Opinions on this heater?

I was considering getting this heater/air conditioner from Charleys Greenhouse but it's pretty pricey so I was hoping to get some opinions on it first. I like that it can heat and cool because our winter nights are definitely cold enough that I need heat, but then on sunny days it can get pretty toasty in the GH too even with the door & vents open so I was hoping this might help out on that too. Plus it sounds like it's more energy efficient than the electric heater I've been using.
http://www.charleysgreenhouse.com/index.cfm?page=_productdetails&productid=6058&cid1=201&cid2=264&cid3=-99

Anyone have experience with this or with similar units? Thanks!

Also a stupid electrical question--it says it's 115V, I'm only familiar with outlets for 120 and 240, can you plug this into a regular 120V outlet or does it need something special?

Here it is a little cheaper.

http://www.amazon.com/Sunpentown-WA-1300H-Portable-Conditioner-Heater/dp/B001G86KDG/ref=sr_1_1?ie=UTF8&s=hi&qid=1223339780&sr=8-1

Yes, you can plug into standard US socket.

Thanks for the link and the electrical advice. I'm a dummy when it comes to electricity :-)

If you plan to use it for cooling it has drawbacks other than costing lots of moola to operate. It will remove moisture from the area as it act as an ac unit. The 450 square feet refer to a properly insulated home area protected from the sun's heat by opaque walls properly insulated.

Luckily I wasn't expecting it to cool anywhere near 450 square feet--my GH is only 45 square feet so I think that'll help make up for not being properly insulated, etc. I'm not sure I want it removing any more moisture though, our humidity is already very low on the days when I'd need cooling so that would not be a good thing unless I install a mist system too.

Unfortunately, adding a mist system will just add to the cooling load of the unit as part of it's byproduct is removing moisture content in the cooling process. A timed misting system along with a good airflow will cool as much as 10-15 degrees in low humidity conditions up to about 45-50 %. At this point the water evaporation slows considerably along with any cooling effect. Here in AZ I use an evaporative cooler to cool, a misting system to add humidity and a propane heater to heat my 10 by 12 greenhouse. Most of the time our dewpoint is very low so this works fine but during monsoon (rainy?) season and 110 temps it takes a lot of air movement to keep it around 90.
Hope this info helps

Thanks everyone for your comments--I'm starting to feel like given the price this might not really be the best thing. I only use the GH during the winter and I was just looking for a way to keep things a little cooler in there during sunny winter days, preferably something that works automatically so if I go out of town for a few days my plants won't fry.