Pavel314 wrote:
Just to clarify the question, here's my original post to the home
improvement group:


We have a small greenhouse attached to the south side of our home.
It's 14' X 12' with a shed roof tapering from 10' on the house side
to
6'. Roughly 1,400 cubic feet. It's a 2x4 frame with double-walled
polycarbonate sheeting, 10mm for the roof and 6mm for the sides.

If you want to cut down on the heating bill you can add some insulation.
Home Despot has 1/2" polyiso (R3):

http://www.rmaxinc.com/

I use it in my solar stuff, works well outdoors and is non flamable and
relatively green.

You aren't getting much light from other than your south facing
vertical wall (with the sun so low), so you may wish to have a winter
cover for this. It would add R3 to your R2 walls and roof. Take it down
when you don't need it. Cut the bill in half or so...

Just an idea.

Jeff

We're
in Maryland, near Baltimore, so it rarely gets below the mid-teens in
the winter.

We heat it with a 220V electric heater, 5,600 watts and 19,110 BTUh
rating. This generally keeps it at the 50 degrees the plants require
but occasionally my wife puts on a 110V supplimental heater on cold
nights.

The power hasn't failed in the winter since we got the greenhouse but
it's probably only a matter of time. I was thinking of getting a
kerosene heater as back-up to the electrical heaters. Home Depot has
a
23,000 BTU heater for $129 which seems to fit our needs. Could I use
home heating oil for this or would it be better to stick with pure
kerosene?

I was wondering about a propane heater; would that be more efficient
than kerosene? We have a propane ball/tank for some other
applications
which aren't used in the winter.


Paul