Ferdinand

Cheers, Jeremy. An ASHP (playing with Stroma) seems to give an increase in the EPC number of a few points - tested by simply replacing the Combi Boiler in the Model with an ASHP. Which is, however, a slightly crude test. @A_L a - thanks for the comment. Keen to hear more of your experience. c - I am not sure that I agree entirely with your "c" reply. My current floor renovations give me a floor U-value of just under 0.25, which I think is the basic requirement for renovated 'flooral' thermal elements (not that I had any formal inspections just a "what if" conversation with the department while considering, and they said 'some improvement is better than nothing'). The wall u-value is 0.55 (50mm filled cavity brick). The roof u-value is about 0.14 (270mm rockwool). The cost-effectiveness or not comes from 2 things ... energy saved and cost of installation , and can be judged-ish on a simple payback. The cost of my whole floor buildup (ignoring the floor finishes and labour as most are self-builders here) was well under £10 per sqm. I will post the detailed buildup next. Even if I include labour, it is probably a 5-7 year payback in energy terms (depending on tariff). (*) I think that perhaps leaves room for a bit more, which would mean either more insulation in the layer-cake or EPS beads pumped into the underfloor cavity. I am already quite close to my doors' 65mm trimming margins at 60mm incl. ventilation gap, so to put more insulation in would need some redesign of the build-up. I could fit 38-40mm of celotex plus Engineered Floor attached directly to battens, or click-laminate/vinyl on 6mm ply on celotex. Just. Putting 40mm in as I planned would have given a u-value of about 0.21, which is still imo not really good enough. I estimate that 300-350mm of EPS beads would give me a u-value of 0.10-0.12, which may be worth it if it put me in a position to use an ASHP not a Gas Boiler. f - Than 10000kWh/yr is all energy. It is a conservative guesstimate as I do not have my EPC back yet with their modelled Guesstimate. The previous EPC (will post) says 13.5k with a potential 50% saving, but includes solar panels as well. Ferdinand (*) There are issues around transferring part of that saving from the Ts energy bills onto a slightly increased rent - say sharing the benefit 50:50, but at least I am now in a position to see if a dramatically better EPC number can give say £595 /month not £575.

@Tennentslager I am not quite clear what your objective is here. You say the front room is now carpet with a 6mm drop to the vinyl (?) Or is that the proposal for this kitchen-area threshold? Wouldn't black tape just make it an invisible trip hazard? What does it do? How deep is it to the base of the wooden threshold - eg does it go through the thickness of the floor? Could you hoick it out and replace it with something thin / flush? I had a hole-in-an-internal-wall like that at the LBB, and we just put the wall back . But that would not be a relief to your coffee-drinkers, who need a sort of site-hut to make their drinks. Are you planning to replace the vinyl (£6-8 (?) per sqm). If so - or if just replacing the vinyl in the coffee area - I think I would just put a 6mm (?) ply later down rather than hardboard, and use that to level it up to the raised threshold? Or make it flush as suggested with a level threshold. F

I think they are not required for rooms opening directly onto a hall which leads straight to an external door. Which was a surprise when I looked it up - on the LBB I have one in every bedroom, and the installer fitted handles without keys. Not convinced that that was correct.

I believe that the 100 sqm exemption does not apply to new build, but as a self-builder you should be exempt anyway, surely? There are elephant traps (ie they will charge you notwthstanding you being a self-builder) if you do not have your confirmed CiL exemption in place, and written in tablets of stone ,before development starts. Putting up tree fences may or may not count as development - someone else might know or confirm that it is foggy. The documents will be on display with the other Council Plans: Ferdinand

I think there may be someone here with the correct answer to that in their head already. it is always the first bit of insulation that saves the most and is the most cost-effective (subject to overheads etc eg if you have to trim doors), and since you are already lifting the carpet etc it is just the extra cost of materials plus adjustments. F

Can you add 25mm or even 12.5mm of Celotex into the build up ? Even that would help a lot.

I notice that you do not contradict the last statement....

+1 to all bedrooms. Different systems are not worth the complexity. I made that mistake in a bungalow in 2010 to "save" money. Only do not install in the bedrooms if the alternative is nothing. Ferdinand

Ohno. Shower with a door. Breakdowns and rescues of trapped people approaching...

Venturing gently into the Boffins' Corner, I am after some help to try and come up with a heating / water / ventilation system for rentals which will: 1 - Not involve gas (trying to get rid of Annual Checks, and the plain worry of gas appliances going wrong). 2 - Will not slug the EPC figure. I am regulated to be D or better from 2025, and C from 2030, and not to comply will be a criminal offence - though there are exceptions. 3 - Will not be overtly expensive. 4 - WIll be essentially maintenance free, which ideally means minimal self-done maintenance once per year, and professional assistance once every 5 years. This will be a slow-burn, but as a starting case study, I want to work on the real world renovation of the Little Brown Bungalow. This has been easy to renovate so is a good example for a first try - and there another 49 identical properties in the street to do next time. I may get a copy of the Stoma data from my EPC an, but the project characteristics are: a - Floor area is 64sqm. 3 beds, reception, kitchen, bathroom. Suspended wodoen floor over a concrete raft foundation. b - EPC will be 76 or 77 in the C band. Previously was 47E. c - I have addressed all the low hanging fruit and a bit more. Underfloor insulation 100mm rockwool + 25mm PIR. 27mm loft inculation. Good double glazing. Modern boiler (Ideal Vogue) + rads. 50mm cavity wall insulation. Background ventilation is a PIV fan at the far end of the hall, one end and an HR Trickle Fan in the kitchen. d - Attention has been paid to airtightness and detailing. e - The obvious weakness is the 0.55-ish U-value of the walls. f - Realistically energy costs should be around £500 per year give or take, and demand could feasibly be under 10kWh per year - the previous EPC number was 13.4kWh predicted from the EPC. g - As a marker, the all new heating/water system and the ventilation kit added up to £4k installed. EWI would be prohibitive unless substantial grants are available - looking at 25-30 year payback on the £8-9k I was quoted. If I need to I can do more modelling; I think I probably need to do some proper thermal modelling eg the @JSHarris spreadsheet. If there was a way of using them effectively without complications, PV would be a good thought as it would also benefit the EPC (2.5hWp would put it up to nearly the A band). My initial questions: How close is this to being practical as a low cost electric only house? Does the thermal demand need to be mitigated further? How can that be done? Pump LECA or EPS beads into the subfloor, perhaps? What sort of technology mix would be suitable in this rental application? ASHP? Storage Heaters? Sunamp? Economy Seven? MHVR combined with warm air heating? What to do with any solar panel output? Are there any creative possibilities? If we can come up with a good ideas, I would be willing to try it out on another identical bungalow in future if one comes up for sale. Cheers Ferdinand

Depends how you have insulated it. A skirt would keep them warm, assuming no side draughts. /metaphor If you have cross flow then you probably have to suck it up. Gable walls into the attic may lose more heat by conduction, as the ground is warm.

Not sure about further tightening. I was just aiming to place my LBB refurb's value of about 76 on the current scale. F

Slander ! Libel ! It was only last week that I bought an 18mm sheet of MDF at B&Q for £19.50 (reduced to £19.36 by B&Q Trade Discount). (*) The nice man on the saw cut it into 11 slices of 3, 4 or 5 inches for me, to make radiator shelves (to prevent Tenants drying washing on radiators) and door liners. F * I shall treat myself to one two-finger KitKat with that.

A quick EPC question to which I cannot find an answer. What would be an EPC value for a typical "building regs minimum" newbuild property? I did however find numbers for how EPC values have changed over the last 20 years. Right direction, more still to do. Source: https://www.gov.uk/government/uploads/system/uploads/attachment_data/file/627688/Potential_stock_improvements_Report_2015-16.pdf

Can we go all Georgian, and tax bifold doors?

I ran across this post from @SimonH from 2008 over on GBF this morning: http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=994 What are the big factors and impacts now? The context is that my Little Brown Bungalow renovation for rental of a 1966 3-bed semi bungalow will be given an EPC value of about 76 in the C band. I have done everything to a good standard, including underfloor insulation of 100mm rockwool + 25mm PIR, but not EWI (so walls are still filled cavity ~= 0.55 U-value) and 2G not 3G. The tenants energy bills are likely to be under £500 per year. But I see from Stroma that adding relatively little PV solar would bring it up to a B or even an A, which is a little bizarre. Ferdinand

(Keeps quiet about the subtle double-entendre).

Highish for a developer house ie better than average eg ufh, an ensuite, and all double bedrooms in the 4 bed. I need to get the gumf as it is quite close. The detailed planing ref, including specs etc, is here: https://www2.ashfield.gov.uk/cfusion/Planning/plan_view_docs.cfm?reference=V/2017/0534 There is an earlier Outline. The site backs onto allotments and has a few mature trees, so it will be pleasant. Given that *this* is the site as of 9am this morning, there is scope for negotiating changes: F

What about a rotating one on the roof (or at a low level) as part of a weathercock for new Builds? Could have a modern version of the Sisyphus myth with @Onoff making his bathroom in cut-out sheeting .

New cul-de-sac development near me with highish spec finish, including .. wood burning stoves. http://www.broadleafclose.co.uk/

Cheers, so already exempt.

The technique is to talk to the EST helpline, and ask for your local organisation involved. 0300 123 1234 There may be some wrinkles around new build vs conversion, occupation etc. You need to check. For rentals iirc I have to have a tenant in situ before I can get it done, but once you ask them it is an inspection then install within a few days. They work quickly, so if eg you have gables that are walled off that you want insulating then make them accessible before the survey. When I had the Little Red House I just mentioned on the other thread done, they were in and out within 20 minutes. I last had one of these at this time in 2016. Given that your building is idiosyncratic, I am not sure how it will pan out. If you can update us with your experience that would be great. F

Sorry ... 'tis for small detached houses. I imagine that the way they measure it is the same as they do when calculating EPCs. Title edited.

PS There was a thread about work I have done on it on Green Building Forum back in 2013: http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=11560

This is mainly for @Crofter, depending on how Wee the new Hoose actually is - put here in case anyone else finds it. In England, detached buildings under 50sqm are exempt from having an EPC done. https://www.gov.uk/energy-performance-certificate-commercial-property/exemptions If it is also so in Scotland, that could save you a little money and hassle - if you are under 50sqm and so minded. I have one under 50sqm - the detached 48sqm cottage my dad was born in, which is now a rental. I have the EPC number up to 51, and the half of it which has been drylined since about 1984 (25mm eps) was ignored by the EPC man, but that is about the limit of what is achievable practically. When push comes to shove in 2026 I will rely on the exemption rather than make a "too expensive to upgrade it" argument. Ferdinand