Couple of PV quotes - what do you think?

eliseboy

Hi - I've had two quotes for my south facing roof:

Quote 1
1) 16 x Sharp 250w panels (15.2% efficent)
2) Samil SolarRiver 3400 TL-D inverter (96.5% efficent)
3) 10 year guarantee on the whole system
4) Scaffolding, roor survey included

Expected to produce 3,728 kwh/yr - cost £6,739

Quote 2
1) 15 x Winaico 255w panels
2) SMA SunnyBoy 3.6TL inverter
3) 12 year guarantee on panels, 5 on the inverter
4) Scaffolding, roof survey included

Expected to produce 3,300 kwh/yr - £6,545

Quote 1 looks better to me - eben if the inverter isn't quite as proven as the SMA, it has a 10 year guarantee so covers it for most of its useful life. It seems a bit on the rich side to me though by a few hundred pounds but maybe I'm just tight !

Any thoughts - very welcome.

Update
Roof faces 5 degrees from south and has a pitch of 45 degrees.
Latitude 52.67415, Longitude -1.83954

The heating and hot water is via a thermal water store - so there is a large tank of water heated by a gas boiler (does have an electric heater also) - there is then a heat exchanger that either heats the heating water or the normal hot water.

tunnel

Location? Roof pitch? It helps so we can check on PVGIS site to see if your expected generation is correct.


Price wise doesn't look bad at all, maybe £500 on the high side, do you have a hot water tank then you could negotiate an immersun or equivalent in with the price to use any spare generation to heat your hot water


I have sharp panels on my first install and they're performing great

Martyn1981

Hello and welcome eliseboy.

Using the info supplied, I got a guesstimate from PVGIS of 3,670kWh pa for a 4kWp system.

The specs look good, though closer to £6k would be a good target to aim for, or as tunnel says, try to get something extra thrown in, like a water heating diversionary switch.

Is there any shading? If not then the Samil is a very decent and efficient inverter, but the SMA has better shade management, if that's an issue. For only a few quid more you should be able to get a 3.68kW model (single or dual tracker, as necessary). 3.4kW probably fine for 4kWp of panels, but 3.68kW may be better. In fact prices are so similar, you'd want that thrown in at no extra I reckon.

Another question, the second quote seems strange being for 15 panels. Is that deliberate? Would your roof better suit a 3 by 5 combination, rather than 4 by 4 or 2 by 8, is there any space issue? If it has to be 15 panels, then better to go for 265Wp panels and squeeze some extra watts out of the upto 4kWp tariff.

Mart.

eliseboy

There are three skylights in the roof and the person who provided the first quote was happy that they could get 16 panels up there and the person with the second quote, thought that 15 would be fine. There is no shading at all either.

Comments above have been really useful and gives me something to go back to both of them on - will report back.

Anyone got experience of how good the monitoring solutions are on the Samil ? The installer has suggested an Owl monitoring solution for less than £100.