Converting to Solar

Phoenix999

Hello everyone.

I am 60 years old and retired. I have a fairly good pension pot and other savings, I did not spend, I saved. I live on my own in a small (never liked large houses) two bedroom detached bungalow. I have decided I want to convert to solar and have done a fair amount of research including this forum, but I am totally lost on all the technical stuff, so please bear that in mind. I was an accountant, not a techy! My roof is tiled, the building a 1970s build, the roof angle is about 30%, and sound as far as I am aware. I took advantage of the free cavity insulation operated by British Gas a few years ago, the house is well insulated and retains heat well. Some extra loft insulation would not go amiss however. The roof is south facing. I currently have GCH powered by a combi boiler. The pipes are not insulated, and the radiators old. I do not own an electric car, and will wait until the prices fall, I have a fairly new, efficient Golf, my car tax is low, fuel consumption good. I am disabled having lost my leg above the knee, therefore will not be able to do any of the installation myself. I take the view that, agree or disagree, UK governments do not like gas, and will discourage usage of it even more than planned in the near future.

My current annual usage is:

Electricity 3,300 kwh
Gas 9,300 kwh 

I was told by the salesman that I need to convert the gas kwh on the basis 1kwh of electricity - 2,2 kwh of gas. This is something I am unsure about, and I cannot find anything to either refute or confirm it. I know a kwh is a kwh, what I do not know is the inefficiency of gas relative to electricity.

My plan is as follows

Rip out the boiler and GCH
Install electric radiators throughout
Install a tankless water heater for hot water. As I am alone I do not need a powerful one.
Install 22 solar panels to power the electricity.

I have rejected ASHP, I do not think they are a good idea, as underfloor heating is not possible, the floor is solid concrete, so the cost prohibitive. The pipes would either need to be replaced or be insulated, again costly.  

For the solar installation, I researched several companies, rejecting one by one for various reasons. I only spoke to two, and only requested a quote from one of them, which I will detail below directly from the quote:

22 LG 380w solar mono neon H E6 - 16 of these on south facing roof with virtually no shade, and six on the garage roof which is flat
22 Microinverters IQ7+ 295w
Tesla Powerwall 2 battery - this will not be until late winter at the earliest, but as I will probably be taking from the grid, I am not too concerned for now. There is a wait for these until at least January.
The company install some form of monitoring system, I was sold this on the explanation that if there are any problems, they can remotely analyse it immediately, and isolate and issues. I am quoting this from memory, I may be a little off with it. This costs around £1,000 so it is not a deal-breaker, but comments welcome
All installation and cabling, and liaison with the electrician who will install the radiators and tankless water heater

Inclusive of 5% VAT, the total is £21,000. I have been told this will pay for all my electricity usage for 10 months of the year. Whether this includes selling to the grid when possible I am not sure, so assume it does. This will generate around 8,400kwh pa.

I  am less concerned with the installation of radiators and hot water heater. I have received one quote that I will probably reject. They include very expensive radiations (£600 or so each), and reading this forum, I know I do not need to spend anything like that. I see another electrician today, as well as the plumber, who I have dealt with before and is top drawer, extremely efficient and outstanding customer service. They recommended an electrician, and both will be here today at the same time.

So, comments would be very much appreciated.

Is the solar cost excessive?
Are the panels the best for what I want?
Is a figure of around 80% saving on total energy bill, including selling to the grid, realistic?
Does what I have read still stand, expensive electric radiators are a total waste? All I need is a thermostat on each, no wifi, no flashing disco, just heat, and aesthetically pleasing.

Finally, am I making a dreadful mistake?

My reason for going solar is not just about renewable, certainly not about CO2, It is what some may say slightly irrational. Following the amputation, I was totally reliant on others for several weeks. I hated it, I am paranoid about it now. I now loathe relying on others, and wish to eliminate this as much as possible, this is clearly a mental reaction to the lifestyle change, and it is never going to change. However, if what I am planning is just not feasible, I won't do it. Hence the request for any advice and comments, , positive or negative.

Apologies for the length of the post, but I have tried to include as much relevant information as possible.

Thanking you in advance.

QrizB

I think you've been badly advised.

• Solar PV is not a good match to domestic heating, as you'll generate far more electricity in the summer than you can use, while having far less than you need in the winter.
• "I was told by the salesman that I need to convert the gas kwh on the basis 1kwh of electricity - 2,2 kwh of gas" is fantasy.
• "I have rejected ASHP" - by rejecting this you've (conseveratively) doubled the amount of electricity you will need for heating. Less conservatively you've tripled the amount you need.
• 80% saving on energy costs is also very unlikely. Your energy costs might even increase.
  

Let's look at the specifics. You've been quoted for a roughly 8.4kWp solar PV system. If installed in the best part of the British isles, near Brighton, on average this would generate 9300kWh of electricity per year. On paper that might sound like it's just big enough but it's at the wrong time of year. Almost 1200kWh is generated in an average July, when (hopefully) you have no need for heating; in an average December you'd only see 320kWh.

Your current year-round electricity demand of 3300kWh/yr is roughly 9kWh/day; assuming no seasonal variation you'll want 279kWh for the 31 days of December. Do you think you can heat your house through December using a total of 41kWh of electricity?

The 9300kWh of gas you currently use, at 4p/kWh plus standing charge, costs you around £450 pa. Making the assumption that your current heating system is only 75% efficient, it will be delivering around 7000kWh of useful heat. To provide that with direct electric heat will need 7000kWh; at current grid prices, that's £1500, compared to the £400 that you're currently paying for gas. supplying the same amount of heat via an ASHP should cost between £500 and £750; still more than your paying for gas.

I would suggest:

• Get the solar PV if you want it, but not the battery. The 8.4kWp of solar alone should cost less than £10k.
• If you don't like gas, fit an ASHP feeding radiators, much as your current combi boiler does, but understand it will cost more than mains gas (unless and until there's a future policy change from government). This will be another ~£10k.
  

Reed_Richards

Phoenix999 said:

Finally, am I making a dreadful mistake?

Yes you are.  You'll get more solar power than you need in summer and not nearly enough in winter when you want heat.  I actually have both solar panels and an ASHP (which is the most economical form of electric heating) and they don't mesh together at all well; I still have a big electricity bill.

Phoenix999

OK, just those two responses are probably all I need unless anyone disagrees, which I doubt owing to the strength of both your replies.

Thank you very much. I still have the plumber and electrician coming, too late to cancel them, but I am well within the cooling off period.

I am thinking up to date aluminium radiators with thermostats is the way forward. It is looking like solar needs to wait until the prices come down, significantly.

Reed_Richards

Aluminium radiators are often stylish and I am told that they heat up and cool down more quickly that steel radiators but I don't see that they are worth the extra cost for any improvement that you might or might not see in the performance of your heating system.  I would advise on keeping your existing radiators until such time as you might want to move to a heating system that works at a lower water temperature, at which point you wilt need to replace all your radiators with ones having a much larger surface area.

Phoenix999

Thank you. I have now cancelled the solar. I would have asked earlier, but I had to wait three days after registering to be able to post. It is no problem, I am well within the cooling off period.

I know how I live, and I know my house. I would benefit a great deal from radiators with their own thermostat. I know nothing about this, so will do some research and see what is what. The boiler is due a service anyway, so I will chat with the plumber when he gets here.

QrizB

Phoenix999 said:

Thank you. I have now cancelled the solar. I would have asked earlier, but I had to wait three days after registering to be able to post. It is no problem, I am well within the cooling off period.
I know how I live, and I know my house. I would benefit a great deal from radiators with their own thermostat. I know nothing about this, so will do some research and see what is what. The boiler is due a service anyway, so I will chat with the plumber when he gets here.

Thermostatic radiator valves are relatively cheap and I'm sure your plumber will be happy to quote to fit them. If they think your radiators themselves need replacing I'm sure they will give you options for that too.

The latest thing is smart heating controls (Nest, Hive, etc) which might also benefit you, depending on your current boiler's capabilities and the control system it currently has. Your plumber will have an opinion on these too!

Reed_Richards

Phoenix999 said:

I would benefit a great deal from radiators with their own thermostat. I know nothing about this, so will do some research and see what is what. The boiler is due a service anyway, so I will chat with the plumber when he gets here.

I'm all in favour of Thermostatic Radiator Valves (which I have on all my radiators).  I've experimented with the "smart" type that can be controlled by my central heating controller but I did not get on too well with those because, unlike dumb TRVs, they took precedence over a room thermostat elsewhere on the heating loop.