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Garage HVAC Questions

Discussion in 'Residential Mechanical Codes' started by rnavarro, Aug 20, 2018.

  1. cda

    cda Sawhorse

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  2. rnavarro

    rnavarro Registered User

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

    Thanks for everyone's input/feedback on this!
     
  3. ADAguy

    ADAguy Sawhorse

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    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?
     
  4. rnavarro

    rnavarro Registered User

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    We already have solar.

    The cars already park in the driveway.

    No HOA on this property.
     
  5. ADAguy

    ADAguy Sawhorse

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

    HForester Member

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    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.
     
    JBI likes this.
  7. ADAguy

    ADAguy Sawhorse

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    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).
     
    JBI likes this.
  8. cda

    cda Sawhorse

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    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???
     
    JCraver likes this.
  9. rnavarro

    rnavarro Registered User

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    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.

    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!

    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.

    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.
     
    JBI and JCraver like this.
  10. cda

    cda Sawhorse

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    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.
     
    JBI likes this.

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