by Damien Wilkinson
When using a heat pump to run underfloor heating we recommend that the underfloor heating pipe is laid at 100mm pipe spacing throughout the property. The main objective of having a heat pump is efficiency and installing the pipes at 100mm spacing maximises the efficiency.
Air source heat pump manufacturers’ efficiency data is 7c air temperature and 35C flow temperature. Ground source heat pumps are the same although it is ground temperature and not air temp in the data and this flow temperature is generally only achieved with the pipes at 100mm pipe spacing. The COP (coefficient of performance – how efficient a heat pump is of converting electric into heat) of a heatpump is from these figures and installing the pipes at 200mm spacing would seriously reduce the COP.