How can I prevent smells coming from my garage and into my home through the air vents ?

Question

I have three dogs that sleep in the garage and I can smell them through the air vents.

Is there something that I can in install or retrofit the ventialtion system to prevent the smell from reaching the rest of the house ?

Answer 1

By code your garage should be isolated from the rest of your house by a sealed firewall.  The reason for this is to prevent auto exhaust and fumes, like from gasoline or other chemicals that might be stored in your garage (fertilizers, for example) from getting into the house.  It also provides a fire barrier to give you some time to get out of the house should a fire start in the garage.  So the dog odors may be the indication of a worse problem.

By air vents I'm assuming you mean the registers for your forced-air heating and cooling (HVAC) system.  I'd start by checking for registers or return vents in the garage.  These are against code, and it could be very dangerous to have them, especially if you do store your cars or chemicals of some variety in there, or even if you have a water heater or furnace in the garage.  If there are return vents, they should be disconnected immediately and the openings should be sealed over with fire-rated drywall.  The same applies to any kind of vent that would allow air to travel between the garage and house, even if it's not connected to your HVAC system.  (If your garage is heated and/or cooled, it should have its own separate HVAC system.)

Next I would check the door between the house and the garage.  It should be sealed with fume-tight weatherstripping of some sort, including the crack under the door.  You shouldn't be able to smell odors or feel air making its way around the door.  If you can, that could be the source of the odors--and they could be getting pulled into a nearby HVAC return inside the door.

Next, check the wall that separates the garage from the house and make sure there are no holes or cracks that odors or fumes could seep in through.  The wall between your house and garage should be drywalled or covered with some kind of fire-resistant material on the garage side.  That material should be sealed around the edges.  Any sloppy drywall work could allow fumes into the wall cavity and from there into a return duct or your house.  If you see problems they should be fairly easy to correct with a judicious application of joint compound and fiberglass tape or maybe even caulk.

If it looks like there is no communication directly between the garage and the house, it's possible the odors are coming in thru the attic.  Some codes allow the garage space to be open to the attic area above the house.  It may not even be obvious--perhaps there's drywall in that area but it may not be well sealed.  If your HVAC system is in the attic, it's possible these odors are being pulled into the system there.  Visit your attic and try to determine if the odors smell stronger there.  If your HVAC system is up there, check the ductwork to be sure nothing has come undone and there aren't any obvious tears or openings.  Correct any you see or contact an HVAC contractor to perform a thorough inspection and mediation of the problem.  Even if your HVAC system isn't up there, it's still possible for attic air to make its way into the system--through a return cavity in a wall, for example.  An insulation contractor can often find these "bypasses" for you at minimal cost.

Do your dogs hang out in the house at all?  It's possible one of them peed into a floor vent or even a wall vent.  I'm told this is a common cause of pet-odor complaints to HVAC contractors.  You might check out your floor vents (if you have any) by unscrewing them, pulling them out and examining inside the duct for odors and, shall we say "contaminants."  

One of my dogs peed in a vent once.  She was waiting to be let out by a glass door that had a return vent below it and she just couldn't hold it any longer.  Fortunately I saw it happen and was able to pull out the vent and clean it up before it dried (much tougher to get then!).

Finally, consider cleaning the garage thoroughly to get rid of the odors.  A solution of bleach and an enzymatic cleaner like Nature's Miracle will do the trick (3/4 cup of bleach and 1 cup Nature's Miracle to a gallon).  Take this opportunity to clean the dogs thoroughly, too, and any other place (an external kennel, perhaps?) where they tend to hang out.  The strong odors could be just a cumulative sort of thing--get rid of the source and the problem goes away.

Hope this helps!

Answer 2

Your ventillation system should not allow garage smells into the house.  By code, it ts suppose to be sealed so you don't carbon monoxide poisioning or gasoline smells from your cars.  If you smell your dogs, the vapor barrier between the house & garage needs fixed.

Answer 3

Best approach would be to keep the animals and their living space clean so there isn't an odor. I have to wonder though why there are ducts into the garage? This is against code everywhere I've lived as it's a way for dangerous gasses and fire to travel from the garage into the living area of your home. I'd consider closing off or removing the ducts personally.