cbk Posted February 10, 2021 Share Posted February 10, 2021 With the big reduction in the feed in tariff it seems like you need to use any power generated to gain any benefit from the PV panels, or add yet more kit like batteries to use at a later time. This is a big investment and with limited winter sunshine, when supply demand is highest, does solar PV still make sense for a typical 4 bed home? Or can I use the money saved in a better way to keep energy demand down perhaps? Link to comment Share on other sites More sharing options...
ProDave Posted February 10, 2021 Share Posted February 10, 2021 My view is it only makes sense if you can buy the kit cheaply and DIY install it. It cost me £1500 to buy and install a 4kW system, which I recon is saving me £250 per year in electricity costs so will have a 6 year payback time. Self usage is the key, I am not convinced battery storage is there yet, when you fully cost batteries including end of life replacement, your "free" electricity is not that cheap after all. The only payment now is the smart (sic) export payment scheme that will pay about 5p for anything exported, but to claim that you will need and MCS certified install which will probably add more to the cost than you will ever recoup in payments. Had I been eligible (I am not) in the first 2 years I would have been paid the grand sum of £12 for my export. Link to comment Share on other sites More sharing options...
Bitpipe Posted February 10, 2021 Share Posted February 10, 2021 It depends on panel & inverter cost (In roof systems can mitigate some of the cost by removing the need for other roof coverings in those areas) but if you think year round it may make more sense. If you're building to a reasonably high standard then you will find summer overheating as much of a challenge as winter cold. In fact, overheating can be an issue in spring and autumn when the sun is low and comes straight through windows. An electric based comfort cooling system (split air con or if you have UFH and ASHP, cooling the slab) will effectively be free when the need it at its highest. We have a solar PV diverter which heats the UVC through immersions when energy is not otherwise being used and that has paid for itself very quickly. Timing laundry and dishwashing to the day time (easy with modern appliances) also means they run for free. If you have or are considering an EV then you can charge that at home during the day for free also. Link to comment Share on other sites More sharing options...
SteamyTea Posted February 10, 2021 Share Posted February 10, 2021 24 minutes ago, Bitpipe said: find summer overheating as much of a challenge as winter cold Fitting PV onto your roof will take up to 20% of the energy away, so mitigates some of the fails. This does depend on roof design, location etc. Link to comment Share on other sites More sharing options...
nod Posted February 10, 2021 Share Posted February 10, 2021 Our Sap predicted £250-350 saving per year Unless you buy cheap and self install From a monitory point of view It will all need replacing long before the initial cost is recouped Link to comment Share on other sites More sharing options...
Dave Jones Posted February 10, 2021 Share Posted February 10, 2021 solar is usefull for planning as you can pass the SAP calcs with solar pv, gas combi and 100mm standard cav insulation. keeps cost down for developers. Link to comment Share on other sites More sharing options...
SteamyTea Posted February 10, 2021 Share Posted February 10, 2021 I just done a very rough calculation comparing the price to heat water with 6 kWh.day-1. Annual cost on standard rate electricity @16p.kWh-1 is £350, E7 @ 10p.kWh-1 is £216. With 4 kWp installed[1] on standard rate it would be £35 a year and E7 £22 a year. So that would be a saving between £200 and £300. Between, and including March and October, there would be excess energy produced. [1] this assumes the PV charges up the water first, based on a SE or SW facing 4 kWp system in Leicester. Link to comment Share on other sites More sharing options...
cbk Posted February 10, 2021 Author Share Posted February 10, 2021 Apologies if this is a dumb question but if I'm using an ASHP as primary heat source for UHF and DHW does this change the electricity consumption for DHW? Link to comment Share on other sites More sharing options...
SteamyTea Posted February 10, 2021 Share Posted February 10, 2021 4 minutes ago, cbk said: Apologies if this is a dumb question but if I'm using an ASHP as primary heat source for UHF and DHW does this change the electricity consumption for DHW? Yes, you can divide it by between 2 and 3. Link to comment Share on other sites More sharing options...
canalsiderenovation Posted February 28, 2021 Share Posted February 28, 2021 (edited) We had in roof solar 12 x 320w panels in roof landscape. It was not as cheap as @ProDave as we had to pay for installation and the equipment was just shy of £2400 alone which included everything - the Solic for diverting the excess to the immersion, the in roof panels, inverter etc We currently only have our heat pump heating the water for a couple of hours a day on the Octopus Go Faster Tarrif (8:30pm for 4 hours of 5p electric) and we find the Solic pv heats the water in between (it's set at 48 degrees for the heat pump to heat it and a sunny day like today the excess pv diverted to the immersion and it's heated way above that and I've had bucket lots of hot water today as I've been cleaning windows and washing the car). Pics taken just now... The solar today and yesterday did well over 10kWh. Earlier in the month it was only around 5kWh a day. Today we have charged everything, had washing and dishwasher going. It's worth it for me but we both work from home and can really make use of the electricity when its there. Edited February 28, 2021 by canalsiderenovation Link to comment Share on other sites More sharing options...
Dave Jones Posted February 28, 2021 Share Posted February 28, 2021 It's a nice feeling isn't it 'free' electric! My own solar has done really well the last week of sunshine, not to mention the 60p fit... I bought a tesla Powerwall 2 years ago so I could time shift my usage and take advantage of the solar and hourly billing. Really pleased with the investment. Link to comment Share on other sites More sharing options...
V22 Posted March 3, 2021 Share Posted March 3, 2021 On 28/02/2021 at 17:12, Dave Jones said: It's a nice feeling isn't it 'free' electric! My own solar has done really well the last week of sunshine, not to mention the 60p fit... I bought a tesla Powerwall 2 years ago so I could time shift my usage and take advantage of the solar and hourly billing. Really pleased with the investment. What are the approximate investment costs on this pls? Does Tesla start selling their solar tiles as well in the UK yet? My enquiry on your website didn't take me anywhere - sadly.. Link to comment Share on other sites More sharing options...
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