Ground or air? For a homeowner considering installing a heat pump, what exactly do you need to know? Heat pump expert Nu-Heat, explains
Types of heat pump A ground source heat pump is the most efficient of the heat pump family as it has the highest Coefficient of Performance (ratio of units of heat output to units of electricity used). Outside space approximately 2.5 times the internal floor area of the property is needed for the pipes to be laid in horizontal trenches. The alternative is to drill boreholes, dependent on geological conditions. The heat pump and system components need to be housed in a plant or utility room. An air source heat pump extracts available warmth from passing air rather than the ground. This type of heat pump is relatively simple to install as it requires no groundwork or building work. The only space required is beside an outside wall, although the other system units will need to be housed inside the property.
How do I choose the model?
Heat pumps can be bought ‘off the shelf’ but this may be risky as the design of a heat pump system is essential to its performance. A design and supply company like Nu-Heat will handle the necessary complex calculations which include insulation levels, double glazing, floor area and heating method. Once heat loss has been assessed, Nu-Heat uses specialist software to run a simulation of performance over an average year, based on local, monthly weather data and taking account of the changing seasons, enabling the correct model to be specified. When a heat pump is to be retrofitted, design is even more crucial as insulation levels are not likely to meet the necessary standards and may have to be upgraded.
What about the heat emitter?
Underfloor heating is an ideal partner for heat pumps and when additional tubing and more efficient floor constructions are used flow temperatures of 35oC – 45oC can be achieved. Conventional radiators can be used although these will have to be oversized – but the latest high efficiency radiators with output boosters are a more practical choice.
You can find out whether your project is suitable for a heat pump by using a specialist calculator like Nu-Heat’s heat pump tool available at www.nu-heat.co.uk/heatpumptool.