Bungalow roof or garage roof?

[TheMitchells]

Is there an advantage to putting solar on a flat garage roof?  Would it be cheaper? 

 

We are thinking of adding solar to the south facing roof of my parents bungalow, with a battery in the garage (about 30m away).  They currently have night storage heaters and do use quite a lot of electric.  I was given a quote from Egg Solar - The design we propose for your property is a 12 No. 390W Trina Solar all-black panels. This will make sure you maximise your output and give you access to an app to monitor everything.
 
Our budget estimate for the supply and installation of the solar PV system is £8,900 and £9,250  for the supply and installation of the Tesla Powerwall. Should you wish to install a battery at an alternate time then VAT rate is 20%. 

 

This was a year ago and we did not go any further with it.  But i am looking at it again and asking a couple of other firms for quotes.  the bungalow has a largish flat roof on the garage and workshop at the bottom of the garden.  It could be far easier to put them on there. Also, we could look at a DIY system as hubby is good with electrics though not qualified any more.  We could find a helpful electrician nearby  possibly.

 

Any advice would be appreciated.

[TonyT]

When it’s that sunny you won’t need the heating and when it’s not sunny you will need the heating….

 

what tariff are they on?

how’s the insulation in the house?

 

 

 

[JohnMo]

Givenergy all-in-one is an alternative to Tesla, I am paying a little over £1k less including vat, fully installed.

 

DIY on £9k is a lot of panels, mounts and inverter. A panel around £100.

 

Best place to install is the place with the least shading at time of the day, summer and winter. Mount angle closer to vertical is best for winter production, at the expense of summer production (when you have loads anyway) close to horizontal is best for summer, but almost kills winter production. I have one array at 45 deg, fairly balanced, the other vertical for good winter production.

[Dillsue]

If your hubby is an electrician then he just needs a roofer to help with the roof work and DIY is straight forward. Buy or borrow a used scaffold tower and flog it afterwards. You'll likely pick up a 4.5kw kit(excl battery) for under £3k and the parts for much less if you are prepared to wait and buy as things as they come up on ebay

[TheMitchells]

1 hour ago, JohnMo said:

Givenergy all-in-one is an alternative to Tesla, I am paying a little over £1k less including vat, fully installed.

 

DIY on £9k is a lot of panels, mounts and inverter. A panel around £100.

 

Best place to install is the place with the least shading at time of the day, summer and winter. Mount angle closer to vertical is best for winter production, at the expense of summer production (when you have loads anyway) close to horizontal is best for summer, but almost kills winter production. I have one array at 45 deg, fairly balanced, the other vertical for good winter production.

Thanks, just read your post re the vertical panels.  I need to work out the angle on the bungalow roof - it is almost perfectly south with no shading.  The garage could be fixed pretty much any angle.  At least the Tesla cost sounds reasonable.   Will do more reading and YouTube watching re DIY.

[TheMitchells]

1 hour ago, TonyT said:

When it’s that sunny you won’t need the heating and when it’s not sunny you will need the heating….

 

what tariff are they on?

how’s the insulation in the house?

 

 

 

Currently on Octopus Green Fixed till December, thank goodness as their bills stayed at £120 all through the energy hikes!  That was one of my better moves.  Insulation is probably rubbish apart from the new shower room we added in 2019.  It was built in 1970's, we think.  Our plan is to 'move in' when they dont need it any more and do renovation to high standard (near EnerPhit?).  So thinking long term.  Also need the PV to be adaptable to any future heating system we use. 

[TheMitchells]

26 minutes ago, Dillsue said:

If your hubby is an electrician then he just needs a roofer to help with the roof work and DIY is straight forward. Buy or borrow a used scaffold tower and flog it afterwards. You'll likely pick up a 4.5kw kit(excl battery) for under £3k and the parts for much less if you are prepared to wait and buy as things as they come up on ebay

We arent in a rush. He used to be but has retired and no longer qualified.  However, he is very 'handy' and can turn his hand to most things.

 

[TonyT]

Good luck in your endeavours

[MrTWales]

As others have said, shading is a big issue potentially and another is weight. The usual fitting method with a flat roof I believe is ballast, so they add concrete to the fixing brackets. With the panels maybe being 20kg each that's a lot of weight so the rafters need to be strong enough.