Extractor fan advice

adidas

Hello all

Wondered if I could pick your brains about which is the most cost effective extractor fan.

Recently had an independent damp survey performed and was recommended 150mm automatic humidity fans for 3 rooms+/-loft ventilation system. Not sure if this is the right size and wondered what your thoughts were.

I asked for any specific brands he knew of and mentioned envirovent. I contacted them and prices seem very high. I looked through the forums and noticed icon airflow/xpelair commonly.

Kitchen (Ground floor extension): kitchen/diner/reception room all open plan, size 106cubic metres. Has an extractor fan. 2 walls exposed, one more weathered than the other. Tool recommends 12 inch fan.

Downstairs loo: 3cubic metres. No ventilation, one window does not open. Tool recommends 4 inch fan.

Bathroom (upstairs): above which is the loft. Size 11-12cubic metres. Window that opens. No ventilation at present. Tool recommends 6 inch fan.

Questions:
1) Given I have an extractor fan in the kitchen, do I need a 30cm fan or could I get a 15cm one?
2) What sort of ducting might I need?
3) Where's the best place to position the fans?
4) Is there a difference between centrifugal/axial/in-line fans?
5) What humidity should you set the fans to extract to, is it necessary to have one that's easily adjustable?
6) Anything else I need to take into consideration when buying?

My priorities:
a) Most cost effective, low running costs and low maintenance/filter changes
b) 25db or lower as would like a quiet fan
c) backdraft cover

I used this tool to calculate dimensions and flow rates.
https://www.tlc-direct.co.uk/Technical/Ventilation/Ventilation4.html

Would be grateful if you have any thoughts or advice. Thanks very much.

wrightk

adidas wrote: »

Hello all

Wondered if I could pick your brains about which is the most cost effective extractor fan.

Recently had an independent damp survey performed and was recommended 150mm automatic humidity fans for 3 rooms+/-loft ventilation system. Not sure if this is the right size and wondered what your thoughts were.

I asked for any specific brands he knew of and mentioned envirovent. I contacted them and prices seem very high. I looked through the forums and noticed icon airflow/xpelair commonly.

Kitchen (Ground floor extension): kitchen/diner/reception room all open plan, size 106cubic metres. Has an extractor fan. 2 walls exposed, one more weathered than the other. Tool recommends 12 inch fan.

Downstairs loo: 3cubic metres. No ventilation, one window does not open. Tool recommends 4 inch fan.

Bathroom (upstairs): above which is the loft. Size 11-12cubic metres. Window that opens. No ventilation at present. Tool recommends 6 inch fan.

Questions:
1) Given I have an extractor fan in the kitchen, do I need a 30cm fan or could I get a 15cm one?
2) What sort of ducting might I need?
3) Where's the best place to position the fans?
4) Is there a difference between centrifugal/axial/in-line fans?
5) What humidity should you set the fans to extract to, is it necessary to have one that's easily adjustable?
6) Anything else I need to take into consideration when buying?

My priorities:
a) Most cost effective, low running costs and low maintenance/filter changes
b) 25db or lower as would like a quiet fan
c) backdraft cover

I used this tool to calculate dimensions and flow rates.
https://www.tlc-direct.co.uk/Technical/Ventilation/Ventilation4.html

Would be grateful if you have any thoughts or advice. Thanks very much.

Have you had a look at the greenwood airvac? they constantly run but are super quiet. The fan speed will pick up when humidity does. There's also the option to pick the fan speed up when you turn the light switch on eg bathroom situation but when you leave it will return to constant extract mode (lowest speed). All the airvacs can be programmed individually or can be automatic according to what room they are in

Dont bother with a backdraft cover- or if you do take the flap off, they are useless! Better off fitting an external grill then maybe a hood over the top

oh and if your planning on doing this yourself you'll need a core drill and some rigid ducting, not to mention the electrical work to connect them up

Jonesya

Normally in the kitchen you'd have a cooker hood rather than an extractor fan as its more effective - it removes the steam, smells and grease at source rather than dragging it across the kitchen. You can get various type of ducting, like flat profile, for getting it across cupboards etc.

Most bathrooms have regular 4"/100mm extractor fans, there's plenty of different models that can shift enough air for a typical bathroom.

Centrifugal fans can produce more pressure, so more force to overcome pressure drops from dampers, long duct runs, grills etc while giving a good air flow. Axial fans develop less pressure so normally limited to going straight out through a wall. Inline are a hybrid of the two. I'd fit centrifugal fans or inline.