MikeGrahamT21

Yeah thought it might :-( Oh well, I guess i'll keep an eye and a nose on where the smoke actually gets to around the property, and hopefully there will be somewhere which is smoke free. Would MVHR actually be worth the cost and effort, if we couldn't use it from say Nov - March?

Another question on MVHR units... Is there any way to operate them in Extract Only? I'm just thinking so we still have a ventilation method to remove excess moisture during times of smoke when we don't want to import air? I guess the air would just come from other places though wouldn't it? And probably be no better off?

Thanks, i've added that to my watch list.

mmm, I think i'd agree with you there! Perhaps BPC are just on the sell sell sell tactics. Plus the filter they recommended is a whopping £800 for the smallest one! And no guarantee of if it doesn't work can i have my money back. I'm going to pay more attention to where we can smell the smoke this winter, it may be that we can only get it at the nearest point to the neighbours house, though i guess it probably depends on the wind direction! They are to our east, so more often than not the westerly's carry it away, but get a cold easterly, and it would definitely be on, and coming in our direction, so its not looking promising! I'm really annoyed to be honest, as I've been dreaming all this up for years. We do seem to suffer from quite high humidity in the house (if i leave the dehumidifier off we reach around 70% in occupancy, dropping back to 65% if we go out), which this would have cured, and currently resolve this using a smart dehumidifier, but obviously it takes a lot of electric, though does give us some heat back being a dessicant version, and this brings it back to a more reasonable 60%, though we can go to 50% if required. We have an extractor in the bathroom which is PIR activated, so is on regularly, but perhaps isn't powerful enough. I don't even know whether to consider a single room MVHR for bathroom when this one breaks, as we'll be in the same situation, just on a smaller single room scale!

I contacted BPC for a free quote, they didn't seem too concerned about the smoke issue, said that the units all come with filters which should get rid of it, and if its too bad, they sell an £800 carbon filter as an extra which would see it off. Opinions on this? I know someone recommended BPC, but they seem to be saying the exact opposite of you guys, and its a lot of money to spend!

Thanks! As soon as I saw the car radiator fan I thought it would be ideal, and very cheap too! Do you have a link to a speed controller? I'll have to give this build a go at some point, should help me massively moving forwards. Got some plywood coming up for use, its temporary flooring at the moment, so this will be a good use of it :-)

Back to my home made blower... I've found the specs of another blower door online, which states: Maximum flow @ 50 Pa 5450 cfm (9265 m3/h) Highest flow of any portable blower door Our house is only small, so I'm not going to need anywhere near that surely? I've had a thought about using 1 (or maybe 2 to get near this value) car radiator fans? http://www.ebay.co.uk/itm/16-120w-Aeroline-High-Power-Electric-Car-Engine-Radiator-Cooling-Fan-/172428823084?epid=0&hash=item28258f0a2c:g:YKQAAOSwkNZUq~Yv This one will push 2500CFM for £30... What do you think? Linked up to some kind of potentiometer to vary the speed?

With a level of 0.6ACH, is the slamming only possible because you have the MVHR vents in place? As this would balance the pressure difference between the rooms, which I presume is what makes the action slightly harder, i.e. it has to balance via the door opening whilst its getting smaller.

Yeah I was referring to the external doors, sorry! The internal doors are also a tiny bit harder to close, these have a 10mm gap underneath, and when you open them with force with no windows open, you often hear the ceiling making a few clicks, with the air rushing in through any small gaps (and i know there are some!)

Yeah, the closing door thing is obviously not a very good way of testing, but without machinery I thought it wasn't too bad to see how i'm getting on, coincidentally, the doors are definitely harder to shut the more work i do, as said with the utility you physically cannot slam the door closed, no matter how hard you try. I had a think last night, how much air would a load of 100mm delta fans (computer fans) fixed onto plywood push? I remember they are quite powerful (and noisy!). How much air does a blower fan push? (I'm guessing quite a bit). I certainly would like to depressurise the house to get a better understanding of where all the leaks are, some are obvious i.e. the big hole in the kitchen floor under the oven, but I know there will be a lot of smaller less obvious ones. Since the idea of MVHR is now just a fading memory courtesy of our neighbour, i won't be going to extremes in order to avoid poor air quality, but i will still be laying taped membranes under the floors in order to do the best that I can, which has always been the goal, taking the principles of what is done to achieve passive house standards, and applying them as best as I can to our house without spending silly amounts of money, I think this will go a good way to reducing our energy demands, and indeed year on year we are requiring less gas for example (I know its hard to directly compare one year to another as they are so different).

OK, and I'd be right in thinking that 3-5ACH is going to be quite hard to achieve? How hard would it be to close a door at those levels as an example?

Very glad I asked about this now. Wasn't aware of the fact that MVHR won't shift the heat, that is a real shame! So sounds like air testing is the best thing to do, whether we go for it or not. We do have spot lights, I plan on installing the airtight boxes behind them next year when I bump up the loft insulation. I also plan on sorting the sockets and switches out as best as I can, but will definitely need some kind of fan to do this properly, i'll see if I can concoct something using the left over plywood i've got. Yeah I looked into the single room MVHR for the bathroom, but because I was considering the whole house unit, I didn't go any further with it, maybe this would be more worth while. At what point would the house become 'unhealthy' if I try and airtight, but don't get it to an MVHR level? So the smoke is going to be a major issue, i had a bad feeling about that! And in winter they have it on every day, multiple times, so basically the MVHR would be off most of the time, which would be rather pointless, they've just taken delivery of another pallet of the damned stuff!! One final thought was a university paper i read from the university of leeds, from years ago (early 2000's), they did some basic airtightness in a number of council properties (going no better than 10ACH from about 28ACH), in half installed demand controlled, and in the other half MVHR. Now this was of interest to me, and the results showed in the MVHR ones, a massive reduction in CO2 (very important to me as I work at home, as well as live here), and not a massive increase in energy requirements, which is what made me think that the airtightness wouldn't be a total killer! Mind saying that, if smoke is an issue, then its a no go anyway! For any type of MVHR! :-( Annoying that we like is a smokeless zone too...

MVHR has always been high on my 'want' list for a number of reasons, and I plan on installing myself, with the help of a design (found several companies who will design free of charge, has anyone had any dealings with anyone they're recommend?). For the MVHR unit, I really like the look of the Brookvent Aircycle 1.2, its SAP Q listed, 93% efficient, and has all the sensors and bypasses we'd want out of a unit, anyone used one before? We do have a number of pro's and con's with it all though: On the plus side... Our extract rooms are all south facing, and gather considerable heat without doing anything additional i.e. cooking, showering, and our supply rooms are joined on to another house, and generally remain cooler (great in summer, not so much in winter). At present when we cook, we open the windows to let out the steam and smell, wasting all that heat, and in the bathroom we have a single extractor fan which pulls out an incredible amount of heat, you don't realise until you feel it from the outside. So one of the major pluses for me would be the balance and distribute that heat throughout the house. Live in a bungalow where the loft isn't to be built in, so plenty of room for the unit and all the pipework (Considering the 75mm radial ducting, with manifolds, to keep pipework as simple as possible). On the negative side... We have a neighbour with a wood burner, and in winter it puthers smoke, and absolutely stinks, this is a major concern, as we don't want that smoke in the house, is there a way round this? I suppose good enough filters should get rid? The house certainly isn't airtight at present, and this is something I am doing the best I can, room by room, but it is taking time. Obviously using Jeremy's spreadsheet, I can see ventilation loses soon mount up with poor airtightness, however I was thinking if there was a way to ensure that the extract and the supply was balanced (perhaps having the same number of both types), would this really make any difference to how we are now? I appreciate if one was slightly out, you'd either push warm air out, or import cold air. Or is simply because the supply and extract are in different rooms, and instead of drawing air under the door into the other room, it would come from the gaps? I'm not sure how achievable low ACH is in our house, but already the doors are starting to get harder to close which I'm guessing is a good sign? We are a 1968 build bungalow, so the walls are wet plastered (thank god), i'm ripping up all the floors anyway as the joists have woodworm, and putting a breather membrane (taped) down before the floorboards (OSB3 smart ply), and I'm ensuring all the windows are well sealed. Recently had a practice run in our new utility, and with everything closed bar one door, if you try and slam the door it bounces back off the air, but again i'm not sure what level of ACH that would equate to, and don't want to pay to have it measured. I did think about making my own blower door, just to find air leaks more than anything with a smoke pen? Another question is can we use a roof tile vent for one of the in/out sources? Currently we already have a 100mm hole in the loft wall to the outside which was from an old extractor fan, which I'd like to use, and rather than drilling another, use a roof tile vent instead? Would that work if it snows? Any input would be greatly received.

Out of all of our windows, we have a single bow window (not a bay, no brickwork underneath it), which has the most cold spots on it out of all of the windows, mostly due to the baypoles. At some point we are wanting to replace it, hopefully with Liniars 90mm profile they've just released, if they decide to use it for bow windows. Has anyone else had any experience with thermally very good bow windows, it'd be a shame to lose it, as its really nice, but also has very high square meterage. We are going to re-design the frame layout, to minimise frame and maximise glass.

Yeah I too have the seek Thermal on android, though mine has started reading temperatures higher than they actually are for some reason, but the colours still show the weak spots. Our frames, even the better ones are about 2-3c cooler than the walls, not bad for upvc I guess. Going to get the new 90mm 9 chamber profile which liniar have just launched for the rest, but it's not available in England at the moment, only northern Ireland which is a shame. I'll be patient! Lol It's a good exercise to see the weak spots for sure, you can hire the lower spec flir ones from jewson for not much money

We had just fibres in our utility floor (Sand, radon barrier/dpm, 100mm PIR, 100mm concrete slab), and thats been spot on, not a crack in sight! utility is 5.4m x 2.5m. I'm sure you will have done this, but ensure that there is an insulant upstand all the way round the room, so the slab never touches the wall, this will also help with any expanding and contracting, and also with thermal bridging, we used 25mm polystyrene for this job

First really cold morning of season has allowed me to go hunting with my thermal imaging camera for cold spots, and as is usual i've found quite a few, but what have others done to sort these type out? Ceiling joists near the edges of the house, show a temperate difference of about 4C, they were 15C this morning, but the PB without timber behind was 19C. I went up in the loft, and checked the timbers were well covered, and they were, so I can only imagine it must be bridging in from the outside, though even from that side I've run 100mm wool insulation right up the wall and over into the loft space, the timber is still exposed though, as its what the fascias are attached to (rafters), not really sure what else i can do for this aside from internal insulation on the ceiling which isn't going to happen. The bottom corners of reveals, both windows and doors - Our triple glazed window in the bedroom is performing well overall, glass was showing 17C (Room temp 17C as I've not had heating on), majority of the frame was 16C, but just on the bottom corners I recorded as low as 13C. I've just recently done all this internally, so I know its correctly foamed around the frame, and there are absolutely no air leaks. In our house (1968) the reveals are closed with medium dense block, so the cold will get drawn through. I'm guessing the answer to this one would be external wall insulation? (its on the cards, but too expensive at present!). Has anyone else had some really awkward cold spots to deal with? I know i'm never going to get rid of them all on a refurb, so its just a case of minimising the ones we do have. This afternoons job is to take some roof tiles off and see if i can see a reason the wall edges (party wall joining external wall) are so cold, I'm guessing i've not run the insulation far enough, so should be easily sorted!

I plan to re-use the chipboard (loft boards) which are already up there, another plus for using 4x2 so I can line the centres up as i need them. I'll keep looking for cheaper timber, won't be doing it til next year now anyway, as I've too much on at the moment, just trying to make a plan of action. Yeah will definitely be taking a close look at the wiring, i know theres a lot which can come out, as we've replaced it with new stuff. There will be more insulation going on the wiring, but as I said before, theres barely anything flowing through them, as its only LED lighting, so I'm not concerned about that.

you know i thought exactly the same thing about 5mins after i'd written that! lol I sure think thats going to be the most cost effective solution, giving the best overall value (i.e. improvement on u value vs cost).

What i really need to know is, will putting 200KG of timber up there affect anything?

They are the cheapest i've seen actually for the legs. Not fussed about paying for insulation, its cheap anyway, and i've got most of it already. How about my idea with the 4x2 crossing the 4x2 which is already there to allow an additional 100mm for around £136? I think thats going to be cheapest, since i'd probably need over 300 loft legs to do it with those, though at that price it may be do-able, i'll work it out.

Yeah good idea for that bit, what about the main bulk of the work?

Hi, I'm wanting to upgrade our loft insulation, and just wanting some confirmation that my idea is OK. Currently we have 100mm fibreglass insulation between the joists (I've just been up and measured, they measure around 107mm deep), and we currently have loft boards, which I'd like to retain for storage purposes. House is 1968, with traditional roof with purlins, so no crossing timbers in the main storage area. Current U value somewhere around the 0.4U mark. Total space is around 6m x 5m (35m2) (bungalow) I've thought about quite a few different methods, loft legs (too expensive), just laying insulation over and losing storage space (not ideal), and then my final thought... my final idea is to cross these existing joists with more 4x2 joists (we would need 24x (47x100x3m) to cover the whole area at the relevant spacing for the loft boards), and then lay another 100mm fibreglass inside these, giving 200mm overall (i appreciate that's still not up to the regulatory 270mm, but the extra 70mm ontop of the 200mm doesn't bring down U values as much as the initial extra 100mm on top of the original 100mm, and the cost is far greater) which would land us somewhere around the 0.21U mark, so effectively halving the U value for the cost of the wood (£136), and a bit of insulation (i've already got 3 rolls of 100mm, so likely wouldn't need much more). Now this is all well and good, and whilst i do all the work, which i'll do myself, i'm going to ensure all of the electric (lighting) cables which are up there are in good nick, and the circuits are as simplified as possible (and theres a couple of junction boxes which need taking out) (Low energy lighting by the way, so overheating cables shouldn't be an issue). I did however think of one draw back, and that is the 200KG of timber required as extra to what is already up there...now in my mind, this will be absolutely no problems at all, but I'd like a little reassurance before i bring our entire ceiling down lol! Theres not a massive amount of stuff in the loft storage wise, certainly nothing heavy, and no water tanks or anything like that. Any feedback greatly appreciated. Regards Mike