Heat recovery fan

[James]

Anyone have experience with heat recovery bathroom fans?
I want one for home, old House with no cavity walls, bathroom moisture condenses on wall and causes mould.

I do the normal, leave doors and window open but it is not enough.

if anyone can recommend a good one then it would be greatly appreciated.

 

[LastManOnline]

Firstly I don't. And have yet to install one. But I have an identical bathroom set up as you and found what's worked best is the traditional bathroom wall fan heater with a built in timer. It's switched on a half hour before the first shower to ensure air absorbs as much moisture as possible. After shower moist air evacuated by opening window. Old fashioned but working well. No mold so far and shower area comfortable to use.

 

[Zerax]

Wow... how long are you boys spending in there ?? There can't be that much to wash ??

I have also not fitted an NVHR system... but from what I understand, the system is designed to run almost continuously with a low volume of air being shifted. Yes, there can be a boost function for showering times or curry cooking sessions... but it sounds like that may not be enough in your situation.

From my research, many of the MVHR systems seem to be sold at a high price with heavy sales commissions in place. I've tried a few times to get information and prices on systems, but they all seem to want to send someone round to do a complete system design and install.

Also... you may want to consider a small in-line heater. Don't forget that the heat transfer is not 100% efficient... so every m3 of moist/stale air being extracted will be replaced by a m3 of fresh air coming in... great for the summer ! but in January ??

Would some insulation on those walls be helpful ? Keep them 'warm' to give less time for the warm moist air to condense, and more time for the extraction ?

 

[DJAndy]

Wow... how long are you boys spending in there ?? There can't be that much to wash ??

In my case there is much girth to wash. Only problem is that it's due to a love of pies rather than being blessed.

 

[Rockingit]

Anyone have experience with heat recovery bathroom fans?
I want one for home, old House with no cavity walls, bathroom moisture condenses on wall and causes mould.

I do the normal, leave doors and window open but it is not enough.

if anyone can recommend a good one then it would be greatly appreciated.

Similar issue here, too. Old house, thick stone walls. There are other non-mechanical options also -
1) Anti-bac paint (no, not the cheap 'bathrooms and kitchen' rubbish sold in B&Q, I mean proper trade anti-bacterial paint with silver oxide in it that hospitals use) gives a head start.
2) We've found that using the solid block style (Aero bond??) dehumidifiers actually makes a massive difference as they just absorb all the background residual moisture
3) Shower in two's (or three's......) - saves water although, might make things more steamy ?

 

[Mike Johnson]

I have also not fitted an NVHR system... but from what I understand, the system is designed to run almost continuously with a low volume of air being shifted. Yes, there can be a boost function for showering times or curry cooking sessions... but it sounds like that may not be enough in your situation.

I have never cooked a curry in the shower, I have always said the Tia food is curry in water, but not that much and I should think the soap ruins the taste.

 

[Mike Johnson]

Seriously though, I have tried a number of Heat recovery systems and eventually gave up on them, I now have a 150mm fan on a timer and humidistat witch works well, fun drilling a 150mm hole through a solid 600mm wall.

 

[LastManOnline]

Similar issue here, too. Old house, thick stone walls. There are other non-mechanical options also -
1) Anti-bac paint
dehumidifiers actually makes a massive difference as they just absorb all the background residual moisture

All of the above (especially the dehumidifier) are a great help. Having lived in 3 really old houses over the last 20 years the standout factor in controlling damp, mould etc has been having a sufficient level of heat in the kitchen and bathroom areas. Nothing (dehumidifier, heat exchanger etc) really works well unless sufficient heat is generated to allow the air to absorb moisture from showers, cooking and of course people. I, ve learned that trying to save money on heating just means I end up spending more on mould remover.

 

[Mike Johnson]

Condensation and mould go together the way to control both is with ventilation, hence the increase in mechanical ventilation in new hermetically sealed houses, the modern trend to block up chimneys makes it worse when open fires controlled it all.