Solar panel quote comparison

Powermalc

Good morning, first post as we are thinking of having solar panels installed.
We are in a 4 bedroom bungalow with oil fired boiler for hot water and radiators, no gas in our village, we do not want heat pumps or an EV.
We have sourced 3 quotes via a solar comparison site.

I would grateful if possible to get some opinion on whether these prices are reasonable with the equipment selected by the three companies.

1.
16 x Aiko gen 2 510w panels
Solax 7.5kw hybrid 5G inverter
Solax 2 x 3.6kw batteries
£10,000

2.
18 x Aiko 460w panels
Fox ESS K Series 7kw inverter
Fox ESS 10.36kw battery
£10,867

3.
16 x Aiko Gen 2 510w panels
6kw SigEnergy inverter
SigEnergy 8kw battery
£11,158

All include scaffolding and Solar iBoost for heating the hot water tank.

I can give names of companies if that helps and is allowed with forum rules

Many thanks for any input.

QrizB

Welcome to the forum!

It's a bit odd that all three companies are quoting Aiko panels. They're not an especially common brand, judging from other quotes that have been shared here recently.

If I had to pick one from those three, I'd probably go with #2, with the bigger Fox ESS battery & inverter. But I'd want to know if they could fit 18 of the 510W panels rather than the 460W ones (the 460s seem to be the same width as the 510, but the 510 is slightly taller).

If you can stretch your budget slightly further, you might be able to get a Powerwall 3 system a bit like this.

Screwdriva

For what it’s worth, the prices aren’t the problem- the component brands are 100% Chinese owned, all with little to none or poor track record. It is unfortunate that these are flooding the market. 

If it were my home, I wouldn’t install any of these brands. 

Qyburn

Powermalc said:

All include scaffolding and Solar iBoost for heating the hot water tank.

It's worth mentioning that nowadays it's almost certainly not worth using solar power for water heating. 

Petriix

Qyburn said:

Powermalc said:

All include scaffolding and Solar iBoost for heating the hot water tank.

It's worth mentioning that nowadays it's almost certainly not worth using solar power for water heating. 

To flesh that statement out slightly, water can usually be heated with one of the following methods:

Gas (6p per kWh) 
Cheap overnight electricity (from 7p per kWh) 
A heat pump (~9p per kWh of usable heat, though could be much lower if combined with the cheapest overnight rate)

Prices may vary but it's basically very cheap. Currently export rates are 15p per kWh or possibly higher so (financially) whenever you use rather than export your solar generation, you should view it as costing that 15p per kWh because that's what you would have earned if you'd let it go to the grid instead. 

The same principle applies to any electricity usage you could switch to a cheap period. Being on a cheap EV tariff, we run our washing machine, drier, dishwasher, slow cooker (occasionally) and dehumidifier (in the winter) overnight as well as charging the car. Then we export as much as possible from solar.

Some people can't do this for a variety of reasons, but it's a good principle to follow where possible. 

Martyn1981

And in addition to Petriix's post, if you have batteries (as per the quotes), then they can act as the buffer for water heating, when PV is fluctuating, so they catch the export (if you don't want it leaving) and prevent import, when the water heating might exceed gen and pull import.

QrizB

Martyn1981 said:

And in addition to Petriix's post, if you have batteries (as per the quotes), then they can act as the buffer for water heating, when PV is fluctuating, so they catch the export (if you don't want it leaving) and prevent import, when the water heating might exceed gen and pull import.

My battery is doing that right now, but then again my 2012-vintage PV system is too small to directly drive a 3kW immersion heater evening perfect sunshine.

Any of the systems in the OP should be able to cover that during the middle of a sunny day from April to September, even without a battery.

Powermalc

Thank you all for the helpful comments.

We have decided to go for option one but with an extra battery (to 10.8kw) for £10,500

greenbee

Qyburn said:

Powermalc said:

All include scaffolding and Solar iBoost for heating the hot water tank.

It's worth mentioning that nowadays it's almost certainly not worth using solar power for water heating. 

The OP has no gas, just oil. It may well be worth having the iBoost to reduce oil consumption if they have a small oil tank (like I do) or so they can turn the stinky boiler off in the summer (mine has the flue below the ridge of the roof so fumes drop into the garden). Or so they can heat water when they run out of oil…

Screwdriva

greenbee said:

The OP has no gas, just oil. It may well be worth having the iBoost to reduce oil consumption if they have a small oil tank (like I do) or so they can turn the stinky boiler off in the summer (mine has the flue below the ridge of the roof so fumes drop into the garden). Or so they can heat water when they run out of oil…

Agree 100%

Martyn1981

greenbee said:

Qyburn said:

Powermalc said:

All include scaffolding and Solar iBoost for heating the hot water tank.

It's worth mentioning that nowadays it's almost certainly not worth using solar power for water heating. 

The OP has no gas, just oil. It may well be worth having the iBoost to reduce oil consumption if they have a small oil tank (like I do) or so they can turn the stinky boiler off in the summer (mine has the flue below the ridge of the roof so fumes drop into the garden). Or so they can heat water when they run out of oil…

The iBoost (or similar) are to make use of excess/export that you previously may not have been paid for, and to heat the water without risk of buying/importing dayrate leccy.

But, a battery does that for you. It catches the export, and if you want to heat the water, you can do so, from the battery/inverter, avoiding import.

So the OP is effectively buying the necessary kit already. An iBoost on top would add cost, but not really any additional functionality, especially as it wouldn't be detecting any export, unless the battery is already full, and generation is exceeding household demand.