jack

Ah, I forgot, thanks for the reminder. Still, all the more reason to try and get solar gain under control. Also, these threads will likely be read by others in the future who don't have these limitations, so hopefully these thoughts will be of use to someone, some day!

None taken!

And why do you think that is? That said, there are plenty of people doing brick and/or block, as well as ICF. We have suspended floors (wood and concrete) and insulated slabs. We don't have a lot of SIPs, but there are good (in some cases historic) reasons for that as set out in the relevant sub-forum. There are good reasons why such a large proportion of people on this forum have used MVHR, including air quality and reduced energy consumption.

Interesting idea, but won't all these sensors and (active) grills be costly too? You'll also lose heat recovery, which over several years will more than pay for any difference between MVHR and DCT. MVHR needn't be expensive. Several of us have installed most or all of the components on our own. Another thing: if no-one's installed one yet, it's probably worth thinking about whether building control will be happy with you being the first!

See red writing on bedroom 2.

Our MBC house didn't get above 23.5 deg C upstairs, and 22 deg C downstairs, during the recent mini heatwave, and that was without opening windows overnight. It's definitely about limiting solar gain imo - even internal blinds are far from an ideal way of blocking the sun. While purging alone works well during short periods of heat, if you get a solid week of high temps with relatively warm nights, the average temperature of the house will likely still slowly rise to uncomfortable levels over several days, even if you're conscientious about purging and using summer bypass. If you can figure out where the worst gain is (often east or west of south rather than south itself, due to sun angles), it may be worth looking into some sort of external screening on those windows. Trees, brise soleil, external blinds, screens with fixed or movable angled slats - anything to reduce the amount of sunlight actually entering the house. We have external blinds on some windows and they work very well. Without solar gain working against you, it's much easier to keep the temperature down over a long period just by purging overnight. One thing I wish we'd considered is insect screens on at least the bedroom windows, which would have allowed overnight purging without letting mosquitoes in. At least one security door with screens downstairs would also have been useful to encourage stack ventilation. As I say to my wife far too often, "next house".

I seem to recall that Crittal are eye-wateringly expensive. We looked into getting some two interior doors done by them and from memory it was going to be thousands.

This is what we did with our MBC slab. Foundation window detail.tif Not shown is an EPDM layer on top of the ply. The reason for the reinforced self-levelling layer is that the initial recess is formed pretty roughly with bits of wood or EPS before the concrete is poured. The slider must sit on a perfectly smooth and level surface, and obviously you need to have it sitting at exactly the right height, especially if you have a level threshold. I was told by the window installers that the final layer needed to be ply. It worked well, with one exception: due to a miscommunication with the window installer, we ended up with the wrong grade of plywood. He said "shuttering ply", which he seemed to think was good quality voidless stuff with a smooth faced (melamine?) veneer. Shuttering ply is actually the cheapest, crappiest, voidiest ply you can buy. In our case, the centre of our 5m door has sunk by a few mm as the ply has settled, meaning that the door sticks about a third of the way open if you raise it to its full height (it's a lift slider). It opens fine if you only lift if halfway. If I were doing this again, I'd go for marine or other high-quality hardwood ply, or possibly even just spend some time getting the reinforced (it must be reinforced!) self-levelling compound to the right level and put the door straight onto an epdm layer on top of that.

I love paying a surcharge for worse service, especially when you're only told about it after you've agreed to spend a load of cash with someone.

But bees are nice

Do a search for "DIY MVHR". Someone posted a link to this: http://handmadematt.blogspot.co.uk/2015/01/heat-recovery-ventilation-heat.html Note that this is a crossflow unit, rather than the counterflow approach which is used in commercial units. Crossflow is easier to make, but has a hard limit on effeciency of (from memory) 75%. Real-world will be a lot lower.

You can get through-wall extractor fans that have some heat recovery. They aren't very efficient compared to proper ducted MVHR units, but still better than constantly opening windows to get fresh air in. Edited to add: Missed the previous post - the Lunos unit above is what I was talking about.

I agree with this. It's so cheap (especially compared to the rest of the cost of building a house) that you'd be mad to cut corners. Someone above mentioned CAT 6. This is a decent standard - CAT 7 has thicker wire, I think, so you may have more trouble with bends and termination. Also, make sure you have solid copper wires, rather than cheaper copper coated aluminium (sometimes abbreviated CCA). I don't know whether CAT6 even comes in CCA form, but worth checking. Another tip: if you have a central place for things like AV equipment, consider running a spare empty duct or two with draw cord to each TV position. That way, you'll easily be able to replace or upgrade cables, or run new cables in the event we end up with a new standard in 10 years. Again, cheap and easy to do now, versus a nightmare in the future.

I'm not familiar with the PHPP details, sorry, but the issue here is the difference between airtightness and ventilation - see the sections dealing with these topics here: https://en.wikipedia.org/wiki/Passive_house See also: https://passipedia.org/planning/building_services/ventilation/basics/air_volumes

The 0.6 ACH per hour standard you're referring to is the tested rate at a given pressure difference between inside and outside. In practice, the amount of air that will be exchanged in such a house will be far below this. In still conditions and where the internal temperature is similar to the external temperature, there'll be very little exchange at all. The ACH per hour I'm talking about is the MVHR setting.

I agree with that, and I'm terrible for overshopping when I'm hungry. Unfortunately, my wife has a list all made up, so it doesn't matter whether she's hungry when she goes.

You may well be right, but a background ventilation of 5 ACHs per hour through window vents and general leaks in a freshly refurbished house seems like a lot to me. From memory, Passivhaus, with controlled ventilation, seeks an ACH of 0.5.

Put in several at each point where you will have a TV. Everything is connected now - Sky box, console (or two), recorder, smart TV - it all adds up. You can get by with wireless for some of these, but in my opinion wired is better where you potentially have a lot of bandwidth. If you have a study, or somewhere a printer/scanner will go, it's useful to include an outlet or two there. While most printers are wireless-enabled, if you read the reviews, wireless problems are high on the list of people's complaints. I have another where our music streamer is located in the kitchen. Lucky catch, as it happens, because putting the microwave on interferes with the wireless signal enough to stop the music!

This was my first guess. Depending on the model, you should be able to change the fan speed for each setting, as @dpmiller said.

I hate it when my missus does a Costco shop, because she always buys more than we can comfortably fit in the fridge and freezer. It takes a good three or four days before we can easily access everything again. Thankfully it's a bit of a hike to Costco, so this doesn't happen more than once a month or so.

I agree, and yet we had it again and again. Sometimes, it's a result of people not caring. Others, it's more a case of them not listening properly, or not remembering. We had the latter several times, where we'd discuss something at length with a contractor ahead of time, then come back a day or three later to find that they'd got to this particular job and done it exactly the way they'd always done it. I had a couple of them try and say that they thought my instructions were just me "talking generally" (whatever that means). Others said that they'd forgotten when they actually went to do it, but in any event it didn't matter because my way was no better than theirs. And then we had those who insisted they didn't recall the conversation, even though it may only have been a day or two beforehand. It was difficult to tell whether any particular person was lying, forgetful, incompetent, stupid, or indifferent. ? If I were doing this again, I'd have a site diary, note every conversation, and get it initialed (or at least email a copy of my understanding of what had been agreed).

Fantastic real-world info, thanks. We heard about the pump priming thing on the day too, and had to run out and buy some cement while waiting for the first concrete truck to arrive. Why they can't factor that into the price or at least tell you in advance is beyond me. We also told the guy with the pump exactly where to put the excess from the pump at the end of the day, and that he needed to avoid the area around the trees due to TPOs. At the end of the day, he moved the truck 2m forward while we were distracted elsewhere and dumped the concrete exactly where we said he couldn't. If he'd moved 10m forward he'd have avoided the trees and given himself more space to clean up, but you could tell he just didn't give a stuff.

One of the guys we had onsite used a Henry. He admitted that he'd bought it second hand and had used it on building sites for years before realising it was even possible to put a bag in it! He figured it had lasted that long without a bag, so why start now. He's since had several more bagless years out of it. I wouldn't go bagless anywhere I wanted to keep the dust down though.

It's insane how adaptable humans are. Well done you for cracking on with it.

Lazy git, actually ?