Homeowners Professionals

Heat pump installation catches TV attention

When home owner, Nigel Armstrong, saw a television feature on heat pumps, it sparked a desire to know more. Less than one year later, Nigel’s experience came full circle when his own air source heat pump heating system was filmed by Channel 5!

Options Energy Solutions Ltd, Michael Paini

Expert advice

Since Nigel Armstrong and his family moved into their three-bedroom, semi-detached property in Pulborough, West Sussex, in the late 1990s, he had barely given the house’s electric storage heaters any thought. This is until in spring 2022, a television feature on heat pumps made him curious about the technology.

“I realised the storage heaters were getting old and I needed to do something about it,” explained Nigel. “There’s no gas supply on our street, and with climate change, a renewable option like heat pumps seemed like a good solution. That said, I was definitely sceptical about the technology’s ability to work in a 1980s property like ours, so I needed expert advice.”

Nigel enlisted the help of director and lead heating engineer of Options Energy Solutions Ltd, Michael Paini, who took the time to explain how the new system might work, and talk through various options. Following a heat loss calculation, Paini specified a Viessmann 8 kW Vitocal 222-A air source heat pump. It was installed in the property’s back garden in March 2022. The Vitocal’s indoor unit features an integral 250-litre domestic hot water cylinder and is backed up by a 3kW booster heater designed to kick in if the heat pump ever develops a fault. 

“Even though the storage heaters were fed by off-peak electricity, energy bills were still high as the property had such large swings in temperature,” explained Paini. “This was because the heaters ran so hot whenever they were on, that the house was overheated and lots of energy wasted as a result. Guided by a 'room by room heat loss calculation', we replaced the storage heaters with regular panel convector radiators, sized to deliver the required output at the heat pump operating temperatures, in order to deliver to much more comfortable and stable temperatures throughout.”

Helpful data

“The Armstrong’s heat pump is designed to run at a 45-degree flow temperature,” says Paini. “This is already a nice low temperature at which a heat pump should run very efficiently, but we were keen to work together over a couple of weeks and tweak the system, under operation, to make it run as efficiently as possible.

“Before he’d even contacted us, Nigel had put up temperature gauges around the house so he could monitor where heat was being retained and where it was being lost. Not only did this give us a lot of data to work with, but it also gave me a backdrop against which I could see exactly how the new radiators were performing, so that we could maximise efficiency.

“With all the thermostatic radiator valves on max, we then set up Viessmann’s weather compensation control technology, which is where the heating system takes temperature information from an outdoor sensor and adjusts its operation accordingly. Over the course of two weeks or so, we kept knocking the heat curve down bit by bit until the heat pump could keep the house at a constant 21 degrees – all fuelled by a system working at the lowest temperature and highest efficiency possible.”


“Our electricity bill for March to September 2021 was £1,400. For the same period in 2022, the cost was lower at £1,357 – this is despite the cost of energy doubling in this time. Taking electricity consumption during the night alone, we used 2,680 kWh for that same period in 2021, and in 2022, this was reduced by almost 75% to just 698 kWh. Considering I was previously paying 4-4.5 p per unit, and I’m now being charged 10p per unit, the bill is dramatically lower than what it would have been had we not taken action.”

A story of firsts and lasts

In autumn 2022, Nigel was approached by the producers from Channel 5 keen to see the heat pump up and running. The system is one of the last in the country to qualify for funding through the domestic Renewable Heat Incentive (RHI), which has since been replaced by the Boiler Upgrade Scheme. Nigel will receive around £4,700 from the government in total.

Paini was supported in this installation by the Viessmann Access Microgeneration Certification Scheme (MCS) umbrella scheme. Launched in 2021, the scheme offers Viessmann-trained, but non-MCS-accredited installers, the opportunity to access government funding to their customers, without the time and financial commitment of MCS accreditation.

“This was my first installation using Viessmann’s MCS scheme, and I can honestly say that without it, installations such as Nigel’s would’ve been a nonstarter for me. I’ve since done a few more on the scheme, and I think it’s just what the growing UK heat pump industry needs. It saves time in terms of running the business and all the convoluted process of hoops and expense along the way. Instead, this navigates all the red tape, and lets us get on with system design – what we do best!”


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