Anyone insulate and HVAC their attached garage?

[newbirdhunter]

Folks,

Want to know if insulating and extending duct work to my garage workshop is a good idea.

Background: Setting up a home workshop (hobby, not business) in my two car attached garage. The garage has to be able to store the cars at night so all my tools are on casters and fit along one wall. Obviously, the cars will be pulled out onto the driveway while I work in the shop. TBH, the shop will not be used every day nor every weekend but, uninsulated, the North Texas heat turns my garage into a sauna most of the year. We would like to move to another home (with land for a stand-alone workshop) within the next 5 years but that is not a certainty.

Plan: I would tear down the sheetrock and add the insulation. Hire an HVAC guy to extend the duct work to the garage. Hire a sheetrock guy to put up the new sheetrock for me. (HVAC and Sheetrock are not my thing  [unsure]) I'd paint afterwards.

So, my questions are: 1. think it's worth it? 2. do people do this? 3. any benefit as far as house re-sale value?

Thanks for reading,

Frank

 

[erock]

Frank,

I've never done what you plan on doing.  But I think that the HVAC system for your house is rated for the CFM for the living areas. 

I could be wrong, but if you tap into a duct line, it could reduce the air flow for the room that duct was ran for.
The garage is a big room to cool.  The system you have now may not be big enough to cool the house and the garage.
Plus, you would want to install new weather stripping around the garage door for a better seal.  That is going to be your biggest problem.  Instillation will help.  I only insulated my attic pace in my garage.  And I heat the 2 car garage with a 60 pound propane heater and it gets 70 degrees fast.  My wall are not insulated, yet.  I'm not a real estate agent, but I don't think it would increase the resale value of the house to run AC to it.
Check out Mitsubishi wall hung AC units. 

Eric

 

[stvrowe]

You should check the building codes for your area.  Most building codes do not allow ductwork from the house to have any opening in the garage for reasons that should be obvious.  I doubt that a legitimate HVAC professional would install such a feature if prohibited by your local codes.

 

[farms100]

Fire code....

I'm not an HVAC person.

You're likely better off putting a seperate heat/cooling system in the garage.

 

[rrmccabe]

I think a well insulated garage is not bad to heat/cooll so consider an aux unit.

That said, around here you don't want return air getting back to your house. Wood shop aside think about the carbon monoxide from the cars. etc. 

You would have to check with local code of course but I think I would skip the hassle and look at one of those package heat pump deals.

I dont have AC but I do have heated floor which is nice. Don't have to worry about the flame of a furnace, etc.

 

[deepcreek]

I air conditioned my two-car attached garage in Houston about ten years ago and it's been well worth it.

I ripped all the old drywall off the walls, put in a sub panel, installed plenty of new outlets, insulated with fiberglass batts, installed new drywall, taped & floated, primed and painted.

Then I added an attic access with folding stairs, installed lots of florescent light fixtures, and fiberglass batts from the attic side of the ceiling.

I also replaced the old garage doors with 2" insulated models.

For the AC, I used a through-wall window unit with a digital thermostat and an energy saver feature that turns off the fan with the compressor.  If I had it to do over, I would install an Amana PTAC unit because they are a standard size when it comes time for replacement and window AC's are not.

 

[JayStPeter]

My last shop was in my old attached garage.  I insulated in the attic and added styrofoam to the doors, but didn't rip down drywall.  It had a small window, so I installed a window unit for the summer.  Only turned it on when I was planning on using the shop.  Also had a portable heater.  Started with a big kerosene one in the morning to cut the cold and then moved to a smaller electric once it got reasonable.  Had to use the Kerosene one all day prior to the ceiling/door insulation.  Could leave the electric one on all night when I was letting finish or glueups dry.

 

[Paul G]

Gets hot here also, definitely insulate. Check with an HVAC co about codes for ductwork, you'd need a return vent also. Around here it would not fly with the codes so I did the insulation and am sorting out details to install a mini split AC.

 

[dltflt]

My garage had a separate AC unit when I purchased the house but I never used it.  My electric bills are already too high just to cool the house.  I've thought about it a couple of times but that is as far as I got.

 

[newbirdhunter]

Thanks everyone for the speedy replies.  Obviously I didn't even think about meeting code, much less about the rating/capacity of the A/C unit: really appreciate the comments about that!  The FOG community is such a great place to learn from.  [big grin]

@erock & @Don T: Thanks. Sounds like as far as resale benefit goes, it's a nice to have but not something anyone would pay for.

@Deepcreek: I can't install a window unit because I don't have a window in my garage but more importantly the HOA doesn't allow window units. I do like that you did (most of) what I was asking about. Good tip about a sub panel, right now the new outlets I added all go to a new 20A circuit I added to an existing sub-panel.

Based on everyone's comments, it sounds like the way to go would be to insulate the garage and attic portion then install a separate A/C unit. Will need to look into those.

Thanks guys!

Frank

 

[rrmccabe]

Frank,  Google "small heat pump for garage".

That will give you some ideas. They have really cool units where you mount the heat pump outside and run the lines through the wall to your heat/AC unit.

 

[tjbnwi]

The UMC (which is what the IRC is based on) does not allow you to run the living space ductwork into the garage. It would also be a violation of NFPA 1.

Look into a mini split system. Solves the heat and cooling problem in one system.

Tom

 

[peter halle]

Maybe Paul Marcel will chime in.  He installed a split system in his garage this past year I believe.

Peter

 

[newbirdhunter]

Thanks fellas. Appreciate the additional information. Will go and Google "small heat pump for garage" and "mini split system" then see what I come up with.  [big grin]

 

[PaulMarcel]

Maybe Paul Marcel will chime in.  He installed a split system in his garage this past year I believe.

Peter

Yes, I did, and I love it.  It's a 30,000 btu mini-split A/C unit (no heating; jezuz we have enough of that!).  Well worth it.  I actually have not noticed it on my electric bills.  I'm sure it is there, but enough to raise my attention.

I have a second floor above the garage so that insulates the ceiling.  The walls are finished so there's a bit of insulating going on, but not much.  The garage door is steel. I tucked insulation rigid foam into each segment.  I had done that many years before the A/C and it was a noticeable difference.

The mini-split runs continuously, but with it's variable-speed compressor and fan, it works minimally after initially getting to the target temperature.  In this minimal mode, it is very quiet.  Even when running, it makes minimal noise.  The oscillating fan/air-mixes keeps the temperature pretty even (no hot spots or cold spots).

What's nice is that when I move, they can easily uninstall it and move it.

Some people install it themselves.  I had my A/C guy doit all and it took two of them a long time to get it installed between the pipe runs, covers, and just plain install.  I don't think you'd save anything doing it yourself unless you had HVAC experience.

In my area, we have time-of-use electrical plans (on-peak/off-peak stuff).  I usually go in the shop after 8 anyway so I'll start it up at 8 and by 8:30 it's nice in there.  It makes a big difference immediately because of the air mixer but after 30 minutes, you don't notice any hot spots.

Well worth it...  my recommendation, though, is when you get the estimate, go sit in the hot shop then open and read the estimate.  When you get the bill, go sit in your cool shop  then open and read the bill.  Takes the edge off.

 

[deepcreek]

You might also want to look into an Amana PTAC unit.  It's a package unit like they use in motel rooms versus a mini-split system where half the unit is on the wall and half is outside.  They make a heat pump version as well as conventional cooling with or without a heat strip.  I paid less than a grand for the one in my 24x24 storage building including the through-wall sleeve and external decorative grill.  Another nice thing is I was able to buy it without a HVAC license (H.D. Supply) and install it myself.  Also, unless something has changed in the past couple of years the Amana PTAC's are made in USA.

 

[HowardH]

We are moving into another house in 3 weeks and it has a 3 car garage which is 600 sq ft.  I originally thought about putting in a split system but two different HVAC companies have told me it would better to install a 3.5 ton conventional A/C system.  It would put out a lot more air and be more efficient.  I will be insulating the main doors and the attic space.  Two of the three walls are shared with the house so I should be good there and I believe the outside wall also has insulation.  I'm not doing a furnace, just the air handler.  We are close enough to Fall to wait until Spring to do it.  No sense spending the money to have it sit for 6 months.  Are the just trying to sell me a more expensive system or will the split system not be robust enough to handle the Texas heat and cool a 600 sq ft. space?

 

[Offshoreman69]

Hi Frank,

It just so happens there is an article in a recent Fine Homebuilding that deals specifically with air conditioning a garage, how to do it the right way and that is basically what Eric suggested; a ductless minisplit.

Here's a link to give you an idea from a fellow Texan about the way he does it

Good luck too, we lived in Houston for 2 years and there are only about 2 months of weather that are proper for humans to be outside or in an garage without A/C

http://www.finehomebuilding.com/item/31322/garage-ac-wrong-way-right-way

Glen

 

[tjbnwi]

The biggest concern with any of these systems is the filters. With what we do, keep the filters clean. Dust is a bigger enemy to an A coil or straight line evaporator coil than just about anything else.

A 1.5 ton conventional with an air handler is probably easier for your AC contractor to get.

Tom

 

[Slappy]

  Are the just trying to sell me a more expensive system or will the split system not be robust enough to handle the Texas heat and cool a 600 sq ft. space?

call about that  mini-split A/C unit directly at the MFGer's customer service , not saying the local guy are up selling Ya but really do your research , you'll sleep better the more informed you are once what ever way you decide to go is installed .