unit of electricity input, up to 4 units of useful heat are output. This offers a great saving in heating costs. For a 4-person household the annual electricity use might be reduced by 75% compared to an all electric heating system. A heat pump can also reduce CO2 emissions by 20-25% compared with an efficient gas or oil boiler system.

Combining Solar Energy with Heat Pumps for FREE Heating & Electricity

Heat pumps, being powered by electricity, are the perfect renewable energy partner for Solar Photovoltaic Panels (PV) as any free energy generated through solar power can be used to heat your home, so with careful use a heat pump and solar PV system in your home could mean an end to heating and electricity bills.

The Renewable Heat Incentive (RHI)

The Renewable Heat Incentive is a new Government-backed measure being introduced to make it worth your while to produce renewable heat. You earn a fixed income for every kilowatt hour of heat you produce. This is likely to be used in your own property, but if you are lucky enough to be connected to a heat network you might be able to get an additional payment for ‘exporting’ surplus heat.

The launch of the Renewable Heat Incentive (RHI) has now been further delayed until Spring 2014. However, the tariffs have been published.

Eligible applicants will receive:

• at least 19.2 p/kWh for solar thermal
• 18.8p/kWh for ground source heat pumps
• 12.2p/kWh for biomass boilers
• 7.3p/kWh for air source heat pumps

Good Energy’s Renewable Heat Incentive

Green energy suppliers Good Energy have their own Renewable Heat Incentive called HotROCs which rewards customers who are generating heat or hot water from renewable sources.