SBMS

Hi @crispy_wafer at present the main incentive seems to be the Boiler Upgrade Scheme which offers a 5k grant for ASHP installation. It kicks off in March and is replacing the renewable heat incentive scheme.

Sorry @JamesP - just found your blog and have seen what you built. U-value makeup not dis-similar to our targets although we are brick and block so may not be as air tight. Just on your figures - " 21000 kWh delivered and 3700 kWh consumed for DHW and heating" - is that 21k kWh total for ASHP heating and hot water, with your Solar PV generating everything except 3700 kWh (i.e. your solar array met 17300 kWh??)

Thanks for this. What insulation did you use and what was your measured air tightness.? Any MVHR?

Owned by tank supplier so standing annual charge of £70.

Nearby supplier provide tank for free. Groundworker a day to dig so few hundred for install. Good LPG boiler around 2500 installed.

it’s a fair point re the tank but most can be sunk underground. Its definitely an over estimate re heat requirement (it’s 260 sq m the house) and we are hoping for lower, but I guess the question was not so much about how to reduce bills with added insulation but how the two energy solutions compare. Might be a relevant question as well for a lot of rural properties with LPG being sold the benefits of ASHP. If electric prices keep rising it gets more difficult to justify. Find it strange that LPG hasn’t risen at same rate as mains gas…

I thought I would resurrect this topic, following the recent increases in the price cap, to canvas opinion.. We're about to start work on our self-build next month, so still within time to decide/change our heating solution. And I must say it's really difficult at present prices to justify the additional benefit of ASHP. I do think it's a bit more of a philosophical decision at times, but wanted to get people's opinions on off-grid LPG vs ASHP. We are estimating a heat demand of circa 16k kWh per annum, and with the predicted cap unit price of electricity estimated to increase to £0.28ppl (https://www.ofgem.gov.uk/check-if-energy-price-cap-affects-you) from April, this is how the numbers are coming out (space heating only, not included DHW) ASHP Total Average heat input 16,839 Electricity ppu £0.28 Efficiency 3.5 Total required kwh 4,811 Total annual electricity cost £1,347.14 Average monthly electricity heating cost £112.26 LPG LPG Price ppl £0.40 KwH Per litre 7.08 Boiler Efficiency 0.9 Required heat input after efficiency loss 18,710 Litres required 2,643 Total annual LPG cost £1,057.08 Average monthly heating cost £88.09 % Saving 21.53% Difficult to justify on a financial basis at present (I've not even included capital costs to install ASHP). Still very much wanting to go this route. I want to 'bet' that electricity will come back down - or that the levy on electricity will be reduced - or that LPG will go up, but a 21% cost delta is quite a difference. Thoughts?

Moved original post to new thread:

Can you explain how the cooling function works? I’ve never really understood it! I’m guessing it cools the water in the UFH and brings the slab temperature down? Does this also work in the upstairs radiators?

How do you find the Nibe? Was there any particular reason you went for this model?

Where in the country are you based?

We've done a lot of research into ASHP for our self build, and I think it's a really difficult topic to approach because there's a huge amount of noise surrounding people's perceptions of "MCS Certified installers". I've been converted from looking at LPG for our off grid self buil, doing a tonne of research into ASHP, upping my build insulation spec and settling on ASHP. However, I keep seeing the same comments regarding 'inflated' prices for MCS certified installs of ASHP (that offset any incentive schemes such as RHI, or BUS). Maybe that's some people's experiences; it's not been mine. I'm also not sure why this particular element of self build people are happy to either DIY install, or give to a yellow-pages plumber, as if there are no expertise involved in the design and commissioning of a system. There doesn't seem to be the same approach to other skilled areas of building (such as foundations, or roof construction!) Firstly, what I would say is that, in my opinion, an MCS certified install should be worth its money, when considering the "Boiler Upgrade Scheme" grant. With the greatest respect to commenters like @markc ("Don’t bother, why pay more than £5k over the odds to get £5K back.") - this has not been my experience from getting quotes, and it shouldn't be anyone else's. If it is, you've found a dodgy installer and you should try someone else! But I don't think a few bad apples should spoil the bunch. The links that I've seen time and again for ASHP DIY (or 'bring your own plumber') installs are - a 2k ASHP, a 1k Cylinder, Maybe a buffer (who knows) and no mention of pipework, electricals, labour etc. So on this basis, at a first glance you might think "well I can install a properly sized, warrantied ASHP for £3k - maybe 3.5k including the plumber's labour". I'd challenge that. Most quotes we've received back from MCS certified installers are in the 10k-11k region. Picking that higher end 11k quote, that can be broken down to: Nibe 2040 12kw Air Source Heat Pump Nibe 300L Heat Pump Cylinder 100L Buffer SMO20 Controller Nibe VST 11 Valve Nibe HR10 Valve Pipework MCS and Commission of System So this system, after the BUS grant of £5k will cost us £6k. For reference, the Nibe heatpump retails at around £7k. Let's assume installers can pick that up for 5k-6k. It's in a similar price range for Ecodans, Panasonic and Samsung units. I appreciate the Nibe is a more expensive unit, but I'd really question a price differential on the unit of £4k - can we really say that we're comparing apples with apples when we're pitching an MCS, 7-year warrantied install with what you can pick up on ebay? By my reckoning, you shouldn't be paying more than £11-12k for an MSC Certified ASHP install, and in my view, after the BUS grant of £5k that system should be costing you the same as the installed heat pump. So you should look at the grant as providing a cylinder, buffer, controllers, commissioning, pipework, labour, MCS Certification and 5-7 year warranty for 'free'. Just my 2 cents worth.

This might have been asked before but speaking to a number of companies it seems they recommend a branch system with rigid ducting versus a radial with semi rigid? For those who have installed MVHR which route did you go down?

Thanks all - makes sense. Just wanted to make sure these were normal, good to hear they are.

Thanks for suggestions everyone.

Thanks will look them up!

Thanks @nod Lancashire, north west

I know lots of members are keen to DIY install MVHR - and we may go that route. I wanted to ask though if anyone had used a turnkey supplier and installer for MVHR that they could recommend?

Standard brick and block on dense clay, so nothing unusual. SE has specified 750mm wide foundations. There are a few things that I think are over specified by the SE but wondered if anyone else had experience of 750mm strips?

Also you mentioned your mortgage broker has suggested buildloan. Just to clarify, buildloan are a financial intermediary - not a lender. It’s actually buildstore that we went with and they hand off to their sister company buildloan. Buildstore are a mortgage broker and I would suggest, if you’re looking at using buildloan, you use buildstore to package everything up.

We used buildloan. They were great and the mortgage broker was really good and got back to us with things like decision in principle within 48 hours. They fully understood how to present us to lender as am technically self employed with own company. Was able to pick the best lender based on how our income was assessed. We also opted for an advance stage mortgage which means funds are advanced prior to a certain stage being started - rather than a valuation and (hopeful) uplift at the end. Completely down to your appetite for risk and we paid a £4000 premium for ‘build out cover’ that goes hand in hand with the advance stage mortgage. Build out cover is for the benefit of the lender and is basically an insurance policy that pays out in the event we default and provides lender the funds to finish the build on our behalf and recoup their lending. For me (and I know others will disagree) there’s enough risk in a self build without the worry whether your foundations have increased in value to the tune of what you’ve spent. So 4K was a reasonable price to totally mitigate this risk and mean we are always in theory cash flow positive during the build. Obviously if you’ve loads of equity, cash, or own plot outright this isn’t relevant! But for us, buildloan have worked out well.

Lancashire - brick and block with 150mm blown eps cavity.

We have recently had quotes back for our self build for those that are interested. 250sqm house plus detached garage and we are coming in at around £1650 per sqm. That’s a good spec, ASHP, MVHR, well insulated and with a healthy 35k budget for the kitchen. Ours has some complex bits with 15k of steelwork, and 2 different ridge heights on roof meaning loose lay with about 3 weeks of joinery building the roof, which added to cost considerably. This is priced for a main local builder/ contractor and clean feet. Just in case this is of interest and this has been priced this week with 2022 prices for everything (which has pushed budget up considerably from last year when we did our budget).

Thanks @Iceverge

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