Hi,

My Mum lives in a 1960's bungalow with reasonably good insulation ,
cavity walls and double glazing. She gets a lot of problems with mildew
behind cupboards and condensation on aluminium window frames. Two
internal walls are single skin but shared with the integral garage, so
these walls get colder.

My feeling is that the house does not have adequate ventialtion so was
wondering about systems which pump out stale air and pump in fresh air,
transferring heat from the former to the latter .

The bungalow has a huge accessible attic space and her kitchen and
bathroom both have false ceilings, si I assume any vents could be
placed easily out of site.

I took a look at the xpelair site but the range of systems is
bewildering. I wonder if :

a) Anyone thinks this is the right approach

b) any experience of the cost and which products are suitable

c) I also have read of systems which create a high air pressure indoors
.. forcing air out. Is that a better approach ? I assume heat is forced
out too !?

My feeling is that the house does not have adequate ventialtion so was
wondering about systems which pump out stale air and pump in fresh air,
transferring heat from the former to the latter .

At the moment these are expensive units, usually only sold through
specialist installers. You're looking at £1500+ for a typical system
from the research I did. The cheapest whole-house unit I could find is
made by Kair. They sell the parts online, so you avoid the
sales/design/install costs. Their unit is about £600 +
ducting/vents/etc.

It will be cheaper to extract at source, so putting an extractor in the
bathroom and the kitchen. While these do waste heat, you have to
consider the total cost over the life of the system. They would also
use very little electricity. Or you could fit a couple of single room
heat-recovery units (e.g. BES sell a unit for about £180). I've
noticed thes pop up on eBay from time to time.

I think as the building regs get tighter, it will soon be effectively
mandatory to have some form of MHRV in new builds. The greater volume
should then push prices down to more realistic levels.

I also have read of systems which create a high air pressure indoors forcing air out.

These require a very airtight building - you don't want the damp air to
be pushed into the loft.

Having been put off by the costs of these units, I'm having a go at
converting a large (microwave oven size) commercial single-room Toshiba
MHRV unit I picked up for practically nothing on eBay recently. I plan
to mount this in the loft in an insulated box connected to ducting,
extracting air from the bathroom and kitchen, and blowing fresh air
into the main bedroom and lounge. A bit Heath-Robinson, I know, but the
whole lot should come to less than £100, and it's an interesting
little DIY project.

-Antony.

On 27 Mar 2006 22:17:48 -0800, wrote:

Hi,

My Mum lives in a 1960's bungalow with reasonably good insulation ,
cavity walls and double glazing. She gets a lot of problems with mildew
behind cupboards and condensation on aluminium window frames. Two
internal walls are single skin but shared with the integral garage, so
these walls get colder.

My feeling is that the house does not have adequate ventialtion so was
wondering about systems which pump out stale air and pump in fresh air,
transferring heat from the former to the latter .

The bungalow has a huge accessible attic space and her kitchen and
bathroom both have false ceilings, si I assume any vents could be
placed easily out of site.

I took a look at the xpelair site but the range of systems is
bewildering. I wonder if :

a) Anyone thinks this is the right approach

b) any experience of the cost and which products are suitable

c) I also have read of systems which create a high air pressure indoors
. forcing air out. Is that a better approach ? I assume heat is forced
out too !?

Try a hygrometer first, to get an idea if the problem really is high
humidity and not just condensation on cold surfaces.

If humidity is high, say above 60% then try a dehumidifier.

In any case try insulating behind cupboards on outside/cold walls with
a sheet of thick-ish polystyrene.

Condensation can be endemic on aluminium windows if they're older and
don't have a 'thermal break'

cheers,
Pete.

On 27 Mar 2006 22:17:48 -0800, wrote:

Hi,

My Mum lives in a 1960's bungalow with reasonably good insulation ,
cavity walls and double glazing. She gets a lot of problems with mildew
behind cupboards and condensation on aluminium window frames. Two
internal walls are single skin but shared with the integral garage, so
these walls get colder.

My feeling is that the house does not have adequate ventialtion so was
wondering about systems which pump out stale air and pump in fresh air,
transferring heat from the former to the latter .

The bungalow has a huge accessible attic space and her kitchen and
bathroom both have false ceilings, si I assume any vents could be
placed easily out of site.

I took a look at the xpelair site but the range of systems is
bewildering. I wonder if :

a) Anyone thinks this is the right approach

b) any experience of the cost and which products are suitable

c) I also have read of systems which create a high air pressure indoors
. forcing air out. Is that a better approach ? I assume heat is forced
out too !?

Open some windows?

Mark