Whats the most frugal path to a/c in my workshop in Mississippi?

[Gary Fowler]

With all those uninsulated garage doors it would take a minimum of two 24,000 BTU window units to do a fair job in 100 degree heat in Mississippi. A lot also depends on how the sun hits it and if it is in any shade.

Sorry, I can't help you with geothermal.

Agree on the uninsulated garage doors, they are a major heat sink. Do yourself a favor and go buy some 1.5 or 2" thick Styrofoam sheets and glue them to the garage door panels. If you can find them with a plastic facing on the sides, so much the better. That is all the insulated doors have on them and they work very well. I have the insulated ones in my house and shop and they do keep the temps very cool with minimal heat or AC. Insulating those big doors will cut your heating and cooling bill in half AND allow for much smaller units to be used.

 

[Pilot]

Check out a ductless heat pump. I don't know how big they get, but we put one in our church to heat a small area, 24 X 30 or so and it only cost a couple thousand $ & it works great. As with any heat pump, it both heats & cools. Probably works a lot like a window unit, but it's cooler & more efficient.

 

[BitChin1]

I agree with several posts about the mini-split units - I have both GSHP and 3 mini-split in my house/garage zone 4 - as for cooling (and heating for that matter) the mini-splits seem to work as well if not better than the GSHP and at a far lower install cost. You could also install several around the shop for distribution

 

[LAFarm]

Well thanks for all the replies about window units, but I don't have any windows.

LAFarm - could I get more details about your system?
Reads like a match.

Unfortunately, the unit is about 20 years old and will probably only last a few more years. Uses r22 refrigerant and gshp specific parts no longer available. Will have to update when it 'dies'.

What is the length? Pipe size and type? I was concerned about getting it deeper.

Have 2 'loops'. Each one is about 550' long and buried 3' to 4' deep. 1" poly loop pipe. Deeper would be better, ditch witch bar was only 42".

That's one of my goals

Great idea!

What do you figure is the tradeoff for an extra 8" of insulation? Seems a little like overkill.

Not sure about calculating benefit, doing in stages as have time and funds. Reason for 8" is wall girts are 8" on 4' centers. Plywood is screwed directly to girts. Attempting to cool or heat 1800 sq ft with 12' wall height is pretty tall order for a 24000 btu unit. Every little bit helps!

Again reads like my situation.

Sounds great.

Initial installation can be much more expensive than conventional heating systems. My situation is unique in that I had an older unit available to experiment with and about 20 years occupational experience installing and maintaining earth coupled heat pump systems.

 

[GPintheMitten]

I cut and glued 1 1/2" pink Styrofoam in my overhead door in my shop. I built in a window AC unit in an opening I made.

I would cost out the start up costs and operational costs of split system and geo. I installed a split system in my son's house in his third floor bedroom and he likes it... much quieter than window units and very efficient for both heat and cooling.

The reason I put the window unit in was it was left over from my old house which didn't have central air.

As I get older i am more interested in how I use my time so I would lean more to split system than to geo because of the difference in my time to install and the cost to install.

 

[George2615]

Well thanks for all the replies about window units, but I don't have any windows.

I don't have windows either. I measured the window A/C's and cut out the opening I needed in the garage walls. Then made boxed frames out of 6x6 for the A/C to set on. Slid them in the openings, screwed them in place and caulked around the cases. All I can say is 2 units work for me and I thought that was the most frugal way for me to get garage cooling in summer time. I do have insulated doors which someone else mentioned you might want to change yours.

 

[GPintheMitten]

I don't have windows either. I measured the window A/C's and cut out the opening I needed in the garage walls. Then made boxed frames out of 6x6 for the A/C to set on. Slid them in the openings, screwed them in place and caulked around the cases. All I can say is 2 units work for me and I thought that was the most frugal way for me to get garage cooling in summer time. I do have insulated doors which someone else mentioned you might want to change yours.

That's pretty much what I did but am trying one AC unit first to see if it does the job. I didnt' use the shop much last summer but expect to this summer.

I'ld have to say that I agree the most frugal is probably the window AC unit(s), but it may depend on how much time you spend in the shop and maybe how long you are going to be there. Window units are probably the noisiest option but a shop is usually a noise generator anyway.