Solar Quotes - Advice Please

mikeuwe2006

Hi all, 

We have been looking at getting a Solar PV system installed and had a few outline quotes. Would be great to get some advice / thoughts on what we've had so far, and any experience of the companies. Apologies if I don't get all the jargon accurate, newbie here!!

We're a 3 bed semi in GU52, Hampshire, 2 adults and 2 young children. Roughly south facing front roof with approx. 30° pitch. Expected space for 12 panels and current estimated annual electricity of around 3200 kWh. We are considering an electric car so need to forward plan for that. We're largely out of the house during the day.

For ease of comparison, I'll try to give the rough quote we've had based on standard PV with no battery from each, and indicate their add-ons 

Project Solar UK
Quick search on here tells me enough to know it's a big fat avoid! They quoted us just under £13k. This was including 4Kw battery and a voltage optimiser. They obviously tried to sell us everything and suggest that their warranties and support are superior to all other companies. All sounded very good, but a bit of Googling after they left suggested it was all BS.

ECH Group
4.02kW Solar PV: 12 x 335W Panel 'Canadian Solar' System - £4,395
• Add £300 for iBoost
• Add £900 for Zappi EV charger
• Add £1,550 for Lux 2.4kWh battery
• Add £2,350 for Lux 4 8kWh battery
• Add £3,600 for Solax Triple 4.5kWh grid trading battery
• Add £700 for SolarEdge
• Add £600 for voltage optimiser

These recommended to go for iBoost instead of battery as would deliver similar overall energy cost savings when considering gas savings as well, with much smaller outlay vs. battery.

First4Solar
12 x Q Cells 345W Black Framed 4.14kW system - £5,300
• Above, plus SoFar 4.8kWh Battery Storage System - £7,000 total

These recommended a battery.

UPS Solar
12 x SHARP 300W All Black Panel 3.6kWp system - £4,300
• Add Hybrid inverter with 2 4kWh Pylontech US2000 plus Li-Ion Battery - £1,450
• Add additional 2.4kWh battery - £1,000
• Add iBoost - £399
• Add Zappi EV charger - £1,250

E.ON - pending quote

On the face of it, ECH seem like the logical route from cost, and they didn't try to over sell anything. They also offer zero deposit and only require payment on completion.

I'd welcome your thoughts!
Thank you.

mickyduck55

For comparison invoice

Rheumatoid

See Sig

Martyn1981

TBF all of those quotes seem reasonable, which for me is really positive news, as is your awareness of Project Solar.

Sorry this doesn't help you much (at all) but just wanted to share my joy. You may find some interesting bits in the PV FAQs (see my autosig) but I'll admit it's getting a bit out dated slowly.

One point, perhaps, given that your quotes are good, perhaps you could consider higher Wp panels (ask for suggestions/prices) but you may find that as you go bigger, the higher tech means that the cost per Wp rises steeply.

Solarchaser

Most quotes look decent.
Id say a good rule of thumb is £1100 /kw for panels at the moment.
Ech looks best.

Batteries make sense if you are a high user for electric imo (over 4000kwh /year), but if you have a hot water tank already, then an iboost or equivalent is a good idea.

Zappi is a great idea, but only if it saves you money long term, if the cost between it and a dumb charger is more than a couple of hundred, you are going to struggle to justify it imo

Petriix

Iboost, eddi etc are almost certainly a waste of money if you have a modern gas combi boiler. Your savings are a maximum of the cost of the gas you would have burned to heat the water, not the cost of importing the electricity that you divert.

Our total gas consumption for hot water is roughly 2000 kWh per year which costs around £60. More energy is required to heat the water in the winter when solar generation is lower so you'd be lucky if an iboost could halve your hot water costs.

I know it seems appealing to use as much of what you generate as you can, but you'd actually earn more by exporting the electricity at > 5p and paying for the gas at < 3p.

pinnks

Afraid I disagree. 

I have records of my gas consumption since 2008 and installed my PV and diverter in 2013. I can see from those records that turning my boiler off between late April and early October saves me about £70 each year.  During that period I get about 99% of my hot water from my diverter, which happens to be an immerSUN but they are all much the same.  During the remainder of the year I get a contribution towards my hot water on perhaps one third of days.  So, overall a saving of between £80 and maybe £100 per year.  This is not based on a calculation of diverted kWh at some rate per kWh but on actual gas consumption data.

Also, the calculation is not as simple as you suggest.  If you are using your boiler only for hot water in those summer months then its efficiency is way done on what is published because of losses in the system.  For instance, I have about 22m of 22/28mm pipe between boiler and tank and back, all of which is unlagged (like most pipe under people's floors) and has to be heated.  Those losses are substantial.  If I look at what I divert and multiply by the electricity rate per kWh, I get close to my measured gas savings.

I now have underfloor heating attached to the diverter as well, which provides a free warm kitchen floor during the shoulder months.  Prior to adding the UFH I purchased a second diverter with cuts in if there is sufficient available power.  This powers 2 oil-filled radiators in the living room (one at a time) which is again most useful in the shoulder months, though less so now that the UHF has been added.

In summary I would recommend a diverter but would go for the eddi as it talks to the zappi (from same manufacturer).  However, with a 3600 Wp system I think you may struggle to fully repay the investment in diverter, zappi AND batteries...

Solarchaser

Id be interested to see how much gas is used to heat water when running the tap, and how efficient it is.

I know i run my hot water tap, then it pours cold, you wait a few seconds, you hear the boiler boot up, and maybe 10-20 seconds later you have warm water, and another 20 seconds or so later, its hot.
Then you stop the tap and the boiler is still going for 30 seconds or so, and then the water sits in the boiler and cools as its not insulated.

Its been said before that gas is 75% efficient, vs electric at ~100%... not sure how true that is.

But it strikes me, that if i have a well insulated hot water tank, i get instant (say 5 second wait once tap opened for water to travel from tank) hot water without having to wait all that time, and when i close the tap, the only heat lost is in the pipes.(which should be lagged/insulated)
This would seem more efficient and certainly more convenient (the cold, warm, cold, hot cycling from the combi is a bind).

From the fit i already get 5p/kwh for half my deemed export, so if im already using more than half (i am) then an export tarrif would lose me money, but using the electricity would be free.

My point here is there are horses for courses, some can make it work on electric, some cant.

Some think they can, and are lining up to take the plunge and stop using gas in the next couple of years, im one of them.
Things like octopus agile having 1p/kwh electric overnight last night is certainly a good help in the theory of going gasless, and that can only get better with more wind power coming online, heating that water tank in the dead of winter at 1p/kwh, and then *free* in the summer, yeah that would be very nice

Exiled_Tyke

Solarchaser said:

From the fit i already get 5p/kwh for half my deemed export, so if im already using more than half (i am) then an export tarrif would lose me money, but using the electricity would be free.

My point here is there are horses for courses, some can make it work on electric, some cant.

An educated (?) guess is that anyone who's getting FIT payments is almost certainly better off sticking with them rather than going over to paid export?  The positive is that presumably those of us with FIT payments now have another option at the end of the contract.  (presuming the system has been maintained!) 

Petriix

The numbers definitely add up better of you're getting deemed export payments, without which I cannot imagine the mental gymnastics required to believe that a diverter could possibly save anyone with mains gas and no FIT any money.

My smart thermostat records exactly how long the boiler is 'on' for space heating. It can't know when the boiler is just running the pump without burning gas, but I'm able to estimate this fairly accurately. That gives me a good idea how much gas is used for heating. Deducting that from my total usage shows what we use for cooking and water heating in the winter. When the heating is off (April to October) it's easy to see how much we use.

Our gas bill (excluding standing charge) for the past 12 months was less than £220 with no more than 1/4 of this going on heating water. That means the maximum possible saving from a hot water diverter in this house would be £55 if it could provide *all* of our hot water. If that required just 1000kWh of diverted solar power that would otherwise have been exported then that's around a £50 reduction in export payments. No matter how much hot water you use, without deemed exports, you are never going to save money with a diverter.

Now, I accept that there are some edge-cases where people who have unusually high demand and particularly expensive water heating setups (oil, inefficient boiler etc) and, crucially, deemed export payments, are able to save a small amount of money over a long period of time. However, it is extremely unlikely that it would make sense to pay £300 as part of a new solar installation for the negligible potential saving should the stars align. 

I also reject the idea that using the energy in this way is better for the environment because the reduction in exported energy will cause an equivalent increase in demand on the grid which is almost certainly going to be met by burning more gas.

EricMears

Exiled_Tyke said:

An educated (?) guess is that anyone who's getting FIT payments is almost certainly better off sticking with them rather than going over to paid export?  The positive is that presumably those of us with FIT payments now have another option at the end of the contract.  (presuming the system has been maintained!) 

I understood that you can separate the two parts of the FIT scheme and continue to receive actual generation payments but withdraw from the deemed export payment (worth only a couple of pppu to early adopters) and re-assign your measured exports to another scheme.

Haven't tried it yet - no doubt someone else will comment.