HVAC for the shop?

[Dan Barber]

Hi Folks,

We've apparently sold our home and are on the hunt for a new abode.

We've found one that seems to fulfill all the requirements. It's got 3 acres with a 4 car attached garage and a separate 30' x 40' shop building.

The shop building is insulated, but has no heating or cooling. I'm thinking that I need to put in AC because of the oppressive heat and humidity here in Middle TN. To my way of thinking, AC means a forced air system and that makes it logical to think about combining the heat and AC functions into a single unit.

My question is, do any of you have a combo unit like this in a shop and what is the functionality like? I expect to have to install a very good filtration system to prevent the dust from getting to the coils of such a unit. Are there any other issues you can think of that I should be considering?

I'm considering an electric heat pump unit totally external to the shop. That should mean the only thing that the unit is subject to is the air that flows through it.

I know about finishes and the like in the air, but I'm thinking of using a separate area already attached to the shop for that purpose.

Any input welcomed.

Dan

BTW, if we get this place it will be a perfect location for a SMC BBQ

[Philip Berman]

Hi Dan
I've been researching HVAC for my basement shop and have found a Mitsubishi ductless split system which does a/c and heat, both in heatpump designs as well as conventional electric heat. The compressor sits outside, the coil/air handler mounts on the wall or ceiling, and it's all connected with 2 small-diameter (3/8 & 1/2") copper pipes. They're a bit on the expensive side to purchase, but on the other hand, you don't need to deal with ducting. The units are available in cooling, cooling/heating, or cooling/heating heatpump in sizes from 12,000BTU up to 3 ton. They also have units that will handle two or more interior units(air handler/coil) with just one compressor outside, again all hooked together via copper pipe. Installation seems relatively simple. Do a google search on Mitsubishi air conditioning - you'll find it. There are other brands out there, too - Sanyo for one.
Good luck.

Phil

[Bob Reilly]

Hi Folks,

I'm considering an electric heat pump unit totally external to the shop. That should mean the only thing that the unit is subject to is the air that flows through it.

Dan, doesn't it get to cold where your located to be considering a heat pump?

[Lee Schierer]

Dan, Most geothermal heating systems deliver heat and A/C now and will operate much cheaper than conventional heat pumps. With 3 acres of land you should have room for the coils to be buried or wells to be drilled. It will be a bit more costly for the initial price than a straight heat pump, but will pay off big time. It will be costly to heat if the temperature routinely falls below freezing for periods of time as conventional heat pumps don't work efficiently once the temp reaches 40 degrees.

I've heated my house with geothermal for nearly 20 years.

[Dan Barber]

Phil,

You said:

Hi Dan
I've been researching HVAC for my basement shop and have found a Mitsubishi ductless split system which does a/c and heat, both in heat-pump designs as well as conventional electric heat. The compressor sits outside, the coil/air handler mounts on the wall or ceiling, and it's all connected with 2 small-diameter (3/8 & 1/2") copper pipes. Phil

Interesting you should mention that type of system, I installed the same thing in my bonus room (above the garage) in our current house. I got a 1 ton unit marketed by Goodman - made by Sayno. I paid about $800 for the whole unit and installed it my-self.

These "mini-split" units are great for areas with limited access to install conventional AC systems. I had forgotten that they made these in heat pump versions as well.

I'm leaning toward a conventional unit just for the fact that I wont have to fuss to much with anything other than a big hole in the side of the shop to mount it to. Plus the fact that I can likely buy a 2 ton unit for $400-500.

Thanks for the input - if you are considering a "mini-split" - I can highly recommend that approach.

Dan

[Dan Barber]

Dan, Most geothermal heating systems deliver heat and A/C now and will operate much cheaper than conventional heat pumps. With 3 acres of land you should have room for the coils to be buried or wells to be drilled. It will be a bit more costly for the initial price than a straight heat pump, but will pay off big time. It will be costly to heat if the temperature routinely falls below freezing for periods of time as conventional heat pumps don't work efficiently once the temp reaches 40 degrees.

I've heated my house with geothermal for nearly 20 years.

Lee, we have to get you to Middle TN for a visit. The envisioned three acres is up and down more than it is flat.

In this area the limestone bedrock is anywhere from 0" to 2 feet below the surface of your yard. Makes a geo unit a little bit on the expensive side. But on the other hand, I always did like to mess with dynamite

Wells are pretty expensive too. I guess I should have mentioned that I intend to supplement with a wood burning stove if the outside temps get much below 30 deg F. That only happens for about 4-6 weeks here in most heating seasons.

Dan

[G.C. Wagner]

Hi Dan,

I live in central Kentucky and have a 30 by 40 shop also. I just installed a 5 ton air conditioner last week and it's not too large when the heat has been in the high 80's. My walls are 10 feet with no ceiling so the peak of the roof is right at 15 feet inside. This makes for a lot of volume hence the large capacity of the unit. I placed the air handler just inside the wall from the compressor so there was just a short run of tubing. I also raised the air handler off the floor about 4 feet thinking that it may help keep from picking up so much dust. This unit is only about 2 by 2 by 5 so it doesn't take much space. I have steel trusses that support the building and the duct work is hung just below that. This unit has can accept heat also except that I had run hot water heat in the floor when the building was put up. If you have a ceiling in your shop, you can install these air handlers in a horizontal position above that. All in all, it cost me about $1700 to do this but I was using a 27,000 BTU window unit through the wall up until now. It had to run constantly to even start to keep things cool and the power bill was pretty bad.

Sorry to ramble on. Hope this is some help to you.

Gerry

[Ken Garlock]

Hi Dan. I agree with Gerry W. regarding the use of a standard HVAC system in a shop the size of your new one.
I only thing I would add is
1) insulate,
2) insulate,
3) insulate,
4) if you don't have a ceiling, put one in to reduce the volume of air you need to condition.
5) insulate the ceiling.
6) storm windows are a good idea also, they work both summer and winter.
7) weather-seal the doors.

In short, treat the shop building just like you would your home, energy wise.

Take some time now and a couple $$, it will pay you back every year henceforth.

BTW, did I mention insulation