RichardL

Re the insulation point... Fair point - its not bad - its not a modern house though! Windows are new, Roofs re-tiled with space blanket type, current building regs, insulation, as well as the existing oldschool glass fibre type insulation. However: Concrete solid floors throughout and probably zero insulation - thats not really going to change - perhaps some thin insulation when I swap carpets to wood - but not enough to make UFH make sense. The circa 1800s end is solid 18" thick stone walls + render The circa 50s/60s bit is timber frame + 100mm external wall insulation. Its never going to be perfect. The 19/20kW oil boiler is sufficient to keep it toasty now - especially since the EWI on the timber frame bit. Decision I think I'm pretty much decided ASHP isn't today's project, I think it might work - I just don't need to make the investment right now & chasing an RHI payback doesn't feel like a priority. If the oil price goes up to £1/litre and the electric price stays at 14p/kWh then its a different game of course. Appreciate the sanity check and comments. I asked here in the first place because I saw the 'reality' in replies on other threads. Thank you.

Hi Temp, Thanks for the responses - yes - aligned with your costing comments - ~20kWh annual heat/hw requirement based on 2 years oil data. I engaged 3x installers to compare quotes - even shared the above data/working for reference. One went crazy and estimated the house needed 2x ASHP in cascade with overall 32kWh capacity - also charged me for the heat loss calcs which were done by a dissolved company still using headed paper whose links to website/phone etc either didn't work or went to another company. Really nasty experience - they got really shirty when I asked any question like - what U values being used to calc Wm2 and how they get from Wm2 to heating capacity required etc quote 'no customer ever asked this before' ? The other two were much more reasonable heat loss calcs and required heating coming out at ~20kWh level which broadly match my numbers & ~15k total install cost before RHI. Calculating a 12kW ASHP requirement. Install cost - all in - inc replacing some rads would end up being the best part of £15k ASHP, £24k GSHP (or 25k ASHP with Mr shonky installer!) Running cost breaks even assuming <~50p/l oil (its 38p right now) and <=14p/kWh electric The question Its RHI going away I'm swaying on. The switch from a potential 10k payback over 7 years if I jump before next April vs 4k grant after April 2022. I'm just wobbling and thinking 15k buys a hell of a lot of house improvements including some re-flooring/and floor insulation etc when my 10 year old oil boiler has at least 5 years life left in it. Also don't want to be a luddite and stick to dying heating technology.

Thanks Peter, Thats in my mind too - my numbers come out evens IF oil goes back to 50p (~36-40p now) and electric stays under 14p (~12-13p depending on tariff now) + I'd need to invest 5k after the RHI payback is taken into account. Even if RHI drops from my potential 10k to the 4k grant level over time the market should approach that 4k level - it will have to right or the market for renewable heat will stagnate. I'm sort of in that fear of missing out scenario, but I don't think it makes sense to rush in the next 12 months even with future subsidy likely to be less than current. I'm posting because I'm trying to double check my thinking.

Hi, I've been reading through and lurking for a while, thinking about changing the heating for my house, triggered by a boiler failure (now fixed) earlier in the year. Interested in the decision - ASHP now, later in the context of RHI changing to grants in 2022. Context I'm in an older property, South Wales so relatively cold/wet location. ~145m2 , Oil fired central heating/hot water ~18-20kWh /(1,891 litres oil) annual equivalent spend on oil averaged from real litres bought over the last couple of years Annual heat loss kW ~10kW Question/thoughts If I went air source this year - upfront investmetnt with the bulk of that coming back via RHI. If I wait until next year (or later, or say when the oil boiler backs up) - the new green grant thing ~£4k On the face of that it would say go air source earlier if I'm going to do it - but Is the current marketplace inflated by RHI to drive the payback into installer upskilling, and will the new lower 4k grant mean the total install costs drop accordingly or just the proportion investment from the end user goes up to meet the gap? Assuming the ASHP market cannot stall - something has to budge? Literally in two minds right now - the ASHP running costs vs. oil are not obviously cheaper - my installer thinks perhaps 20% saving, my back of the envelope calcs come out anywhere between evens and 15%, and that needs heating oil to go above 50p/Litre.