Is my house just unsuitable for Solar PV?

Rogtronic1

Hi all,

I have been lurking in these forums for a year trying to do my homework and have recently had a few quotes. I'm getting the impressions from fitters that they either

a) don't think I'm suitable (i.e. wont generate enough electricity) for solar pv

b) don't want the job due to the limited roof space, multiple roof orientations, the fact my attic is converted, my fuse board is on the second floor etc

I'm curious to know what is the minimum size setup people would recommend? Currently I'm getting quotes for 9 panels with 4 on the south side and 5 on the west side.

I'm also being told a battery isn't worth it due to costs. I'm having serious doubts of going ahead with Solar right now and was wondering if anyone else has been in a similar position?

This is my house and the image is oriented with North at the top

Thanks!

DC999

TLDR, dig in and keep trying :)

We’ve a tiny Dublin ex council house (2 up, 2 down) and have 16 panels. We maxed out the roof. We’ve 3 orientations over 4 roofs. So it’s all possible!!

You’re in the ‘trough of disillusionment’ – many of us were there! I’d say dig in and get more quotes. It was much harder than I expected to get it all live (from quotes to delays, snags, design changes..) – but 5 months after going live, I’d do it all again tomorrow if moved house. We’re getting solar for my folks too. I’ll never live in a house again without solar.

Our split is East (main roof & flat kitchen extension), South, West. Took me a few installers to get the design we wanted (which was to cover as many orientations as possible to get good coverage during the day (as don’t have a battery). Most installers want an easy install, not a good design for the person paying!

If a battery is impacting you, don’t get it. Solar works fine without it. You get paid FIT of 17c+ per unit you don’t use and ‘sell’ back to grid. You can always get a battery in time.

Not having to worry about energy bills is amazing. We went from 3 energy bills (petrol, electricity and gas) to one really – electricity, and we generate a decent chunk of that via solar. We got an EV so petrol is gone. Using electric rads to heat parts of the house, so gas is way down.

Then it’s down to finding a design. 

DC999

Then the next is design options. Design wise, and others will chime in and offer other ideas, your roof has East, West, South and North (North is only usually considered when all else is maxed out). So you’ve loads of options. But that makes the install slower for installers, which they don’t like. Plus it bumps the cost up once you start slowing installers down (as your roof will). I was the same.

In general (and your house may differ), max out South (including extension) as that produces the most. Then you can pick E or W (if you use more morning or evening sun) and run panels all the way along that orientation). Get as many panels as you can afford on install day. Will cost more to upgrade in time if you got installers back out.

• South looks like it has some extension  where the ‘6’ is. What’s that and what is on the roof of it? Flat or angled? I used a flat roof as well as the main roof – works perfectly. South will produce the most. Panels are about 1m wide x 1.7m – what size is that flat roof roughly? Needs space at the sides between edge of roof and panels for the SEAI grant regulations.
• East has velux x 2 and chimney. Easy is good for morning sun.
• West has hip where other roof comes in and 1 small velux. West for evening sun. If West is closer to N, output will drop hugely in autumn and winter. But it’s good in spring + summer. I’ve a NW that hibernates from end Sept.
• Shade impacts output so remove the shading where possible (or move the panels). Or add optimisers just on the ones affected by the summer shade (like ones beside a chimney depending on how the sun moves around). People debate the benefit of optimisers. I’ve optimisers on 5 of 16 that get shade and works great for me (or the shade would drag down output from another 5 panels on the main roof above it)

Gerry

I wonder if there are some roof vents which if moved would let you get another 1-2 panels on. worth checking. the solar installers will not want to move them, you'd need to organise that yourself.

Rogtronic1

Hi @DC999 Firstly thanks so much for restoring my faith :D

Hopefully I can give you more context

• South looks like it has some extension where the ‘6’ is. What’s that and what is on the roof of it? Flat or angled? I used a flat roof as well as the main roof – works perfectly. South will produce the most. Panels are about 1m wide x 1.7m – what size is that flat roof roughly? Needs space at the sides between edge of roof and panels for the SEAI grant regulations.

This is a flat roof (house came like this). It is lower than the rooves around it so wouldnt receive as much light as the south facing roof. Do you think its worth getting panels there knowing they will only get light around the middle of the day? I did suggest it to one fitter and they said the angle panels would be at (15 degrees) wouldn't be great for this efficiency.

• East has velux x 2 and chimney. Easy is good for morning sun.

Some fitters have told me they cant do a south/east/west split. Only two can be done but others have quoted all three. I think they just dont want the job

• West has hip where other roof comes in and 1 small velux. West for evening sun. If West is closer to N, output will drop hugely in autumn and winter. But it’s good in spring + summer. I’ve a NW that hibernates from end Sept.

Yes this roof is where I can fit the most panels but I'd be concerned in winter that the sun wouldn't ever get high enough to hit them.

Thanks again for your help here. I guess I just have to press the fitters to build what I want in the end.

AndyBoBandy

I had a guy come out and look at my roof and say I'd maybe get 4 panels up, 5 at a push... I also had an installer just look up my house on Google Maps and said no, it wasn't worth getting Solar PV..

In the end I used a highly recommended installer from Enniskillen who initially quoted me for 14 panels (but my remit was to install as many as possible). In the end they managed to get 17 panels installed over 3 aspects (4 facing SE, 7 facing SW & 6 facing NW). the 4 & 7 are all 1 string so all have optimisers on them. The 6 facing NW (2.04kWp) have probably never maxed out, but I have seen them producing 1.5kW at one stage, and in high summer, these panels keep producing long after the SW/SE string has tapered off... so they keep the house ticking over before the battery needs to kick in and start supplying the house...

So I went from some installers saying the house wasn't suitable and it just wasn't worth it and maybe I'd only get 4 panels up, to having 17 panels installed and last year in my 1st full year of having the system installed produced just shy of 4MWh...

AndyBoBandy

https://www.boards.ie/discussion/comment/120191611#Comment_120191611

Some fitters have told me they cant do a south/east/west split. Only two can be done but others have quoted all three.

It can be done, it would just mean that 2 of those aspects would have to be on the same string, so therefore all panels on that string would require optimisers

unkel

https://www.boards.ie/discussion/comment/120191700#Comment_120191700

That's incorrect. I wouldn't put 2 aspects on the same string either in series as you will have extremely limited production all day long (current in the string is equal to the current of the lowest performing panel in that string) or in parallel as it will blow up your inverter because the current will go over the rated max current at times, unless you put other electronics in place. Bad advice. You can have two aspects on your string inverter and the third aspect on one or more microinverters (many can take 4 panels) or the lot on micro inverters.

There are also some inverters on the market that have 3 input strings and / or some that can take twice the usual current (so you can parallel strings), but these are not very common / hard to get / possibly don't have Irish certification

graememk

https://www.boards.ie/discussion/comment/120191952#Comment_120191952

Well you can do it if you put optimisers on all the panels..

if you do that you might as well just use microinverters for the extra panels!

AndyBoBandy

https://www.boards.ie/discussion/comment/120191952#Comment_120191952

As I mentioned, all the panels on the string that's split over 2 aspects have optimisers on them.. 11 panels= 11 optimisers. 4 panels SE, 7 panels SW and production from that string is usually excellent.

unkel

I didn't even consider that option as it wrecks your pay back time and using several optimizers is only suitable for a masochist who likes climbing up on his high roof at least once a year to replace a faulty one, if he even notices it's faulty 😂

In other words - don't do it!

Microinverters of course go bad as often as optimizers or any other electronics. But at least if you have 3 micro inverters rather than 11 optimizers, you'd only be up on your ladder once every 3-4 years 😂

DC999

https://www.boards.ie/discussion/comment/120191611#Comment_120191611

Check the sun now. then you know what sun they get in winter. Check your old photos to see where it is in summer time. Might have pictures our the back with the roof in the background.

On your flat roof, I've one too and it rocks!! Better for summer sun when it hits the panels more. Winter hurts it more but it's still output. I fitted 5 on the flat roof.

unkel

I have 14 panels on my shed, near flat. Great particularly in summer as they produce all day long

Rogtronic1

https://www.boards.ie/discussion/comment/120192593#Comment_120192593

I've had a look just now (11:28am) and there is some sun on the west roof. Not enough to cover all 5 panels that will theoretically be installed. So I imagine it will get a bit more as the day progresses.

Are you saying they are lying flat? The fitter was suggesting putting them on an angle (or at least thats what I interpreted him to mean.

DC999

https://www.boards.ie/discussion/comment/120195856#Comment_120195856

You work with the roof angles you have usually. I've a nearly flat roof so used that. It's maybe 20% type thing. A little of an angle is likely better than pure flat. Will stop water pooling on it and means rain will clean dust, dirt, bird poo.. off it.

You could put at an angle behind it somehow, but you're going to have to pay for some solar mount to turn a flat roof into a non flat one. Might be some pics of flat roofs here: Renewable Energy Photo Thread - Page 3 — boards.ie - Now Ye're Talkin'

usual_suspect

This was really interesting thanks. I'm in a similar propter in Dublin - would you mind PM'ing me the details of the installers you'd recommend. I've had two quotes, however, they were wildly expensive for the size of the job....

Rogtronic1

@usual_suspect I've just been making my way through this list

https://www.boards.ie/discussion/2058243236/solar-pv-boards-members-installer-information

When you say wildly expensive what kind of numbers and for what systems. Throw the quotes into this thread if you want some good feedback

https://www.boards.ie/discussion/2058219537/domestic-solar-pv-quotes-2022-no-pm-requests-see-mod-note-post-1#latest