For the first time in my life, Christmas 2021 was fossil fuel free! Our 400 year-old house was finally warm and toasty thanks to our brand new air source heat pumps.
This article describes how we came to choose air source heat pumps as the replacement heating system for our old house, our experience of the installation process, and finally all the technical details of the system that we opted for.
Part 1: Choosing a replacement heating system
Antique heating systems
Prior to Christmas 2021, our leaky old farmhouse had been barely heated by a combination of gas, oil and wood burning stoves. In the autumn and winter months, we were never warm. Our boiler, a sinister looking oil-fired monstrosity, that closely resembled the furnace from ‘The Burbs’ (1989 black comedy starring Tom Hanks and Carrie Fisher), was almost as old as me, having been installed in 1975. We also had a Rayburn of a similar vintage that devoured gas and heated the kitchen and the hot water, but did very little else.
Replacement heating options
We knew that the heating needed a complete overhaul, and in a house that needs
almost complete renovation, the decisions were difficult. We were clear that replacing the oil-fired boiler with another oil-fired boiler was out of the question, but what about replacing it with a modern, efficient gas boiler? The house is served by mains gas and it would be a relatively cheap option.
And then there was the Rayburn, the warm heart of the home, that helped dry our
clothes in winter, provided the extra oven space we needed for Christmas dinner and other
family gatherings, and was used as seating for my daughters when they got
The decision was a difficult one - what we really wanted was to move away from
fossil fuels completely, but the alternatives are vastly more expensive. Would we be
better going with the cheaper option of gas, and using our remaining funds to
renovate other parts of the house, or do we throw all our money into sorting out the
Gas or air source heat pumps?
We had many quotes for various different heating systems, and rapidly decided that
a ground source heat pump was definitely not an option. We narrowed the choice
down to either a gas boiler, or air source heat pumps.
At this point, I should explain that our house is quite old (about 400 years), is Grade
II listed and when it was ‘upgraded’ by the previous owners, they made one bad
decision after another, which among other things culminated in an upstairs room that
can only be accessed from outside, with the aid of a ladder and hook on the window,
to pull it open. THERE IS A LOT OF WORK TO BE DONE!
But… we knew we had to replace the heating system, so isn’t that the perfect
opportunity to look to the future and seriously reduce our carbon footprint?
In the end there really was only one option: an air source heat pump.
Part 2: Our installation experience
Decision made, the work begins
The boiler came out, along with the Rayburn, the immersion heater, four cold water
tanks hidden in random lofts and attic spaces, all the old pipework (which was so furred up, it was barely functional), and all the radiators.
To heat the house, we actually needed two air source heat pumps. The pipework was
replaced and the hot water system completely overhauled. The radiators were all replaced with bigger ones - they sometimes doubled or even tripled in size. New ones were added to many of the rooms to ensure the heat was constant, throughout each room and indeed the entire house.
The process was expensive and time consuming, and involved an awful lot of
upheaval, as the plumbers moved from room to room, and we shuffled around to
accommodate them – all in the run up to Christmas. We had two gangs of plumbers
working for the best past of a month, taking up every floor and moving most of the
furniture. We had ‘homework’ most evenings – trying to get rooms ready for them to
work on the following day, but it was absolutely worth it!
And Finally, warmth
The plumbers finally left, and we raced to restore a degree of order, before our guests arrived for Christmas, but more significantly, we were finally warm. It is a different sort of heat to that which we had experienced previously in the house: no hot or cold spots, just a constant, pleasant temperature everywhere.
There is only one downside: I no longer know what to wear when going outside!
Previously, it was one additional layer on top of the many, many layers of indoor
clothes. Since the heat pumps came online, the process has been very hit and miss,
and a period of re-education is underway.
Part 3: The technical detail of our air source heat pump system
Cost of the heating project
We initially got quotes for the work in November 2020, not just for the heat pumps,
but the removal and replacement of our existing heating and plumbing systems,
including the removal and safe disposal of the oil tank, Rayburn, boiler, immersion
heater and numerous cold-water tanks. The initial quote was for £36K, but by the
time we could afford to go ahead with the work, the Brexit dividend had kicked in, so
the cost significantly increased.
We eventually decided to go with the quote from Greenscape Energy Ltd,
based in Ipswich, who proposed installing Steibel Eltron heat pumps (which my
husband with an engineering background, determined were the most suitable for our
needs). Greenscape understood the nature of our somewhat random house and our
future energy needs.
With the Brexit ‘surcharge’ the work ended up costing about £45K. This was split into roughly half for the heat pumps and half for the radiators, installation, and removal of existing
Our house is long and thin and in the newer part (only 300 years old) is four stories,
and whilst we haven’t added heating to the cellar, we have added radiators to ensure
that the attic bedroom is now usable all year round. In total, we are currently heating
14 rooms and an 18 metre-long hallway, but as renovations progress this will
increase to 16/17 rooms.
The plumbers estimated how much copper piping would be required to replace the
existing pipes, then had to get more and then had to get even more – did I mention
that our house is long and thin and tall? From the outdoor units to the heat stores, there is
15 metres of pipework and from there to the tanks, about another 15 metres
The heat pumps are big. We have two units that each produce 14KW, and measure
(w)1.5m, (h)1.2m, (d) 0.6m, and sit along the exterior wall of our garage. We then
have two 400 litre storage tanks inside the garage.
How noisy are the air source heat pumps?
We were quite concerned about the noise of the heat pumps when they’re running –
as were our neighbours, who are in fact much closer to them than we are. We
discussed the issue with the neighbours and promised to install a soundproof fence
if the noise bothered them at all. But we were all worried for nothing: when going,
the heat pumps run at 57dBA at 1metre – which is between the level of a quiet library and
The neighbours can’t normally hear them running, but, when sitting outside they can
sometimes hear a very quiet hum, which is far less intrusive than the sound of the
Running costs for the heat pumps
When it comes to running costs, the recent energy price rises means that running
the heat pumps to heat the house is slightly cheaper than the combined costs of oil,
gas and wood that we were previously paying, but more importantly, the house is
now warm. In addition to this, we are due to receive our first payment from the
Renewable Heat Incentive Scheme, later this month, which will go a small way to
help offset the costs.
In an ideal world we would be adding solar panels to the roof to compensate for the
increased use of electricity, but our 400 year old farmhouse is Grade II listed and in a
conservation area, so there is no chance of us getting permission to do this. Instead
we have bought shares in Ripple Energy, so we now own part of a brand new wind
farm, that will soon supply our home with green electricity.
Was it worth it?
Our old heating systems were decrepit, smelly, inefficient and ineffective, and
constituted the lion's share of our carbon footprint. Whilst we were sad to see the
Rayburn go, I’m not at all sad about removing the gas supply, or the oil tank from the
The work involved a lot of upheaval, but it was definitely worth it - it’s lovely to feel
warm, without feeling guilty about burning fossil fuels. We'll be paying for it for a long
time to come, but there's never been a more urgent need to invest to protect our
future. I wish that we could have done this years ago.