Cumhill House

The Project.

Cumhill House in Somerset was built approximately 35 years ago and at over 400sqm is one of the larger homes we’ve fitted a heat pump to. The house itself has great insulation values however did suffer from being heated by an oil boiler. The home owner contacted us and asked us to replace the system with an air source heat pump.

Cost savings of running an air source heat pump are fairly secure, however there is always a greater cost when 2 heat pumps are required. The goal for this homeowner was to replace his ageing boiler with renewable technology and help to future proof the existing heating system.

Luckily a house this size came with a large plant room for the hydro box units as well as a buffer vessel with plenty of outside space for 2 new stylish Daikin Altherma 3 HT heat pumps.

The Solution.

Due to the well designed and well insulated walls, windows, floor and roof the house itself had a heat loss of 24kW. Too much for one air source so we proposed a second heat pump. These were installed alongside a 300 litre buffer vessel for the heating system and one of the heat pumps was connected to a 350 litre twin coil hot water cylinder.

With the Daikin Altherma 3 HT capable of reaching flow temperatures of 70°C without drastically altering the efficiency of the heat pump the customer was able to keep most of his existing heating system, the system was flushed and cleaned before commissioning to ensure maximum performance can be achieved.

The Heat Pumps.

Air source heat pumps are often limited in size, with single compressors as apposed to ground source heat pumps which often use multiple compressors to increase the overall capacity of the heat pump.

The customer was very keen to remove the need for fossil fuels entirely so rather than install a single heat pump with the boiler to take over as the temperature dropped 2 HT heat pumps were installed sized to cope with the entire demand of the property throughout winter.

The buffer vessel was installed to increase the volume of the system, working almost like a battery storing warm water to allow quicker delivery to the radiators and prolong the life of the system.

Value.

The approximate value of this project is £18,000 and included the 2 heat pumps, buffer vessel, power supplies and connection to the existing heating system. All our quotations for designing and installing include the commissioning and MCS certification of the heat pump where required.

The expected RHI income for this home over 7 years is £11,709 and significantly lower running costs compared to the old oil boiler the system should have a payback period of 7 years and a life expectancy of 20 years.