# Hole in the Wall Vents



## buyingabroad (22 Dec 2009)

Hi all,

I need to put the above into habitable rooms in the house.  I'm interested in two types but don't know which one to go with.

i) A passivent which is responsive to humidity levels but not inside or outside tempatures. Basically, when humidity rises, the vent opens up and vica versa.

ii) A temperature sensitive vent - 
(A self contained, temperature sensitive thermostatic piston controls the opening of the indoor vent disc. In automatic operation the aperture decreases with declining outdoor temperature and increase with rising outdoor temperature.)

I would wecome your thoughts on which one I should run with.

Many thanks​


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## 3CC (23 Dec 2009)

I am inclined to say that a vent based on humidity rather than temperature difference would be better. I presume the thermo controlled vent just closes when it is cold. So during the winter it closes at night (when people are sleeping in bedrooms and creating moisture) and opens in the day (when the bedroom is unoccupied).

Just out of interest, how much do the Passivent 99H units cost? (assuming this is the one you are considering)

3CC


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## buyingabroad (23 Dec 2009)

3CC - thanks for your opinion.

I left the prices on my desk at work. Thought they were around the €100 mark each, Yes it is the 99H I would be looking at - with one or two having the acoustic feature added. Will confirm in January.


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## 3CC (23 Dec 2009)

So if you were to do the whole house, that would be €600 for a 3 bed semi plus fitting.

I am a bit of a slave to the idea that something should have a payback. Do you think the 99H's would at that price?


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## colm5 (27 Dec 2009)

Just wondering what happens in the event of a build up of CO, natural gas, smoke etc.. in these rooms if the vent only responds to humidity? Do these vents pass the building regs?


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## buyingabroad (27 Dec 2009)

colm5 said:


> Just wondering what happens in the event of a build up of CO, natural gas, smoke etc.. in these rooms if the vent only responds to humidity? Do these vents pass the building regs?


 
In my case these vents would be in the habitable rooms and would be intaking air only from outside. Extracting bad air would be via the wet rooms.


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## scuzz (28 Jul 2010)

Hi Buyingabroad,
I am also going to use natural ventilation and was looking @ passivent and thermostatic controlled vents in a low energy house. Not totally convinced on mechanical ventilation as there are varying issues with cost, ongoing maintainance cost, dryness, noise, etc. Going to also look at DCV 
What did you decide on in the end, have you any feedback on using these vents?


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