Energy and a house with a massive south-facing roof and 'loft conversion' style upper floor

RHemmings

Hi all.

One of the houses in my list of houses I'm considering is a weird near triangular semi-detached house. The roof is one big triangle, and the side that is for sale appears to have a massive single flat area, facing south.

There are also no buildings around that may shade the roof. And no trees - though I know that people can plant ash trees and they grow quick, but that can happen anywhere. 

I'm planning to add solar panels to any house I buy. Is this house likely to be the best-possible-case for solar panel installation that it seems to be for me, or are there issues with such a house style? 

Also, the upper floor of the house looks 'loft conversion'. Is this going to restrict the amount that I can insulate the roof? And, how would insulation of a loft conversion space happen? 

Any advice/information/discussion would be greatly appreciated.

I hope that posting two threads for two different houses is OK. Apologies to moderators if not. 

Qyburn

I think the ideal for solar would be a roof with different aspects so you can have some panels to the East and some to the West as well as to the South. Of the four cardinal points due South gives best generation for a single aspect, slightly W of S may mean generation is better matched to your time of use.

You say loft "conversion", do you know when that was done?  Adding insulation will be a pain.

RHemmings

Qyburn said:

I think the ideal for solar would be a roof with different aspects so you can have some panels to the East and some to the West as well as to the South. Of the four cardinal points due South gives best generation for a single aspect, slightly W of S may mean generation is better matched to your time of use.

You say loft "conversion", do you know when that was done?  Adding insulation will be a pain.

Thanks for the information. I see your point about having parts of the roof facing different ways, and this roof is not as 'ideal' as I thought. I do intend to eventually add more solar panels than I will ever get the money back for through savings - I want to minimise energy consumption as an expensive insurance policy against the future and also want to minimise my environmental impact even when it costs me (heat pump). 

The inside of the house looks like a loft conversion style room, as the ceilings slope up from the sides. However, I believe that this will be the original design of the building, not a conversion. Let's see if I can get a picture. 



That's what I mean. It all seems quite complicated. The outside of the house looks like this:



I'm not 100% sure what they were thinking with those houses. There are a whole lot of them up that major road. 

My plan is that energy I don't use will be trickle charged into an electric car that I only use on weekends. So, the timing of the energy is less important.  Having just seen an offer of 10 solar panels + a Tesla powerwall for £11K, that's definitely of interest. 

Thank you so much for your help and advice. 

Gerry1

Make sure you have special pointy hammers so you can smash a window if you're trapped by a fire !

The limited ventilation and the ceiling fan suggest it may get very hot in sunny weather.

Qyburn

RHemmings said:ain.

My plan is that energy I don't use will be trickle charged into an electric car that I only use on weekends. So, the timing of the energy is less important.  Having just seen an offer of 10 solar panels + a Tesla powerwall for £11K, that's definitely of interest. 

That sounds a great deal on the solar and battery. Unless there are DNO limits I'd want more than 10 panels if you have room.

The outside photo suggests it's not a conversion, you wouldn't build a house like that without the upstairs rooms. Its a bit more modern than our house which was built around 1850 with four attic bedrooms.

RHemmings

The powerwall plus solar panels deal was a google ad that popped up. My attempts to get google search to show me the ad again failed. 

There's this deal here, but the battery is a brand unknown to me. 

https://www.itstechnologies.shop/products/complete-kit-12-panel-4kw-solar-13-5kwh-givenergy-battery-storage-with-choice-of-panels

I don't know what a DNO limit is, so I'm off to search about this. EDIT: Reading this: https://www.theecoexperts.co.uk/solar-panels/dno-application

While this deal looks good, my aim will be to build a good system, not necessarily a cheap system. I figure that if I have an electric car and a controller capable of diverting energy to it, then that will be enough storage of excess energy for me at the beginning. If I put panels up, I will locate them with the idea of adding further panels in the future. 

Qyburn said:

That sounds a great deal on the solar and battery. Unless there are DNO limits I'd want more than 10 panels if you have room.

The outside photo suggests it's not a conversion, you wouldn't build a house like that without the upstairs rooms. Its a bit more modern than our house which was built around 1850 with four attic bedrooms.

I should have been clearer in my first post that I thought the upstairs looked like a loft conversion in that it looks vaguely similar to a loft conversion in having angled bits of ceiling.. Not that I thought that anything had actually been converted. 

This room was in my mind when I said that - and I think this is a loft conversion. I was extra mean and didn't show my family this house as I think it doesn't tick some boxes but I was worried my son would see the following loft conversion (probably) room and insist on this house with this room being his bedroom. 



For both this house and the triangular house that is the subject of this thread, I was wondering how loft insulation works. However, cross-referencing to my other thread I guess the same sort of insulation that works as interior wall insulation would work here.

Qyburn

RHemmings said:

For both this house and the triangular house that is the subject of this thread, I was wondering how loft insulation works. However, cross-referencing to my other thread I guess the same sort of insulation that works as interior wall insulation would work here.

The challenges with attic rooms are (1) there won't be much space between the sloping part and the roof, and you need to leave an air gap anyway. (2) Access may be difficult unless insulation is fitted before the plaster.

Qyburn

RHemmings said:

I don't know what a DNO limit is, so I'm off to search about this. 

The DNO may restrict how much power you can export, and/or total system size. For example we're limited to 4kW export, 7kW total. An AC battery like the Tesla counts towards that total, even if not configured to export, so if went for the PW2 we'd be limited to a tiny inverter.