Toilet extractor fan and vent draught

ConorC1

Recently bought a new build and there is strong draught coming in the toilets from the vents If you look out the vent you can see right outside. It's particularly bad on a windy day. Surely this isn't normal? See inside fan and outside vent pics attached

ConorC1

ConorC1 wrote: »

Recently bought a new build and there is strong draught coming in the toilets from the vents If you look out the vent you can see right outside. It's particularly bad on a windy day. Surely this isn't normal? See inside fan and outside vent pics attached

Anyone??

colm_mcm

You could change the external vent to the likes of a cowl vent.

We have one with a flap on it that only opens when there’s air flowing out. Not sure if that meets regs

Calahonda52

colm_mcm wrote: »

You could change the external vent to the likes of a cowl vent.

We have one with a flap on it that only opens when there’s air flowing out. Not sure if that meets regs

Yes re regs with a fan
OP you need one with a backdraft flap built in or you can source the one in the attached in the fatherland

its electrically powered and wired through the fan switch, used in passive houses

ClosedAccountFuzzy

Just don't fit something too heavy or the fan may not be able to lift it.

You're usually better to get a fan that includes a backdraught flap or mechanism that's activated by the fan itself.

Vent-Axia models for example all contain a system that opens shutters when the motor has been running for about 1 minute or so.

Calahonda52

FuzzyThinking wrote: »

Just don't fit something too heavy or the fan may not be able to lift it.

You're usually better to get a fan that includes a backdraught flap or mechanism that's activated by the fan itself.

Vent-Axia models for example all contain a system that opens shutters when the motor has been running for about 1 minute or so.

Have edited my post, my bad..:(
its electrically powered and wired through the fan switch, used in passive houses

ClosedAccountFuzzy

Only thing I would say is we had one of those cowels with a flap and it kept rattling all night if there was a lot of wind. You'd hear bang, bang, bang every so often.

The Vent-Axia fan was more expensive, but no issues since and pretty quiet too.

I also picked up a Bosch bathroom fan on Amazon.de for a reasonable price. Very nice looking device & has simple plastic backdraught non return flaps that work pretty effectively.

ConorC1

Apologies for resurrecting this thread. I'd forgotten about it until the strong north wind arrived yesterday. The fans in the bathrooms were spinning away (when powered off) due to the wind coming in from the external vent. So it was like having a mini air cooling unit installed in the bathrooms. Surely it's up to the builder and not me to address this?

Yellow_Fern

https://www.boards.ie/discussion/comment/118230912#Comment_118230912

You might be able to convince them if they are still on site

bb12

you could try fitting a cowl to the wall outside to cover the vent. still lets the air out and prevents direct wind blowing in. i had to do this with my extractor fan vent. on windy days the wind would blow through the shaft down into the kitchen. the cowl stopped all this. cheap and easy fix. something like this: https://www.amazon.co.uk/Rytons-9x6-Cowl-White/dp/B008OVP6CE/ref=sr_1_13?keywords=cowl&qid=1638229260&sr=8-13&th=1

ConorC1

https://www.boards.ie/discussion/comment/118242761#Comment_118242761

They are gone a few months ☹️

ConorC1

https://www.boards.ie/discussion/comment/118242818#Comment_118242818

Good suggestion. Thank you

Surely the builder should have done something similar from the outset? It's an A rated house and yet the bathrooms basically have a 3 inch diameter wide open hole in the wall

Yellow_Fern

https://www.boards.ie/discussion/comment/118244018#Comment_118244018

I share your feelings. I think if you invest in a good heat recovery system you won't regret it.

zg3409

OP I am not sure how technically minded your are and at electrics or DIY. I doubt builder will rush back and replace working items with more expensive items if BER is met. Research the types of fans with flaps. As said cheap ones rattle in the wind, expensive ones move the flaps open when the fan is on and don't rattle.

You need to know the diameter of the whole as various sizes exist, e.g. 4 inch. If your fan has an over run timer that keeps it going after light is turned off you need that to exhaust shower steam to prevent shower damp causing walls to go black. You may be able to relatively easy DIY from inside but beware over run fans are always live, even when not moving, so cut all power to house or get an electrician.

There are some downsides to fans with shutters. 1, the cost 2 your room is less ventilated afterwards so more likely to get black mold and you may have smells linger for hours. Leaving the bathroom window open during showers and leaving door open after showers helps room naturally vent.

Builders design for a certain BER for sales and marketing purposes. It's the accountant and bank that want the cheapest house to meet that BER so they may skimp on quality or cost of items. If it's not made clear by architect or builder the electrician may just grab the cheapest non brand fan they can find. Sometimes they dont build as the plans or use the insulation they are supposed to, but the BER is typically based on plans, not actual built reality. Ireland tends to be windy is and on windy days it's more noticeable. Similar problems exist in kitchen extractors, does yours have a hidden or visible flap? And fireplaces that are not lit often that is a massive vent, try a chimney balloon. That said you need some ventilation in a house for fresh air and to prevent mold, a bathroom is probably the room most in need of ventilation.