Ventilation

DavidJonas

I could really do with some advice on improving home ventilation.

It's driving me crazy. We used to live in a Victorian terrace, draughty and cost a ton to heat in the Winter. If you turned off the heating the house would be cold in about an hour. But we never had condensation!

Now we live in a house that has been insulated by the prior occupants to the nth degree. Everything is double glazed, even the interior door of the porch, the loft is thickly insulated and boarded, the hatch is insulated, they even put this wallpaper on the external walls of the house that has a polystyrene like underlay. There are no airbricks in any of the walls (there are a few underneath the floors, I can see them from the outside).

Yes there is an externally ducted hood in the kitchen and a fan in both bathrooms, but that is it. The floors are carpeted.

The moisture seems to have nowhere to go! Even with a dehumidifier which we run all night in the winter, the cold corner in the bathroom still gets mouldy. If we forget to run the dehumidifier the windows are running by the morning.

How can I fix this? Air bricks? Trickle vents? I don't especially want air ducts snaking through the whole house. I took out the hatch panel because that is all I could think of.

27col

You have answered your own question. Remove the cold corner. There must be a reason why it is cold, and it can only be a lack of insulation somewhere. My house is heavily insulated and has no ventilation at all. I have never had any condensation apart from a very light misting on the bedroom window in the morning. Even the bathroom does not get condensation. You can still see your face in the mirror after using the bath. Although to be fair the bathroom does have an extractor fan. Why do you think that letting cold air in via trickle vents will in any way remove condensation.

ed110220

27col wrote: »

You have answered your own question. Remove the cold corner. There must be a reason why it is cold, and it can only be a lack of insulation somewhere. My house is heavily insulated and has no ventilation at all. I have never had any condensation apart from a very light misting on the bedroom window in the morning. Even the bathroom does not get condensation. You can still see your face in the mirror after using the bath. Although to be fair the bathroom does have an extractor fan. Why do you think that letting cold air in via trickle vents will in any way remove condensation.

I agree - insulate, insulate, insulate!

Modern practice is for well insulated, airtight homes with controlled ventilation to reduce energy wastage.

Unfortunately many people stick to the outdated practice of uncontrolled ventilation (ie gaps and cracks, open vents etc) that simply lets the expensive heat escape uncontrolled to the atmosphere.

DavidJonas

I want to get rid of the moisture. The humidity meter reads 80% at times.

Heating up the house doesn't dispel the moisture, it just means the air can carry more of it. Guess we could leave the needle at 25 all winter but even this probably wouldn't heat the bricks in the walls which get cold at night, cool the moisture laden air in contact and that is where the condensation comes from.

I don't know where the moisture goes in your house without ventilation, but with 4 people, cooking, showers etc it doesn't seem to leak out easily from here.

Perhaps it's the cavity walls. The prior occs said the walls weren't right for cavity insulation for some reason. Maybe that is why the walls get so cold.

globalds

would a heat exchanger be a good idea ?

http://www.homeventilation.co.uk/



http://www.homeventilation.co.uk/heat-recovery.php

globalds

read this thread about people with a similar problem to you ..

Page 8 is the posting by a guy who has had a system fitted if you can't be bothered trawling through the thread

http://www.diynot.com/forums/viewtopic.php?t=110195&start=0

DavidJonas

Many thanks

DTDfanBoy

Are your bathroom fans automatically operated by a humidistat, if they're not fitting some may solve your problem at least in your bathroom, you might be surprised by how long they run until the moisture is cleared after a bath or shower. Ours run for a good 30 minutes after you've finished in the shower.