Cold bathroom - due to vent fan opening

xyz123

Hi our bathroom gets quite cold on many days and I suspect it is due to the opening for vent fan. We have a standard vent axia fan which is on outside wall of bathroom

Is there anything I can do to improve this. I have seen some "back draught shutters" but are they retrofittable easily? Do I fix them from inside of bathroom or have to get ladder up on outside.. Thanks.

Smiley_Dan

This is a problem with all dumb extractors. It's a wonder they are allowed.

Anyway....

Backdraught shutters work best when installed in a ceiling, because then gravity closes them. They can still be a nuisance with noise and flapping.

They will reduce energy loss a little, but they are not a good solution because they are not air tight and something called the stack effect will still push energy out of the room, even when it isn't windy.

You might want to look into single room heat recovery ventilators (search for SRHRV). These ventilate constantly at a low level, and exchange the heat that would otherwise leave the building into the fresh air coming in.

But that's a broad recommendation - what's best for you depends on your house. Unfortunately, HRV ventilation works best at high levels of air tightness, and the UK's building stock is dreadful in this regard.

silverwhistle

I'd add that some units (certainly from VentAxia) also have humidistats and come on when there is a certain level of moisture in the bathroom air - I'm considering one myself on the list of jobs to do.

dbriggs

Why not brick it up and use a window to vent out condensation when needed?

phil24_7

There will not be enough extraction from an open window. Mechanical ventilation will likely be needed to avoid condensation/damp problems.

Regards

dbriggs

phil24_7 wrote: »

There will not be enough extraction from an open window. Mechanical ventilation will likely be needed to avoid condensation/damp problems.

Maybe. I've bricked up a few in older houses. I assumed the reason they had them was because when the houses were built there was no central heating and so damp could become an issue easily.

Whenever I get a shower I just leave the window open for 30 minutes afterwards while the heating is on and when everywhere looks dry I close the window. In summer it's even less of an issue.

Surely there is little difference between having a small vent which is always open (letting in cold air) or having a larger vent open (i.e. the window) for a shorter amount of time?

Seems odd to me that we buy double glazing and get insulation only to leave a vent in the wall open all the time?

phil24_7

Forced extraction is much more effective than an open window. It is also possible to have extraction that doesn't let much, if any, air back through the vent when off.

This would always be my preference.

Regards

Grenage

Opening a windows drops the room temperature quickly and forces the moisture in the air to immediately condense on the nearest cool surfaces. That the steam ostensibly disappears does not mean the situation has improved.

A good extractor with an in-build shutter or non-return flap is the best option. A good extractor normally being a powerful in-line centrifugal unit (£100+), not a £40 wall-mount.

Went off a bit there. I'd replace the unit for one with a powered shutter, or fit an external cowl, if you're set on keeping a wall extractor.