Dan F

@oranjeboom If you know any German and one to go one step further than Jeremys sheet, without going as far as (or paying for) the latest version of PHPP, then you coud look at the freely available PHPP 2002 as another option. https://passiv.de/en/05_service/02_tools/02_tools.htm

@ProDave I'm pretty sure these are Scotland-only building regs. Not saying an airtight garage with no ventilation is a good idea, just updating thread with findings. Good point @joth, simplest solution to door might be just to walk outside. Will have to look at door options and "airlock" alternative more serisouly I think..

Harvey or Twintec. Search the forum for either of these for plenty more info. Or take a look at this thread:

@DamonHD Sorry, it's same thing they told me about, just a different website https://hydropath.com/hs38/ So that thread I linked to, is about exactly the same product..

@DamonHD Sunamp suggested Hyrdopath to me, seems just a magical though....

That's a very good point, and not one I was aware of, thanks! Will look this up to see the specifics.. That's what I heard, but I didn't know how good/bad something like the "Hormann LPU67" (which is class 3 airtightness) actually is. Yes, this is the current/default plan. I just wanted to pick peoples brains on the alternatives.... Yes, was aware of this, but hadn't looked at prices yet! This would be one reason to include garage in airtightness envelope, but as you said that not allowed due to BRegs. Very useful, thanks @ProDave!

Ha, I knew certification isn't very popular on this forum! ? We're doing it to aid in decision making and for the quality assurance, not the certificate. It means we are sure that timber-frame and window installation detailing etc. is fully reviewed, that we're choosing the best glass specification (u/g value) and overhang sizes to best balance insulation/solar gains, and to ensure the investment in external blinds makes sense amoung other things. Yes it's a couple of thousand £, but so it's the structural garantee, building control, site insurance and everything else. And if it improves our confidence in what we're doing and potentially also our comfort living in the house for the next however many years then it's money well spent in our minds (we don't have time or knowledge to play around with PHPP ourselves). Maybe I look into the Hornam spec from a u-value and airtightness standpoint, and if it's good consider including everything in thermal envelope and keeping things simple...

I agree it's a bad idea, but sometimes planning limitations (or space) dictate things...

That makes sense yes, but because we decided to certifiy we can't have it both ways and we either need to include garage in the thermal/airtight enveolope and get a very good garage door or exclude it and use a seperate slab and full insulted internal garage walls. It does make some sense, because if you don't have a really good garage door and/or garage threshold detail, then it's not really a good idea to share the garage slab with the rest of the house..

Hi, We are now at the stage where our archtects construction drawings are being converted into timber-frame drawings and we're giving doors, windows and UFH more thought. Our design has an integral garage (a detached garage wouldn't have got past planning) which means we have to work out exactly how to best treat it the garage in the contect of an airtight, highly insulated house. In our case the garage isn't just attached, but it's integral with 2 walls being shared with house, and 60% of garage ceiling being below an upstairs room. Three approaches I can think of: - Include garage in thermal envelope: This is the easiest from a timber-frame and insulation perspective, as the continuous layer of insulation is on all the exterior walls and a single slab foundation can be used. The major challenges with this approach are i) ensuring thermal-bridge free garage theshold ii) finding a garage door that is insulated and air-tight. - Exclude garage compleltly from airtighness/insulation perspective. This involves using a seperate slab (seperated by EPC upstand) for the garage, the house->garage walls being 300mm twin-wall will full insulation (as garage is considered outside temp) and the garage roof also needing to be as insulated as possible (which hard given only 253mm deep). We could use any garage door we like, but garage would typically be close to outside temp. - Middle of the road. Exclude garage from thermal envelope and air-tightness layer (seperate slab also), but i) ensure external garage walls have fair amount of insulation, ii) put some thought into the threshold iii) find a fairly airtight and well insulated garage door (something like Hormann LPU67 Thermo maybe?), and iv) put UFH into the slab just in case we want to use it as anything other than a garage in the future. Which approaches have others gone with?

Exactly, our design-phase modelling explicitly didn't even include trees for this very reason! But for certification, we can't have no trees... Good luck with the move!!

@Dreadnaught I did come across that yes, although it does say "deprecated" now, not sure why. This sheet has been useful for my own modelling of trees, even there is a fair amout of guesswork though given: - It's hard to estimate the transparency of trees. - Multiple trees can impact a window and not just the tree (if any) in a perpendicual line from the window. The other thing that's somewhat guesswork if the size of reveals. We have a south-facing house with a breakfast room projecting from the back and a westerly 3m patio door out of the breakfast room onto a patio. This patio door technically has a 5m reveal on both sizes (average of 0m and 10m), when in fact the 10m reveal (the back of the rest of the house) is north facing and not going to shade at all. Anyway, for us, given we are certifying, we're just going to have to wait and see what designer/certifier agree on and then see where we stand.. Thanks!

The heat pump looks fine in ours (fairly standard spec one currenlty only though). I can't see any circulation pumps though, unless they haven't been added. Other thing like the length of DHW pipes can also have a suprising impact! @joth Can I ask how you (or your designer/certifier) have dealt with tree shading. Tree shading has a huge impact on numbers but modelling them correclty is impossible and it's seems it's mostly rough approximation. Until our designer/certifier agree on the tree shading, we don't really know where we are...

Are you doing the modelling yourself? We're using someone else, but I have the PHPP (read-only) and it's great fun playing with all the variables ? Be interesting to see what bugs you found, I've noticed that the PER calculation includes a lot more inputs than the basic "heating demand" calcuation and length of pipes, UFH supply temp, size of UVC etc all start to have an impact..

@Russdl I know this was 18mths ago, but I was just looking at exactly his in our PHPP model, and I think I can see your issue. It seems you modelled a single stud wall with 300mm of timber at 600mm centers, rather than a twin-stud wall. The 6.4% applies to the two 89mm sections, but not the 122mm section. The 122mm section does have some timber (the noggins with nail plates), but its a lot less than 6.4% I beleive. I'm not sure if this brings it down to 1.2, but certainly not as high as 1.37. I was a bit concerned when seeing your 0.137 intially, as I know MBC use a "foil/membrane" product in their u-value calculation for their closed-panel/PIR system which has (I'm told) a questionable impact their u-values, giving an advertised 0.14 with the foil vs. closer to 0.18 without the foil! Based on @Jeremy Harris's numbers, and assuming his external cladding isn't particulalry insulating, it would seem this isn't the case with the 300mm sytem though, I hope so anyway! Dan

We're in Berkshire. We are demolishing in next couple of weeks and laying foundations in March if everything goes to plan. We did design phase PHPP and have now updated it based on tweaked layout, window sizes and window spec, but we're waiting on the timber-frame design before exact u-value and thermal bridge details can be completed. We should get TF design in the next couple of weeks. Tree shading and thermal bridges both have a significant impact on PHPP numbers so need to wait for TF company to TF design, and get input from cetifier on trees before we can be confident.. Sorry I mis-read, you are correct it seems there jus one "enerphit plus", 4-5 new builds. We're not targetting plus explicitly and haven't designed anything around this. In fact, because we have a stepped design, our "projected area" is farily high compared to the actual roof space available for PV. We are planning i) ASHP ii) decent amount of PV anyway though, so if getting a more efficient (R32 or R290) ASHP and/or using 330/350W instead of 300W panels gets us there and there are also longer-term cost benefits, we might hit it..

@joth We'll be somewhere around there, depending on thermal bridge calcs, efficiency of ASHP and amount of PV. Unsure how much sense it makes to try to explicitly to meet PH Plus standard though, we'll see. (We will be certifying though) Do you now have the construction numbers? Are they along the same lines? Timber frame? Are you certifying? Think there are 4-5 in U.K now for what its worse.. Dan

Was told product is currently going through MCS and then PCDB (??). I will chase for specs in Jan now I have their email etc.

1st June 2020 (pre-launch in April). Clik on tweet below and expand the replies to see further info on dates.. Also: https://www.vaillant.co.uk/downloads/aproducts/r290/r290-leaflet-final-aw-1604751.pdf

@Nick1c The product Vaillant are launching, that Sunamp have mentioned, is an R290 (propane) Monobloc ASHP, not CO2. Expected lauch date is 1st June 2020.

We do a a few months longer, as foundation will only be going in early March, but yes similair situation. I was committed to the idea of Sunamp initially, but M&E guy talked me out of it, and the lack of tested LT monoblocs didn't help, so our spec now contains UVC. If there is a PCM49 available prior to installation that i'd be very keen to switch to Sunamp though. My info was from conversation with Sunamp rep 7-10 days ago.

The LG R32 Monbloc does support cooling. It hasn't been validated by Sunamp though. Suamp are testing another manufactuer who has released (or is about to release) a R32 LT Monobloc. They last told me in was panasonic and not samsung, so not sure.. In theory they are testing PCM43 and PCM49 currently. These seem more interesting than trying to find an ASHP that heats to 65C and then hoping it works well with Sunamp and can still deliver 65C in the middle of winter when incoming water is cold and ambient temperature is low. PCM49 would also give same COP's as you get heating to 55C for UVC while saving the cost of direct electricity needed (if i understand correctly) to regaularly heat the UVC to a higher temperature to avoid Legionella.

There are already R32 monoblocs that can provide 65C. Sunamp are currently testing one and are supposed to officially support it next month.

Our house is 1.65m to boundary. Our neighbours house in on the boudary. The ASHP will be be literally just 1m from their boudary and their house. But, in theory this should still comply with MCS planning conditions, as our neighbours have no windows to habitable rooms on this wall.

It'll be only just over 1m from side boundary, so close! I'm not sure if I really need to ammend application just to add ASHP (mixed messages from council). We will be submitting an ammended for something else though, so I was wondering if it made sense to add it into this ammendment, or not bother and go ahead anyway.. That's a good idea!