Before the invasion of Ukraine, the idea of getting off gas was a minority interest, but now suddenly it has become a moral as well as an environmental one. Last month I managed it, partly through luck and partly by planning. There are three areas in a typical home in London where gas is used, for cooking, for hot water and for heating, so most people have a gas hob/cooker, and a gas boiler. I have neither, now. After having both for most of my adult life.
I changed my gas hob to an induction hob a couple of years ago, because it’s safer, cleaner, and greener, it was a pretty simple process and I haven’t regretted it at all. Getting rid of the boiler took a bit longer and I had some help.
In 2020 the UK Govt introduced the Green Homes Grant (GHG) to assist people in the expensive process of upgrading their homes to be greener. The scheme was stopped by April 2022 because of poor takeup and administration, but I managed to get a grant, having applied for it when the scheme was announced for a number of reasons.
- I was curious about how such schemes are administered and I wanted to be knowledgeable about the process so that I could advise clients and friends about it. At that point, I was expecting the scheme to be a long term one and to run for a number of years.
- Like many others, I live in a draughty Victorian home in London and I was keen to improve its energy performance while still living in it.
- I had planned to replace a second batch of single-glazed windows, I did the first batch about five years ago and since the GHG covered single-glazed window replacements I thought that I could speed up this work.
- The original aim of the GHG was to encourage people who were planning work to include some energy efficiency improvements as a secondary measure.
Fast forward twelve months and I now have a solar thermal system installed but I have made no progress with the window upgrades. The plan was to change my windows and I added a solar thermal system because that worked well with the gas boiler and cylinder system I already had, or so I thought.
The path to getting an installation done was tortuous and really only happened because I was both knowledgeable and determined. How anyone who wasn’t a professional in the field managed to get work done I don’t know.
I couldn’t have managed it without a committed and enthusiastic solar installer. (Dominic Skeaping and London solar Co.) this was the second installer I engaged with during the process. The first one had to pull out of doing my installation because the GHG scheme awarded them too many projects in too short a space of time for them to fund or manage, so I had to find a replacement after all the paperwork was done and the grant approved.
I had intended to do the windows at the same time and split the funding between the two measures but in the end, I couldn’t proceed with the window replacement because there was no timber sash window installer who met the bureaucratic requirements of the scheme. I called a number of companies and their response typically was “too busy mate, I have better things to do with my time” The only company that did meet the requirements couldn’t renew their accreditation in time because of the pandemic, so I had to abandon that idea. There seems to have been little or no effort on the part of the administration of the scheme to engage with companies, particularly SMEs and get them involved.
Some of them needed administrative support to deal with the bureaucracy, but without their involvement, some measures couldn’t be done. How can you have an energy efficiency programme in London, or anywhere else in the UK, that doesn’t include timber sash windows? I could have had plastic ones installed but (a) they are plastic and (b) they don’t look as good and (c) they tend to have larger frames which cut out more light which is unhelpful. After all, the reason most people like old Victorian properties is the large windows with plenty of light!
There was a second fundamental problem for small installers as the scheme only paid on completion of the works. They were paid directly by the administrator. This meant that small companies had to pay for the equipment upfront and carry that cost until the installation was finished and then wait for weeks or months for the administration to pay them. This risked the solvency of small companies and led to them limiting the number of installations they were willing to carry out. Future schemes should investigate a solution to this as it seems fundamental to get the involvement of SMEs.
Another unexpected consequence for me was that the MCS scheme (MicroGeneration Certification Scheme) which certifies renewable energy systems requires installers to upgrade existing plumbing systems to comply with current rules if a major change is made. In my case, the old vented 150l cylinder wasn’t big enough to cope with a solar thermal system so has to be replaced with a pressurised 220l cylinder and this led to a number of small changes elsewhere in the system. This added unanticipated time and cost for the installer. There are long-term benefits to the householder in moving to a pressurised system but it made life difficult for the installer who had other projects to complete before the scheme deadline.
The system has a 3m panel on my roof which I expect to deliver most of my domestic hot water from April to September. Part of the control system includes an energy monitor so I will be able to check this in the coming months and years.
A potential longer-term benefit, or so I thought, is that the cylinder was going to make the system heat-pump ready. So if I were to install one I could do it without changing the cylinder. Given the long-term plan for the UK seems to include heat pumps, this seemed to be a good strategic move.
Discussing this with my installer I was surprised at his suggestion that I could move to a heat pump immediately, without installing external wall insulation. The received wisdom across the industry is that older homes need to be insulated to bring down the heating demand to a point where the heat pump can cope.
His point was that, provided the heat pump is sized correctly then there is no problem with moving to heat pumps now, it just won’t be as cheap to run as it would be if the house was insulated. It would need to be a larger capacity system to cope with the larger demand at the coldest point in winter, although for a Victorian terraced house with the capacity to have a roof extension it makes sense to over-specify the heat pump anyway to cope with future demand if I do decide to extend upwards. If I insulate the house meanwhile the heat pump would have more spare capacity.
This opens up a potential path to decarbonisation of our older housing stock where people are not in danger of fuel poverty. (which is relevant to large parts of London) Switching to heat pumps immediately lowers the home’s carbon footprint, and is relatively painless compared to the issues around installing external wall insulation. The appearance of the home doesn’t change, the resident doesn’t need to move out, but they will need a new cylinder and potentially larger radiators depending on the original radiator design. Both changes are relatively easy to make and are much less problematic than installing insulation inside or outside the dwelling, particularly at the present when high-performance insulants are being avoided due to perceived fire risks.
There is a potential path where the existing gas boiler stays in case there are concerns that the heat pump can’t meet the demand, and the heat pump deals with the average hot water demand and some of the heating demand, but the gas boiler augments it mid-winter. But since all cylinders have an electric immersion this can take the place of a gas boiler for peaks where the heat pump cannot cope or is down for maintenance. The heat pump can be specified to meet the midwinter demand in any case. Whether a heat pump will be more expensive, at the moment, will depend on usage, but with the recent gas price rises, the long-term likelihood is that electricity costs will come down and gas prices will rise.
Fast forward a couple of months and now I have a heat pump installation in use, thanks to Dave Turner and the London Heat Pump Co. The RHI Renewable Heat Incentive finished in April 2022 but the installation was finished in time to qualify, and met the MCS certification required (v. important). This is likely to make the heat pump a cost-neutral installation albeit over many years.
The system is a 12kW Samsung that connects to my cylinder in place of my gas boiler which was decommissioned at the same time.
I have collected my energy bills for several years so I will be able to identify cost and energy changes over the next six months.
In some ways, it would have been better to run the solar hot water for a year before installing the heat pump, so I can identify the heat pump efficiency more easily, but once work starts it’s better to continue and finish and leave a substantial period of time before embarking on further work. Family relationships tend to fray when the heating system is not working in winter!
Fast forward again and the heat pump is installed and working. The installation was pretty straightforward and took three days or so with a team of two people. It is working well in terms of efficiency at a CoP of 3.3, (a measurement of heat pump efficiency, above 3 is good, 4 is better) but has a configuration problem that means that the heating sometimes has to be on to run the hot water circuit, obviously not helpful, so the controller board will be switched out to solve the problem. I was surprised that this couldn’t be solved by a firmware update, but the manufacturer is the one holding the warranty so that’s what is going to happen.
The system is being controlled by weather compensation as this seems to be the agreed best approach for heat pumps. This is where the heat pump measures the temperature of the returning water from the home and tries to heat the hot water going into the home to a set temperature relating to it, rather than using an internal thermostat as the goal. The logic is that in colder weather more heat is required and the heat pump can meet the need by building up slowly to the required temperature and then minimizing the effort to maintain the temperature of the return water.
Once the house is at a steady temperature the heat pump doesn’t have to work hard to inject large amounts of heat quickly when it is least efficient. The quoted benefit of using weather compensation is that it reduces demand by about 10% which is quite a lot of performance to give up by using a thermostat.
A related issue is that heat pumps are most efficient when used to bring the home or the hot water cylinder to the right temperature, and then keep them there with small amounts of input. They don’t like to produce a lot of energy quickly, which leads to a change in behaviour. Instead of bringing the heating on early in the morning, it’s best to leave it on constantly, and control the ventilation to manage heat losses. This ends up making the home more comfortable, and reduces those points in the day when the house is cold sometimes and then perhaps too hot when the gas heating is on. A heat pump is less dramatic, and slower to respond.
So, within a couple of years, I have gone from using gas, to not using any, my bills haven’t gone down (like everyone else) but my carbon footprint has. When I get my changed EPC I will post the impact of the combined solar thermal and heat pump on the house CO2 footprint and I will post some data on the temperature and energy use of the system which I am tracking carefully.
To summarise, it’s perfectly possible to install a heat pump into an old property, but it’s not always going to be the cheapest way to heat the home Because of the way gas and electricity tariffs are set up, gas is artificially cheap because most people use gas to heat their homes. Because of the efficiency of the heat pump (3.3) I am getting 3.3 kwh of heat for every 1 kwh I buy. So every kwh is about 8.5p compared to current gas tariffs of 7.5p per kwh,(dividing 28p for electricity by 3.3) so heat pump users are effectively being penalised 1p per kwh. UK govt has signaled a set of future changes to reduce electricity bills by moving some taxation to gas, but perhaps in the meantime, the energy companies need to set up a tariff for heat pump users to reward them for moving off-gas? (or more accurately, to not penalise them for moving away from gas). Meanwhile I will work on reducing my heating demand to see if I can nudge my heat pump up to 4, which will make it cheaper than gas. More soon.
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