Looking for a bit of insulation advice to see whether I can (and should) improve my roof space further.
We put extra mineral wool insulation in a few years ago, but our actual roof is the original unfelted one with nothing whatsoever underneath the slates. The guy who came to do the survey for the solar PV suggested I should look into having foam-insulated boarding put between the rafters and it would probably qualify for the Green Homes grant. He specifically advised against having blown insulation put directly on unfelted slates as that can be a real problem if maintenance is required later on.
The house in London had exactly the same unfelted construction and the layer of rain deposited soot that built up over 120 years was a right nightmareâŚwe had it professionally hoovered out and cleaned before fitting 70-100-140mm Polyisocyanurate R-6.8 foam board between the rafters and wall studs âŚDoes a good job,cannot help re the grant angle Iâm afraid Mark as we didnât consider it at the time
Polyfoam is good idea but just make sure that you have at least 25mm gap between the tiles and the insulation for ventilation. You could also use a product like Tri-iso stapled directly to the underside of the rafters, itâs expensive to buy, but the labour to cut all of that polyfoam between rafters is saved.
The latest grant scheme might apply but good luck getting a quote mark, I have been trying for months on ours
I am nervous about too much insulation in Victorian roof as they were designed to have air flow, you will have to have vents in bathrooms and kitchens and have a bit dawn off sll your doors
We had our roof redone and had the modern breathable felt and 50mm of kingsman fitted between the rafters which worries me but still decent air flow. Our tiles can leak all they like now as the felt will keep us dry.
If your skates are in good condition and you have the option to insulate the floor of the roof space to max level not sure what the benefit of doing the roof itself would be
Itâs a minefield this insulation, I am currently replacing the casements from my big front windows to give some double glazing, will cost a fortune and proll6 wonât make any difference but worth a try as itâs freezing here from dec to march
So spoke to eon today. They reckon I can get 8 panels on the roof. Roof has no shading or obstructions, they suggested 360W panels. Battery size they said 5.2kW but also quoted for 8.2kW (ÂŁ800 more).
As we havenât lived in the house I have no idea on consumption. But we will have electric cooker and induction job, combi boiler for water and heating, my electric car. The rest is pretty normal I guess with it being used weekends and evenings only.
Because of our usage their guesstimator suggests maybe 20 years to pay it off
But that doesnât stop me wanting it
Edit: the alephs probably eat a shit load of electric mind
Depends on how much you use a dishwasher/tumble dryer as to what your usage will be, with 1 dishwash and no tumble dry we seem to be about 10kWh a day. In the frozen midlands with a 5kWp system a wall to wall sunshine day in January generates 10kW-ish, so aout 6kWh from your planned setup.
I think the important consideration is that you have an EV - especially post-pandemic when we start putting more miles on - youâll always have a battery sink for dumping excess solar into. Once you get on a tariff like Octopus Go with the 4 hours of 5p/kW you can fill the house battery for evening or cloudy day discharge.
My only worry is my lack of wanting faff. Setting the timer for the car, checking when the battery for the house is full etc. I kind of just want to use it without knowing about it or using an app.
So not sure itâs right for me, I still like the idea of running off my own power mostly and the benefits of that and the money saving
Saying I donât want faff, have been googling plenty, still seem interested.
Do you know if the giv energy hybrid packs they supply are 3.6 or 5 kW for how much they can output at once?
Hopefully getting the final designs back early next week. They are hoping to squeeze and extra panel or two on which will take the system above 3.9kW. Apparently they have to get sign off from the DNOs for output above that threshold. Takes about 10 days.
Iâve held off contacting a EV charger installer as I assume it will be easier for that to be integrated into the system once the PV is installed, rather than the other way around.
My fixed rate energy deal is coming to an end as well. I havenât jumped for Octopus yet because the guy from E.On mentioned something about an isolator needing to be fitted and if I went with them they would fit it FoC. Sounds a bit weird though as I would have thought thatâs part of the core design for the PV install and would be included anyway. Will have to clarify that. Either way, I wonât be staying with E.On, their dual fuel prices are insane, even with the 20% discount rate they are offering their solar customers.
Yep will be easier when your system is in. Donât forget the grant money to help with the charger.
I will probably go with the eon system too and octopus go. Charging the battery when itâs cheap after a dark day. Agile seems like a good idea, but a bit too much faff for me atm. But something I could switch too, especially as givenergy works so well with it.
I will also probably 8kWh battery when I finally decide. Going to put a chunk of money down (50%) and do the rest on their interest free, so tiny monthly payments.
Edit:
Is your battery going in the house or in a garage? We can fit one under the stairs, which will make a big difference in cold temps like now with capacity.
