Guess no one wants to talk about heating when it's 95 out huh!

I need a few questions answered if you don't mind.
What are you planning on doing with your house this winter?
You stated "If the greenhouse freezes all my precious plants will be done for"
What type of pants will be in the house?
Yes you are correct the house will NOT hold any heat on it's own.
What's your projected heating budget?

There are many choices concerning heaters. I would stick with a Modine (or similar) forced air/forced exhaust propane or NG heater. As far as propane generally speaking the more you purchase the less expensive it is.

4 mil double poly is not very thick for your zone. Is there any way to return it and install 8 mil instead?

What does this mean "I might look into some sort of light-transparent covering as well."?

DgreenR, have you considered a solar pool cover. There is one called Magni-clear that doesn't block much light.
I used three of these on my greenhouse this past winter. I managed to keep my greenhouse between 45-47 using 3 space heaters at 1500 watts each. I also had 7 55 gal. barrels filled with water and the north wall lined in plastic on the inside. Once or twice my kerosene heater kicked in but I used less than 5 gals. of kerosene all winter.
I have a power vented Modine 200,000 BTU's but I spent more in propane in 6 weeks than I spent all winter in electricity. That was before I had the solar pool covers.

You might try doing a search in the gh forum. There are tons and tons and tons of replies to your question.

X

The onle way you are going to heat a Rion in your Zone is to bring it indoors.......It just ain't made for all year round gardening, and you should of figured that out before you bought it - either keep your plant load down to a level where you can bring them inside for the dec, jan, feb, march months or look for a better model greenhouse designed for what you wish to accomplish and sell the Rion to somebody who wants to extend their gardening season a couple of months on each end, which is what it is really designed for.

I agree with Cactusfreak about the clear solar pool cover. At her advice I bought one for my small 6 x 8 HF and it made all the difference in the world. I have an electric space heater and kept the temp at 55 degrees all winter for about $30 a month. I think with a clear solar pool cover and a reliable heat source you would be able to over winter your plants ok.

Don't give up on your dreams because of some naysayers.

Cindy

I decided to get a Magni-Clear cover for my HFGH based on cactusfreak's advice. I linked to a site that seems to have good prices.

I also insulated the north wall with styrofoam. I think it's a really good idea to do that and it doesn't cost much. I'm going to use rectangular storage containers to add 150+ gallons of water for thermal mass.

Stuart

Here is a link that might be useful: Solar Pool Covers

The only problem with the BestBuyPool supply link is that they all seem to be oval or round. That would make it ackward to work with because you would be missing the square ends. That's why they 'seem' cheaper. They are not full size. Also double check and make sure you get the Magni-clear and Not blue.

Thanks, cactusfreak. I'll make sure I get a rectangular one.

Hi All,

Thanks for your response. Cactusfreak - where did you purchase your pool cover? I have been planning on getting one of those eventually.

When I bought the greenhouse I thought it was much more insulated and a lot of people (including the distributor), told me it would be more than warm enough with two oil radiators. It sounded like I would need more heat than that, but I thought it would work out. I think what I will do for this winter is insulate the greenhouse like crazy, get a good heating system and hope for the best. I'll have to look up Pittsburgh's weather records as well for the winter. If it doesn't work I'll just use it as a cold frame.

I will be growing a bunch of orchids in the greenhouse and a handful of 'annuals' including Fushia, hibiscus, mandavilla and more. Some of the orchids are probably the most sensitive to the cold.

I bought the 2 20x40's at Amerimerc and the 16x32 at Americans Best Pool Supply. It seems like the prices went up a little. Of course it is summer and I bought mine in late autumn. They may be on sale later in the season.

Here is a link that might be useful: solar pool covers

I was just curious to follow up with you people about how it went last year with your heating bills.

I'm considering the little HFGH to over-winter my cattleya orchids which need daytime temps of 60-70 and nite time temps of 50-60 degrees.

Am I making a huge mistake and could someone give me a dollar figure on what their heating bill for the greenhouse was in say Jan or Feb, the two coldest months.

Thank you for your help.
Erica

Try SolarCovers.com.

I am guessing that their 16 X 24 at $89.99 (free shipping) would pretty well cover an 8 X 12 Rion. Keep in mind the need to have enough length to drape down to cover the front and back walls too.

You could also do some measuring and cutting and with really strong tape, create what would be in effect a fitted cover, like the old small appliance covers.

Insulate the north wall, and optionally the east and west, with everything that you've got -- preferably reflective insulation on the inside. You're not getting any sunlight from the north wall, and in the winter you get very little from the east and west walls. For everything else, add layers separated with an air gap (whether it's a solar pool cover, film held apart by a blower, film held apart by a spacer, or whatnot). 2-3 layers is optimal. 1 layer loses too much heat by conduction, and more than 3 loses too much light.