SBMS

That would make sense, and I guess would make it really clear that the authority had decided to impose an optional regulation. There weren't any conditions related to this in our planning approval, so I think we can inform BCO we don't need to adhere to these optional conditions.

Thanks for the responses. I've been told that there are "Optional Technical Housing Standards" which are standards local authorities can choose to apply or not (or that housebuilders can choose to optionally adhere to). The summary for these standards (and how they inter-relate with Building Regulations is): "In March 2015, following consultation on accessible design standards, the government issued policy in the form of a Written Ministerial Statement on housing standards. It introduced new additional optional Building Regulations on water and access, and new optional national space standards referred to as the ‘new national technical standards’. The new standards complement the mandatory Building Regulations 2010, SI 2010/2214." The example for water efficiency from the Govt's guidance on optional technical housing standards is this: "All new homes already have to meet the mandatory national standard set out in the Building Regulations (of 125 litres/person/day). Where there is a clear local need, local planning authorities can set out Local Plan policies requiring new dwellings to meet the tighter Building Regulations optional requirement of 110 litres/person/day." So it does indeed indicate that there are optional standards that complement Building Regulations that a new home can adhere to, but that may also be set at a local authority level as a mandatory requirement? I think I should have named this topic something better than 'optional part of building regulations' as these are not those, but are 'optional technical housing standards'! My question, for anyone that's come across this, is, can a local authority mandate them? The govt document I read is here: https://www.gov.uk/guidance/housing-optional-technical-standards

Hi all We are just kicking off our self-build and have appointed our private Building Control firm. They have asked us whether we are requiring: -regulation 36(2)(b) (optional water efficiency requirement of 110 litres per person per day), -Schedule 1 Part 1 optional requirement M4(3) (category 2- accessible and adoptable dwellings) Reading online it seems that these are optional parts of Building Regs that you can elect to comply with, but that some local authorities can mandate this? Is this correct, and how would we know if this was something our local authority insisted on? Further - if we are using private BCO - does the local authority have any input on these two in any event? We would, of course, prefer not to elect to comply with these, but interested to hear other's thoughts!

We are looking at PIR insulation on our slab and are looking at 200mm insulation. Has anyone put this much down, and if you did, would you advise doing it as 2x 100mm boards, or a single 200mm board?

Thanks everyone ?

With whole house MVHR, is an extractor fan necessary in kitchen area, or does MVHR in the kitchen perform the same function? We are considering adding MVHR and we currently have specced the kitchen with a ceiling extractor unit, but am hoping we can get rid of this if we add MVHR.

@nodWhere abouts you building? We are just outside preston so have the dreary, wet lancashire climate so interesting you've gone ASHP as some state northern, wet climates are not ideal for ASHP.

@joe90 firstly - thanks for the welcome, forgot earlier. Secondly - what was your insulation strategy, construction method and level of insulation for a 5kw ASHP?

This is interesting. So from a financial point of view, so far the following: The install differential between LPG and ASHP doesn't seem as large as first thought. Looking at that quoted price difference of 11k vs 14k, that 3k difference could be more than compensated for by a 5k Boiler Grant. Future proofing a LPG gas install to ASHP might require additional future costs of £2k (1k for cylinder swap, 1k to buy the LPG tank - even if we left it in the ground) Rising fuel costs - LPG price could rise and Electricity prices could fall if green tariffs removed It does push the needle a little more toward ASHP. Out of interest, we're doing traditional construction (brick and block with 100mm full fill cavity and 150mm floor insulation with UFH). I assume from previous comments this isn't 'the best' for ASHP, but does anyone have any general guidance on recommended insulation levels? Its a 2.5 storey house with second storey in attic space, almost a perfect square footprint.

Interesting concept @Iceverge. Would the engineer, data-geek in me love to try this to arrive at a data-driven decision? Yes. Would my 'nesh' wife who stabs the boost on our current wall stat so much its fallen off, let me? Not in a million years.

Hi Temp - yes, as mentioned my parents have just signed up (here in Lancashire) for 38ppl fixed for 2 years with extragas. I think the LPG prices on nottenergy as based on variable non fix. But wholesale LPG commodities are now increasing in line with natural gas so its likely that price is going to shift over next few months.

This is really interesting - is this a recent quote? A 3k price differential in capital outlay is certainly compelling. We are not at the quoting stage yet so perhaps my assumption that ASHP install costs would be 5-10k higher than gas are simply wrong. Are you currently building?

Good point regarding the tank removal charge - especially if we are sinking it. Would likely have to buy it off the provider. I would provision for a system LPG boiler with an unvented cylinder so that at a later date only the heat source (boiler) were switched out. Would a cylinder for a gas boiler be compatible with an ASHP or would that need replacing too?

Ironically at the moment LPG is sitting around 5.5ppl and mains gas Is around 4ppl - on govt price cap so a third more sounds right. Come April, will the price cap shift mains gas nearer to LPG levels? Average standard mains gas charges are 20-25p per day equates to £70-90 per annum, same as standing charges for LPG tank.

The current draft regulations seems to specifically include self build properties, see regulation 7 in the DES’ draft legislation for the boiler upgrade scheme: Requirements for new-build properties 7. A property meets the requirements in this regulation where— (a) any building that forms part of that property was built principally with the use of the labour or resources of the first owner (including where the resource was a loan which the first owner was liable to repay), and (b) the property has not, while the building was built or at any subsequent time been owned wholly or partly by a person who is not an individual. from: https://assets.publishing.service.gov.uk/government/uploads/system/uploads/attachment_data/file/1040470/Draft_Boiler_Upgrade_Scheme__England_and_Wales__Regulations_2022.pdf so it does look like 5k grants are available for self builders, just not property developers. Would welcome anybody else’s interpretation of the regulations!

Thanks ProDave. I’m trying to compare them like for like and we are building well insulated. Like for like both energy sources are going to have to provide the same level of input energy so I’m just considering the functional and financial sides to the two technologies. The LPG standing charges are fairly low - we’ve been paying £60 per annum for last 5 years with previous supplier. joe90 - if you were being completely objective, assuming that LPG were the same cost but ASHP has higher install costs and I guess arguably were functionally more restrictive (even if that functionality is never used - because you’ve got a good setup), what would you say were the reasons for choosing ASHP in this scenario? Ianr - yes my parents just signed a 2 year deal with extragas at 38ppl. I agree that there’s a political argument to go ASHP in the event green taxes increase on LPG. In all likelihood I would suspect levies are focused on mains gas; LPG makes up such a tiny fraction of usage in the UK - and bearing in mind off grid properties are already limited in energy choice, I think it will be targeted last. But it’s certainly a point to consider and hence my covering by having a system that ASHP could be slotted into. But for the next 5 years say, does ASHP make sense? I guess what I am trying to cut through is the subjectivity around the topic (there’s a lot!) and for a well insulated, new build is there a compelling reason that I’ve missed to go with ASHP over LPG.

Hi A bit of context - currently about to start on a self new build - 280sqm 2.5 storey brick and block house. It’s green belt with no mains gas. North west of the UK. We are evaluating whether to go ASHP or sink an LPG tank. If we forget the install costs for ASHP which will be a fair bit higher than LPG, and the lack of ‘instant’ heat with ASHP, am I right in thinking it’s difficult to see how ASHP stacks up financially? LPG prices currently hover around 35ppl to 40ppl. A litre of LPG contains roughly 7kWh of energy so equates to circa 5 - 6ppl. Assuming we averaged a COP of 3.5 on an ASHP, current electricity prices are circa 20p per kWh so energy cost for ASHP is roughly the same. But deviations in COP (especially as 3.5 would be unlikely for DHW) means it’s pretty close and LPG is likely to be more economical in the short to medium term - along with some functional advantages (instant heat, no large unit etc). My current thinking was to design the house for ASHP (oversize rads, UFH, unvented cylinder, mains electric circuit for future pump), put a 2k LPG boiler in, and only switch if LPG prices grew over electricity. I really want to go all in on this technology because burning hydrocarbons is ‘last century’ but I also want to be objective regarding the cost. Thanks in advance