Questions for Solar Installation Sales Interview

NoobSolar

Hello. Tonight we have a Zoom meeting with a solar installation company, and a few more booked over ensuing weeks. We have a hipped roof victorian end of terrace with a south and a west aspect - hoping for approximately a 3kw system including a diverter to the immersion on the hot water cylinder. I don't particularly want a battery at this stage. Clearly the interview is intended to try to persuade us to sign up now and commit. I have two types of question here. Questions I am asking myself, and questions I should ask them. I would appreciate your contributions. Also advice or warnings about what I should expect?!

Myself:

Do I need a structural report to assess the roof's load bearing ability? Will the installer provide this?

Should I be aiming for 1 to 1.2 £ per W?

1 How much would you charge for a diverter to the cylinder?

2 What spec of panel?

3 Can a battery be installed at a later stage?

4 What do the panels look like?

5 How do you ensure the roof tiles and mounting arrangement avoids any damp or water ingress?

6 Are you MCS certified etc

2nd_time_buyer

"What is the maximum number of panels I can fit on my roof?" to both you and them

arty688

warranty / guarantee ?

how long have they been going ?

Any other installations in the area ?

If you are looking to have standard panels and diverter and your install is also standard then £1-£1.2 is ok but it also depends on the size of your system as there are fix costs which will be the same for putting 1 panel or 10 panels which is one of the reasons people advise the as big as you can approach.  

NoobSolar

Very helpful - appreciated, thanks!

[Deleted User]

Think VAT. If you are not careful you can end up paying 20%. If the installer knows his stuff, then he should be able to get VAT down to 5%. Also, think battery. A battery fitted at the same time can attract 5% VAT. Fitting it later, it defaults to 20%. Finally, think carefully about a solar diverter for hot water heating. You will never recover the cost on a 3kWp array.

Verdigris

[Deleted User] said:

 Finally, think carefully about a solar diverter for hot water heating. You will never recover the cost on a 3kWp array.

At what size of array would an immersion diverter become cost effective?

arty688

It also depends if you are having the diverter purely for financial reasons.
The 20%/5% vat thing would also apply to the diverter so cheaper to install with panels.
Also where are gas prices going?
I am 100% electric with a heat pump so its not something I have investigated though , but don't be under the illusion its free electricity as you have to compare it to gas price and export price.

Exiled_Tyke

If you are currently using gas to heat your water them remember that gas is still cheaper than electricity. So a diverter is saving heating with gas, at a much lower rate than the cost of electricity.   Of course you also already need a cylinder with immersion heater for a diverter. If you don't already have these then the cost of installing all this is unlikely to be recoverable. - It wasn't for me. Others on here though have had great success with their diverters. 

The most major issue we see with installers is the claims they make about savings and the amount of electricity generated. I would be asking questions to really check these out.  How have they calculated generation figures, did they take into account any shading etc..  Where do the assumption on self-consumption come from.    

Of course walk away from anyone who doesn't want to give you time to consider. 

Finally come back here to share your findings before you decide.  It's best if you can get two or three quotes though. 

Verdigris

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.

jimjames

I'd say the interview gives you a very good chance to assess the way the company operates. Any that do the hard sell, fiddle the increase in electricity prices to boost the returns can be binned off immediately. Any that answer your questions, explain the setup and let you decide are the ones to have on your shortlist.

I'd also suggest doing a google search for any you're considering with "company name" + "complaints" or "scam"

arty688

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.

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