Air vents & constant drafts in new/renovated house

05-12-2018 9:33am #1

By law I had to put in these vents in each room of the house. In the sitting room with the inset fire the vent is permanently open by law. However, in the other rooms it is a flip vent. In the study, where I spend much time, it's a constant breeze coming down on me (obviously the vent is "closed"). I can't really move unless I were to redesign the study layout (the desks/bookshelves are built in and I would lose window light anyway if I could). It seems mad that this is happening in a house I put so much money into making warmer (external insulation, new heating system, etc).

But the main bedroom is worst. At this time of year I'm waking up each morning with a cold as the flip vent is beside me and despite it obviously being kept closed, there's a lot of winter air coming through (it's not possible to minimise it by moving the entire bed). Apparently the law stipulates their existence to prevent carbon monoxide poisoning but is there anything I can do to reduce the above effects while not undermining health and safety? Thanks.

Gumbo · 05-12-2018 9:51am

These vents are separate to the air tightness and heating. They are to ensure an adequate air change rate to keep the air in the house fresh and keep moisture out.

What size are the vents and what’s the build up behind the vent cover.
I recently done my house, built in 1996 and the permanent vents were 8” square holes.

I reduced them down to 100mm diameter and slieved them with 100mm box piping and fitted 100mm vent covers to reduce the excess draughts.

gctest50 · 05-12-2018 9:52am

Anyway, get a room-sealed fireplace instead like so :

https://bpmsupplies.ie/pages/room-sealed-stoves-with-external-air-supply

Install good carbon monoxide sensors

Then go get a whole-house ventilation system

( this uses the heat in the air being extracted to slightly warm the incoming fresh air )

Then you can seal up draughty vent thingys

lawred2 · 05-12-2018 9:53am

kceire wrote: »

These vents are separate to the air tightness and heating. They are to ensure an adequate air change rate to keep the air in the house fresh and keep moisture out.

What size are the vents and what’s the build up behind the vent cover.
I recently done my house, built in 1996 and the permanent vents were 8” square holes.

I reduced them down to 100mm diameter and slieved them with 100mm box piping and fitted 100mm vent covers to reduce the excess draughts.

we have a mechanical heat recovery ventilation system - does that remove the necessity for vents to the outside as there are none in our place..

Lumen · 05-12-2018 10:28am

What height is the bedroom vent?

Maybe you could put a picture over it, and some draught stripping along the bottom rear edge and one corner to divert the cold air flow. There would still be plenty of clearance around the top and sides of the frame.

DOCARCH · 05-12-2018 11:57am

lawred2 wrote: »

we have a mechanical heat recovery ventilation system - does that remove the necessity for vents to the outside as there are none in our place..

Yes.

Gumbo · 05-12-2018 12:08pm

lawred2 wrote: »

we have a mechanical heat recovery ventilation system - does that remove the necessity for vents to the outside as there are none in our place..

That's fine.

punisher5112 · 05-12-2018 12:11pm

I've seen where a cover is made to go over vent, not blocking it but directing the air up towards the ceiling and seal around the bottom part to stop draughts coming down on you underneath.

sydthebeat · 05-12-2018 1:35pm

lawred2 wrote: »

we have a mechanical heat recovery ventilation system - does that remove the necessity for vents to the outside as there are none in our place..

have you any combustible stoves?

lawred2 · 05-12-2018 2:25pm

sydthebeat wrote: »

have you any combustible stoves?

we have something like this

http://www.naglefireplaces.com/products/wall-fires/Dovre-Zen-100

sydthebeat · 05-12-2018 2:30pm

lawred2 wrote: »

we have something like this

http://www.naglefireplaces.com/products/wall-fires/Dovre-Zen-100

those particular stoves are "external air intake" which is perfect for MHRV systems.

if your stove takes its air from the room, you may need a fixed openable vent.

lawred2 · 05-12-2018 2:44pm

sydthebeat wrote: »

those particular stoves are "external air intake" which is perfect for MHRV systems.

if your stove takes its air from the room, you may need a fixed openable vent.

it's never on anyway - gets unbearably warm

Wartburg · 05-12-2018 2:44pm

lawred2 wrote: »

we have a mechanical heat recovery ventilation system - does that remove the necessity for vents to the outside as there are none in our place..

Your mechanical heat recovery ventilation system is your ventilation strategy. The best one, in case everything is installed & balanced properly. No need for vents in your case.

In general - the so called natural ventilation by vents or trickle vents in windows is not the best option, because it is dependend to differential pressure. No wind means no ventilation. A small breeze in the cold season can create discomfort, because you get cold air blown into the house. If you have to go with vents, get them installed away of sitting areas or beds, whenever possible.

kuang1 · 07-12-2018 1:53am

lawred2 wrote: »

we have a mechanical heat recovery ventilation system - does that remove the necessity for vents to the outside as there are none in our place..

With this system, are you able to feel any air movement whatsoever from the vents? They're located in the ceiling I think?

lawred2 · 07-12-2018 9:44am

kuang1 wrote: »

With this system, are you able to feel any air movement whatsoever from the vents? They're located in the ceiling I think?

Yeah.. it's always blowing at a low level.

kuang1 · 07-12-2018 1:42pm

lawred2 wrote: »

Yeah.. it's always blowing at a low level.

Cheers for that.

So would you recommend making sure that the vents are not directly over a bed or a couch... Is the air movement significant enough that it should influence decisions like that?

lawred2 · 07-12-2018 2:58pm

kuang1 wrote: »

Cheers for that.

So would you recommend making sure that the vents are not directly over a bed or a couch... Is the air movement significant enough that it should influence decisions like that?

you don't feel it

firstly - you can only hear and feel it if you get up on a chair and stick your head up close

secondly - the incoming air is already preheated to almost room temperature so you wouldn't get that 'draughty' feeling anyway

kuang1 · 07-12-2018 3:28pm

lawred2 wrote: »

you don't feel it

firstly - you can only hear and feel it if you get up on a chair and stick your head up close

secondly - the incoming air is already preheated to almost room temperature so you wouldn't get that 'draughty' feeling anyway

Lovely. Exactly what I wanted to know. Thanks!

08-12-2018 10:43am

Ok, some very informative responses here. The problem really is the bedrooms as we're all waking up with colds (little ones just arrived into my bed sniffling like bedamned).

So, should I get the builder, plumber or spark back to install a Mechanical Ventilation with Heat Recovery System (which I had never heard of until this thread)? Is it noisy? If that is the best solution available, would there be a specialist installer who would be better? What sort of money would it cost and does it take long to do the job?

I have carbon monoxide sensors and the whole house passed the SEAI inspection (and the RECI inspection, incidentally) this year and nobody ever proposed an alternative to vents - admittedly it has become a more pressing issue in this cold weather.

Regarding the downstairs sitting room with the permanent vent, I put in a Stovax Studio 1 inset fire, and here are its features. From those specs, did I have to put a permanent vent in the external wall after all? Legally, could I close that vent in that room entirely? (I was told categorically that a permanent vent in the wall is required where there's a fire installed but this thread seems to say it's not if the fire itself has its own ventilation. If this is correct, does my stove fit into this category?)

Thanks very much to everybody again.

lawred2 · 08-12-2018 11:04am

[Deleted User] wrote: »

Ok, some very informative responses here. The problem really is the bedrooms as we're all waking up with colds (little ones just arrived into my bed sniffling like bedamned).

So, should I get the builder, plumber or spark back to install a Mechanical Ventilation with Heat Recovery System (which I had never heard of until this thread)? Is it noisy? If that is the best solution available, would there be a specialist installer who would be better? What sort of money would it cost and does it take long to do the job?

I have carbon monoxide sensors and the whole house passed the SEAI inspection (and the RECI inspection, incidentally) this year and nobody ever proposed an alternative to vents - admittedly it has become a more pressing issue in this cold weather.

Regarding the downstairs sitting room with the permanent vent, I put in a Stovax Studio 1 inset fire, and here are its features. From those specs, did I have to put a permanent vent in the external wall after all? Legally, could I close that vent in that room entirely? (I was told categorically that a permanent vent in the wall is required where there's a fire installed but this thread seems to say it's not if the fire itself has its own ventilation. If this is correct, does my stove fit into this category?)

Thanks very much to everybody again.

The mvhr system pretty much needs to be built in to the house at construction time. It requires ventilation ducts into every room. Not an easy retrofit I'd expect.

Lumen · 08-12-2018 11:18am

lawred2 wrote: »

The mvhr system pretty much needs to be built in to the house at construction time. It requires ventilation ducts into every room. Not an easy retrofit I'd expect.

I've been wondering about this. Specifically, the idea of using a 100mm hole saw to go through flooring and ceiling in the corners of rooms, and then fit low speed inline fans. You could orient the fans to move the air in a particular direction through the house.Then the only ducting (apart from the short sleeves between floors) would be in the attic. Presumably the difference between a centralised DCV system and MHRV is that DCV goes only one way whereas MHRV circulates.

gctest50 · 08-12-2018 11:51am

lawred2 wrote: »

The mvhr system pretty much needs to be built in to the house at construction time. It requires ventilation ducts into every room. Not an easy retrofit I'd expect.

Bit of creativity with some built-in wardrobes upstairs might get you a long way there

Goldengirl · 08-12-2018 1:25pm

lawred2 wrote: »

The mvhr system pretty much needs to be built in to the house at construction time. It requires ventilation ducts into every room. Not an easy retrofit I'd expect.

Looking at humidity control passivents for our renovation, as it would be less disruptive.

Air vents & constant drafts in new/renovated house

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