The house is one of thousands built to the appalling standards prevalent in the 1970s. It hasn’t really been a project but more a process of steady improvement as and when I could over the last 30 odd years since we moved in. When we bought it it was next to open fields. Since then a housing estate has been built on the fields although, luckily, there is a very large open space next to us and more or less everything we need is within walking distance. I did the loft and cavity wall long before the government woke up to the idea. When we installed the heat pump we also knew that we weren’t eligible for grants or payments of any kind but I thought it would still pay off. I think I was right and we haven’t regretted it for a moment. My son Tom did a lot of the building work for us and he has also been bitten by the energy saving bug.
I don’t like waste in any form so energy conservation is a fairly natural thing for me to do.
By far the biggest change we’ve made is the extension. Being built to higher building standards, I think it improved the thermal insulation and air tightness of the house. That, coupled with the refurbishment, has resulted in a house without draughts and altogether warmer for a much lower energy consumption. It also allowed us to put in a downstairs toilet and completely redo the bathroom which, in turn, made possible the internal insulation. We added an unheated conservatory in the winter of 2009 and this further helps reduce our heat loss.
I don’t have figures for the cost savings because the process started about 30 years ago with me adding more loft insulation followed, a little later, by having the cavity walls insulated. In the early days I couldn’t have easily quantified our energy figures because we had a coal fire. In terms of energy usage, this has dropped from 16965 kWhrs in 2007-2008 to 6947 kWhrs in 2011-2012. I’m hopeful that this year will see a further reduction, down to about 6500 kWhrs.
There is no single feature that stands out, everything we’ve done has either improved our living space or reduced our heat losses.
After the gas fire was taken out, for a time we heated the house using a 2kW wall-mounted heater. During December and January we used an average of 27kWh per day. In the previous winter when we used the 2kW electric fire we used 34kWh per day. The heat pump is rated for 0.7kW. On the face of it 0.7kW, to heat a house? Could it possibly be big enough? In our experience: yes.
We knew from past experience that the old gas fireplace in the living room could adequately heat the whole house without using the radiators, so I was fairly confident that a new source of hot air in the living room could do the job. And so it has proved.
The floor area of our house is 98 square metres and the volume is 225 cubic metres. The old gas fire our heat pump replaced was rated at 11.7kW. So 0.7kW replaced 11.7kW (although it doesn’t heat water). A huge gain in efficiency I think!
Since we installed it, our electricity consumption has gone down. Last year we got by on just under 7,000kW hours, and no gas at all.
Thanks for your letter. The first thing I note is that your house is much larger than ours. Our floor area is 98sq metres with an internal volume of about 252 cu metres. The next very important difference is insulation. We have cavity wall insulation, and in the case of the bathroom, and above the stair well, internal wall insulation as well. Our internal wall insulation is plaster board backed with 42mm of foam insulation. I have also done my best to make the house as airtight as possible. We also have about 250 to 300mm of loft insulation, and of course double glazing, and an insulated front door. All of that effort went into minimising our heat losses before we worried about what heating system we needed. During the summer, from say early in April to mid to late September we switch the Heat pump off completely. However, we have used it for the odd day or two as a cooling unit for the occasional heat wave. Try doing that with a gas boiler. I think your best course of action is to insulate the house as much as you can before doing anything else. A book that I found useful was the Green Building Bible.
Our entire house has been nice and warm since we installed our air source heat pump in December 2011. We leave it switched on 24hrs per day and it keeps on blowing out warm air at about 35 degrees-even on below freezing days. After being off for the summer we switched it on again on in the third week of September.
We have never used any additional heating, except for a 300 watt towel rail in the bathroom. Even on below freezing days, it keeps blowing out warm air at about 35 degrees. Our house is open plan and the heat from the living room makes its own way upstairs where it keeps all the bedrooms warm too.
The indoor unit is very quiet, and the only noise that the outdoor unit makes is the sound of the fan blowing air out, but you have to be standing very close to it to be aware of it. Our cat sometimes stares at the indoor unit for long periods, so it’s possible that she can hear something that we can’t.
Our installation was probably very simple. The outside unit is just about 150mm above the decking and the indoor unit is the other side of the wall about 1,500mm vertically above it. So, no long pipe runs, and no need for ladders or scaffolding. We got three quotes, one for £8,000, one for £2,100, and the one we accepted for £1,200, plus the lower VAT rate for qualifying renewables installations.
Our heat pump was supplied by:
ACS (UK) Ltd
Tel: 0800 085 4737
The model we have is a Mitsubishi rated at 1kW. Although rated at 1 kW, my best estimate is that it uses about 0.5 kW. Even on a cold December day we rarely use more than 25kWhrs per day , which includes cooking, hot water TVs etc. We don’t use any gas. Our house is open plan which means that the warm air goes up the stairs to heat the bedrooms, we have no control over how much heat goes upstairs but in spite of that it all seems to work very well. We are very pleased with it and our electrical consumption has gone down since it was installed.
I can’t claim any expertise about heat pumps and we accepted the recommendations of ACS (UK) Ltd with regard to the size and make of machine. So far it has performed very well and we are very pleased. They do offer a maintenance package at a cost of about £150 per year. They also suggested that we needed this package to comply with certain regulations, I looked up the regulations and discovered that our machine was too small to be covered by the regulations, frankly I thought they were trying it on so I declined their servicing package and clean the air screen/filters myself.