renovator123

TL;DR Got ours installed last month. Obsessed with the details now. Energy Savings Trust PV calculator is excellent although we went for double the size. I think you are overestimating the number of panels that will fit. They are big and don't come in that many different sizes or shapes. Similarly crap solar PV forecast in my location, but it cut our usage by 50% in Oct-Nov. Ours is the SE roof only, 45 sq m in 22 panels giving 9.8kwh peak, house footprint is 75 sq m, generated 6.5kwh last month with a large battery. Info dump to follow. Scroll to pics. Estimated solar PV needs We started off with the Energy Savings Trust PV calculator, super helpful but it wouldn't do calculations for our size of system and limited our annual electric use to 6,000kwh when it is double that (yours will be on your bill). Solar PV depends on location - not just roof direction - west coast UK being the worst area (dark clouds and thick clouds)- put it in a calculator to find out, but it also depends far more on time of year. It can vary a lot between days - batteries will smooth this out - but what you will notice more is exporting excess to the grid most days in summer, and rarely being self-sufficient in winter (depending on your calcs). Several apps will do a daily solar PV estimate if you enter your longitude and latitude, expected system size, and the angle ("azimuth") which is usually degrees from South. Typical roof pitch is 35 degrees. PV Caculator and SolXpress are free ones. You can monitor the predication charts this winter, compared to average daily usage (from your bill). Heat pump cylinder Some of solar PV compatible and some aren't. I have no idea what this means since that's next year's job! Batteries are big They can go outside (under a shade canopy), in garages and I think probably in lofts. Might fit in a garage loft if it has a sloped ceiling. It CANNOT be fully boxed in because ventilation is needed but this can be at the top, sides, and underneath if wall hung. If you put it outside the garage you can hide it with planting on trellis or similar. We can't get them outdoors here due to limited space. Our house layout is extremely complicated with no garage, and internal thick stone walls. We have a 13.5kwh Givenergy All in One battery unit and it fits in a typical "alcove" - its at the side of our disused chimney breast where you might fit a bookcase and takes up almost the full depth and width of the alcove. It is about 1.2m high x 0.65 x 0.65 (I think), above it are 2 small string inverters (Solis ones about 0.30-0.35m deep) and 3 isolation switches plus the cabling between them so basically nearly up to ceiling (which is quite low) and about 0.20m off floor. It actually works well with something similarly sized in the other alcove. It is similar to a 250L heat pump cylinder but boxier, and has string inverters above it (they are not much bigger than A4 paper but shouldn't be right next to each other). You can probably get much smaller batteries but ours is a modular system we can easily add to. It does hum, the smaller string inverters are much quieter. It is a large capacity battery given the size of our panels, although your home is much bigger I think (assuming you have 2 floors) so you might want similar battery size. It is in the office/study and I plan to cover the front of it with (removable, painted) ply sheet with top and underneath gaps for ventilation - luckily we have a MVHR supply valve right above it that gives continuous ventilation moving heat away from it. I wouldn't be able to tolerate working with the hum but it is fine for my other half. LAN cables needed for us (dodgy wifi) go up to ceiling and under upstairs hallway down to router. I think I remember that the battery should be near the string inverters and panels, ours is directly below the middle of the panels. Further away works but you can lose some power I think. You can fit to outside of house under opaque canopy, or in an unheated porch (it will warm the porch a little). They should have shutdown safety features, fire risk didn't come up when were seeing installers but they can get hot especially boxed in. Ours briefly got to 31C in October indoors which is fine (we are in a stone house that doesn't overheat). I wouldn't put one in direct sunlight though. And don't put it in the lounge or a bedroom lol because of the bright LEDs and hum. Wide hallway would be fine, under the stairs if not enclosed by a cupboard. Kitchen or utility would be ok but I would raise it a bit off the floor in case of flood from washing machine. You don't have to have batteries but if you do then you will be able to get the bonus export prices during high demand, and it will pay for itself quicker, and in winter yoy can charge batteries from the grid at night for us in peak hours on gloomy days eg 5-7pm when it is dark. Calculations example 43sq m of panels (22 panels), all SE facing, 9.79kwh peak, 13.5kwh storage, West of UK (poorer solar irridiance), no shade, typical usage 13kwh/day. Installed last month (mid Oct), first electric bill since showed 50% less electricity usage. Our typical electric bill is £120-150/month, in summer we except export amount may cover the £13 standing charge and zero usage. 13kwh/month going up to 15kwh in spring, autumn and winter once we get a ASHP and EV. For us at the moment (mid Nov which is the 3rd worst solar month, we are in the west coast, by hills), today Sun is forecast 18.6kwh, Mon 21.5kwh, Tue 3.8kwh but last 2 days were less (storm and power cuts). Our usage is 13kwh/day (no heat pump yet but an electric immersion heater runs the hot water, induction hobs and electric oven). Our batteries are 13.5kwh so these few sunny days this week will be self-sufficient and charge our pretty flat batteries enough for an extra day (75 sq m footprint, 9.8kwh system only on the SE roof so not ideal setup. BTW we have A LOT of battery given the number of panels, and the fact we only use 13kwh/day. Exactly 1 month after getting solar PV our electric bill was halved (and that's for October!). We haven't yet got income for exporting and the standing charge came to £15. We are expecting close to 100% electric met by solar in summer because there won't be a heat pump on. It will be a 8kwh heat pump with SCOP approx 4.2 so should run at about 2kwh when it's on, given it is an old house it will need more heating than many. We don't know how not having an immersion heater will reduce the bills. We can decide after a few years on whether we should do the NW roof, since adding to the system is cheaper than the initial install and we won't increase battery capacity. It is a modular system so adding or upgrading the string inverter plus the new panels is all that is needed, but pv panels may have improved efficiency by then. We went for extra batteries to smooth out the times when there are several darker days in a row particularly in spring and autumn. Payback time In general UK solar PV payback time should be 7-10 years usually (it is better if you have some batteries), occasionally up to 15 years payback but it can be up to 20 years for direct North facing. (This is assuming that you are getting hot water from electrics.) For us having off-grid generation and battery use during power cuts was about 2.5 years extra payback time. Electricity standing charge currently approx £0.50/day (£15/month) but this can be offset by money from exporting. MCS certified installers will do very helpful calculations for you including estimated kwh, price savings and payback time. Some energy companies will give you a much higher export rate if you get them to do the install as well. Export rates (SEG tarrif) can be anywhere from 1p/kwh to 21p/kwh and you need a smart meter (with a working half-hourly signal) for this Power cuts If you want to generate or use your solar for the ASHP during powercuts you need extras eg a gateway (often there is a single plug EPS that can work from batteries but solar PV generation disconnects for safety during power cuts. We had 3 brief power cuts during the storm Fri/Sat but being November and dark already the battery was empty (we plan to tweak the settings to reverse some battery for the next power cuts, we had 30 last year!) Heat pump size has a big effect here, and that is based on insulation (especially wall insulation vs uninsulated solid walls and windows) - assuming here that loft insulation is topped up as needed for the heat pump BUS grant. So 8kwh heat pump vs 15kwh heat pump dramatically alters what electricity you need from autumn to spring. The gateway for off grid needed to be near our consumer unit, which is actually in the lounge, we have the gateway outside directly through the wall to the consumer unit, it is I think 30-35cm deep, not that big and wall mounted under a canopy (rainfall is heavy here, and we get wind driven rain from that side, it is IP 65 or 66 rated. Panel choice Vertical panels aren't as good because they don't get as much light as roof panels. Integrated solar (that looks like roof tiles) generates maybe 10-15% less than "on roof" but are far better in strong winds and there is easier cleaning and maintenance with no need for netting to keep birds from nesting up there. I think your roof surface area calc are most likely too high because it depends on the panels and what sizes are available plus manufacturer clearances from the edge and working around any chimney. If you want to work it out, we just had Viridian Clearline Fusion panels and the sizes and specs are online. Wifi If inverters or batteries are in garage or outdoors then check the wifi signal because although you can do fit it and forget it being able to monitor it and checking when it is at peak so you can run washing machine, dish washer etc will save you from drawing from the grid when out of battery. If you don't have wifi you need to run LAN cables to your router, and possibly between consumer unit and batteries, and have a system allowing a LAN connection. Our installer was crap with commissioning (I was literally reading him the manual) and tried to convince us to "just try wifi" so we had to insist on LAN. EV charger Worth getting at the same time if you don't have one yet. Photos 1. SolXpect forecast graph for week of Nov 16, 9.8kwh system on SE roof in west. 2. Electric bill from mid Oct - mid Nov compared to last year shows 50% less usage, it does not including export to grid but unless we want to pay ££££ we can only export 3.6kwh at once (40% of what we could generate).

thanks, I will have to get my tape measure out to check but for the upstairs windows I think we might need a restrictor for the tilt, as well as to stop side opening. For the downstairs window it sounds promising.

I am also looking into this with Internorm tilt and turn windows - fitter was not FENSA registered and we need retrospective building regs certificate. But also it is kind of scary doing DIY near such a big low window. Building Regs K2 I think means restricting to opening 100mm max for our 2 low windows (I haven't spoken to building control just yet). Guarding is the typical norm, it had to be non-climbable (vertical rails) or glass panel and can be internal or external but both will look awful on our period house. The alternative is a window restrictor but only the ones meeting specific BS standards for force are allowed and it has to be keyless and permanent I believe, so it can't be left unrestructed, plus you need toughened glass. This is in BCA technical guidance note 1 from the Building Control Alliance for: Window openings in external walls with cill heights between 300mm & 800mm above finished floor level. A few of these window restrictors have a two-handed way to open the window further in order to use as a fire escape - Angel WOCD is one I've seen mentioned - but can internorm timber/alu have their sashes removed? The R02 egress window restrictor says its building regs approved. Jackloc permanent cable restrictor might be strong enough? I would really like something that doesn't need drilling into the frame. We have a GF window we'd prefer to only open one way so I'm also interested in a turn restrictor. The integrated ones show in @craig's photos is shown in internorm brochures as suitable for care homes (not sure on building control)o'

re solid wall insulation - wood boatds are a much less specialist option, Gutex or Lime Green Warm Shell for instance - level walls first though - both can be used as IWI or EWI. EPS/XPS is the popular EWI option. https://www.lime-green.co.uk/products/lime-systems/woodfibre we currently have a bag of Lime Green Ultra which can be used as render but we are actually using for patching plaster and holes, using that instead of gypsum plaster gives breathable walls that are mould resistant (alkaline) and greatly improved U value compared to uninsulated solid walls. Diathonite Thermactive you can also hand mix and buy per bag for small repairs and leveling https://www.lime-green.co.uk/products/lime-render/ultra_render re: EWI: with Diathonite (Evolution) at 55-60mm thick which is 0.60 U on rubble/sandstone (with original concrete render hacked off first, and a few mm lime green WP finish over the top), we did not need to extend the roof line at all. The walls were very uneven - especially thicker at the bottom and in places curving from one side to the other (kind of concave) over the, so that was a nice surprise. You would also lose the stone look with EWI (what we found was missing stone and old blocked off doorways etc). Diathonite EWI case here sums up a lot of our issues With Diathonite if you go IWI you can use Thermactive which has a better U value, with our EWI we still have gypsum plaster internally so unless we replace that on external walls they won't "breathe" (though it may not matter with MVHR in soon). The reason we didn't do IWI was need for new render and lowering outside ground level (which is still higher than inside), as well as less mess to live with. Diathonite needs hose on water tap and electric if machine applied. MVHR: you need an accessible room and unless sound proofed room (they are noisy), so under stairs, boot room, or shower room on left of stairs by bed 5/study. Central to the house is even better with air intake plus connecting to internal drain ie near plumbing - but the big issue we had was avoiding crossing the many exposed ceiling beams downstairs and ceilings way too low for false ceilings (under 2m in places). You would have to plan where the valves go for vaulted ceiling spaces - supply valves that are wall mounted are apparently really large. If you have a central chimney you can run ducting along it and box in and fit valve from there. You also need a recirculating cooker hood and to block/remove all bathroom extractors plus breather membrane in loft, and insulation on any loft ducting, and ideally avoid window vents in triple glazing. MVHR are extremely efficient and kitchen and bathrooms will always be warm and should dry laundry easily indoors. MVHR planning resulted in finding 2 unknown and well hidden ceiling beams. If you have never had oil before then it's really inconvenient - you end up having to buy over 1,500 litres at the (uncapped) Kerosene market rate at the time, in the month you need it, and it doesn't run without electrics anyway. Basically get fleeced once or twice a year, boilers are less efficient too. Skylights that aren't passive house standard will lose a load of heat especially with uninsulated floors - internal stone walls act as a cold bridge unless you de-couple walls from floor eg dry lining. Insulated lime based plaster is a good option for problem spots internally eg Lime Green or Aerogel ones (40% less heat loss compared to uninsulated solid walls). Weirdly we have internal damp at above electric socket height on 2 internal walls, one socket has been replaced multiple times from rust. Ground source heat pump is likely to be better than ASHP for the size of your house. If you do enough energy efficiency improvements eg towards EnerPHit standard then you probably won't need a central heating system. Good luck with the rest of the plans

Update: we weren't impressed at all with the Cork Sol info and found it easier to get Diathonite installers. The other options seem rarely used externally and won't help so much with air tightness or mould. Diathonite is excellent, not fully cured for a few months (but dry to touch and re-coatable). We had advice that we should have XPS plinth across the bottom where we get a lot of water spray - on to get a bead on it so that the XPS can be recoated in future years/decades if there is water damage. The same top coat is on both and it looks awesome. We had a few external concrete window sills so got those knocked out and replaced with XPS, which is ridiculously loud when it rains (or was until the top coat was on). Diathonite has greatly improved the air tightness (less drafty), and the mould situation too (because it's alkaline and because damp can move to the outside). It's a colored top coat so no painting needed. To keep moisture moving from inside to outside needs lime plaster or similar, although there's still a lot of benefits with gypsum... a lot of internal plaster is persistently mouldy or blown so needs sorting anyway. One part is so mouldy that the metal edging under the plaster has rusted through. It's very noticeable how warm it is overnight and the phase shift of the thermal mass. No good pics yet since top coat is still in progress and has to dry gradually before you get to the final color. It's already much better than the concrete render (which had a lot of damage). Diathonite evolution is a sandy color going on, drying to light grey. Top coat is by Lime Green in woad blue. The window bands need reforming unless you want to just paint them on after.

Just saw this and actually I also have an update: and lowering part of the ground floor is on the list for another year - there's no foundations here either. We got the EWI with Diathonite, great so far although not fully cured yet. Damp and mould were factors in the decision- Diathonite is very alkaline so inhibits mould, and with no floor insulation the internal solid walls have damp in a few places. We decided to go for MVHR in preference to heat pump and even just having the kitchen extractor recirculating with the wall insulation it's noticeably warmer and less drafty. The utility/downstairs loo extractor is gone in preparation for MVHR. Heating-wise it seems new builds and big renovations are going for heat pump and underfloor heating (at least for ground floor). That's not workable with low ceiling heights and low beams. We got an advice report drawn up from a charity that provides them and that's helped a lot with planning although the cost estimates are on the low side. The report broke it down into 3 stages and outlined risks eg condensation causing damp. With windows and glazed doors trickle vents are heavily suggested but optional- going the MVHR unit satisfies the ventilation needs and allows you to look more at EnerPHit/Passive House standard triple glazing, which is much better than argon filled double glazing. The "pink house" retrofit in Scotland is a mid terrace with real life figures on different combinations of options, and MVHR was particularly good value and was very good combined with ASHP, we have also discovered 2 further ceiling beams during the MVHR design process https://www.esru.strath.ac.uk//Documents/MSc_2015/MacLean.pdf It's been pretty crazy this year for us, and part of last year so we have a break planned for at least a year, which should mean we get time to patch the numerous holes in walls and ceilings (and floors). The planning is actually more hassle than having the builders in and the endless small jobs and mess.

Interesting, thanks. We are facing similar issues. Diathonite is actually a range of products with Thermactive being IWI and Evolution being EWI, plus extra products for areas with a lot of salt crystals, a tanking solution and top costs. They do a top coat cork spray which can be colored and is less prone to cracking and better able to move with minor movement compared to most render. I think we have given up with CorkSol, U value is not a good and they don't seem so good at getting back to you, and unsure of the quality / consistency of it. Another Diathonite EWI case, the House at the Northern Gate has it too (far North of Scotland and coastal). https://www.fca-magazine.com/features/product-specific-features/1396-ecological-building-systems-cumbrian-period-property-overcomes-issues-of-damp-and-mould-in-major-renovation

I live on a hill in one of the wettest parts of the uk, but the water runs down the hill into a river and French drains are typically as part of that, it is not such as issue with the type of ground and the fact it's so steep - it would be an issue if we had chalk ir clay but we don't. It drains without a problem. DPCs are perfectly good when you have cavity walls and a fairly modern build and you don't have any rooms below outside ground level. It's not exactly practical to expect a DPC on 600mm limestone and cob with render and gypsum plaster to keep the wall dry, especially not when you do not have a floating floor or real foundations - we've been down that route and not had it work. So the focus needs to be on what materials work for the existing building and the limitations of it. Keeping 100% of damp out is highly unlikely so going with traditional but updated building products means moving further to vapour open, and MVHR (heat recovery ventilation) will be reducing any excess humidity further, although I doubt we will see damp on internal walls in the same way later.

Lime is extremely alkaline which discourages fugus/mould/rot but the additional breathable means the damp has somewhere to go (via diffusion) which right now it's the case with the concrete render slapped on the external walls. Externally it will be coated to keep out driving rain.

Yes about the lower walls, something not so vapour open it needed for the lower part of all of this, I should have said. Diathonite Demix and tanking are needed for the bottom 30cm+ for at least some part of the house given about a third sits on a concrete slab over rammed earth and house is 1830s and has never seen a DPC. By "breathable", think "vapor open". Figures for vapour permeability by diffusion and air tightness values are available for all the materials mentioned, although some (foil quilt and Supasoft) have to be filled in specific ways for EWI - supercoil have a breather quilt for instance. Currently we actually have some damp in a fully internal supporting wall coming up from this. Hopefully we will be getting this resolved as part of the work. The electric back box for unused sockets have rusted a second time after having measures done to fix it before.

The walls are nothing close to level so a flexible insulation allows you to fill any gaps and level things out. EPS or other boards must have the gap between them and the wall fully filled. It's a period house that was built as both vapour open and breathable and keeping it that way it's going to cause its less problems.

Any suggestions or feedback for comparing breathable EWI options for a home aiming for EnerPHit (U 0.15). These options we are looking at: * Diathonite (clay/cork/lime) * CorkSol / SprayCork - how does it compare to Diathonite? * Wood boards eg Steico, Gutex (Pavatherm prices seem crazy) - durability? Bowing? Water ingress? * Supasoft (recycled PET) * Superfoil is advertised as breathable All seem very similar U value, prices vary a lot and Diathonite installers are hardest to find. We have ruled out thermafleece wool for reasons I won't get into here. This is to go under render (existing concrete based render is cracked and will be removed first), for an old house (500-600mm solid walls) with no damp proof course. IWI we have ruled out due to construction/layout and internal issues. It's a semi with very limited space on one side (under 100mm thickness needed). Anything extremely durable and really good for non-coastal but very windy area would be good.

I'm wondering about your EWI options- do you have a price per sq m for Diathonite, and have you had difficulty finding an installer? We are also looking at breathable EWI and options seem limited- although Diathonite looks excellent it's very expensive. I wondered your thoughts on CorkSol / SprayCork, or wood eg Gutex / Steico for EWI instead? I am not sure about durability of wood or about the ability to keep it dry when render over it will crack/decay sooner or later. We had calculations done for EWI using Diathonite, giving approx 57-60mm thickness (evolution, agrathem, etc) over 500mm stone but have recently found some solid walls are not uniformly that thickness, which affects ability to reach EnerPHit U values. Diathonite is similar in U value to rockwool and supasoft/thermafleece options which leaves me wondering about value.

TL;DR: Internorm EnerPHit prices above Windows approx £700-1,000 each inc VAT, fitting, removal of old, larger windows would likely be cheaper per sq m. Internorm only do single panel windows (glazing bars are an option) and only tilt and turn. Doors were in excess of £5,000 inc VAT and fitting, with only the HF410 model able to made in the shallow height we needed for retrofit, and us having a custom design. With no porch or conservatory on the house, the doors have made an incredible difference. Door designer prices are online: https://uk.internorm.com/internorm-door-designer/ Thumb turns & split spindle were fitted after by installer included in price, which were Winkhaus - amazing for keyless emergency exit, and keyless locking from inside without risk of accidentally getting locked out. Trickle vents - England - current UK regs state trickle vents are needed, clearly not suitable for EnerPHit or Passivehaus - but this regulation has some exceptions including certain other ventilation methods. https://www.gov.uk/government/publications/ventilation-approved-document-f

Some prices are specs... we went with Internorm and the quality is excellent, really noticed the difference and they haven't even finished installing so it's not close to air-tight. Velfac V200E we also looked at - prices similar to Internorm. specs: Internorm Retrofit Timber/Alu Argon filled triple glazing 48mm (4b/18/4b toughened/18Ar/4) HF410 windows, 0.71 W/m2K stated, calculations were 0.73 to 0.84Uw HF410 doors, 0.73 W/m2K stated Doors had to be custom due to height, with 1/3 triple glazed obscure, 2/3 timber-alu. 9 windows, total 7.96 sq m 3 doors, 4.85 sq m with unusually low height that was unavailable from all major sellers (Solidor do Tinidor but no other big firms do). Dec 2022 price £14,435 excl VAT £17,320 with VAT included Fitting was all thermally broken eg compreband to our solid stone walls (EWI is planned). Extras: * Removal of old, retrofit, * 2 thumb turns and split spindles on doors * Hirest weather resistant color * 1 window obscure glass + Full fitting including removal of old and scaffold brought up * Cat flap fitted in 1 door * Presumably a charge for overnight accommodation (2 people, 4 nights) and travel due to distance Final cost: £24,342 incl VAT - May 2023 (discount of about 5 or 10% at the time) (£17,320 excluding 20% VAT). Skip costs extra. Not a single supplier in our county was willing to quote for any EnerPHit standard spec from any manufacturer so travel/hotel bumped our costs. Green Building Store wouldn't do fitting for their windows and doors and neither would local tradespeople. Well worth it but we absolutely need a HVAC for condensation since extra insulating the loft. Cat has been sunbathing near a window ever since it got replaced and the heating is on noticeably less despite it not quite being finished yet.