Pulborough, West Sussex – Viessmann air source heat pump installation.
📍 Project Location: Pulborough, West Sussex
📍 Property type: 3-bedroom semi-detached house
System Installed: Viessmann 8 kW Vitocal 222-A air source heat pump.
Key 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.
The following case study was written by the manufacturer Viessmann.
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!
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 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.”
Saving despite spiralling energy costs
The off-peak electricity meter Nigel was previously signed up to has remained, and the new system is programmed to heat hot water, more cheaply, during the night. He says, “By 9am on a normal day, we’d have already consumed 30 kW of electricity from overnight heating of the storage heaters. We’ve not used 30 kW in any whole day since the heat pump arrived.”
“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.”
This project was chosen as Highly Commended in the National ACR & Heat Pump Awards 2023
About Us
At Option Energy Solutions, we serve Sussex, and the surrounding areas, delivering Vaillant and Viessmann heat pump installations with up to 7 years’ guarantee.
We’re also proud to be Heat Geek Approved, which means our design and install work is based on the best-practice engineering principles set out by the UK’s most trusted renewable training platform.
Want to See If a Heat Pump Will Work for You?
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Call us: 01903 366 099
Visit: optionenergy.co.uk
