We’ve got a bit of a condensation / damp problem in our house and are running dehumidifiers at the moment.

Have been wondering about heat recovery ventilation systems that take fresh air in from outside and extract heat from the warm inside air then expel the old stale damp laden air back outside.

Anyone got something like this fitted, are they mega expensive to install? Cant seem to find much about costs online. Its a 4 bed bungalow. I know costs vary from property to property, but just wondering about very rough costs to see if its a possibility before i start arranging surveyors to come out.

Any good reccommended companies to look at?

Thanks

A single heat exchanging extractor fan is about £300 on it’s own.

http://www.amazon.co.uk/Kair-Heat-Recovery-Extractor-Fan/dp/B004VW3RGW

have you considered trickle vents in your windows? It would be a lot cheaper.

We had such a system in our old house, no idea of the cost, it was installed as part of a new build.

It worked really well – there was a vent in each ‘wet’ room, and two inlets, one in the lounge, the other in the hall. The central fan ran continually in the loft at a low speed. The humidistat signalled the fan to run at high speed (e.g. when the shower was being run. Two vents on roof, one inlet, one exhaust. One small pipe for condensate.

I think they’re great systems, wish we had it in this house

I would have thought that it’s a reasonable job for a competent diy-er in a bungalow – you don’t need special ducting, grey plastic soil pipe will work and be a lot cheaper.
Hope that helps!

They do work very well. But its my understanding that you have to have a pretty much air tight house in the 1st place for them to work. Again, if my understanding is correct, its very difficult (read expensive) to air tight an existing building, hence why they are only generally fitted to new builds.

Don’t mean to be negative about the idea, just my experience with looking into them.

Not sure how well the extractor vent replacements, like footflaps posted, work in practice. Keen to hear anyone’s experience.

Doing this in a bungalow could be really easy – providing you can get access to the ceiling above each room from the loft.
As others have said, grey plastic solvent weld soil pipe, and a heat recovery unit of the ‘web.
You’ll need to do a bit of research to make sure you get a suitable sized unit, but the installation should be DIY if you’re pretty handy.

I fitted one to the Barn during construction.

Mainly because I didnt want to put nasty vents in my nice new wooden window and french window frames to meet building regs.

So glad I did though. Brilliant bit of kit. Keeps the ait in the house clean, no sign of damp in the bathrooms – just 15mins of boost clears the air after a steamy shower.

Because mine was a barn conversion I was a little more limited on ducting so layout isnt perfect but I get enough circulation. I used http://www.cvcdirect.co.uk/Whole%20House%20Ventilation/wholehouseventil.html and they can helkp with planning ducting layouts as well.

http://www.cvcdirect.co.uk/Whole%20House%20Ventilation/cvcdirect-heatre.html

I have one of these
http://www.cvcdirect.co.uk/Whole%20House%20Ventilation/cvcdirect-acompe.html

Easy to look after and clean the filters.

What can you do to reduce the condensation / damp generation? If it is damp, you need to get that sorted ASAP. If it is condensation from cooking / cleaning, can you reduce that? You may still end up with such a system but treat the root cause of the problem first rther than pay to treat the symptoms.

We just open the window after a shower and the condensation just evaporates…..

surely though, foot flaps, the heat goes with it?

surely though, foot flaps, the heat goes with it?

You won’t get all of the heat back with a HEX, at lower ambients you’ll not get a lot of it at all. In fact, you may lose less heat opening a window momentarily than running a fan continuously (also consider the electrical energy used to run the fan), particularly the all in one unit footflaps linked to (which I’m skeptical of BTW; no offense footflaps).

condensation is in all the bedrooms + obviously bathrooms after showers and we have extractor fans in kitchen / bathrooms + open windows.

No trickle vents on DG though so might fit them first see if it helps a i think the house is pretty airtight at moment

Urban hiker is exactly right. For a whole house system it is only worth it if you have very good air tightness, and you will not get this on an existing house. There is the cost of powering the fans as well as the purchase and install costs. In a leaky house all you will do is suck cold air in through the building fabric. Either use an extract fan or perhaps a stand alone unit in your bathroom. Treat the source of problem as already mentioned. Extract fan when cooking, showering, don’t dry clothes without lots of ventilation. Trickle vents in bedrooms.

Op, unless your house was built in the last couple of years it will not be ‘pretty air tight’ and unlikely to be even then. You need a leakage of less than 3 and preferably 1.5 to be worth having mvhr. current build regs is 7.

surely though, foot flaps, the heat goes with it?

Yes, but can’t say it’s a real problem. Once you whack the power shower on the room can go from -5 to a sauna in about 30 seconds.

We generally leave windows open all year round when the heating is off e.g. during the day (the sashes have the option of locking a couple of inches open), which airs the house.

If we lived in Scandinavia, I can see that heat loss would be more of an issue, but our winters are pretty mild, so leaving the window open in the bathroom is no big deal.

ok ive been thinking about this and theres something i dont understand…

its said above the house needs to be airtight for heat recovery systems to work. I started thinking about them as initially i read that you could use a PIV system like this

drimaster

to reduce condensation as it forces fresh air in from the loft into the house, and the stale air leaks out the gaps.

But if i put vents in the rooms leading back into the loft via ducting to a heat recovery unit then wouldnt the forced air into the house force air out throught the heat recovery thing? Especially if it was fan assisted.

Anyway am going to look at trickle vents as suggested above but just been wondering why my theoretical method above wouldnt work provided the house wasnt completely draughty?

I fitted one on a house we built a few years back. Big central extraction/exchanger unit situated centrally in the loft. Yours would be easy to fit with it being a bungalow as non of your ducting runs would have to pass between floors. It’s basically in lamens, insulated copex joined where required with a sleeve and silver duct tape to each room. Mainly extract in bathrooms/kitchens to one inlet of the exchanger. This removes moisture and blows back mild (I wouldn’t say warm) dry air back.
We however achieved on that build the best pressure test results the testing company had seen in at radio at ally built house which helps the whole ventilation scenario work efficiently.