Green Building Forum - Health issues with passive houses?

Health issues with passive houses?

Mike1 — Wed, 22 Jun 2016 14:51:05 +0100

Posted By: CWattersSome discussion and controversial comments here..
https://sourceable.net/passive-houses-cause-health-problems/" >https://sourceable.net/passive-houses-cause-health-problems/

The original paper is available from https://www.researchgate.net/publication/268098972_Passive_Houses_What_May_Happen_When_Energy_Efficiency_Becomes_the_Only_Paradigm_CH-12-032

The main conclusions relate to the risks of the incorrect installation of ground pipes / earth warming tubes (a well recognised issue), and issues of interstitial condensation in timber frame structures.

Health issues with passive houses?

MarkyP — Wed, 22 Jun 2016 14:57:51 +0100

would a passive house change the air as frequently as our drafty UK housing stock? If it doesn't, would concentrations of indoor pollution (chemicals given off by goods and building fabric) be relatively higher in a passive house than a typical air leaky example of UK housing stock, by virtue of the air changing less often? Couple this with passive houses typically being new build - potential for building fabric pollution must be higher in the first few years of life, all those new carpets, that nice epoxy grout, etc, etc.

Health issues with passive houses?

djh — Wed, 22 Jun 2016 15:31:46 +0100

Posted By: MarkyPwould a passive house change the air as frequently as our drafty UK housing stock?

Yes, more frequently and consistently. Except for people in drafty houses who leave windows wide open and aren't experiencing a windless day.

edit: for clarity

Health issues with passive houses?

Simon Still — Wed, 22 Jun 2016 15:49:17 +0100

We've got a Vent Axia Sentinal Kinetic MVHR. We got to 6 months or so and the filters looked pretty filthy. Genuine ones were Â£40+ but I bought some from here
http://www.fairair.eu/en/vent-axia-sentinel-kinetic-plus.html
and they worked out at about Â£12 each shipped if I bought a few sets. Appear identical except lack a small metal hook so you have to locate them a little more carefully over the inlet.

The incoming one was impressively black (but we are in London).

Health issues with passive houses?

djh — Wed, 22 Jun 2016 15:56:35 +0100

Are they the type with foam/textile fixed around a metal frame? Have you tried washing them?

Health issues with passive houses?

tony — Wed, 22 Jun 2016 16:49:02 +0100

Re draughty houses, they will tend to be too well ventilated when it is windy and not ventilated at all when it is not.

I would never go back to living without MVHR, it is so nice, perfect air quality all the time (better than outdoors).

Health issues with passive houses?

Simon Still — Wed, 22 Jun 2016 16:58:20 +0100

Posted By: djhAre they the type with foam/textile fixed around a metal frame? Have you tried washing them?

Yes, they are. I did give them a vac once or twice in the first 6 months (we were/are still finishing off so making more dust internally that we will long term). I'll try giving them a wash next time (having at least 2 sets makes sense then) but I can deal with cÂ£25 a year to replace the filters.

How often do people give their units a more thorough service than changing the filters what do you do? I'm assuming the extract ducting and manifold must get fairly grubby over time but the supply pipes should stay clean

Health issues with passive houses?

Rick_M — Thu, 23 Jun 2016 14:26:47 +0100

Presumably having a dirty filter is not great but the alternative is having draughts supplying air which travel via the various dusty floor, roof and wall cavities which will be both cold and dirty

Health issues with passive houses?

djh — Thu, 23 Jun 2016 15:27:22 +0100

Posted By: Rick_MPresumably having a dirty filter is not great but the alternative is having draughts supplying air which travel via the various dusty floor, roof and wall cavities which will be both cold and dirty

A dirty filter doesn't make the incoming air dirty. It just means the fan has to work harder as it gets dirtier so costs more to run. Up to some limit, of course. And as you say, the alternative is much worse.

Health issues with passive houses?

ringi — Thu, 23 Jun 2016 15:39:32 +0100

On a lot of units the fan is fixed power so a dirty filter results in less air coming in to the building.

Health issues with passive houses?

tony — Thu, 23 Jun 2016 17:38:31 +0100

Even if the fan has variable speed settings it will still result in less air coming in.

Health issues with passive houses?

djh — Thu, 23 Jun 2016 21:28:49 +0100

Posted By: tonyEven if the fan has variable speed settings it will still result in less air coming in.

No, not on the system I am describing it won't. It self balances by adjusting the power to the fans so they deliver the set airflow rate.

And since the people that write the UK regs (and Passivhaus regs for that matter) are still apparently not aware of sensible system design like that, we still have to jump through (IMHO) unnecessary hoops to prove the system is doing what it does. But at least we didn't have to waste hours balancing the thing.

Health issues with passive houses?

tony — Thu, 23 Jun 2016 21:55:12 +0100

Sounds nice mine works on variable power input with no flow measurements. It works very well and I run it at about half of te designed fan power inputs and don't change the filters as often as they say I should.

Health issues with passive houses?

ringi — Thu, 23 Jun 2016 22:35:48 +0100

I change our filter at the end of summer, as that way we get good air floor at the worse time of year for condensation.

Health issues with passive houses?

Jeff Norton (NZ) — Thu, 23 Jun 2016 23:03:14 +0100

I am tracking my air quality with a Netatmo weather station, it has a Co2 sensor in internal unit..
I turned of the ventilation for one night and the results are about 1300 ppm compared to half that on a ventilated night!

Health issues with passive houses?

cjard — Fri, 24 Jun 2016 08:02:17 +0100

If balking at the filter cost, is it not possible to adapt a vehicle engine air filter? a 2 litre engine at 4000rpm is shifting 480 cubic metres per hour - 0.5 ach for a reasonably sized house

Health issues with passive houses?

djh — Fri, 24 Jun 2016 09:24:22 +0100

Posted By: cjardIf balking at the filter cost, is it not possible to adapt a vehicle engine air filter?

Filters aren't expensive (unless you happen to buy an MVHR without checking first ) so there isn't a problem. But in general the filters fit into a narrow slot, so they're inserted like a gate valve into the air flow, which would make it rather difficult to use a car air filter if it's like any that I've seen.

Health issues with passive houses?

tony — Fri, 24 Jun 2016 12:21:27 +0100

Piece of wood or foam board with filter in it, exhaust filter can be almost anything.

Health issues with passive houses?

djh — Fri, 24 Jun 2016 13:30:07 +0100

All the car air filters I have seen are too thick to fit in the slots in the MVHR. And the pukka jobs that Simon linked to are cheap enough anyway.

Health issues with passive houses?

borpin — Tue, 28 Jun 2016 22:07:59 +0100

Posted By: djh
Posted By: Rick_MPresumably having a dirty filter is not great but the alternative is having draughts supplying air which travel via the various dusty floor, roof and wall cavities which will be both cold and dirty

A dirty filter doesn't make the incoming air dirty. It just means the fan has to work harder as it gets dirtier so costs more to run. Up to some limit, of course. And as you say, the alternative is much worse.

From experience, I can tell when the filter is dirty as I get some dust around the supply vents.

Health issues with passive houses?

borpin — Tue, 28 Jun 2016 22:13:59 +0100

Ed, I hope he knows what he is talking about as he is the BCO manager for the area!

On CO2 meters, I came across this yesterday https://www.indiegogo.com/projects/vthings-co2-monitor-dual-beam-wifi--2#/

Health issues with passive houses?

borpin — Tue, 28 Jun 2016 22:15:47 +0100

Posted By: Jeff Norton (NZ)I am tracking my air quality with a Netatmo weather station

Blimey, that is some price! I'll stick with my Maplin one :)

Health issues with passive houses?

borpin — Tue, 28 Jun 2016 22:18:18 +0100

On Filters, I looked at my Helios MVHR for the specification of the filter material. Doing a bit of digging I did find someone that sold it by the roll. Not really cost effective so I splashed out on some replacement filters and I change and wash them gently and regularly so they do not get excessively clogged up.

Health issues with passive houses?

Ed Davies — Wed, 29 Jun 2016 08:54:33 +0100

Posted By: borpinEd, I hope he knows what he is talking about as he is the BCO manager for the area!

I admire your confidence.

On CO2 meters, I came across this yesterday https://www.indiegogo.com/projects/vthings-co2-monitor-dual-beam-wifi--2#/

â‚¬65 isn't a bad price to start with for a COâ‚‚ sensor plus the combination with a sensible design makes that quite interesting.

Health issues with passive houses?

djh — Wed, 29 Jun 2016 20:05:37 +0100

Hmm, anybody tried signing up? I'd like to sign up for a CO2 unit and a temp+RH extension but I can't find any way to combine the two. And I can't even send a message to the builder without creating an account on the site!

Health issues with passive houses?

CX23882 — Fri, 08 Jul 2016 09:25:49 +0100

That vThings monitor looks interesting. He's just posted an update today that it will be possible to order it with Temperature and Humidity sensors in addition to CO2, and also some details on the sensitivity:
https://www.kickstarter.com/projects/1426779659/vthings-co2-monitor-dual-beam-wifi/posts/1624694

Health issues with passive houses?

Ed Davies — Tue, 04 Oct 2016 23:13:04 +0100

I got one of the vThings monitors about a fortnight ago. I first signed on to the Kickstarter thing but he canceled that and just put them up in his online shop [Â¹] so I ordered from there (with a small discount for having signed up to the Kickstarter, which was nice). Got the COâ‚‚ monitor with temperature and humidity sensors. Not played with it all that much for various reasons but it seems to work OK. The temperature sensor overreads by a few degrees but that's pretty normal, I think.

The only problem I've had with it is that it seems to be a bit sensitive to which USB power supply it's running from, missing readings or switching itself off on ones it's not happy with. Found one other than my laptop port which it's been happy with for a few hours so about to try sleeping in the small spare bedroom with the door shut tonight - so if I'm not on here again you'll know I've suffocated

[Â¹] http://vair-monitor.com/

Health issues with passive houses?

CX23882 — Sat, 08 Oct 2016 19:19:12 +0100

I went for the CO2 + Temperature + Humidity model. Not a bad price for a low-volume product assembled and tested by hand. I've set mine up to send data to ThingSpeak for now - longer term I'll be setting it up to talk to something running locally.

I noticed the same issues with USB power. No issues plugged into my laptop, but I had to try a few different standalone power supplies before finding one which worked. It's running fine on that though.

I'd be interested to hear how it compares to more expensive devices. The CO2 numbers seem to make sense - ~600ppm right now with it in an unoccupied room, 850-950ppm yesterday afternoon sat on my desk whilst I worked.

Health issues with passive houses?

Ed Davies — Sat, 08 Oct 2016 22:38:17 +0100

Ppmv numbers I'm getting:

- Hanging out of a roof window on a windy sunny afternoon: 450 to 460.

- Empty bedroom, haven't been upstairs much this evening: 660 to 685.

- Just me in largish bedroom with door open, got up to about 1260 in the early hours.

- Same but with door closed, peaked at around 2020.

- Small bedroom, door shut, trickle vent (in Velux) open: around 1700.

- Small bedroom with door and trickle vent shut: around 2180 when the computer doing the logging crashed at 05:17 (bit of a mystery why - it was downstairs so not affected by the COâ‚‚ ).

There's a lot of variation in the readings (+/- 10 ppmv, perhaps) though the maker seems to be seeing larger variations sometimes:

http://forum.vair-monitor.com/showthread.php?tid=16

It's good to see that he's actively developing the product:

http://forum.vair-monitor.com/showthread.php?tid=10

So it's all a bit early-adopter for the moment but worth encouraging, I think.

Health issues with passive houses?

fostertom — Sat, 08 Oct 2016 23:30:36 +0100

Posted By: Ed DaviesHanging out of a roof window on a windy sunny afternoon: 450 to 460

Wow, I thought worldwide atmospheric CO2 had only just peaked thro 400.