Is heat recovery ventilation for me?

[willcjarvis]

Hi all,

We are currently renovating a flat in a 100-year-old building and we are looking into various fixes for various problems.

The flat suffers from poor ventilation, mould, freezing cold in winter, too hot in summer, condensation, high heating bills, draughts, and other things.

We plan to replace the windows, most probably insulate the exterior, and hopefully draught-proof the flat a little, but I don't think it will ever be airtight...

Would a heat recovery ventilation system be a feasible fix?

[homebild]

"Would a heat recovery ventilation system be a feasible fix?"

Probably not.

Heat Recovery Ventilators are a good option for air tight homes, but not for drafty ones.

Since almost 40% of heat loss and heat gain in a building comes from air leakage, one can usually do best by caulking and sealing the building against in infiltration and exfiltration.

http://www.popularmechanics.com/home/improvement/interior/1275121

[willcjarvis]

Hmmm. Thats what i feared.

I do plan to make the envelope more air tight, and perhaps carry out a door blower test [or whatever it is called] to find out how much we are leaking and from where.

Is there a measurement or standard which dictates how air tight a building should be to benefit from HRV?

If so, what would be the best way to go about achieving higher air tightness?

[homebild]

Here in the States (and if I remember correctly) a house that has less than 4 air exchanges per hour is classified as 'exceptionally tight construction' and is required to add make-up or outside air.

Most older buildings have many times more air changes per hour because they have so many air leaks.

A heat recovery system only works with tight homes because you must add make-up/ventilation air from the outside and can therefore warm it as it enters in its controlled method.

That can't warm other air that enters in a leaky building so installing a recovery system would be a waste of time and money.

That said, the simplest and most effective way to cut down on energy losses and gains due to air leakage is to use caulk or expandable foam around window and door frames, at wall and floor intersections, around receptacles and switches and ceiling boxes, at attic accesses, around basement doors, etc...

[willcjarvis]

Do you think it's possible to get a good air tight envelope using new windows, doors, caulk, foam and so on?

If i did manage to make the flat relatively air tight, what would be the best way to keep humidity, damp, mould, and, just as importantly, bills under control?