Largest HVAC solution for DIY

[marrt]

I recently built a 1080 sq. ft. garage. It's well insulated but has a lot of windows (I like natural light). From my research, I need about 20K BTU's for cooling. I'm interested in an HVAC solution I can install myself (cooling and some heat) to save money. I could go with two portable units (e.g., Amcor) or 2 PTAC's. Could I install a mini-split myself or is a professional needed to charge the system? Any other ideas?

 

[timgr]

The cheapest would be a single AC window unit, and some kind of aux heat like electric baseboard or an electric space heater; Lowes had both 18K BTU and 25K BTU AC units on sale at the beginning of the season for under $400. They come with instructions and brackets for through-the-wall mounting. Not the quietest unit, but an 18K unit cools my little house just fine, and there are not a lot of cooling days in MA; $349 IIRC. The 18K needs a 10A 230V outlet, which I installed myself. The 115V units seem to be limited to about 12K BTU, but you can get a much larger unit if you install a 230V dedicated outlet.

 

[bgarrett]

I dont know what you call'em but my last two houses, I lay a concrete pad next to the house, then buy all-in-one-box heat and air.
they have big holes for supply and return air.
I run ducts under my houses but for a garage, just run duct thru the wall.
its easy to run electric and natural gas to 'em, no permits needed for anything mentioned here

 

[Vicegrip]

The work to install a mini split is not over the head of very handy homeowner if he can get a vacuum pump and gauge set or the help of a HVAC guy. Check that the gear is compatible with the charge used. (R22 and R410 are not compatible) You must vacuum the lines and more than a car AC. Leak test by letting the vacuum stand for a good long while and if good burp 50 to 100 PSI of charge into the lines and bubble test. Electrical skills for 120 V power, plumbing skills in setting up and installing the lines and condensate drain and good overall skill at reading the instructions and thinking.

 

[chad pickens]

I dont know what you call'em but my last two houses, I lay a concrete pad next to the house, then buy all-in-one-box heat and air.
they have big holes for supply and return air.
I run ducts under my houses but for a garage, just run duct thru the wall.
its easy to run electric and natural gas to 'em, no permits needed for anything mentioned here

This is exactly what I did.I bought a 4 ton heatpump for my 1800 sq ft shop. I was real worried about what it was going to cost to run it but I have been very happy.

 

[marrt]

I should clarify my question. I can do the installation. But I thought these units needed to be charged after the install. In other words, I would plumb the exterior unit to the interior unit. However, someone would then come out and add the R410 (although I assume there's some pre-charge from the factory). I'm concerned this last step will cost $500. In that case, I'd be better off, financially and perhaps performance-wise because of two zones, to go with two PTACs.

 

[chad pickens]

I should clarify my question. I can do the installation. But I thought these units needed to be charged after the install. In other words, I would plumb the exterior unit to the interior unit. However, someone would then come out and add the R410 (although I assume there's some pre-charge from the factory). I'm concerned this last step will cost $500. In that case, I'd be better off, financially and perhaps performance-wise because of two zones, to go with two PTACs.

MY unit was complete all you have to do is wire it .

 

[1320stang]

http://www.marvair.com/modpac1.html

 

[bigdav160]

(although I assume there's some pre-charge from the factory)

They are.

I've done four installs in the last two years.

It's not for the average home owner but no matter what a pro tells you, it's not rocket science.