other Conventional Heating/Air vs. Mini-Split for Garage and Work Shop

[02tom]

I'm trying to make a decision on my garage / work shop before it gets too hot to work out there again.  In the summer, it can be 100+ in my garage / work shop and it's not conducive to working on the '02s.    If money were not a huge consideration, would you go with a conventional heating and ac or are the mini-split heat pumps good enough?  I'm being told they are, but I'm concerned about the sun's radiant heat (with the garage doors on the west side) and air circulation issues for the  that I already have.  There's plumbing and a laundry room in the back of the garage that I'm also worried about in the winter.   I could add 6 - 9 inches of insulation in the attic too, but that's not as high of a priority as getting a system in before my work space becomes unusable again this year.  I have a couple of estimates already and the traditional system is about $2500 more and just seems like it would be a better long term solution.

[chadley]

I know you mentioned not insulating first, but you can't size your system properly if you modify your building after you put in your climate system.  The biggest waste is oversizing your a/c and ending up with a system that short cycles.

Having a well insulated and properly ventilated attic is crucial to the performance of your system (and will save a ton of money on cooling expenses if it's done properly), and designing your HVAC equipment carefully is money well spent.  I like mini-split systems, but I also like swamp coolers, so there's that...

[Simeon]

Swamp boxes are good for leaky spaces but be aware that they increase humidity significantly. If you are assembling freshly machined race engines or panel beating a media blasted bodyshell, they might not be for you.

[foreste2002]

I have a mini-split system in a 100 year old historic house where conventional ductwork was nearly impossible in an upstairs bedroom.  I really like it.  They have been used in Europe for a lon time and are very efficeint.  Your biggest bang for your buck is always insulation in the attic.  Radiant sun warming can be addressed by rigid foam with the foil reflective coating.

 

Good luck

 

Eric

[foreste2002]

Also....I went with a knock-off unit sold on EBAY....it has worked built well and the seller supplied me with the shop manual.  I think "sogoodtobuy" was the vendor

 

Eric

[02tom]

I'm not sure how much the insulation will play into what unit is chosen as the garage is already insulated.  It was just that one of the quotes I got mentioned additional attic insulation - and they could put it in for another $900 - but both estimates was for a specific unit regardless of what was done with additional insulation.  If it's not enough, I'm looking at adding the insulation next winter anyway, just to get things where I want them to be.  I've had to add insulation to the whole house so the 6" that I've put in was just a starting point.  I believe that the mini-split units are capable of drying the air from what I've read.  I guess that's something I need to find out from the estimators.

 

There's plenty of room for duct work in the attic, and I don't have much in the way of room for fans - let alone fans that will actually be able to get the air to circulate from the East wall where they've proposed installing the unit to the West wall where the garage doors are at along with the worst conditions for keeping things cool with the insulated garage doors vs. the sun's radiant heat.  I guess this is what concerns me the most, it that I won't be happy with the level of comfort in the front garage vs. the unit being in the back work shop/garage area. 

 

I did look at a swamp box at a local hardware store, and quickly realized that the increased humidity is something I don't want.  The humidity in the summer around here is enough to cause rust on vehicles especially if they aren't able to dry out.

[gfairchild]

I have a large window unit built into the back of my garage that keeps it nice and cool during the Houston summers.  The garage is insulated.

[Arizona02]

The website  Garagejournal.com has forum just for HVAC  and ways to insulate the garage door.

[Marsattacks]

We like our no name unit but installation can be tricksy and leak condensate everywhere. Not as big a deal in a garage of course. Good luck. Probably also louder than trad.

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[JackF]

I will never install another piece of ductwork in any uilding of mine. I have 3 Fujitsu ( whom I represented in the 6 New England States from '98-'11) systems in my home. I tore out the terrible ductwork in the house and took it to the dump, happily!

Mini-splits are great. High seer/hspf, zone control, quiet and pretty simple install, if you have the tools. i installed my first mini-split in '78. Having lived with them for many years now, I will say that IMHO, the Achilles heel of mshp's is cleaning the indoor evaporator. It shouldn't be much of a problem in a garage, but that depends upon your garage. That said, you would also have to clean the evaporator coil in the attic too.

My advise is tighten the envelope as you mention. Don't oversize it. How big is the space? Where are you? Minot or Miami? It matters.