The tricks & treats to installing ground source heat pumps in historic builds
It’s not witchcraft, it’s (super) natural!
This renovated 17th century church in rural Wales may give some the chills, but thanks to modern energy efficiency measures and a ground source heat pump from UK manufacturer Kensa Heat Pumps, its owners are toasty warm by harvesting free energy from their grounds, which also attracts seven years of quarterly income through the Renewable Heat Incentive (RHI) as a big treat on the side.
With the support of Kensa Partner Installer, Ground Sun,the property has been converted to a modern, energy efficient residential dwelling.
The rural off gas location of the site made a ground source heat pump the ideal solution.
Naturally, the church required extensive energy efficiency improvements to ensure the project’s suitability for a ground source heat pump. Ground Sun worked closely with the architects and the builders on this project making recommendations about underfloor heating and insulation to ensure the heat pump would work as efficiently as possible and to satisfy the client’s desire for a sustainable, energy efficient home.
Thanks to the energy efficiency measures installed the heat loss for the building was reduced to c.30W/m2. Typically buildings of this nature prior to fitting modern energy efficiency measures would expect a heat loss of 100-120W/m2 (this would mean the project would have been looking at a 24kW heat pump rather than an 8.5kW High Temperature heat pump!).
Following the energy efficiency improvements a Kensa 8.5kW High Temperature Single Compact heat pump was chosen to provide all the heating and hot water for the 274m2 property.
It was also important to get the heat loss for the building lowered as there was only enough ground to install 3 x 50m long slinky trenches to accommodate the 8.5kW heat pump. The trenches were dug by the builders on the project and filled with a total of 900m of PE32mm slinky pipe.
The MCS accredited renovation qualifies the client for quarterly payments from the government’s Renewable Heat Incentive (RHI); these payments will continue for a 7-year period.
The ground source heat pump is installed in a subterranean plantroom to the rear of the church. As it’s a very wet part of the country it was decided the heat pump should be fitted on an elevated steel reinforced shelf in case of flooding (although Kensa heat pumps have been reported to work even after immersion, it is best not to design on this assumption!).
When we decided to convert an empty and near-derelict former church in Powys to be our future home we had a number of pre-requisites. We wanted the conversion to be sensitive to the original building. We also wanted its future as a domestic dwelling to be sustainable and as environmentally friendly as was practical.
For heating and hot water we investigated using a ground source heat pump connected to underfloor heating and hot water generation. Opting for a Kensa system recommended and to be installed by Ground Sun was easy. They impressed from the outset with their depth of knowledge and obvious enthusiasm for sustainable energy.
Ground Sun worked very closely with our builders and made recommendations about underfloor heating technology and insulation, in order to maximise the efficiency and effectiveness of the system. They were both reliable and neat in carrying out the installation and the after-sales service has been second to none. They advised and assisted on registering the system with Ofgem to access funding from a Government’s Renewable Heat Incentive Scheme.
One year on we have a beautiful home which is comfortably warm throughout the cooler or cold months, but is able to retain its cool interior at the height of the summer. Hot water is constant and plentiful. It almost feels magical to be able to flick a shower on each morning without having to rely on gas or electric central heating boilers. The system is intuitive to use and easy to adjust seasonally if required.
The guaranteed funding for 7 years which we have accessed is a considerable bonus, virtually paying for the cost of all the heating and hot water system. Needless to say the running costs of the ground source heat pump are negligible compared to more traditional systems.
We cannot recommend Ground Sun and this form of heating too highly.
Brian Connell, Director at Ground Sun comments:
The Kensa heat pumps are uncomplicated, robust and no-nonsense; ideal for this size of job. Their heat pumps have proven to be robust in operation over the years.
- Encourage your heat pump designer/installer to work closely with the architect and builder.