Genous Earth: A makeover of a tired dowdy 30 year old

Genous Earth: A makeover of a tired dowdy 30 year old


Air Source Heat Pump

South East

Converting a 1993 Construction 4 bed house from an unvented (low pressure hot water) system with a gas system boiler to a heat pump.


The project started with a gas boiler, an un-pressurised copper hot water cylinder, a mechanical room stat in the hallway and poor controls.

The original boiler had no temperature display, so there was no clear indication on how it was running. It had only one outlet temperature for both heating and hot water and no weather compensation. Therefore, the option was to have either a warm shower and red hot radiators, or cooler radiators and a cold shower. It was also badly installed with no modulation on the boiler so it cycled erratically and when it was running the pump was noisy and could be heard everywhere in the house. The room stat was also unpredictable and difficult to operate as well as issues with water pressure, amongst others.

Therefore a new, more efficient, heating system was required.

The first job was to rip out the hot water cylinder and the boiler. the homeowner chose a pre plumbed Ideal heat pump cylinder which once installed gave them high pressure hot and cold water everywhere in the house.

The only issue they encountered was when upping the pressure was to expose weak points in the system, with one valve developing a leak. 

Next the heat pump was connected to the existing boiler pipework and radiators. They had chosen not to upgrade the heating system following calculations based on running the heat pump up to 55C 24/7. The pipes were extended from the boiler cupboard to the heat pump location and connected.

The heat pump is an Ideal Logic Air 10kW and has a variable speed PWM pump inside which is capable of pumping the water round the whole house with no assistance. Therefore, the homeowner chose not to use a buffer vessel and connected the heat pump straight in, just like the boiler and did not include anti-freeze valves, buffers, volumisers, shunt pumps etc.

'The set up of the system was quick and easy, the unit asks three questions and then runs, it’s a self-learning unit so it adjusts itself to the house using a tactile thermostat which is wireless. All I needed to do was time clock the hot water to run in low tariff periods.'

The homeowner chose not to use TRVs on the radiators and elected to balance the system manually by tweaking the valves 1/8 of a turn at a time to get the perfect temperature in every room.


The paperwork was the biggest challenge with the need to visit four separate websites to complete the required forms, however Genous Earth uses software to automate the process and so any issues were negated.


Unit cost from city plumbing £4853.

Plumber’s labour and material £1100

MCS costs and paperwork £1000

Electricians costs £1000

Total £7953 - £7500 BUS grant, £453 supplied and instal

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