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If the weather cooperates this week, I hope we can break ground on an extended single car garage addition that will be my workshop. The room will be 10 X 30 with an insulated garage door and insulated walls. The recent thread on shop lighting will help me with that part of the shop, but I could use some help planning the heating and AC.

The current plan is to build an insulated room with no built in heating or duct work. Due to the location, patching in to my current duct work is not practical. The builder is recommending I use a portable heating and AC unit that could be purchased at HD or Lowes, but I wanted to see what other suggestions any of you might have. Window units are not an option, but a wall unit similar to what hotels use may be.

A bit more information, I live in North Carolina, So in the summer it can be very hot and humid. Inside, our AC usually is enough to keep the humidity in check, but I am thinking I may need a dehumidifier and in the winter will probably need a humidifier. Are there any good units out there that combine all these functions?

Any feedback is appreciated, Greg

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Greg Hatcher
North Carolina

I tried the portable route. Not a good idea. I finally ended up getting a "Mini-Split" AC system. It's great. I still have to dehumidify in the summer, as it does not take out all of the required moisture, My portable may have been under sized, but it hardly had a chance with the added heat from the dehumidifier. The Mini split will keep it where I want it even with the dehumidifier running full. My shop is almost 30 x 10 as well, and is insulated, but not sealed very well, however, I'm now able to control things both ways. The mini split I bought also has a heating capability, and, though limited, makes the temp all over the shop much more even than just using one of the radiator type heaters. Be prepared to spend a couple of bills, though, on the system.

The problem with portables is that they use inside air on the back side of the unit, and exhaust it from the shop through a big ol' 5" hose. That makes the shop, negative pressure, so it pulls in outside air(@90% RH) to replace it. The front side cools just fine, it just can't keep up.

By the way, if you want to try the portable, I know where you can get a 7000 BTU version at a steal. Only one summer of use.

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Waddy

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Congrats Greg on your new shop!!! 300 square feet is an excellent size and you should be able to be pretty comfortable in there.

I agree that the AC will not be capable of dehumidifying to the levels that we need for guitar building. A small dehumidifier will be important too. Dehumidifiers put out heat as they take water out of the air so the AC will have to work harder.

You might want to do some serious planning about your electrical since you will be running heating/cooling/humidifying/and dehumidifying devices as well as your power tools. Also a good quality hygrometer that can be calibrated and a sling psychrometer will be pretty useful too.

Good luck

I've never heard of anyone being happy with one of the portable units. My main shop is 12' X 20'. I've got a 12000 btu window unit with 11800 btu heat. I don't have a window, it's installed through the wall. If that won't work a mini split like Waddy has would probably be best. Check with you local HVAC contractors. For a shop full of power tools ect you want to size if bigger than most estimations say you need. Tell the contractor to size it like he would for a kitchen.

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I didn't mean to say it, but I meant what I said.
http://www.brackettinstruments.com/

As a matter of fact, my mini split is 12000 BTU, too. My wife wouldn't let me install a window unit. I could have saved $1500.

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Waddy

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Sound Clips of most of my guitars

All: Thanks for the replies.

Waddy: How difficult was it to add the Mini split to an existing structure? If you are happy with your system, can you tell me the model? How large is the outside portion? I am meeting with my contractor tomorrow. I will see what he knows about these. You say that you need to dehumidify - do you have much need for a humidifier?

Woody: Does your unit heat and cool?

Hesh: Thanks for the advice about planning the electrical. I need to work out the placement of the heating/AC and humidity control as well.

Greg

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Greg Hatcher
North Carolina

Greg, make sure you have your dehumidifier set up to drain directly to the outside. They fill up quick. If you get a portable one make sure it has provision for a hose connection to drain.

I've also got a through the wall unit for heating and cooling. It is big enough to do the job but if I ever replace it I'll get a split unit.

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Steve Smith
"Music is what feelings sound like"

Greg, the wall unit mounts at about 6.5 - 7' above the floor on the wall, and the freon lines, electrical, and drainage tube can punch through the wall to the outside and run down the outside wall to the compressor unit, it can be hidden in a downspout looking thingy, or it may be able to run between studs, and punch out at the bottom. Mine actually punches through an inside wall, runs down and punches through the outside wall. It's a shop, and I didn't care on the inside. It is designed to install in completed structure, though it can't hurt to plan for it. Here is a link to the pricing page for the one I got. They are all made in China, and mostly in a couple of plants with a bunch of different names. I didn't know this name, but he knew installers, and made me a turnkey deal that I couldn't turn down, compared to the HVAC Contractors I called. They were all in the $5000 range, which I didn't feel was a very good deal, considering you can buy the units all day, uninstalled, for anywhere from $900 to 2500, depending on brand and so forth. You might be able to install yourself, but you'd have to get a technician to charge it for you anyway. Personally I didn't want to install it myself. The guy who installed it will service it too, on mine, and I liked him, so it worked out for me. Tomorrow he is installing a new Furnace and AC in my house, because mine died yesterday morning. I hope I'm as happy with that! Not an expense I was ready for. The last one only lasted 13 years. It was a High Efficiency Carrier unit. I expected more. The first lasted 30 years.

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Waddy

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I've got a 12,000 BTU portable unit that I think is just fine for the garage.

I also take it tent camping with me in 100+ deg temp and that tent was in the 50's at night and very comfortable in the daytime while it was 100+ outside.

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Thanks,
Blain

http://www.ullrichguitar.com

"89.67% of all statistics are made up on the spot."

I went with the Soleus portable AC unit, biggest mistake I ever bought even though the website said it was big enough for a garage size workshop(14K BTU's) it couldn't even start to keep up in the summer. So, I had a mason knock a hole in my brick wall, I installed a window and a 25K window unit with electric heat strip to supplement my gas heater when needed. Does the job for me in the hot weather and winter but it doesn't get to cold here in the winter as other parts experience. I think portables are mostly suited for small bedrooms and such.

René

Let me add to my response.....

If you're wanting to get your garage chili cold, then a portable is not for you.

If you just want to get it bearable and comfortable. The portable that I have at least, doest just fine.

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Thanks,
Blain

http://www.ullrichguitar.com

"89.67% of all statistics are made up on the spot."

I believe a portable, the right size, and set up right can cool a shop just fine. Where I had the problem was that it drew in humidity, and the dehumidifier had to work twice as hard, producing twice as much heat. The problem is exhausting inside air which is then replaced with outside humid air through every crack and crevice in the structure. Impossible to keep the RH at 40 to 50% and cool too. Or, at least, I found it so.

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Waddy

Photobucket Build Album Library

Sound Clips of most of my guitars

When to post? When not to post?

I'll chime in on this one, newbie luthier, seasoned builder (www.philmorrisco.com). A mini ductless split system is what you want, when sized properly they can heat and cool like a conventional HVAC system. We don't have the humidity issues that you appear to have so I'd listen to the others regarding dehumidification. Unfortunately they're not cheap but when I have clients who request them in their garages at the 11th hour of construction, we use a ductless split system.

Sealing the concrete floor with an epoxy concrete paint will prevent moisture transfer through the slab which can help with excessive humidity levels.

Also, you might wait on getting a humidifier. You might not need one.

Thanks for all the responses.

Waddy: Did you consider an in wall unit rather than a window unit? The chart on your link has some and I found others online. Here are the specs for one I found:

12,000-BTU cooling power and 10,000-BTU heating power regulates the temperature in rooms up to 640 sq. ft.
Dehumidification function removes up to 3.5 pints of humidity per hour. Are the dehumidification numbers good or will I still probably need an additional unit.

Mark: Do you have any experience with these systems. As Waddy mentions I could save a significant amount, and with the need to purchase some tools as well, that would be nice.

Greg

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Greg Hatcher
North Carolina

My only experience is with the wall units as they seemed to be a more permanant solution. Toshiba has a very nice unit with a clean install. If you'd like I can make a call and get you more details, let me know.

Greg, I didn't try a wall unit. I don't have a place in my shop with any free space below bench level. I'm long and narrow. Only 9' wide x roughly 30' long. Benches on two sides + RA Saw, Floor drill press, Band saw, and sanders on a corner bench, door. That's about it.

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Waddy

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Sound Clips of most of my guitars