Will this work for garage AC?

[GarageSpider]

I have a 550 sq-ft room above my 600 sq-ft garage that has it's own 1.5 ton HVAC unit. I rarely use the room, and I can't use both the garage and the room above the garage at the same time, it serves as a media room, big TV, xbox.

So I was thinking of ducting thru the closet down from the upstairs attic into the garage, insulating the garage and adding a return with some dampers to switch from garage to media room. Then I'd have an ecobee with remote temp sensor for control.

I'd end up cutting the closet in half for the ducts.

Before I talk to a contractor, is this even a valid idea?

 

[Git]

Is this a detached garage - there is no access at all from the house or what?

 

[larry4406]

Living spaces and garages are supposed to be fire separated and not share the same ventilation equipment (carbon monoxide poisoning, etc).

 

[GarageSpider]

Garage is attached to house. Room above garage has no access to house.

 

[dave89iroc]

i'd do it, that said, get good CO detectors, and several different types

 

[GarageSpider]

Well I don't park in the garage, it has never seen a car inside. But I want to make sure its up to code, which sounds like it might not be.

 

[theoldwizard1]

But I want to make sure its up to code, which sounds like it might not be.

Using the garage "attic" for a spare (non-storage) room may not be "up to code", but that depends on if it was permitted when the garage was built.

You will need some good fans to pull the air down. It will find it way back up !

 

[James-W]

Well I don't park in the garage, it has never seen a car inside. But I want to make sure its up to code, which sounds like it might not be.

I don't think it makes any difference if you park your car in the garage or not. What I mean is, if you sell the place and move, maybe the person who buys it will be parking cars inside the garage. Codes were not written for each individual and their particular situation, the codes were written for everyone to abide by. My point being, while it may work out just great for you, if you sell the place you MAY find yourself doing some repairs to bring it back up to the current code.

Another thing to consider is, normally the register and the return are on different sides of the room, in this case on opposite sides of the garage. You do not want the cold air register and the return right next to each other. How are you going to do that by going thru the closet with both the cold air and the return? You will need to run duct work along the ceiling to get to a different area of the garage. Will that be acceptable?

 

[James-W]

Using the garage "attic" for a spare (non-storage) room may not be "up to code", but that depends on if it was permitted when the garage was built.

You will need some good fans to pull the air down. It will find it way back up!

The cold air will need to be pulled down and it will find its way back up?

 

[zmaxmotorsports]

Using the garage "attic" for a spare (non-storage) room may not be "up to code", but that depends on if it was permitted when the garage was built.

You will need some good fans to pull the air down. It will find it way back up !

Heat rises,cold air sinks.

 

[Big Daddy Chop Shop]

The fire wall solution, if needed by code, is very simple- fire dampers. These go in- line with the duct work, and have a fusible link that when heated, release a spring loaded, fire- rated damper. This will block all air flow. these are code compliant when properly installed, and available thru your contractor or Grainger.

This is a good idea, just know it will sacrifice cooling in that Media room, and the "cool- down" period between switch over will take time. Sounds like an economical way to do it.

Zone dampers are pretty inexpensive, and you can just put them on a toggle, and have that toggle on a relay that when it is switched to "garage" will also switch the thermostat wiring to a stat in the garage, and vice-versa. Pretty smart, simple, and easy. You will run your equipment more, so you may have to update your maintenance schedule, and I would have a separate return int he garage utilizing a 4" thick filter or a carbon activated filter.

 

[larry4406]

The fire wall solution, if needed by code, is very simple- fire dampers. These go in- line with the duct work, and have a fusible link that when heated, release a spring loaded, fire- rated damper. This will block all air flow. these are code compliant when properly installed, and available thru your contractor or Grainger.

This is a good idea, just know it will sacrifice cooling in that Media room, and the "cool- down" period between switch over will take time. Sounds like an economical way to do it.

Zone dampers are pretty inexpensive, and you can just put them on a toggle, and have that toggle on a relay that when it is switched to "garage" will also switch the thermostat wiring to a stat in the garage, and vice-versa. Pretty smart, simple, and easy. You will run your equipment more, so you may have to update your maintenance schedule, and I would have a separate return int he garage utilizing a 4" thick filter or a carbon activated filter.

How would fire dampers stop migration of CO if that is the issue the OP has to face?

 

[Big Daddy Chop Shop]

How would fire dampers stop migration of CO if that is the issue the OP has to face?

They won't.

Period and simple.

You will need to use common sense as no dampers are 100% close off, and even having dedicated supply and returns, you will have cross-over as a possibility.

But even if he does not condition the space, it is possible. Any space over a shop should have a CO detector, and use some sense.

 

[justinjoyal]

The fire wall solution, if needed by code, is very simple- fire dampers. These go in- line with the duct work, and have a fusible link that when heated, release a spring loaded, fire- rated damper. This will block all air flow. these are code compliant when properly installed, and available thru your contractor or Grainger.

This is a good idea, just know it will sacrifice cooling in that Media room, and the "cool- down" period between switch over will take time. Sounds like an economical way to do it.

Zone dampers are pretty inexpensive, and you can just put them on a toggle, and have that toggle on a relay that when it is switched to "garage" will also switch the thermostat wiring to a stat in the garage, and vice-versa. Pretty smart, simple, and easy. You will run your equipment more, so you may have to update your maintenance schedule, and I would have a separate return int he garage utilizing a 4" thick filter or a carbon activated filter.

They won't.



Period and simple.



You will need to use common sense as no dampers are 100% close off, and even having dedicated supply and returns, you will have cross-over as a possibility.



But even if he does not condition the space, it is possible. Any space over a shop should have a CO detector, and use some sense.

I agree to all of the above.

Regarding the CO... With or without the ductwork, the room over the garage is subject to contamination, if not properly built (and we don't know that). The ducting would of course carry the CO faster though.

 

[GarageSpider]

House was built in past 5 years to code. I'm sure it's properly built. Has fire sprinklers, smoke detectors with CO sensors I believe.

Anything I do will also be to code, just don't want the headache later.

Looking at ductless now.

 

[NUTTSGT]

First of all get the garage and the overhead door (if it's not already) insulated. You will notice a huge difference with that alone.

If you have any windows, have you considered a simple window A/C unit ?

 

[GarageSpider]

Thanks, good advice, insulate first.

There are no windows in the garage.

 

[Shiftless]

Thanks, good advice, insulate first.

There are no windows in the garage.

Yes, insulate first. You get the most bang for your buck with insulation.

Have you considered that it might be easier to add a double hung window and then put in a window AC unit? Is that possible in your situation?

 

[LS6 Tommy]

The fire wall solution, if needed by code, is very simple- fire dampers. These go in- line with the duct work, and have a fusible link that when heated, release a spring loaded, fire- rated damper. This will block all air flow. these are code compliant when properly installed, and available thru your contractor or Grainger.

This is a good idea, just know it will sacrifice cooling in that Media room, and the "cool- down" period between switch over will take time. Sounds like an economical way to do it.

Zone dampers are pretty inexpensive, and you can just put them on a toggle, and have that toggle on a relay that when it is switched to "garage" will also switch the thermostat wiring to a stat in the garage, and vice-versa. Pretty smart, simple, and easy. You will run your equipment more, so you may have to update your maintenance schedule, and I would have a separate return int he garage utilizing a 4" thick filter or a carbon activated filter.

X2, but if you do the 4" filter. Keep an eye on the evaporator when you run cooling the first time. That thick filter may be restrictive enough to freeze up the coil.

Tommy

 

[Big Daddy Chop Shop]

X2, but if you do the 4" filter. Keep an eye on the evaporator when you run cooling the first time. That thick filter may be restrictive enough to freeze up the coil.

Tommy

A 4" filter is no more restrictive than a 2". The media is the same thickness, but with more surface area due to the deeper pleats. Unless, of course, you change the MERV rating. But a MERV 8 2' and a MERV 8 4" filter use the same media, just more surface area, and you will not need to change it as often due to this.

 

[GarageSpider]

Wife doesn't want to add a window to the garage.

I'll start with insulation.

Unfortunately, the walls are already drywalled. Does that mean ripping off the drywall and putting it back up or should I look at blowing insulation or foam into holes?

 

[James-W]

A lot of people do the blow in and it works quite well. On the other hand, drywall isn't all that expensive so if you put spray foam it will really seal up the building from air infiltration. You can put fiberglass insulation over the spray foam and have a really well insulated structure. If you can do the taping, mudding and finishing, then the cost to redo the drywall will be minimal.

As an added benefit of ripping down the old drywall and putting up new is that you can also rewire anything that you feel is needed. You may not need to rewire anything, but it does give you that option.