Whole house heat recovery?

I've not looked at this for a while and it had seemed to have gone out of favour - possibly due to the upheaval of proper installation. your situation seems idea from that point of view. I suspect the success depend heavily on an intelligent control system and as large a duct as possible to maintain laminar flow for quiet draught free operation. Make sure the warm, wet, stale air exhausts outside and not dumped inside the loft. Put as much loft insulation in as part of the exercise as retrofitting that with an "octopus" in the loft will be a pita. Consider a vapour barrier under all the insulation as more and more properties are suffering from loft condensation these days as the insulation levels are increased.

In message , Andy Dingley writes

I did my wife's flat. Tenants never open windows and tend not to use a condensing drier cycle to save on fuel bills. Result is mould on cold surfaces.

The flat was constructed with ducted hot air from a central off peak store so I was able to make use of existing ducts. Otherwise difficult in a flat with no floor or ceiling voids. Some unavoidable noise from the fan.

I think turbulence losses in flexible piping would be an issue in a 2 storey job. I did consider the flat section rigid stuff for the cooker extract but never got around to it.

Loft condensation in this place is merely a way of slightly diluting the ra inwater pissing in through the knackered chimney flashings! (three stacks, all bad - naturally the surveyor didn't spot a sausage) There's enough new lead going up there in the next few weeks that the whole house will be endi ng up top heavy.

There's what looks like 4" of '80s rockwool down in the loft at present and I have a workshop crammed with spare rolls that I've been trying to offloa d for a while (long story!). It's likely we're lifting the lot out, checki ng for water damage to the timber, then relaying a moisture barrier and new 6" rockwool across the lot.

Advice on decking out a loft (light storage only, but it's needed - anyone want a lifetime of theatre props and a giant conical panto hat?) would be w ell received. Needs to integrate flooring, thick rockwool, fitting a loft ladder to the now-thickened floor (evil job last time I did it) and maybe a lso ducting for ventilation.

I took my loft insulation from 100 to 250 as the local green brigade were giving the insulation itself away free. I made simple I beams from sawn up old floor boards and 11mm OSB glued into grooves in the 50mm strips top and bottom. Laid these at right angles to the ceiling joists on 600mm centres and skew screwed into the joists. More OSB as a new loft deck. Would have been better to have used 400 centres as the 11mm OSB deck is sagging slightly under its own weight. Remember to feed any extra network cables as I had to take some of the deck back off to run these!

Waste of space. I have seen several. Every one had been shut down and was redundant.

I have have installed this on my last 2 places .... would not have house without .... I included electrostatic filters this time to stop pollen as one of kids has hay fever.

Have fresh filtered air to living rooms, kitchen & bedrooms, extracts in kitchen & bathroooms, heat exchanger saves cold air coming in in winter.

IMHO great product.

Mine haven't and having lived with them for 20 years ... can vouch for them being very good indeed. Has to be designed to suit the house though.

With modern regs requiring airflows per room ... much better to have controlled ventilation rather than just trickle vents in windows.

Thanks harry, if you think they're a good idea then I'm sold!

why?

NT

Which means they must be excellent ...

They are indeed, we had it installed into this house when it was being built and it has worked very well for two decades. Would certainly want it in any new house.

I have half of one so far. DIYed a filter for the incoming air from the hydroponic kits they sell on ebay for removing the smell from cannabis growing. Looking for a cheap DIY heat exchanger to do the other half now if anyone has some ideas.

corrugated tin in an enclosure. Galv does rust eventually though.

NT

Thank you for that. Just the incentive I needed to go ahead and install the system I bought at the beginning of November. Just need to wait until the loft warms up a little.

John

I am doubtful that an old house with 3 chimneys stacks needs a whole house heat recovery system. There must be loads of ventilation (cold wind)