To vent or not to vent ..

sfag said:
I have vents up high on the walls. There is no heat loss or drafts. Reconsider.
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Lucky you..........ours produce howling gales in the rooms. I put covers with sliding grills on mine and close them when there is a breeze.
 
pullandbang said:
Lucky you..........ours produce howling gales in the rooms. I put covers with sliding grills on mine and close them when there is a breeze.
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PAB - where did you manage to get the covers with the sliding grills ???? I need them badly before we are blown out of it :D I have this thing in my head that they changed building regs to ensure these vents were left open at all time and thought perhaps thats why they got rid of the covers with the sliding grills (??!!) - I could only find open covers when I went looking, would love to find the open/close covers!!!
 
Aimee said:
PAB - where did you manage to get the covers with the sliding grills ???? I need them badly before we are blown out of it :D I have this thing in my head that they changed building regs to ensure these vents were left open at all time and thought perhaps thats why they got rid of the covers with the sliding grills (??!!) - I could only find open covers when I went looking, would love to find the open/close covers!!!
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You must have a fixed vent in a room with a gas / oil burning appliance (unless it's fully separately vented and enclosed), or anything liable to produce substantial carbon monoxide - so presumably for any type of non-electric stove, and possibly for an open fire too.

I think the sliding vents are okay in other rooms, and you can get those vent covers in plenty or normal home supplies and DIY outlets. We got some in either Atlantic or Homebase.
 
Dreamerb said:
You must have a fixed vent in a room with a gas / oil burning appliance (unless it's fully separately vented and enclosed), or anything liable to produce substantial carbon monoxide - so presumably for any type of non-electric stove, and possibly for an open fire too.

I think the sliding vents are okay in other rooms, and you can get those vent covers in plenty or normal home supplies and DIY outlets. We got some in either Atlantic or Homebase.
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Thank you Dreamerb - I need one badly for our ensuite and bathroom - unfortunately we live "high up" and experience severe winds - we could really do with being able to close these vents on specific days when it is v windy - I didn't want to close them off completely - good to know I can get the sliding vents - I will go in search!

Thanks again!
 
I always wonder about these vents. I seen some which are simply a square hole in the wall with a grill on either side. The problem with this is that the air can go straight through, especially on an exposed wall creating massive draughts and heat loss. I've seen heavy rain get through them aswell. I thought they had to be offset to prevent this but maybe I'm mistaken. The other problem with this is that the wind and rain, actually gets into the wall space. If you run your hands on the wall around the vent you can feel how cold it is. Which can't be right.

I think they should be replaced with something along these lines...I don't know if how they fit with the building or saefty regulations, you'd need to check that out.

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seals the wall space and stops draughts and rain from getting in. On a powered extractor vent there should be a back draught protection flap or some means of preventing air from coming in when the fan is not one. Most I've seen in Ireland don't have these either.
 
Hi f0zzy,
I hope I can be of some help.. The first thing to try, is to stop the build up of humidity (water vapour) in the first place. Install mechanical extractor fans in your Kitchen, Utility Room, Bathroom and En-Suite, in the last two preferable with 15-30 Min overruns. Run a small amount of cold water first in your bath before adding the hot. Some windows in addition to having trickle vents can be left slightly opened in a locked position. Don’t dry clothes inside. Check your radiators and hot water supply for any leaks, indeed any water pipes supply or waste? Insure your Tumble Dryer is properly plumbed. Don’t leave Bedroom Doors open during the day especially if there is no heating on in them, and you have cooking or washing going on elsewhere.

I agree with You we spend a fortune Insulating our houses and heating them and then we have to go and put “Holes in the Walls” to ventilate the house. These “holes in the walls” are compulsorily under current Building Codes. Their surely must be a better way?

An earlier post on “Ask about money .com” touched on a similar topic
http://www.askaboutmoney.com/showthread.php?t=16903

Quinno‘s Reply on the 21-01-2006, 10:16 am- the second last post, is a comprehensive and informative reply and explains the need for these “hole in the wall” vents.

I know these “hole in the Wall” air vents are draughty but they are a requirement under current Building Regulations in so far as :- they are a means of achieving this requirement under the Technical Guidance Documents (TGD)- Quinno explains this very well. Now (TGD) Part F deals with Ventilation & (TGD) Part J deals with Heat Producing Appliances.

Basically in Part F it states that.. a Habitable Room (which may be taken as a bedroom or Living Room should have a ventilation opening (background) of 6500mm² ( 81mm x 81mm or 91mm Ø) AND an opening (window or door) for rapid ventilation of not less than 1/20th of the Floor Area. In a Kitchen & Utility Rooms a ventilation opening (background) of 6500mm². AND A suitable opening 1/20th of the Floor Area .. AND a Mechanical Extract Ventilation) ie a Fan. or Passive Stack Ventilation (PSV) .. Bathrooms and WCs requirements are somewhat similar to Kitchens.. But there are - if, buts & ands …

In Part J ..An room with a cooker should have an open-able window or if it is a small room a permanent ventilation opening at least 5000mm². A room that contains an open-flue appliance (Fire Place – Solid Fuel – Range, Stove etc.) should have a permanent ventilation opening at least 150mm² for each kW of appliance input rating, but never less than 6500mm²

Now the above is as I see it??? There may be further requirements?? You can see basically the requirements for all these “Holes in the Wall” ?

I am currently Building a “New House” and I’m not if favour of these “Holes in the Walls” and a looking for suitable Alternatives. But I don’t know all the answers and have many Questions of my own.

If you install a gas Range with a balanced flue do you need a Permanent Wall Vent. (PWV)…

If you install a Baxti Burnall Fireplace (this has its own Air Supply under floor) do you need a PWV? http://www.c20fires.co.uk/fireplace_accessories/burnall.htm
Does any know where I can get a Stove with its own air supply? (From a duct plumbed to the outside)

Can the PWV have shutters and can it be closed if the Fire say is not lit? I know an open flue is a very effective fresh air intake.and most of the heat goes up the chimney when it is (70%)! Check out the “Air Flow Stoves”. http://www.airflowstoves.ie Air Flow Stoves can supply two alternative methods of heating to the conventional oil and gas systems. The first ‘The French System’ this method pipes hot air around your house. The second ‘The German System’ where the energy is absorbed by the core of the fire place and slowly releases it as radiant heat over a 12-24 hour period.

Here is a nifty idea.. http://www.darco.com.pl/eng/oferta.php?o=1&kid=6&xid=0&pid=565
AN Air intake set with a heater that provides fresh air to the building and warms it up.

OR .How about this one http://www.allvent.com/product_a30.html from an Irish company?

As f0zzy said “”HRV is one option .. but an expensive one ..””


Check Out This Site ..
http://oikos.com/esb/39/VentOpt.html

Its seems pointless fitting Insulating (under floor, in walls, in ceilings, in attic etc.) , Fitting double glazing with E glass, stopping thermal bridging around doors windows floors etc, Sealing around draughty fitting !. Recess front Porches. Lagging hot pipes, Everything to make our homes Warm ( all above now Regulations) And the same Regulations then say you have to put a big 4” Ø hole or two, in all your walls to let the cold wind blow in..

Any Body with and Ideas ????
 
ospreymate said:
Any Body with and Ideas ????
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HRV systems...

these will become the standard by 2010... passive vents will be seen as a backward method of ventilation...

there is a new draft TGD F that deals with these...

unless someone can come up with an method of passively recovering heat in ventilation systems, then mechnical HRV systems are the way forward...
 
I've had similar problems with draughts - in bedrooms/living room etc I got the internal sliding covers which keep 90% of draught out so still getting a small bit of ventilation even when closed in winter!
For my extractors in kitchen and bathrooms I finally sourced backdraught dampers in Ireland which fit in between the inner and outer covers (cavity) and come in various diameters.They work a treat as the force of the extracted air opens the damper but it cannot be opened from wind/draughts from the outside.
Sliding Grills from Kingstons Hardware Pembroke St and Dampers from www.ventac.com

 
This might be of use to some. Not sure how it fits in the house, probably in the wall, but it might sort out the heat loss problem with standard vents!!!! I haven't used this myself but it might be worth a go!!!!!
 
sydthebeat said:
sfag is talking rubbish aircobra.

typical wall vents are designed to allow generally 4 air changes every hour.

so picture this, you have a room with a rad and an air vent.
the air is completely changed 4 times every hour in the room by the vent, therefore the radiator has to heat the whol eroom 4 times every hour. thats how it works.

with a heat recovery unit working at say, 75% efficiency, and assuming the same room... then....
the rad heats the room once, during the next hour the HRv system change sthe air 4 times, as like the passive vent, however, every time it changes the air it retains 75% of the heat of the room. therefore with HRV systems the room only needs to be heated once every hour instead of 4 times with a passive vent. thats the principle its based on and the reason they are relatively expensive pieces of machimnery (approx 5k for a standard house)
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"The air is changed every 4 hours" - How can this be?.

Heres a real life experiment for you.
Every summer my heating is switched off.
Lets say the tempature drops outside to say 10 degress.
The tempature in my vented bedroom room will stay at 20 degrees - without heating - all night.

If the air inside the room is replaced every 1/4 of an hour the room tempature should be the same as outside. It is not - it never is - in fact it never cools.

Regarding draughts from holes in walls there is only ever fierce draughts if the wind blows from the direction on which the vent is placed and you can always flip shut the vent cover on the inside anyway - and still let some air in.

The wind blows most often from a southerly direction . Dont place your vents on these walls.
 
No - Louth.
My vented upstairs bedrooms - hole in the wall vents - rarely drop below 18 degrees even on the coldest winter day with the bed room heating off. Insulated with 60 mil cavity insualtion. Thats it. I can tell because all rooms have thermostats on the walls.

As regards the wind. Almost always from the south. The next 14 days:



No vents on the south side = no draughts.

Hows that for a low tech solution.
 
Bit hard to believe that a room will stay at the temp temperature all night on a freezing cold night with no heat. Unless its getting heat from other rooms, like the one beneath it. Even with no vents at all.
 
My house is a modern build.
I guess the heat rises a bit - but not much. The floors have insulation so not too much should get up. I
It has very large windows with light blinds - not condusive to keeping the heat in.
I guess the wife is hot. Have to say the kids give off a lot of heat too while they sleep.
Its a three storey house. The top floor is under used and does not have the heating on all. It stays at 18 - 19 degrees.
I consider that bloody cold but others on these boards switch their heat off when it hits 18 degrees.

And last but not least every room in the house has hole in the wall vents letting air in and out.
 
sfag said:
My house is a modern build.
I guess the heat rises a bit - but not much. The floors have insulation so not too much should get up. I
It has very large windows with light blinds - not condusive to keeping the heat in.
I guess the wife is hot. Have to say the kids give off a lot of heat too while they sleep.
Its a three storey house. The top floor is under used and does not have the heating on all. It stays at 18 - 19 degrees.
I consider that bloody cold but others on these boards switch their heat off when it hits 18 degrees.

And last but not least every room in the house has hole in the wall vents letting air in and out.
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I think you have built yourself a passive house without knowing it,nice one.
 
Yes, if the temperature is warmer than outside with no heating, then the vents are not working, simple as that.
 
sfag said:
No vents on the south side = no draughts.

Hows that for a low tech solution.
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So put them on the north side instead?? Just wait for one of those freezing northerlies and your ass is frozen.

Here in the west of ireland the wind comes from all directions, but South Westerlies are most prevalent.

I suspect your missus is heating the house while you are away and turning it off when she expects you home. Either that or you have a severe radon problem and the radioactivity is heating your house. Or perhaps its a goddam miracle.
 
sfag, you probably didnt realis ethis but most draughts are formed when the wids blows parallel with the wall... not directly at it.

try blowing into a bottle.... blowing directly at it makes no effect on the inside...

its called 'positive and negative pressure'.....
 
The theorys are interesting. I'm just quoting my objective experience. Air is good. Let it in.
 
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