jack

The only thing I'll add is that I wouldn't ever email an ultimatum in such a situation. If you can make your next communication in person somehow, that would be ideal. Next best would be a phone call. Putting things in writing just seems to inflame things in my experience, especially in "difficult" situations, or where something doesn't seem/feel right.

Definitely include provision for heating in bathrooms. Not including this was one of the biggest errors we made during our build. We have a house with PH-level insulation and airtightness, but even when the air temperature is a consistent 21-22oC, it's still slightly cooler than desirable when you step out of the shower in the middle of winter. Tiles on the floor, in particular, tend to suck heat from your feet, giving the impression that the room is colder than is actually the case. Personally, I'd put UFH in the bathroom (low temperature) just to take the chill off the tiles in the morning, and wire for a radiator of some sort in case you find you need it. We're planning on retro-fitting some infrared panels to address this issue. It would have been a lot cheaper and more effective to include UFH when the house was being built.

No, we used a shower wastewater heat recovery unit like this (can't remember the actual brand - edited to add: think it was the Recoup Pipe+ HE), plumbed into the two showers we use the most. They offer a several percent increase in SAP rating, depending on size. I believe the unit you're looking at is intended to collect heat from all wastewater, not just from showers. I don't know what it costs compared to the shower-only version, but I seem to recall that I didn't like the prospect of the inside of the whole house version gumming up with all sorts of 'orrible stuff over time. I don't doubt the shower recovery version will look pretty skanky on the inside as well, but in theory it's cleanable. The other thing is that in our house, the main sources of hot water are showers, with the washing machine and dishwasher a distant second. Neither the washing machine nor the dishwasher are in positions that would have made connection to a whole house unit convenient. The shower unit just sits out of the way in the back of a cupboard in our utility room, which puts it midway between the two showers from which it drains. Edited to add: @Thedreamer, look here and at page 12 of this document for some info on getting the most out of SAP with this technology.

In theory, this shouldn't be a long term problem. Most likely, the flies that are in the ducts will be pushed out by the moving air (they're probably already all out). Unless they're actually getting by the filter, that should be the end of it.

I've no doubt you're right. Interesting that after 35 years of data and improving knowledge of how to build, we're still stuck with exactly the same figure, with no allowance for climate or house size. I think there's decent basis for starting again based on what's now known, and developing a more realistic standard that allows some flexibility based on, eg, location and climate, while not punishing smaller houses.

The only thing I lost from start to finish was an electric chainsaw (and to be fair, I can't remember when I last saw it - I may have lent it to someone), and a spare unbranded battery for my Makita stuff. By the time everyone left, we'd gained a small aluminium platform, a fluorescent worklight, a couple of cheap handsaws, and a hammer. Same for us. I think they're so cheap now that people treat them as disposable. I seem to recall seeing a basic Stanley saw for around a fiver - crazy stuff.

Waste water heat recovery is worth a few SAP points for not too much money.

Might be apocryphal, but I believe that the Passivhaus space heating standard (15kWh/M2/annum) was originally chosen based on the maximum amount of energy that could be delivered via duct heating without scorching dust. That's one of the reasons the PH standard annoys me - they've chosen this number based on an arbitrary decision to assume warm air heating via MVHR. The number could just as easily have been higher if they'd assumed, eg, underfloor heating.

Had to talk the missus out of these for our house. Do they meet regs?

Are you sure the filters are completely across the pipework (ie, so no flies can get past)?

Well he learned something that day, didn't he? Our SAP assessor was highly experienced, but had never seen a SAP number as high as ours. I suspect that's partly because he does a lot of work for developers!

I do think it's nice to have a three-digit number for your SAP score though

Agreed. I think it's nice to hit 100 (ours is 100 or 101 from memory), but I can't see the point in making much effort - or more importantly paying anything more - to go beyond that.

Don't be silly. You want the proper high octane leaded version.

They probably meant Greek yoghurt.

Was just going to say the same. Did the tester not say anything about doing this? 2.66 with the MVHR on is actually pretty good!

+2 on the Spax flooring screws.

What sorts of gaps do you have around the doors (and underneath in particular)?

Ubbink: http://www.ubbink.co.uk/products/ventilation-ductwork/air-distribution/Semi-rigid-ductwork/Semi-rigid-ductwork-(1).aspx. It wasn't cheap, and I found the d-shaped cross sectional ducts a little hard to manoeuvre in some places (someone else on here who used it said they didn't have any problems). All the fittings were good quality though.

The Chinese made ones may be the Japanese standard I mentioned before. You run into them now and then on electrical equipment. Another useful tip (pardon the pun) for recognising a pozidriv tip - as well as the flatter end, they have triangular wedges in the main recesses of the cross.

We're below 0.6 ACH and closing doors is fine. Interestingly, no matter how windy it is, if only one external door is open the wind will never slam it shut!

And there's a slightly different Japanese standard as well, from memory. I only learned there was such a thing as a pozi drive screw a few years ago. For many years I'd just assumed that the extra little wedges on that odd screwdriver I had in my toolbox were just a design feature!

We ended up going for floor-mounted MVHR outlets in our bedrooms. In theory, floor-mounting might result in slightly poorer mixing, but we've had no issues.

@JSHarris, apologies, but in attempting to delete what looked like a duplicated post, I seem to have lost your reply to Ferdinand. Not sure what happened - maybe you or another mod were deleting the other post at the same time. Would you mind posting again? thanks

I did at the time. From memory, Z-wave is cheaper , but there's a much more limited selection of components, and I seem to recall there being issues with range and reliability of the protocol as a whole. That might have been FUD from Loxone though. The programming environment for Loxone is extremely powerful and easy to use, which was really what swung it for me. Loxone does occasional open evenings at a pub near where they're based in Reading. Worth getting along to if you can. Failing that, they have a few videos on Youtube showing how it all works. I will caution that since I bought it a couple of years ago, Loxone does seem to be moving more and more towards closed systems, and are increasingly reticent to support self-installers. There are active forums with very helpful people that can get you around this though. You can also mix and match Loxone with other stuff. They have DMX and modbus interfaces, for example, plus their outputs are relays and so can be used to control just about anything that uses switched contacts (eg, many MVHR and ASHP units). The one thing that I didn't realise at the time was just how rarely I'd open the interface. Mine isn't connected to the outside world, so I can't control anything remotely. Just about everything else is controlled automatically or by hard switches, so I typically wouldn't open the mobile interface more than a couple of times a month!