On Dec 18, 8:34 am, Sheldon wrote:
[snip] .... I've been contemplating a greenhouse of sorts
myself, but I'm thinking more along the lines of a smallish (12' X
12') four season shed-like structure attached to my house, I need
something substantial if it's to hold up to the winters here... [snip]
The rear of my house faces
dead south so it's in full sun all year, but even so I wonder what it
would cost to heat! hehe What a stupid question, anyone installing a
greenhouse realizes it must cost something for maintaining temperature
in cold climes...[snip]

And I'm not sure you need to think in terms of heating the whole shed/
room. A friend in Oregon has a stand-alone greenhouse about 8' x 12'
which he heats only a few days per the typical winter when they get a
hard freeze. The rest of the time he uses some kind of warming
devices that just keep seedbeds and pots/trays warm. Task lights on a
timer targeted for specific plants when he wants to jumpstart
something. This approach, he says, minimizes the electric bill. -
aem