garo99 Posted January 17, 2020 Share Posted January 17, 2020 Hi All. Found this forum when investigating getting an MVHR to deal with condensation and boy did I go down the rabbit hole! In brief, 1990 build, detached house on two floors plus partially converted attic. Looking to improve energy efficiency of te house without getting mouldy windows. Cold roof, 20+ year old insulation. Some DIY skills but happy to learn more. Link to comment Share on other sites More sharing options...
PeterW Posted January 17, 2020 Share Posted January 17, 2020 Welcome. if you’ve got the space to do it, there is a decent offer on loft insulation so a good start would be to top it all up. Link to comment Share on other sites More sharing options...
garo99 Posted January 17, 2020 Author Share Posted January 17, 2020 I started by trying to improve airtightness and went after perceptible drafts. Draught stripping the front door, the doors into the cold attic crawl space, the skirting boards under the bay windows. We have hole in the wall vents and I tried closing them and got insane amounts of condensation so had to open them again. But not happy with status quo as on windy days there is too much ventilation and on still days not enough. Still considering getting an MVHR. The bedrooms will be fine but routing the ducts in the downstairs rooms would be a pain. Is it worth it? The air in house is often musty and when we cook fish for instance the smell lingers in the entire house for hours despite the ancient extractor hood. The second query I have is regarding attic insulation. There is 100mm mineral wool insulation over the first floor ceiling and attic conversion in the middle with cold crawl space with full ventilation on either side. Attic room gets very cold when heat is off with temp commonly down to 10 degrees after overnight heating off. There is no roof insulation on the bare attic crawl space but polystyrene board insulation over the converted area and mineral wool on the walls. What do you suggest for improvements? I had the roof retooled last year and kicking myself now for not getting a proper insulation job at the same time. Link to comment Share on other sites More sharing options...
garo99 Posted January 17, 2020 Author Share Posted January 17, 2020 3 minutes ago, PeterW said: Welcome. if you’ve got the space to do it, there is a decent offer on loft insulation so a good start would be to top it all up. Thanks PeterW. I was planning to top up the insulation in the attic space by running 200mm earthwool on top of the existing glass fibre. Planning to run it perpendicular to the joists. A quarter of the area has floor boards to cannot do anything there. And also planning to leave the area under the converted room alone. It has some insulation there which probably explains why the attic gets so cold. Ideally I would like a taped up layer of insulation running from ceiling joists to sidewalls to roof. Link to comment Share on other sites More sharing options...
joth Posted January 17, 2020 Share Posted January 17, 2020 Welcome to the scope creep! @Ferdinand summed it up so well for me here: Link to comment Share on other sites More sharing options...
JFDIY Posted January 17, 2020 Share Posted January 17, 2020 Snap, I was looking into MVHR and there seems to be a closed shop from installers and suppliers to some extent, this place has by far the most info, and real world experience. I've DIY'd my own install from scratch (as have many others) and while I don't have figures to back it up, I'd say it has transformed the feel of our house, no condensation at all, previously I'd have wet windows every morning and a stale feeling to the place. I've yet to balance it up and I'm about 50% over suggested rates at the moment based on a quick check when I got my anemometer. Enjoy the banter, the 'bogus' thread has some interesting views 1 Link to comment Share on other sites More sharing options...
garo99 Posted January 17, 2020 Author Share Posted January 17, 2020 Thanks JFDIY. Read that one and a few others. I feel it’s a chicken and egg situation. If I improve airtightness I need an MVHR more. If I get an MCHR I need to improve airtightness more. Will never get anywhere near passive standards in this house but still would like to do all the easier cheaper improvements. On your self install, was it new build or existing. I am dreading having cut through plasterboard and running the ducts on the ground floor ceiling. There isn’t a huge amount of room and there is a mess of electrical cables. Link to comment Share on other sites More sharing options...
mike2016 Posted January 17, 2020 Share Posted January 17, 2020 I installed a Vent-Axia PIV (Positive input ventilation) last year. I used to get all the cooking smell in my upstairs bedroom. Once running it dealt with that immediately and improved the air quality upstairs a bit too. I put an F7 filter on it as I live beside a main road. Having it putting air into the landing beside the main bathroom meant I knew it was keeping moisture levels down a bit. The only issue was over winter, I've disconnected it as it made the landing freezing. It does have an electric heater but I was never keen on the idea. I'm now looking at MVHR myself. I'll probably go with an installer. Finding it difficult to run to the downstairs too so hope to use a space along the wall on the landing to route into the utility room below and drop the ceiling in there to manage the runs. We've already had a quick look under the landing floorboards and think we can get through there. I've still a good bit to do on air tightness but interested to see how it goes. I could always just self install upstairs but want a whole house system and given the difficulties thought getting help this time around would be worth it. Will see what the price looks like in a week or two! Link to comment Share on other sites More sharing options...
JFDIY Posted January 17, 2020 Share Posted January 17, 2020 Mine is a 100yr old barn, converted 10 years ago, by no means passive standards, I'm adding on a large extension and wanted to avoid the cost of a downdraft extractor for a kitchen hob in an island. We've always had issues with condensation and we've tried various things like keeping the place hotter and having windows on vent etc. I saw the £1k+ for a kitchen extractor and decided to put it towards MVHR, I'm yet to couple up the extension, but all the ducts are in. I've sited our unit above the bathroom in the original barn as this is the only place without vaulted ceilings. By comparison I was quoted £5.5k for an installed system, about £4k for self install but my own spec etc is going to run to about £3.5k with what I believe to be better hardware. Sure you can do it cheaper, but I wanted a self managing unit with humidity control, summer bypass and also a cooker hood mode, the last requirement only really left one option which was a vent-axia unit. Link to comment Share on other sites More sharing options...
Mr Punter Posted January 17, 2020 Share Posted January 17, 2020 I have fitted a Vent Axia Sentinel Kinetic plus in a house. Simple enough to do but make sure you have decent access for servicing / filter cleaning. It was designed in the loft space but the house is 1 1/2 stories so it is stupidly tight. Doubt the new owners have ever cleaned the filters. Link to comment Share on other sites More sharing options...
MJNewton Posted January 17, 2020 Share Posted January 17, 2020 17 minutes ago, JFDIY said: I wanted a self managing unit with humidity control, summer bypass and also a cooker hood mode, the last requirement only really left one option which was a vent-axia unit. Can you elaborate on the 'cooker hood mode' bit? Presumably, given the choice of words, it doesn't come with a cooker hood but is some sort of changed behaviour when the cooker hood is running? If so, I would imagine most units could be manipulated to do similar without too much effort (and a £10 smart relay) - unless the feature is more advanced than I am imagining. Link to comment Share on other sites More sharing options...
Gone West Posted January 17, 2020 Share Posted January 17, 2020 4 hours ago, garo99 said: The air in house is often musty and when we cook fish for instance the smell lingers in the entire house for hours despite the ancient extractor hood. Hi, welcome to the forum. Does the extractor hood extract to the outside or recirculate. If it recirculates have the carbon filters been changed? MVHR is certainly worth it if you can reach reasonable airtightness. Link to comment Share on other sites More sharing options...
Triassic Posted January 17, 2020 Share Posted January 17, 2020 1 hour ago, MJNewton said: Can you elaborate on the 'cooker hood mode' bit? When the cooker hood is switched on the boost setting kicks in on the MVHR unit. Link to comment Share on other sites More sharing options...
garo99 Posted January 17, 2020 Author Share Posted January 17, 2020 Mike2016 I am in a similar situation except I cannot get under the floorboards so it will have to be done from the ground floor ceiling. We redid the floors 2018 summer and that would have been a good time to put the ducting in. But hindsight is 20/20. I will probably ask for quotes next week and decide if I want a DIY upstairs only job or full house installer job. Looking at Vent Axia Sentinel Kinetic BH or Airflow Duplex Vent. Link to comment Share on other sites More sharing options...
Patrick Posted January 17, 2020 Share Posted January 17, 2020 7 hours ago, garo99 said: Hi All. Found this forum when investigating .... and boy did I go down the rabbit hole! I think this how every good Buildhub story starts. ?? Welcome 1 Link to comment Share on other sites More sharing options...
garo99 Posted January 17, 2020 Author Share Posted January 17, 2020 2 hours ago, PeterStarck said: Hi, welcome to the forum. Does the extractor hood extract to the outside or recirculate. If it recirculates have the carbon filters been changed? MVHR is certainly worth it if you can reach reasonable airtightness. I am embarrassed to admit I don’t know the answer. I did clean the whole thing and change filters summer 2018. Maybe need to do it again? Link to comment Share on other sites More sharing options...
MJNewton Posted January 17, 2020 Share Posted January 17, 2020 53 minutes ago, Triassic said: When the cooker hood is switched on the boost setting kicks in on the MVHR unit. That should be straightforward to recreate. Most (all?) MVHR units have boost inputs and as a boost switch in the kitchen makes sense anyway a non-contact current sensing relay wired in parallel (example) should work well. Link to comment Share on other sites More sharing options...
JFDIY Posted January 17, 2020 Share Posted January 17, 2020 2 hours ago, MJNewton said: Can you elaborate on the 'cooker hood mode' bit? Presumably, given the choice of words, it doesn't come with a cooker hood but is some sort of changed behaviour when the cooker hood is running? If so, I would imagine most units could be manipulated to do similar without too much effort (and a £10 smart relay) - unless the feature is more advanced than I am imagining. It's a little bit more involved than suggested in the posts above. Certain models of the vent-axia range allow you to couple up a cooker hood, from what I can see, the hood is no more than a housing with greese filters and lights, its power is supplied from the mvhr unit, when the hood is switched on the extract speed increases to 100% (or your desired speed) and the inlet speed changes to 30% (again this is programmable ), the bypass is also opened to stop any fouling of the heat exchanger. I intend to build into my celling an extractor/hood arrangement with grease filters, and some electric actuated valves, so when this happens the increased extraction is mostly in the kitchen. I've wired the unit as a trial to test the mode switching which is pretty straightforward I've found the standard humidy controlled setting works so well the boost function doesn't really need hard wiring in at the moment, but it's there and might be better suited to when our next bathroom comes on line which is a lot further away from the unit so could be used to reduce lag. I also use the low mode (supposed to be when house is unoccupied), but I use it on an overnight timed basis to lower the noise (it's barely audible anyway) when sleeping. So work out the unit size you need and look through all the manufacturer documentation you can, there may be others, but I settled on the vent-axia one because of this and all the other features that come as standard, I guess there are other makes which may have similar, but they don't make it easy to find out, hence my closed shop comment in the earlier post. Link to comment Share on other sites More sharing options...
Declan52 Posted January 17, 2020 Share Posted January 17, 2020 I done something similar to what you propose in my last house. It was a 1960s mid terrace house that was plagued with condensation. I installed a pretty basic mhrv in my loft and ran a pair of extracts to the first floor. Due to the position of my airing cupboard I was able to run the ducts from the attic down through the first floor to the ground floor. Even though this was a really poor machine, cost about £200 and was fairly loud but it did get rid of the excess moisture which then meant the condensation didn't form on the wall and cause mould. Is there any way of running ducts from a central location in the attic to both floors and just box the ducts in on the first floor. The ducts can be as small as 75mm so it won't be an eyesore. Your maybe only talking about an extract in the kitchen and living room so 2 bits of boxing in. You could put the clean air intake over the stairs on the first floor. It would mean you won't have to rip the ceilings out. You will just have to cut the grill hole out and connect it up. Link to comment Share on other sites More sharing options...
garo99 Posted January 17, 2020 Author Share Posted January 17, 2020 (edited) 1 hour ago, Declan52 said: I done something similar to what you propose in my last house. It was a 1960s mid terrace house that was plagued with condensation. I installed a pretty basic mhrv in my loft and ran a pair of extracts to the first floor. Due to the position of my airing cupboard I was able to run the ducts from the attic down through the first floor to the ground floor. Even though this was a really poor machine, cost about £200 and was fairly loud but it did get rid of the excess moisture which then meant the condensation didn't form on the wall and cause mould. Is there any way of running ducts from a central location in the attic to both floors and just box the ducts in on the first floor. The ducts can be as small as 75mm so it won't be an eyesore. Your maybe only talking about an extract in the kitchen and living room so 2 bits of boxing in. You could put the clean air intake over the stairs on the first floor. It would mean you won't have to rip the ceilings out. You will just have to cut the grill hole out and connect it up. Thanks for the reply Declan. I was not really sure how I could run the ducts down without them being a significant eyesore. But through the hot press (airing cupboard) and down into the boiler room. Now that’s an idea! Is there any problem having the ducts running close to the hot water pipes? Apart from having to be super careful not to damage them during the install process. Once in the boiler room I suppose they can be routed within the false ceiling. It is possible in theory but there are lots of unknowns... Edited January 17, 2020 by garo99 Link to comment Share on other sites More sharing options...
garo99 Posted January 17, 2020 Author Share Posted January 17, 2020 2 hours ago, garo99 said: I am embarrassed to admit I don’t know the answer. I did clean the whole thing and change filters summer 2018. Maybe need to do it again? I checked and it does indeed exhaust to outside the house. The fan is mighty loud but pretty lousy as I could barely feel the air flow on the outside. Explains why cooking smells linger for longer. Link to comment Share on other sites More sharing options...
Declan52 Posted January 17, 2020 Share Posted January 17, 2020 2 minutes ago, garo99 said: Thanks for the reply Declan. I am not really sure how I can run the ducts down without them being a significant eyesore. Maybe through the hot press and down into the boiler room. Now that’s an idea! Is there any problem having the ducts running close to the hot water pipes? Apart from having to be super careful not to damage them during the install process. Once in the boiler room I suppose they can be routed within the false ceiling. It is possible in theory but there are lots of unknowns... Can you not have them in a corner of a room for example. Then you can have the grill in the room below out from the corner as far as your arm can stretch to pull the duct to the grill hole. There would be no issue with running it beside hot water pipes. Link to comment Share on other sites More sharing options...
garo99 Posted January 17, 2020 Author Share Posted January 17, 2020 Ah so you mean the grill and duct both below the ceiling. Yes that’s a possibility. Not as neat but a feasible option. Link to comment Share on other sites More sharing options...
Gone West Posted January 18, 2020 Share Posted January 18, 2020 11 hours ago, garo99 said: I checked and it does indeed exhaust to outside the house. The fan is mighty loud but pretty lousy as I could barely feel the air flow on the outside. Explains why cooking smells linger for longer. It may improve airtightness and noise quite a bit if the extractor was replaced with an efficient recirculating type. Link to comment Share on other sites More sharing options...
garo99 Posted January 18, 2020 Author Share Posted January 18, 2020 8 hours ago, PeterStarck said: It may improve airtightness and noise quite a bit if the extractor was replaced with an efficient recirculating type. Thanks yes that is on the agenda but we might redo the kitchen next year so will get a new hood and everything. 1 Link to comment Share on other sites More sharing options...
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