# Garage HVAC Questions



## rnavarro (Aug 20, 2018)

Hello,

I wanted to see if I could get some help around codes for installing a ductless mini-split in my garage.

I'm located in Corona, CA and the plan check manager told me:



> We adopted all 2016 Codes.
> 
> California Plumbing, Mechanical, Electrical, Residential and Building Codes.



I understand that normal, ducted HVAC units can't draw/distribute air to the garage because of contaminates (which makes sense).

However, being that this is a ductless unit there is no "sharing" of air between the habitable space and the garage.

Is there anything that would prevent me from installing one of these units?


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## cda (Aug 20, 2018)

Welcome

So did he give a section saying you could not do it??

Or just said comply with the code??


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## mark handler (Aug 20, 2018)

Don't do it, the condenser will not work well. 
The units are designed to work outside. 
Not enough air changes in garage.
Talk with the manufacture.


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## rnavarro (Aug 20, 2018)

Hello,

Thanks for the reply! When I inquired via email:



> I am a homeowner and I wanted to get some more information about what plans would be required to install a ductless mini-split for a garage.
> 
> 1) I will have to add an electrical disconnect and run an additional circuit for the outdoor unit. So, I assume this means a single line drawing for the electrical?
> 
> ...



I got this response:



> HVAC systems are not permitted to be installed in unconditioned spaces. Unconditioned spaces are spaces like the garage or unoccupied attic spaces that are considered not habitable. Therefore, these type of spaces were not originally designed with the elements of a building envelope. (Insulation, fenestration, air leakage sealants, etc.)
> 
> Sorry that I’m not able to help you with your request.


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## rnavarro (Aug 20, 2018)

mark handler said:


> Don't do it, the condenser will not work well.
> The units are designed to work outside.
> Not enough air changes in garage.
> Talk with the manufacture.



I'm planning to install a _ductless_ mini-split.

The actual condenser will be outside.

The only thing inside would be the head unit.

https://www.highseer.com/ultra-high...ductless-mini-split-heat-pump-wys012am22.html


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## steveray (Aug 20, 2018)

When a space becomes "newly" conditioned"....You would have to meet today's energy code...Which would be very difficult in an existing garage


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## mark handler (Aug 20, 2018)

What is the "head unit" are you talking about the interior evaporative fan?


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## Pcinspector1 (Aug 20, 2018)

Is the garage attached or detached? 
Ceiling and walls Insulated or not insulated?

I would recommend a window AC unit, the price is more reasonable than a Mini-split and you can install without the need of an HVAC professional.


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## rnavarro (Aug 20, 2018)

steveray said:


> When a space becomes "newly" conditioned"....You would have to meet today's energy code...Which would be very difficult in an existing garage



Thanks for the reply, could you elaborate a bit more on this?

Are you meaning to say I have to insulate the garage and air seal or something different?



mark handler said:


> What is the "head unit" are you talking about the interior evaporative fan?



That's correct



Pcinspector1 said:


> Is the garage attached or detached?
> Ceiling and walls Insulated or not insulated?



The garage is attached. A bulk of the walls are insulated (all the walls that touch the living space).

The one exterior wall that isn't attached I've already insulated with mineral wool to help keep the heat down.

There is one section of the garage that isn't covered by living space and opens to the roof deck.

The actual garage doors have whatever the highest available factory insulation was at the time, I need to lookup what that was.

Here are some pictures to help the imagination:
https://drive.google.com/open?id=1_Vz0sx7C0bY_qgJV53OLB_X6dRxiTzoT
https://drive.google.com/open?id=17tGjAc9d_VFN3lBuVZuWG4P-5guHzRBU



Pcinspector1 said:


> I would recommend a window AC unit, the price is more reasonable than a Mini-split and you can install without the need of an HVAC professional.



There are no windows in the garage, I would have to cut a large hole in the wall to get a window unit in somewhere.

Additionally I think the mini-split would be more efficient in the long run.

I'm a pretty avid DIY-er so I feel comfortable installing a mini split.


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## cda (Aug 20, 2018)

rnavarro said:


> Thanks for the reply, could you elaborate a bit more on this?
> 
> Are you meaning to say I have to insulate the garage and air seal or something different?
> 
> ...





Ok a few things 

Why are you wanting to do it

Work on your cars, pool table, man cave??

Seems like have a company install it, it is not required and just extra.

To me no difference than installing a window unit in the garage window!!!


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## rnavarro (Aug 20, 2018)

cda said:


> Ok a few things
> 
> Why are you wanting to do it
> 
> ...



I want to do this for a few reasons:

1) I gets unbearably hot in the garage. In the evenings (after work, around 6pm+) the temperature is still very high outdoors and it wouldn't do much for cooling to open the garage doors.

Because of this I can't use the space for projects and to just work on things in the garage.

2) I am going to move some servers/computer equipment into the garage which would require cooling.

I had considered building out a small conditioned section in the garage just for the servers but then I wouldn't get any benefit for scenario #1

That's what drove the decision to just cool the whole garage.

Please take a look at the photos I linked above, there are no windows in the garage.

I would need to cut a whole in the exterior wall to add the unit. Additionally, the interior side of that wall has storage racks all along it so I'd have to figure out what to do about moving those.

Thanks for the reply!


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## Rick18071 (Aug 20, 2018)

Any insulation in the ceiling?


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## rnavarro (Aug 20, 2018)

Rick18071 said:


> Any insulation in the ceiling?



For the two car bay part of the garage that is covered by living space, yes it is insulated.

For the sake of clarity, the single car bay of the garage doesn't have a true "ceiling". It opens up all the way to the underside of the roof deck and rafters.

For the single car bay that isn't covered by living space, no, the "ceiling" is not insulated.

The only thing I've done to the "ceiling "on that side was to install a radiant barrier on the rafters to cut out some heat.

Picture to help the imagination:

https://drive.google.com/open?id=1QVz8THG79DqQJZKMdeo2K42F9JWuuQ43


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## steveray (Aug 20, 2018)

rnavarro said:


> Thanks for the reply, could you elaborate a bit more on this?
> 
> Are you meaning to say I have to insulate the garage and air seal or something different?



Yes....All of it....


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## steveray (Aug 20, 2018)

N1101.4 (R101.4.5) Change in space conditioning. Any
nonconditioned space that is altered to become conditioned
space shall be required to be brought into full compliance
with this chapter.


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## rnavarro (Aug 20, 2018)

steveray said:


> N1101.4 (R101.4.5) Change in space conditioning. Any
> nonconditioned space that is altered to become conditioned
> space shall be required to be brought into full compliance
> with this chapter.



Awesome!

OK thanks for that reference I'll read up on that some more!


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## cda (Aug 20, 2018)

Install it

Is the city saying you need a permit to do it???

They would not ask if you stuck a window unit in.


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## rnavarro (Aug 20, 2018)

steveray said:


> Yes....All of it....



Before I dive into the cited code sections the only real area of concern would be the actual garage doors.

How would those be brought into compliance? Would they have to be replaced with actual walls or something different?

A majority of the walls in the garage are already insulated and sealed since they are attached the the living space.


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## rnavarro (Aug 20, 2018)

cda said:


> Install it
> 
> Is the city saying you need a permit to do it???
> 
> They would not ask if you stuck a window unit in.



The city didn't ask for any permits, I asked (maybe that was my downfall?).

I was trying to play by the "rules" and get it properly permitted.

I am very capable of just running the electrical and installing the unit, that's the easy part for me 

I've just never really pulled any permits (this would be my second one, the first was a water heater swap out. Very easy!)


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## cda (Aug 20, 2018)

rnavarro said:


> The city didn't ask for any permits, I asked (maybe that was my downfall?).
> 
> I was trying to play by the "rules" and get it properly permitted.
> 
> ...




Well than 

As long as you do not burn your house down?


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## Pcinspector1 (Aug 20, 2018)

I see in one of the photos you have a gable vent but do not see any *roof vents* and you mentioned your single garage was open to the underside of the roof. Not familiar with CA housing construction but do you have *soffit vents*?

If you do not have roof vents or soffit vents, you could improve the ventilation by adding those and maybe find a electrical exhausts fan for the end wall gable vent opening that's controlled by a thermostat in the garage. 

Just wondering if these observations would help.


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## rnavarro (Aug 20, 2018)

cda said:


> Well than
> 
> As long as you do not burn your house down?



Sure, even if I don't get it permitted I'd rather do it reasonably "to code" to help prevent that situation.


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## tmurray (Aug 20, 2018)

Our code specifically exempts a garage serving a single family home in meeting our energy code. People can choose to heat and insulate to whatever standard they want. I'm wondering if the same applies here.

I would absolutely make sure to insulate the portion of the ceiling that isn't insulated. As other indicated, you will also want to air seal everything as well. Get a weatherstripping kit for the garage doors.


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## rnavarro (Aug 20, 2018)

Pcinspector1 said:


> I see in one of the photos you have a gable vent but do not see any *roof vents* and you mentioned your single garage was open to the underside of the roof. Not familiar with CA housing construction but do you have *soffit vents*?
> 
> If you do not have roof vents or soffit vents, you could improve the ventilation by adding those and maybe find a electrical exhausts fan for the end wall gable vent opening that's controlled by a thermostat in the garage.
> 
> Just wondering if these observations would help.



Good observation!

There are no roof vents in this construction: ridge vents, dormer vents, static vents, whirlybirds, none of those. Just gable venting. (That construction style is pretty typical in this neighborhood)

I went out and checked the garage, it doesn't have any soffits, instead it has vents near the ground.

If you look at this picture:
https://drive.google.com/open?id=17tGjAc9d_VFN3lBuVZuWG4P-5guHzRBU

The venting system for the garage consists of the 3 vents in the lower left (next to the blue filtration canister)

I believe that would be the intake for the garage venting system and the gable vent on the garage wall would be the exhaust.

As far as I can tell, those are the only intake areas for the garage space.


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## rnavarro (Aug 20, 2018)

tmurray said:


> Our code specifically exempts a garage serving a single family home in meeting our energy code. People can choose to heat and insulate to whatever standard they want. I'm wondering if the same applies here.
> 
> I would absolutely make sure to insulate the portion of the ceiling that isn't insulated. As other indicated, you will also want to air seal everything as well. Get a weatherstripping kit for the garage doors.



Good to know, I'll have to see if I can find a similar type of exemption in our codes.

I definitely want to take care to insulate anything I can, no sense in "wasting" even more electricity than I have to.

Due to the cost of spray foaming, I probably won't spray foam the roof deck of the single car bay.

Instead I will likely end up adding a ceiling to the single garage bay and using that as the air sealing "boundary", creating an attic section above.

This would make the construction more similar to the second story of the home and probably cheaper.


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## cda (Aug 20, 2018)

rnavarro said:


> Sure, even if I don't get it permitted I'd rather do it reasonably "to code" to help prevent that situation.




For the actual device

Just electricity correct??

It does sound like you do need to seal and insulate a little, to help the unit and the servers


You are inland some and miss the sea breezes


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## rnavarro (Aug 20, 2018)

cda said:


> For the actual device
> 
> Just electricity correct??
> 
> ...



You're correct, I suppose it would just be the electricity requirements that would be a problem. But I'm pretty familiar with those codes.

I checked the garage doors, and they already have weather stripping.

I think I'll take the group consensus and insulate a bit more and just go for it.


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## JCraver (Aug 20, 2018)

Don't just go for it, get a permit.  Getting caught without one, especially since you've already talked to them, will end up expensive - typically 2 times the normal permit fee, and they could make you rip everything out.  You don't want that.

Go here:  https://www.energycodes.gov/rescheck  input whatever code you're under and then play around with the numbers until you get something that passes.  Then hand that to your city with your permit application.


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## rnavarro (Aug 20, 2018)

JCraver said:


> Don't just go for it, get a permit.  Getting caught without one, especially since you've already talked to them, will end up expensive - typically 2 times the normal permit fee, and they could make you rip everything out.  You don't want that.
> 
> Go here:  https://www.energycodes.gov/rescheck  input whatever code you're under and then play around with the numbers until you get something that passes.  Then hand that to your city with your permit application.



Nice site!

I was looking at the certification list and didn't see mine, so I found this page:

https://www.energycodes.gov/adoption/states/california

Which links to approved software. I'm going to use one of those instead since CA has all of it's Title 24 requirements and such.


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## ICE (Aug 20, 2018)

Oscar is not going to issue a permit under any circumstances.


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## rnavarro (Aug 20, 2018)

ICE said:


> Oscar is not going to issue a permit under any circumstances.



You're correct in stating that the plan manager is Oscar (Not sure if you just looked it up or if you work for the city)

Is your statement meant to be a matter of fact or are there other ways I can go about this?


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## cda (Aug 20, 2018)

So if the garage had a window 

And he put a window a/c unit in it 

An plugged it into the wall outlet,,,


Would we be having this code conversation ??


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## rnavarro (Aug 20, 2018)

cda said:


> So if the garage had a window
> 
> And he put a window a/c unit in it
> 
> ...



It wasn't my ideal solution because it would be more work but man it sure seems like this is the right move to "get around" the planning department limitations.

I don't like portable units but even just getting an additional 240V outlet and plugging this thing in would solve this.

https://www.amazon.com/dp/B01AAAY9R4/ref=twister_B01BQ1UX1W?_encoding=UTF8&psc=1

It's just a shame because I want to install a high efficiency unit to lower running costs but the powers that be are against it.

Just seems so backwards.


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## ICE (Aug 20, 2018)

Ya no I don’t work for the city. 

I have seen many bootlegged mini-splits.  From an inspectors point of view they are small potatoes.  Unless the condenser is where it shouldn’t be or there’s some scary thing with the electrical I doubt inspectors will deem it worth the agravation.  For starters the inspector knows you can’t have it.  That inspector also lives and breathes the same hot air as you.....in his garage.  Without a complaint from someone else I doubt you will find an inspector that’s willing to raise a ruckus. 

If you ask Oscar if you can do it he will say, “We can’t issue a permit for that”.  Of course that didn’t asnswer the question of can you do it.  That’s up to you and Oscar doesn’t know if you can do it.....he does know that you will not get a permit.

You can get a permit to convert the single car space from a garage to habitable space and condition the space.


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## cda (Aug 20, 2018)

rnavarro said:


> It wasn't my ideal solution because it would be more work but man it sure seems like this is the right move to "get around" the planning department limitations.
> 
> I don't like portable units but even just getting an additional 240V outlet and plugging this thing in would solve this.
> 
> ...




Me I would install the ductless and call it good.

I am not into electrical, so I would hire an electrician.


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## cda (Aug 20, 2018)

I guess the same comments if a BAF ,, was installed in the garage??


https://www.haikuhome.com/outdoor-fans


You are not turning it into a bedroom to living room, more hobby area


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## cda (Aug 20, 2018)




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## JCraver (Aug 21, 2018)

rnavarro said:


> It wasn't my ideal solution because it would be more work but man it sure seems like this is the right move to "get around" the planning department limitations.
> 
> I don't like portable units but even just getting an additional 240V outlet and plugging this thing in would solve this.
> 
> ...




You'll still need a permit if you're cutting a hole in the wall to install the "window" AC unit - you're "altering" the wall, which triggers the permit requirement.

What I'd do, were I you, is get that permit.  On my application I'd say I was installing a window, and then I'd install a cheap window _just_ big enough to hold the AC unit.  Get window installed/inspected, watch the inspector drive away once I had my final inspection report in hand, then install the window AC unit and have a cool garage.  You'll have met the code, been completely legal, and accomplished your goal.  If your municipality is not going to issue a permit for the mini-split, then that's really your only option.

There are plenty of window AC units that are high efficiency - you just have to pay for them.  Enough dollar bills will buy you almost anything you want.


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## mark handler (Aug 21, 2018)

tmurray said:


> Our code specifically exempts a garage serving a single family home in meeting our energy code. People can choose to heat and insulate to whatever standard they want. I'm wondering if the same applies here.
> 
> I would absolutely make sure to insulate the portion of the ceiling that isn't insulated. As other indicated, you will also want to air seal everything as well. Get a weatherstripping kit for the garage doors.


If you condition the space, adding the mini-split, you need to comply with the energy code.


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## cda (Aug 21, 2018)

Man

There goes my man cave with pool table

Now I have to share the dog house, with the dog.


So I have to do the entire code to cool my garage a little::


https://i0.wp.com/www.dkbilliards.com/wp-content/uploads/2012/10/IMG_4760.jpg


Where is Conarb when you need him.


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## cda (Aug 21, 2018)

Truly inspector, it is a car   !!!!::

https://autowise.com/wp-content/uploads/2015/06/pooltable8image_2.jpg


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## rnavarro (Aug 21, 2018)

JCraver said:


> You'll still need a permit if you're cutting a hole in the wall to install the "window" AC unit - you're "altering" the wall, which triggers the permit requirement.
> 
> What I'd do, were I you, is get that permit.  On my application I'd say I was installing a window, and then I'd install a cheap window _just_ big enough to hold the AC unit.  Get window installed/inspected, watch the inspector drive away once I had my final inspection report in hand, then install the window AC unit and have a cool garage.  You'll have met the code, been completely legal, and accomplished your goal.  If your municipality is not going to issue a permit for the mini-split, then that's really your only option.
> 
> There are plenty of window AC units that are high efficiency - you just have to pay for them.  Enough dollar bills will buy you almost anything you want.



Yup, I think this is what I'm going to go with.

Thanks for everyone's input/feedback on this!


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## ADAguy (Sep 16, 2018)

All this talk and no mention of solar to lower your cost, also what of parking required for single family, going to use your driveway, no HOA limitations?


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## rnavarro (Sep 17, 2018)

ADAguy said:


> All this talk and no mention of solar to lower your cost, also what of parking required for single family, going to use your driveway, no HOA limitations?



We already have solar.

The cars already park in the driveway.

No HOA on this property.


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## ADAguy (Sep 17, 2018)

Conditioned space must comply with energy codes as noted by many already..


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## HForester (Sep 17, 2018)

Reading between the lines, I think that the mfr misunderstood what you were doing...I believe they think that you want to put the condenser in the garage (evaporator in the house or somewhere other than the garage). Ignoring the code (_for a just moment_), there is no technical reason why you can't cool this space with a mini-split. And certainly, such a unit will cool it more efficiently than a window (or through the wall) A/C unit. 

But as steveray said, you are wanting to turn an unconditioned space into a conditioned space. The codes are concerned with energy consumption of buildings and as such, require conditioned spaces to be built in a certain way to limit energy use. Insulating walls, ceiling and _floors_ is a big part however, limiting air infiltration/ex-filtration (leakage) is a also a large part. The key problem in meeting the energy code requirements will be the vehicle garage door as it doesn't have sufficient insulation and certainly, can't meet the leakage requirements. In other words, you won't begin the meet the code unless you remove the garage door and replace it with wall construction. Then, the insulation values in the wall and ceiling would need verified (remove all of the gypsum board on the walls for inspection and get into the attic to check depths of insulation. (In Corona, CA, below slab insulation is not required?) Install vapor barrier on walls and seal the heck out of everything. Have a blower door test run and check to make sure the leakage values are within spec. Intall new drywall and finish. Ta-Da! Conditioned space. NOW, have a mechanical contractor run cooling load analysis (and don't forget about telling him about the servers that are generating heat to the space.) ONLY THEN, can the proper size of HVAC system be chosen for that space. And you don't want to oversize a unit as short cycling is hard on the equipment and doesn't result in proper de-humidification of the air. Excess moisture within buildings can cause significant problems.  Of course, EVERYTHING I have talked about requires one or more permits, even if YOU, as the homeowner, is the one doing the work. As cda indicated, it is strongly advised that ant electrical work be performed by a qualified and licensed electrical (who has pulled there own permit for the work). There are so many nuances to electrical wiring installation that is is not worth taking a risk on this part of the work. Sizing conductors is only part of the challenge.

In conclusion, you come to this forum (of mainly code officials) asking for DIY advice. I am (we are) not going to be too helpful towards a DIYer who wants to do something like this on the QT. The building codes department only exists to protect the public (you _and the future owners of you home_) from improper, perhaps dangerous, construction. Your taxes mostly pay for this service (the permit fees are only a small slice of the costs.)  Let's put it another way: Suppose you purchased another house and someone (like yourself) did some work on the QT. The work was improper resulting in you having to spend money to make it correct. You wouldn't be too happy, right? Please don't try to circumvent the codes and enforcement that are put in place for good reason. The code officials on this forum have seen it all...done incorrectly.


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## ADAguy (Sep 17, 2018)

Good comments all, he will also have to disclose if this work was permitted at time of sale.
We do have some architects and engineers  on this forum too (smiling).


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## cda (Sep 17, 2018)

So if he already had a wimdow in the garage

And stuck a window a/c in it 

Would he be required to jump through the highest hoop still???


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## rnavarro (Sep 17, 2018)

Sorry to dig up the old thread, I just saw a post and wanted to answer open questions.

Didn't mean to solicit a bunch more feedback.



HForester said:


> But as steveray said, you are wanting to turn an unconditioned space into a conditioned space. The codes are concerned with energy consumption of buildings and as such, require conditioned spaces to be built in a certain way to limit energy use. Insulating walls, ceiling and _floors_ is a big part however, limiting air infiltration/ex-filtration (leakage) is a also a large part. The key problem in meeting the energy code requirements will be the vehicle garage door as it doesn't have sufficient insulation and certainly, can't meet the leakage requirements. In other words, you won't begin the meet the code unless you remove the garage door and replace it with wall construction. Then, the insulation values in the wall and ceiling would need verified (remove all of the gypsum board on the walls for inspection and get into the attic to check depths of insulation. (In Corona, CA, below slab insulation is not required?) Install vapor barrier on walls and seal the heck out of everything. Have a blower door test run and check to make sure the leakage values are within spec. Intall new drywall and finish. Ta-Da! Conditioned space. NOW, have a mechanical contractor run cooling load analysis (and don't forget about telling him about the servers that are generating heat to the space.) ONLY THEN, can the proper size of HVAC system be chosen for that space. And you don't want to oversize a unit as short cycling is hard on the equipment and doesn't result in proper de-humidification of the air. Excess moisture within buildings can cause significant problems.  Of course, EVERYTHING I have talked about requires one or more permits, even if YOU, as the homeowner, is the one doing the work. As cda indicated, it is strongly advised that ant electrical work be performed by a qualified and licensed electrical (who has pulled there own permit for the work). There are so many nuances to electrical wiring installation that is is not worth taking a risk on this part of the work. Sizing conductors is only part of the challenge.



This information is useful, and productive.

The garage doors that are installed are steel backed and have 2" of polystyrene insulation, the spec sheet has them at an R-10.

All of the other walls in the garage are already insulated, i would have to do some air sealing for the existing vents.

I appreciate the additional information!



HForester said:


> In conclusion, you come to this forum (of mainly code officials) asking for DIY advice. I am (we are) not going to be too helpful towards a DIYer who wants to do something like this on the QT.



I think the average DIY-er gives the few good ones a bad name. I came here in search of knowledge on how to do this _correctly_. I don't have a day to day working knowledge of all codes, which is why I sought assistance from a "forum of mainly code officials".

I could have easily just done this without asking anyone. However, I figured this place would be more about the pursuit of knowledge than a shaming.

Most places online seem that way, it's a shame really for the few of us that want to do things "by the book".

Everyone is so defensive and dismissive of the few of us that genuinely want to learn.



cda said:


> So if he already had a wimdow in the garage



This is the best option by far, and the one I will likely choose.

We can lock this thread, I've got the knowledge I need to move forward.


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## cda (Sep 17, 2018)

Another route to go

Not sure if was put out there

Is just set down with the Building Dept and say hay for my own comfort, while working in the garage, I want to install a mini unit over a window unit

If I do that will there be any other requirements

See what the answer is.


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