Portable AC in garage. Concerned about safety issue.

[kryten]

I had an AC guy suggest a portable AC unit for my garage. It's a fairly large unit and I had to cut a hole for the exhaust (not sure if I'm using the right term). It's a two car garage.

My concern is the fact that I have a gas water heater in the garage and I'm afraid the unit may be sucking the water heater exhaust out of the flue and into the garage.

When I turn the unit on my garage door gets sucked in a bit. Also when I open the door to the house you can feel it being pulled shut and you can hear air being sucked in through the opening in the door.

The guy told me that I shouldn't be concerned because any carbon monoxide that gets pulled out of the flue would quickly be sucked out of the garage by the AC unit. Since it seems to be creating suction it seems like the AC unit is pulling more air out than it's putting back in causing negative pressure.

I don't want my family to be on the news because their idiot dad set up a dangerous situation in the garage leading to carbon monoxide build up that seeped into the house and killed them all. Is this a concern or no big deal?

 

[Jazzman442]

Is it a sealed electronic ignition water heater?

 

[sublime68charger]

picture of your setup?

due you have a carbon monoxide detector in the house?

 

[kryten]

Is it a sealed electronic ignition water heater?

I don't think so. It's a large tank. It stands about 6 feet tall if you include the base. It has a self lighting pilot light.

 

[kryten]

picture of your setup?

due you have a carbon monoxide detector in the house?

I don't have a carbon monoxide detector. I'm planning to get a few later today to put in the garage and on both levels of the house.

My water heater looks similar to this one with the pipe coming off the top. My concern is that exhaust that should be going up the pipe will be sucked out and into the room by the negative pressure created by the AC unit.

The AC unit is like this one.

 

[markietas]

So the A/C unit only has a outlet hose and no inlet? That's not very efficient sucking the air you just cooled outside.

 

[oldgoat]

I thought about them when I built my garage and from what I read I wasn't impressed with the reviews. Ended up buying a window unit and cutting a hole in the wall. Doesn't take up room and I don't have to worry about exhaust. So far it is working out good for me.

 

[dsimatt]

I have a portable ac unit in my bedroom, its a higher model one with a inlet/outlet hose setup so i don't have to worry about creating a vacum.
Mines a 12,000btu one and honestly i don't think it could cool down a garage without running basically non-stop for a day and even then i'd be surprised so i would try to find a window unit.

 

[LS6 Tommy]

So the A/C unit only has a outlet hose and no inlet? That's not very efficient sucking the air you just cooled outside.

Almost every portable of that basic design is exactly that way. They're made for short term or "emergency" use. They're not really intended for permanent istallation. You also have to dump the condensate out frequently.

Tommy

 

[Falcon67]

I have a portable ac unit in my bedroom, its a higher model one with a inlet/outlet hose setup so i don't have to worry about creating a vacum.
Mines a 12,000btu one and honestly i don't think it could cool down a garage without running basically non-stop for a day and even then i'd be surprised so i would try to find a window unit.

I used a 12k in my old 480 sq/ft shop. It cycled like a normal window unit.

 

[markietas]

Almost every portable of that basic design is exactly that way. They're made for short term or "emergency" use. They're not really intended for permanent istallation. You also have to dump the condensate out frequently.

Tommy

I have seen them with in & out hoses as well.

But I agree the only real use for them is in very temporary situations.

 

[Falcon67]

My experience with them at work is - meh. Not worth the expense. Much better to have a dedicated unit. And to the OP - IMHO anything that creates a negative pressure in that space will pull CO back in from the flue. As for exhausting it out - no, I think that is not guaranteed. If you go forward with it, get a good CO detector.

 

[LS6 Tommy]

I have seen them with in & out hoses as well.

But I agree the only real use for them is in very temporary situations.

I have, too. I just meant the ones similar to his photo.

Tommy

 

[dsimatt]

I used a 12k in my old 480 sq/ft shop. It cycled like a normal window unit.

I'm glad yours worked fine, i paid good money for mine and it does its job cooling my bedroom but now 3 years in i'm hoping it makes it thru the summer.

 

[Falcon67]

I can keep my new 960 sq/ft cool with 18500 btu. If you have one of those home center Frigidaire units, that is likely an issue. I had a 6500 in the work room (240 sq/ft) and it didn't cool for ****. My 10.5K Samsung can handle the 24x28 area. I replaced the 6500 with an LG 8000. You can feel the LG from 20' away.

 

[6768rogues]

Hold a match near the vent hood on the water heater and see if air is passing from the vent into the room. It probably is and it contains CO. Got a headache yet?

 

[HaroRider]

Regardless of what you do from here on out you should have a carbon monoxide detector..