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Code now requires houses to have exhaust systems that run a fixed number of hours per day to insure that fresh air is introduced into the house. Most often this is done by putting a bathroom vent on a timer. I would like to combine the bathrooms and utility room exhausts together into a single exhaust system with a single penetration through the building envelope. I would like to solict any comments from those who have had any experience or thoughts about these systems, (the good, the bad, and the ugly). I also saw an advertisement that combined the bathrooms exhaust with the kitchen exhuast. Is that a good idea?
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Has the world gone daft? Now that we've been coaxed and prodded into insulating and sealing up our homes, getting all sorts of utility and tax credits to do so, there are now codes requiring that we open them up again?
*I think what these codes are trying to do is encourage builders/homeowners to install HRVs (Heat recovery ventilators). I have heard that they are required in some parts of Canada and many/most commercial buildings. HRVs are a good thing, but are not cheap - I think they start at around $1800. Another draw back is that these things are not %100 efficient(or anywhere near that).For an example of one such HRV go to:http://www.resprod.com/pa.html
*I once lived in an apartment house that had shared bathroom vents. When the guy below me was smoking in the john and the wind was blowing against the outlet vent, it spilled all of the cigarette smoke and other fumes into my bathroom - got rather ripe at times... I assume the same thing could happen if somehow there was a window open in the kitchen and it caused a negative pressure in there, it could suck up a few choice aromas from the bathroom. Perhaps rare, but possible.
*Steve - as long as you mention that, get a load of this. Here in Western Washington they've legislated the homes so tight, they now (depending on heat source) often require one "vent unit" per room to draw outside air. Typically these are little louvered vents in the window frame (at increased cost, of course) that the homeowner can OPEN or CLOSE! If they can open the vent, why the hell can't they crack the window? You think I'm kiddin', I know. But I'm not. It's absurd. - jb
*Perhaps a backdraft damper at each inlet would help. i would be sure to join the duct runs as far from the inlets as possible. Fantech has some inline fan solutions for this sort of thing.If by kitchen exhaust you mean the vent hood, I wouldn't combine it with the bathroom.
*I am a Canadian West Coast Designer/Builder. Our codes do require a whole house ventilation system as a result of the legislated airtight construction. A well insulated airtight house has an incredible energy efficient performance but needs the controlled ventilation to prevent moisture and backdraft fumes from soaking the home and poisoning its inhabitants.An HRV is expensive (usually $3000 to 4000 CDN )but will return its value over the long term. Especially in colder climates. Depending on how fast it runs, it can be up to 80% efficient. (Returning 80% of the heat normally lost to the required ventilation.)Whole house ventilation is set to a humidistat rather than a timer and an outside supply air must equal exhaust to prevent backdrafting wood stoves or furnace gases.The result is dry fresh air, no mildew and a longer life for wood buildings. This is definitely an improvement for the colder/wetter areas.