How we upgraded our new build detached house
Local resident, Andrew, shares his household's journey...
We are a retired couple and recently moved from a large waterfront property to a 4 bed detached house on a new housing estate. The house has an Energy Performance Certificate (EPC) rating of 83 and a conventional gas boiler and radiators for heating. I have had a varied career in business, science, IT and academia – mainly focused around meteorology and the maritime environment. I have a PhD in Meteorology and am a Chartered Meteorologist.
In the summer of 2021, against a background of concern about future fuel costs and the increasingly urgent need to mitigate the impact of climate change, we researched the options to move away from gas and install a more efficient domestic energy system. The obvious solution was a heat pump and the most efficient type is a ground source system which draws heat from the earth, but as we live in an old quarry with a small garden this wasn’t an option. The other system is an air source heat pump, which is less efficient but can be installed just about anywhere.
The house was originally constructed with 4 solar panels on a roof which faces south. We asked the house building company how much we would have to pay them to have more panels, but they said it was not possible. I think this related to the Government subsidy they received for renewables on the development as a whole and then adopted an approach that maximised their profit margin. So our new system would increase the number of solar panels and also add battery storage.
It seemed likely that the demand for heat pump installations will increase rapidly in the near future and so it would be prudent to get the project underway before the winter sets in. The system was installed in October 2021 and has been 100% reliable and definitely uses less energy overall – and no gas!
However, it is important to understand that we did not invest in this system to save money, it was driven by the desire to play a small part in the battle against climate change. I have been asked about the ‘payback time’ for our system and I can honestly reply that I have not attempted to calculate it. Of course that depends on how long we live and the future cost of electricity – both of which are unknown.
I wanted to find a contractor who could take on the whole project and deliver a total system and whilst it was easy to find solar panel installers and heat pump vendors the two groups were somewhat mutually exclusive. After receiving some quotations we signed up with a company that was effectively a marketing organisation that had a good track record with a specialist subcontractor based in the north of England that could supply and install the whole system.
They would also take on all the documentation and certification to comply with the Microgeneration Certification Scheme (MCS ) and to be able to access the currently-available government available subsidies.
Prior to the installation we had visits from one of their consultants who advised on the detailed specification for the system and conducted a survey of the house. Older properties with conventional radiator systems sometimes need a major upgrade or a change to underfloor heating, but a modern house like ours with relatively large and efficient radiators may be able to operate effectively with no modification. In this case the new heat pump can just connect to the pipes used by the old gas boiler.
There was also another independent survey relating to the MCS certification. There were some recommendations for minor enhancements to some of the radiators, but we declined these. However, the internal water cylinder had to be replaced with a model optimised for use with the lower flow temperature generated by an air source heat pump.
8.5 KW Mitsubishi ECODAN Air Source Heat Pump
Grant HPFR250C/BS High Performance Cylinder
12 x JA Solar 380W Mono MBB Solar Array
Luxpower 3600ACS AC-coupled Inverter
2 x Uhome- LFP 2400 Lithium Batteries
All costs include installation and VAT
We receive £295 each quarter for 7 years under the Domestic Renewable Heat Incentive Scheme (DRHI) – which is now closed.
The functionality of the whole system is significantly enhanced by the following features:
- Data from both the Mitsubishi heat pump and the Luxpower system can be monitored and downloaded remotely which enables a detailed analysis of the performance of the system, even when away from home.
- The ECODAN control system includes a ‘Holiday’ mode which switches into a mode that minimises energy use over a prescribed date range.
- The ambient temperature of the house is controlled by a remote thermostat unit which is connected by WiFi and can be located anywhere in the house.
- We used Trustpilot to find contractors with a good track record in the relevant sector.
- When researching air source heat pumps, it is not unusual to find reports about the noise they make. We cannot hear our unit from inside the house and the noise when standing next to it when running is not intrusive.
- Make sure you have an MCS-certified system.
In many respects this is the perfect system, but potential improvements would be to add more storage batteries and solar panels as well as solar water heating.