Homeowners Professionals

An MCS performance calculation forecasted a 53% reduction in annual running costs.

As space was limited, a Vitocal 222-A 8 kW indoor air source heat pump with a 220-litre built-in cylinder was selected, to be used for both heating and hot water.

Air Source Heat Pump

Project Overview

When a homeowner decided to replace the costly and ageing liquid petroleum gas (LPG) boiler in her stone-built three-bedroom 1940s home in the rural Scottish Borders, she initially expected to be installing an  electric  combi boiler. Now she’s saving hundreds of pounds each year on fuel costs with an  air source heat pump  that fits in a kitchen cupboard.

Fuel costs almost halved

Ms Walter contacted Glasgow-based renewable heating installation experts Optama in 2021 looking for a new heating solution that would future proof her home while reducing her fuel costs. Her LPG boiler dated from the 1980s and was costly to run and, with gas prices increasing, she was keen to reduce her reliance on fossil fuels.

After carrying out a detailed survey to ascertain the building’s heat loss and heat demand for the desired level of comfort, renewables expert Chris Collins of Optama proposed an air source heat pump, using the government’s  renewable heat incentive (RHI)  and an interest free loan from Home Energy Scotland to cover the costs. An MCS performance calculation forecasted a 53% reduction in annual running costs.


As space was limited, a Vitocal 222-A 8 kW indoor air source heat pump with a 220-litre built-in  cylinder  was selected, to be used for both heating and hot water. Optama removed the shelving from a kitchen cupboard to make room for the compact new appliance. The heat pump operates for three hours in the morning and six hours at night, which is sufficient to keep the property warm all day while Ms Walters works from home as an IT professional.

Switching from the old LPG system was not a small undertaking as it required new radiators and pipework throughout. Ms Walters and her partner took the opportunity to carry out some other renovations to their property at the same time to improve its energy rating. In future they plan to install solar panels and underfloor heating and to move the heat pump into a new utility room.


Vitocal 222-A air source heat pump with integrated 220-litre cylinder

Rated output


Partner - Optama Heating

Chris Collins of Optama commented,  “A lot of heat pump manufacturers only have two or three models; 4kw- 8 kW, or 12 kW. You’re pushed into oversizing because that’s all that’s available, but it can mean the heat pump is overworked and doesn’t run efficiently. Viessmann, on the other hand, has a great product range. There’s a different product for each type of installation. The  Vitocal 222-A  is very good. And Viessmann’s technical support is very professional.”

Customer quote

“When my LPG boiler came to the end of its life, I thought the solution for us would be an electric boiler, as we have no mains gas in our village. I discussed this with experts at Optama and they suggested an air source heat pump from Viessmann instead. I liked the idea as I wanted to reduce our reliance on fossil fuels. They assured me that my property was sufficiently insulated and were able to provide me with a clear schedule of upfront and running costs. Optama also helped me get government funding. I work from home and am pleased to say that the house is very warm day and night. I’m looking forward to channelling the 53% projected savings in annual running costs into even more energy-efficient home improvements in the future."

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