Air Vents

daheff

Hi

We bought a new house a couple of years ago. there are air vents in every room...i use the term lightly...i had to take one down the other day and its just a hole in the wall with a plastic tube around it. Does anybody know if this can be done another (proper) way? I've been to some house that dont have air vents like this...but dont know how it would be done.

Added to this with the recent cold weather these "vents" have just been allowing freezing cold air into my house

thanks

Supertech

Traditionally ventilation requirements have been met in two ways, either with the placement of a pvc pipe through the external wall which is then fitted with a steel grille externally and a 'closeable' plastic grille internally (this sounds like what you've described) or alternatively by means of vents fitted into the windows. More recently heat recovery ventilation systems have entred into the mix.

Depending on your window type and size, it may be possible to retro fit vents into the opening sections, which would allow you to remove the existing wall vents, but you must provide ventilation to comply with Building Regulations. It would also be important to properly remove the existing vents rather than just block them up, as they form a direct path from outside to inside across the external wall.

daheff

thanks for this. Windows are new pvc type...surprised they dont have this already built in as standard....although the patio door does.

when u say

It would also be important to properly remove the existing vents rather than just block them up, as they form a direct path from outside to inside across the external wall.

what exactly would be involved?

icbarros

Hi,
Have a look at some of the humidity sensitive air inlets, they may be a good option for you.
http://www.passivent.com/downloads/Background_Ventilation.pdf (last few pages)
http://www.aereco.com/int/ie/product.php?product=eht

daheff

Thanks for this ICBARROS...it might be more suited than retro fitting to existing windows

edanto

Thanks icbarros for those links, I've been looking for a solution to upgrade the vents in our house.

We have an old (40yr) house, and the vents are literally a 300sqmm hole in the wall, with an aluminium grate out the outside and a plastic grate on the inside. The previous owners have part-filled the gap with newspapers and old clothes (eeeewww).

We have 5 of those in the upstairs of the house, a 4 bed semi, and there's a strong wind that comes through them.

To replace the existing vents, what would be the difference between the various Fresh wall vents that are in the catalogue? I see the air flow rate is different, how would I calculate which ones I need?

I'm guessing the ones with the pull string are probably cheaper, and I don't need any noise insulation. Would the Fresh 80db be the ones to go for?

BostonB

I always thought those vents should be offset to wind can't come directly through. But its seems over the past few years they are building them simply a hole with a grill on it. Which is crazy. No point in all the insulation and energy ratings if you just leave a hole in the wall. It fills the wall space with cold air. I've seen rain come through them with driving rain.

I'm planning on replacing mine with a tube (stop airflow in to the cavity), then a hooded and one way flap on the outside. It won't be airtight but it will dramatically reduces the draught/heat loss from these.

icbarros

edanto wrote: »

To replace the existing vents, what would be the difference between the various Fresh wall vents that are in the catalogue? I see the air flow rate is different, how would I calculate which ones I need?

I'm guessing the ones with the pull string are probably cheaper, and I don't need any noise insulation. Would the Fresh 80db be the ones to go for?

I'm not sure if I can mention brand names here but I'll just call them A and P and let you use your imagination...
I'm not familiar with the products from P, but a quick look at their catalogue makes me think there is only one Fresh (99H) that has humidity sensitive control. That would be the one I would get, providing the air flow suits your needs.
I suggest you ring the manufacturer/supplier and ask for advice. Brand A is very good with this and if you have your house plans they can look at the all system for you. Mind you that the all system (from A) includes wall air inlets, extract units (for wet rooms) and a fan. Other options are possible though. Installing only the wall air inlets is not the ideal system but it will probably be better than what you have at the moment.
In relation to the air flow rate, I guess the only accurate way of finding out what you need is to have a air tightness test that will tell you what is the air pressure you have in the house. According to that the correct vents can then be selected.

beyondpassive

Its worth also considering the following decentralised mechanical extract with heat recovery units (dMEV): These are classified as cascade ventilation and you would generally use 4 in a house. I've used cascade ventilation in low energy renovations. The fans run constantly on trickle and have a boost function when kitchens or bathrooms need purging. Caveat, They don't strictly comply with Part F.

http://www.vent-axia.com/range/lo-carbon-centra-selv.html
http://www.polypipe.com/ventilation/products/mechanical-ventilation-with-heat-recovery-mvhr-/decentralised-mvhr
http://www.viking-house.ie/fine-wire-hrv.html
http://www.pre.ie/Upload/Upload/Data%20Sheets/Heat%20Recovery/Paul%20Mechanical%20Heat%20Recovery%20Ventilation%20Units/Paul%20Ventos%20Heat%20Recovery%20Ventilation%20Data%20Sheet.PDF