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Clean green heat in my cold old house

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.


View of gable end of old, mellow brick farmhouse with trees in background

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.

A very rusty, very old central heating boiler
The ancient oil-fired boiler

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

particularly cold.


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

heating system?


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.

Complex array of new central heating piping
There's a lot of brand new piping

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

heating systems.


Specifications

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.

Two storage tanks for a domestic air source heat pump, with lots of piping
The storage tanks

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

falling rain.

The two air source heat pump units

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

passing cars.


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

garden.


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.

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