Question on Heating shop with PTAC unit

[Matthew Curtis]

I live in central Ohio and was wondering if a PTAC unit would be an OK choice to maintain an adequate temperature in the shop through the winter months. That is to say can I set it low enough as when I am not working it will maintain a safe temp for all the glues and finish products that will be stored in the shop?

will not have a gas line to the shop and an external tank is not an option.

Thanks

[Jim Finn]

PTAC ? What is that?

[Ken Fitzgerald]

PTAC ? What is that?

I am glad someone finally asked!

[Ron Jones near Indy]

Some type of through the wall heating, A/C???

[E. Paul Wheeler]

A PTAC unit is a through wall HVAC unit like motels use. Similliar to a window unit but normally a little larger. Not sure how well it would work though.

[Thomas Bank]

Packaged Terminal Air Conditioner - as Ron and Paul say, a through the wall air conditioning unit.

Just for the heck of it, what Matthew really wants is a PTHP - Packaged Terminal Heat Pump - if he is talking about winter months.

Typically, you're talking somewhere in the range of 6000 to 18,000Btu out of one of these units. Without any idea of how large your shop is or how well it is insulated or sealed, it is impossible to say what size (or quantity) of unit you would need for your application.

[Don Bullock]

A few years ago one of the woodworking magazines did an article on a shop build. The shop was a little larger than a two car garage. The author used a PTAC unit and claimed it was the best choice for his shop. They seem to work well in motel rooms.

[Matt Meiser]

Assuming you are building a 2 car garage+ sized shop, 18K BTU seems really small for this part of the country.

[Eric McCune]

PTACs are a great choice for shops. The heat pump is a very efficient way to heat and cool a shop using a single device. Easy to install. Most heat pumps will heat efficiently down to an outside temp 25 degrees or so. After that, the back up heat strips kick in. Heat strips are straight electrical heat like a space heater.

If you are limited to electric heat, I believe this is the best choice for a single unit that both cools and heats.

Some units have an anti-freeze feature that automatically kicks on if the indoor temp drops below 40.

[Ben Franz]

I did exactly that in a 28 x 24 garage/shop a couple of years ago. IIRC the unit is 12K BTU PTHP (heat pump with electric heater assist). I insulated the walls and lid before sheetrock and the unit keeps it real toasty in winter. Our lows are typically +10 F so the heat load isn't as severe as your midwest climate. One thing to check - the thermostat on my PTHP in heat mode cannot be set lower than 62 so I don't leave it on when I'm not in the shop. The unheated shop does get below freezing on colder nights so I keep glues, etc. in a cabinet in the utility room. If I'd checked into the specs a little better I'd have selected a different model, maybe with the anti-freeze settting Eric mentioned.

[Jim Finn]

I am a former HVAC contractor in Wisconsin: Two things come to mind.
(1)Airborne sawdust clogs heating cooling coils no matter the filtering attempts ,so an easily accessable coil for cleaning is essential. (2) Heat pumps are slow to heat up an area unless allowed to run all the time, as in a home. Not a quick response machine like a qas or elect heater is. If you want to go to your shop, in the winter ,for just an hour or two, it may take that long to get the room warm if it was off all day.

[Matthew Curtis]

Thanks for the help guys. I am building an 18 x 20 x 10 garage. Going to insulate well. I think about 18,ooo BTU. Does this sound like the correct size unit? Does anyone have a recomendation on a unit? One that has an anti freezing function??

Thanks

[Greg Urwiller]

I just asked my local HVAC man about one this afternoon after work. My shop will be 24'x28'. A while back I was checking on a ceiling mount heater, and said I'd planned on a window air unit installed in the wall also. He suggested the PTAC instead. Not too much more money compared to the two individual units. But today when I priced it, he quoted $950, about $150 more than before when we were just throwing the idea around. This will require a 30A line (220) where the 2 units would probably each(?) take a 20A line. Of course since they won't both be running at the same time, you should be able to run just one line, right?? Obviously I don't know a lot about electricity! Unfortunately, $950 is really stretching the budget. By the way, this is an Amana unit. Greg

[Kirk Poore]

I have a PTHP in my shop (14K BTU, IIRC). It worked very well last winter, and the whole front of the unit comes off to allow you to clean the aux heating coil. I never got that "burning dust" smell from it. It will take my 576 sq ft, high ceiling shop from under 40 to mid 60's in maybe 45 minutes. I do run my ceiling fans to keep the hot air from pooling up high, though. It does have a minimum setting on the thermostat, like 48 degrees I think, so I usually just turn the unit off unless I'm planning on spending a lot of time over a weekend. I live near St Louis, so I'm in a warmer area than you, however. Cost was $1400, I think. I had the contrator leave a hole in the wall and install a dedicated 30 amp 240V line, and installation was a snap. The A/C works well, too.

Kirk

[Doug Carpenter]

I am considering the same option. I too would like to heat and cool the shop. I have gas lines, I assumed the heat would use gas and air would use electric. I wonder if that is possible. Or just not neccesary.