Garage HVAC Questions

[rnavarro]

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?

 

[cda]

Welcome

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

Or just said comply with the code??

 

[mark handler]

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.

 

[rnavarro]

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?

2) I think I will need to include/submit the technical specification sheets for the unit in question? Along with a certificate of compliance? (I got form CF1R-ALT-04-E from the front desk)

3) In terms of plans for the actual AC, would that just be pictures of the home with line set routing and unit placement drawn on?

Any help, hints or clarifications you can provide for a homeowner to get the you best possible set of plans would be greatly appreciated!

P.S. Sorry for all the questions. I just want to make sure I'm doing this by the book so to speak.

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.

 

[rnavarro]

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

 

[steveray]

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

 

[mark handler]

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

 

[SCBO1]

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.

 

[rnavarro]

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?

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

That's correct

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

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.

 

[cda]

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?



That's correct



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



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.

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!!!

 

[rnavarro]

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!!!

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!

 

[Mr. Inspector]

Any insulation in the ceiling?

 

[rnavarro]

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

 

[steveray]

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....

 

[steveray]

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.

 

[rnavarro]

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!

 

[cda]

Install it

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

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

 

[rnavarro]

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.

 

[rnavarro]

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!)

 

[cda]

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!)

Well than

As long as you do not burn your house down?

 

[SCBO1]

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.

 

[rnavarro]

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.

 

[tmurray]

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.

 

[rnavarro]

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.