Energy Efficiency in Historic Buildings: GSHP


Source:  St Mary’s Church, Welwyn.

Could Ground Source Heat Pumps (GSHP) be a great low-carbon emission alternative for oil or gas based system in Historic Buildings? What are the advantages? Are there disadvantages?


The conversion or refurbishment of historic buildings often raises the need for a new heating or/and cooling system.  Although many listed buildings (for example buildings which are used primarily or solely as places of worship) are exempt from the requirements of the Part L of the Building regulations (Conservation of fuel and power), we believe it is really important to balance the requirements for a comfortable space, with solutions that benefit both the building and its significance, as well as the environment.

GSHPs come with a series of advantages. Only a small amount of energy is necessary to run a GSHP and in some cases this can be easily obtained from ‘green’ sources. Heat pumps provide heat at constant temperatures, although a bit lower (around 30-40 degrees) and over long periods of time. GSHP are more efficient if they run continuously, and consequently may help reduce problems relating to damp, condensation or mould in buildings that are normally not used continuously throughout the week (like churches). In cases where the land around the building is not much, or in sensitive areas, vertical holes may be dug for vertical pipes, instead of using horizontal loops. GSHPs do not need high maintenance and could be great alternatives to more traditional heating systems that use gas or oil. Similar systems can also be used for cooling the space.

Consideration of high installation cost and most importantly, their high impact on the surrounding terrain, will make them unsuitable for many heritage sites, particularly churches.  There are however, several examples in the UK that suggest that if carefully designed and installed, their impact is not harmful and they can work extremely well. St Mary’s, Welwyn is one of these examples. A GSHP system is being used for heating both the listed church and the newly built Church House. Besides considerably increasing the comfort inside the church, it is estimated that the system helped lower the carbon emission by around 25 tonnes of Carbon Dioxide a year. You can find more information on the church’s own website: