Original Greenhouse Heating Question

[Pavel314]

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. 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

[Rick]

We use a propane non-vented heater in a personnal greenhouse and it works well in conjuction with automatic roof vents and a circulation fan. I'm not sure you need as much heat as this unit puts out, but I assume they make many sizes. I suppose the CO2 put out may make a difference, but have not noticed it.

[jeff]

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

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

[Bill who putters]

Lots of stuff.

Bill

[gunner]

Here is a BTU and an Area calculator that may help, however it sounds like you have a good primary and a very good supplement/emergency system.

transparent bubble wrap insulation inside instead of insulation material and clear packing tape to secure it. Comes in 4 ft rolls but buy it from a place like here: and not the UPS or the FEDEX stores. Much cheaper and free shipping.