IanR

I'd go with (1) Local to me right now is 17°C with 85% RH. Warmed to 20°C this would give 70.5% RH

I had a similar experience with the SAP calcs, although the over-estimating is handy for RHI, so I didn't argue to hard. But, MCS Installs don't use SAP for their heat loss calcs (as far as I know), at least for me they came up with more accurate calcs than did the SAP chap. Still over-estimated a little, but that's not surprising as I make the most of solar gain. PHPP was the closest, with Jeremy's spreadsheet a close second.

I believe the 2022 Building Regs require Energy Loss calcs to be done for the "low temp" heating system. (haven't read the detail and am going by the headlines) I wonder if the Home Owner will be able to rely on the Professional Indemnity Insurance of who ever does the heat loss calcs, if they prove to have under estimated the heating requirement and led to the incorrect size HP being installed.

Can't really add a lot other than Nibe recommendation for the family of Heat Pumps I have, up to 16kW, is 22mm, although they do (and so did the installer) recommend a max 10m run. I did a longer run of nearly 20m and did choose to go with a pre-insulated 32mm. But, this is new pipework that required as part of an ASHP Install. It's not ripping out existing to replace it. ie. a gas install doesn't have a unit outside, and if it's a combi it doesn't have a UVC, and probably doesn't have a buffer. It's not really worth arguing with people that are comparing to Gas. Gas is off the table so is no longer an option. The comparison needs to be to low carbon heat sources. It's just not clear what's included in that group, apart from heat pumps and direct electric. I'm waiting to see if a door's going to be kept open for "hydrogen ready" boilers in the hope that there's going to be a step change in hydrogen production technology, with all the lobbying the gas industry is doing.

Really? It's an unsuitable thermostat for a Heat Pump then, since HPs should not be short-cycled, otherwise the compressors expire before they should. Keep it set to "1" until you've fully understood it, and replace if your analysis proves to be correct. Setting it to 1.5 degrees higher than desired may get your house to the temp you want, but the HP is still cycling every 30 mins (which is not terrible occasionally, but that's not how you want it all the time). Is there any chance it's a "priority" thing? ie. the ASHP space heating is being disabled to allow the hot water cylinder to be recharged. Then, you would hope, if there's not a call to recharge the HWC, the ASHP will remain in space heating mode until the desired temp is reached.

The ASHP will require new piping from the ASHP to the Buffer/UVC/Manifolds. I can't speak for all, but thought most domestic installations required 22mm. Microbore pipes to radiators will need replacing through. Regs next year set the max flow temp to 55° fro all new builds.

You'd be eligible for RHI now, if you can get the ASHP installed and commissioned before the scheme closes 30.03.2022. Otherwise you need to wait for the details of this new grant that will replace the RHI scheme in April next year. While it may not cover new builds, I would have thought it would cover your situation, but only the detail will tell.

Agreed. No idea why Kwasi Kwarteng and Bojo did the rounds last night just talking about Heat Pumps. That's "only" £450M of a £3.9B package of Heat in Buildings strategy that was due to be announced yesterday, but will hopefully go ahead today. The bigger story I feel is the EPC improvements. Let's hope they've stopped arguing between themselves about how it will all be funded and come out with an end-to-end strategy.

https://www.ofgem.gov.uk/environmental-and-social-schemes/domestic-renewable-heat-incentive-domestic-rhi/applicants

And new players like Octopus that already have a training academy set up to train lots of new staff are going to come in and nick all his business. There's going to be lots of disruption, and opportunities for agile operators. Quote: "90000 out of 22 million home qualify " The pool of money is very small. I'd assume that's to get people to move early. More cash will be released, but no guarantee the terms will be the same.

Because "industry" requires policy statements and legislation, it tends not to act on press briefings and leaked disputes between Ministers. The Government has been slow to come out with concrete information on "the plan". Also because the developers are paying for that supply pipe in the connection charges, so there's no loss to the network provider.

There's no detail yet, the first official acknowledgement was last night with Kwasi Kwarteng talking to a the BBC. We'll have to see if new builds will get any incentives from 2022 - 2025. The Building Regs banning fossil Fuel boilers doesn't come in until the Future Homes standard is brought in in 2025, so while there is no need for new build incentives after 2025, maybe there will be something from 2022.

Yes, has to be MCS to be eligible for RHI

That's the easy bit and costs the government nothing since it will be legislated (Building Regs) and no incentives need to be offered. As much as the industry says it can't happen, it's going to happen. I feel your friend needs to get better at his energy calcs to better size the heat pumps to the properties he's installing them in.

Flow temp is the temp the ASHP heats the water to that is sent to the rads. And Return temp is the temp of the water returning to the ASHP from the rads. The lower the flow temp, the more efficiently the ASHP runs, but you need larger rads or UFH to get the flow temp down. Until you know otherwise, I'd leave the heat curve at default, and get the rads warming up. They won't be as hot as your previous gas/oil/LPG boiler could get them, but they shouldn't need to be if they've been enlarged. Have you found a setting for the space heating flow (or return) temp on the ASHP controller? This will be different to the flow/return temp for the hot water. P.S. unless your floor area is on the smaller size, I fear your ASHP is undersized, until your insulation is upgraded. The installer should have done heat loss calcs to determine the ASHP size.

I can't give specific Ecodan advice, hopefully someone will be along that can help with that. But a couple of general questions. How was a 6kW ASHP chosen? That's a relatively low output, so would typically be in a well insulated (above Building Regs) and air tight home. Does that describe your home? Have you increased the rad sizes as part of retro fitting the ASHP? Has any one done any calcs to suggest your flow temp to the rads? Heat curves are to finesse the performance of the ASHP as the temperature drops. We're not really in the heating season yet for a well insulated home, so if you are experiencing space heating issues, it's unlikely they will be fixed by changing the heat curves, it's more likely to be a general flow/return temp change that is required.

More detail was due today, as part of the Heat in Buildings Strategy statement, but normal Commons business has been postponed due to the death of the Leigh-on-Sea MP. The Statement may now go ahead tomorrow. £4k for ASHP was the initial claim, but the briefing is suggesting that has been talked up to £5K. But, the pool of money is very small, again briefing suggests around 80,000 installs. If that's the case it will be gone in under 2 years and there will likely be some filtering to who it is available to. The briefings also suggests the ASHP install will be reduced to the price of a gas replacement in around 2 years, which is rubbish, but may be used to justify the low budget. Edited to add: Incentives may well be dropped for new builds since Building Regs next year will be start to level the costs of Gas v. ASHP

Hi and Welcome. Have you identified your plot yet? Don't be daunted by PassivHaus energy loss targets, if that's your aim from the outset, and you let it guide/inform your build process choice, it's not difficult to achieve.

Welcome to the forum. Can Glosfords not provide a good steer on the heat loss calcs? wrt to heating system, whichever you choose (ASHP or Gas), just ensure the design is for a low temp system, ie. with a UVC and ideally wet UFH on the ground floor. It will save a big rework if you choose to go with a Gas combi now and have to change to ASHP when the gas boiler needs replacing. Personally, if you can get the heating system commissioned by March next year, I'd go with ASHP, as the RHI on offer now is more generous than what will be available after April 2022 and should easily cover any additional cost of ASHP over Gas. You may be disappointed with Bojo's announcement next week.

But, alas, our allowable particulate limits on Biomass heating are appalling in the UK, when compared to, say, transport. I was referring to Particulates and NOx in the main.

If you're not in an AONB you'll have PD for a 4kW system once you've moved in. Can you wait, or do you want an in-roof system? Otherwise stick in an amendment a see if they've really got the guts to refuse. As long as you are sensible I think they'll back down or risk loosing at Appeal.

I'm guessing you're reading that as a caveat to Rule 5. ie. a Septic Tank installed pre-2007, with a rainwater soakaway, gets away without meeting Rule 5. Maybe, but I'd prefer an affirmative statement to that fact to be comfortable relying on it. The link I provided was to the guidance, if you just read the General Binding Rules, Rule 5 seems more black and white. ie for existing Septic Tanks:

Yes, that's correct. Yes, also correct, accept units are 1m³/m².h (it is of course @50Pa, before someone corrects me)

@saveasteading, I didn't appreciate you were quoting from the document I linked to. It gives the answer a little further down, it definitely requires upgrading. If you use a non-standard system (such as a well, borehole and soakaway) You cannot meet the general binding rules if you are using: a well or borehole to discharge waste water into ground a soakaway (designed for draining rainwater) installed after December 2007 Instead you must either: upgrade to a drainage field that meets British Standards and check whether you meet the other general binding rules that apply to you connect to the public foul sewer when it’s reasonable to do so – you must apply for a permit if it’s not Do not create or use a new discharge to ground through non-standard systems such as boreholes, shafts, concrete rings or similar structures. These are not appropriate ways of disposing of sewage under the general binding rules because of their increased risk of pollution. If your sewage effluent discharges directly to groundwater (at any time of year) through any of these non-standard systems: the Environment Agency will not grant you a permit you must replace this with a correct treatment system So they're saying it's not even worth applying for a permit, you won't be granted one, you must replace with the correct treatment system. I've checked up on the Welsh rules, they're now even more strict than the English rules. If you are not on Mains Sewage, you are legally bound to Register your Sewage system with National Resources Wales, and declare how you discharge. If it doesn't fit the rules, your registration is refused and you then have to fix it.

I've not seen what you have posted in context, but I would believe "you can not meet the General Binding Rules" will mean that you need a permit from the EA.