Questions for Solar Installation Sales Interview

Verdigris

arty688 said:

sort of depends if you can integrate your heat pump with your solar you couldn't with mine unless you manually did it when the sun came out.

also when comparing electric prices to gas you need to use the export price if you are on GO for example its 3p

Good point. It would need something to signal there was excess solar available, I suppose. I guess if I have batteries the stored electricity would be either from solar or cheap TOU, so perhaps batteries reaching full charge fairly early in the day could be the trigger?

NoobSolar

So we had the meeting. Here is what was proposed:

4.8 kwh system

13 Panels with 25 yr performance guarantee 375 KWh

Inverter with 15 yr guarantee

Immersion heater diverter

The price they wanted was £8300! A friend in an adjacent street has an agreement to get a 10 panel installation from the same supplier (without a diverter) for £4350. What on earth is going on here? Surely at that sort of price our 13 panel install could be done for about £5000 plus the diverter?

Anyway when I put that to them, the salesperson said she would 'speak to her manager' and get back to me later in the week.

2nd_time_buyer

Yes, you are right. You should reckon on £2-300 for each extra panel. 

Regardless of what they come back with, that they tried it on would put me right off.

Spies

@NoobSolar where are you based? 

Reed_Richards

Verdigris said:

Having thought about my own question, I realise that a diverter would be counter-productive in my proposed set up of a large (10kWp ish) solar array and a heat pump. Better to use "free" electricity from the panels through the heat pump, as that will be recorded for RHI payments.

Based on my experience, solar panels are of little use with a heat pump.  Either it's "summer", the heat pump is only used for hot water and you have masses of spare solar electricity.  Or it's "winter" and the solar panels don't generate nearly enough to make much of a dent in the requirements of the heat pump.  My system made a rapid transition from "summer" to "winter" at around the beginning of October.  This was probably exacerbated by the fact that my panels spend more time in shade when the sun is lower in the sky.

My RHI payments don't require any recording of electricity usage.  That's the norm.    

Verdigris

Either it's "summer", the heat pump is only used for hot water and you have masses of spare solar electricity.

That's what I was talking about, using the summer excess, so perfect for me.

My RHI payments don't require any recording of electricity usage.  That's the norm.

I thought you had to have a meter in the heat-pump feed. If what you are saying is true, then it is best to not insulate the house, get big RHI payments because of the larger heat demand, then fit insulation later to minimise power use. Seems a bit counter-intuitive.

Reed_Richards

Verdigris said:

Either it's "summer", the heat pump is only used for hot water and you have masses of spare solar electricity.

That's what I was talking about, using the summer excess, so perfect for me.

But it's a massive excess.  In my case I use typically 2 kWh per day for hot water and the heat pump needs up to 5 or 6 kW of power.  I actually use the 3 kW immersion heater which is less efficient but better matched to the panel output and enables me to heat the hot water to a higher temperature.

Verdigris said:

My RHI payments don't require any recording of electricity usage.  That's the norm.

I thought you had to have a meter in the heat-pump feed. If what you are saying is true, then it is best to not insulate the house, get big RHI payments because of the larger heat demand, then fit insulation later to minimise power use. Seems a bit counter-intuitive.

Counter-intuitive but true.  You have to have an electricity meter in the heat pump feed which you can completely ignore if you wish.  What you cannot do is qualify for the RHI if your EPC (which has to be at most two years old) recommends loft or cavity wall insulation.  So it's only true to a degree. 

Verdigris

That's good news. I've got a very good for loft insulation (300mm) and it assumes the cavities had inbuilt insulation.

So I guess I install to meet the heating load, as is, and add external insulation, later, to cut the running cost right down. It will also leave me with sufficient extra capacity for a "phase two" rooms in the roof extension.

Merlin139

We have a Solar iBoost on our system since May 2014 installed for £150 when our panels were fitted. Prices now are around £270 to £300
In that time ours has diverted 9.3MWh out of 30.6MWh generated. Only works when we have unused spare generation. 
Gives us a free tank of hot Water most days between mid march and mid October.
We have only used the boiler to heat the water half a dozen times during that time.

Gas boiler for the rest of the year. Looking back at our records we had free hot water 24 times between November 2020 and February 2021

Your quote appears way over priced. A simple Google search can find a good wholesaler where you can find the trade prices of Panels, Inverters and Batteries to give you a good idea. Obviously the prices are shown without VAT.

Where in the country are you?

Maybe others could recommend an installer? 

Heedtheadvice

For anybody considering solar, diverters batteries etc the latest Which? articles are well worth a read https://www.which.co.uk/reviews/solar-panels/article/solar-panels/solar-panel-costs (or a quick search with those terms).

Now the full article is only available to members but that costs a very minor amount compared to a potential purchase and could be well worth it to save making purchase and installation mistakes!!

Not suggesting that reading and posting on MSE should be omitted as you can get great answers to specific questions from experienced posters.