Heat Pump / AC Question

[Tom Kelley]

This summer I would like to find a way to keep my 2 car garage/woodworking shop cool enough to be able to work comfortably. My garage is very well insulated in the walls, ceiling and door. My HVAC guy suggested a split heat pump/air conditioner system. Does anyone have anything like this in the garage? And if so does it work effectively for heat in the Winter and Air Conditioning in the summer?
Thanks,
Tom

[Howard Acheson]

Misubishi makes some good solutions.

http://www.mrslim.com/products/Category.asp?ProductCategoryID=24

[Marlin Williams]

How big is it and how low is the ceiling?

Do you have a window?

[Dwight Boesiger]

Tom

In 1999, I installed a Carrier AC/heat pump in my roughly 25' x 27' shop with 10 ft ceilings and many windows. It is fairly well insulated but the unit has just worked great for yo these past ten years. I can't find the paperwork or readily see the plate which would give you size and model but I'm sure your HVAC guy can spec size. I have been very pleased with this approach to comfort in my shop. It has always been able to keep up either in cold or hot , 100+F, weather.

Dwight Boesiger

[Paul Ryan]

Tom,

I have a heat pump that I heat and cool my house with. It works great. It cut my heating bills in half this winter. I don't know if you get the cold weather we do here. But a heat pump if sized correctly should make enough heat for you until the outside air temp gets to about 30 degrees. At that point it is going to stuggle by itself. In my house my heat pump runs by itself down to about 30, from 30 to 0 an electric plenuim heater helps the HP out. Below 0 I have to use stricly LP.

All an air heat pump is, is an air conditioner. In the summer the refrigerent is sent to the coil inside your house that works as and evaporator to produce cool air. The heat is then expended outside of your house. In the winter the refrigerent is pumped the oposite direction then the coil inside your house is used as the condensor and the heat is expelled inside your house.

My house is about 3600 sq feet so you should be able to find one to heat your shop too. Depending how warm you want your shop you maybe able to get enough heat out of the HP below 30, but you will have to check with your HVAC guy about that.

[Tom Kelley]

The garage is 25x30 with a 12 foot ceiling. I forgot to mention that I do have a ductless natural gas heater that provides plenty of heat. But I don't like the smell and I'm not too crazy about the open flame either. The heat pump/ac unit sounds like it would do a good job. Thanks for all the help!! Now all I need is some stimulus $.http://www.sawmillcreek.org/images/icons/icon12.gif

[keith ouellette]

I don't know how much humidity you have to deal with. I bring it up because here in Florida some people try to oversize their ac system and end up disappointed because it doesn't run long enough to remove the humidity from the air. 78 deg with high humidity isn't as comfortable as 80 deg with low humidity.

I just thought I would bring that up.

There are large window units (or you can just put a hole in the wall like I did) that will handle that kind of space. It would be cheaper than a conventional ac and blower and take up less space.

The draw back to that option is the filter. The air filter on a blower could be very useful in a wood shop. When the ac is on it will also act as a 3micron air filter (if you use the good filters)

[Joe Jensen]

I installed a 2 ton Sanyo 17 SEER mini spilt heat pump in my 3 car garage last summer. Here are some links.
http://www.sawmillcreek.org/showthread.php?t=84191&highlight=mini+split

http://www.sawmillcreek.org/showthread.php?t=89136&highlight=mini+split

I am fairly happy, but apparently the mini split units go into a lower output mode when the temp exceeds a high limit. Most are spec'd for 110F or so. the Sanyo was rated for 115F. I live in AZ and it is regularly 110 or more in the summer. If I start the unit in the morning it will quickly cool to 78 and I can hold it there with 48 forty watt florescent bulbs, the dust collector, and power tools running. It won't go any cooler when it's over 110F outside. If I start the AC in the heat of the day, it will struggle to get below 90F in the shop, (start temp might only be 95F in the shop). I may build a sun shade for the ourdoor unit as it gets direct sun in the heat of the day (not sure this will matter). In hind sight, I may have gone to a 3 ton unit so it could cool better even when crazy hot outside.

[Jim O'Dell]

When I was roughing in the porch to be the finishing room on my shop, I made space for a PTAC A/C-Heat unit. These are the units that motel rooms use. Most of the unit can be outside. If you know of a motel that is remodeling, you might be able to get some of their old ones. My BIL did that, got 3 for 100.00 each. I couldn't get him to sell me one though. Some of these units that you can buy are heat pumps as well. You do need to size the room for what you need to heat in your area. I think the PTACs max out at about 15,000 btu. The run about 900.00 or so new with the sleeve to mount them, and the outside louvers. Jim.