Cool!

Yeah, cool. But apparently it has everyone dumbfounded.

To answer your question, double pane windows, or double anything, reduces the heat loss by about 40%. If you have a choice, and care about the heat loss, go for the double.

The way you have described, it will not be able to function as a greenhouse for Z6., just a cold frame. Unless you put some effort in doing it properly.

It doesnt matter if it is warm in the daytime if the night freezes everything.

Very nice setup.

dcarch

As he said, a little "alternative heating", and if he adds a little thermal mass, bingo, he has a great way to extend the season in the fall and in the spring. Nice.
~tom

If that's a horse barn, add enough insulation on all but the dividing wall between the hay burning thermal mass producers and the GH, and while it won't be tropical by a long shot, it will still be warmer.

I agree about the windows. Single glass loses too much heat, but if thermopane's would be too pricey for you, what about double, or even triple wall polycarb?

You might want to think about making one or both of the end walls transparent as well for the added light.
Don't be upset about not getting answers right away :-). Remember it is spring and everyone has their minds on WHAT TO PLANT IN THEIR GH's

halfNosed Jack and the Dawg

Is that tree casting shadows all through your greenhouse going to completely shade it in spring and fall?

Tom

My greenhouse also has a solid north wall and only glazing on a small portion on either end. Situated the same direction as yours. Works great! I added two (that's what I had room for) cattle watering tanks (painted black) for thermal mass. Filled them with water and covered with black plastic to eliminate as much evaporation as possible. They heat up enough during the day to keep the night time temps warm enough so my plants don't freeze. Of course I only use my greenhouse to extend the spring and fall by about 1 month each.
I also wouldn't worry about the shade casting tree, by the time the temps are getting warmer that tree will leaf out and provide you with a natural shade that you will likely need (to prevent overheating).
When considering windows I would be sure to get some that you can open. Your greenhouse will need ventilation. My unheated greenhouse now will easily reach well over 100 degrees even when the outside temp is still below zero!

Looks like a great start to your setup.

ok, that looks great!! i read on guys post, he said if you don't isulate the ground, you have nothing, (something like that) and he dug or she, LOL 2 ft down, and they put rock, lime, rock and styofoam i think, and maybe rock, actually wasn't it you birdwidow?? ok found it,
For those who asked: The cheap heat in my GH started with ground insulation that covers the entire base under the floor, then runs 2 ft. down the outer edge of the foundation and 2 ft. out, all the way around it.

We started by digging out about 2 ft. below the level of the eventual floor and installed a floor drain that leads to a sump pit under the sink in the GH that in turn, connects out below frost line to a 100 ft. gray water drain.

We first laid in about 6" of med. sized river stone, to assure good drainage, then fine limestone siftings, screed and packed to a slight slope from the front and back walls, to a gutter drain in the center that spans the width of the floor.

Over that, we laid a moisture barrier: heavy, nylon reinforced plastic sheeting. Over that, 2-1/2" thick type 250 insulating foam.

Over that, 3/4" OSD and over that, 3/4" cement board, as a solid base for the glazed quarry tile floor that is as warm to bare feet in winter as the basement floor of the house.

On the outside of the foundation, we dug a deep narrow trench and lined it vertically with 2" type 150 foam, down 2 ft. then laid more, from the base out 2 ft., sloped a bit away from the the foundation. We lined the outer edge of that foam "flange" with garden timbers, then filled in the space between the timbers and the base with decorative stone. It hides the foam and the 1/2" mesh hardware cloth over it (critter proofing) and gives the foundation a nice, finished look.

The heater is a direct vent, dual combustion 45,000 btu Sterling, which is highly energy efficient and due to the dual combustion and direct venting, burns only fresh air, so it allowed me to seal the GH like a tomb.

Another great help is a pair of 52" ceiling fans that run continually in opposite directions, keeping the air continually circulating front to back, floor to ceiling.

The interior of the GH is lined entirely with heavy 1" bubble wrap and excepting only for the door, which is an insulated, standard storm door, is wrapped in a heavy solar blanket. It's called "Diamond Clear" and as much of a chore as it is to get it on, then off twice a year, it laughs at any wind that comes at us.

We calculated that between the insulation, vapor barrier, flooring materials and the upgrade on the heater, we spent about $600.00 more than if we had just set the GH on some timbers and poured in some gravel. But it's not that much when you think of how little it's costing to keep it warm this bitter winter, and the many more to come, that I hope to live to enjoy using it.

Sorry for the long post, but I couldn't describe it all in just a few sentences.
i had to copy it, it was way tooo cool not too and i thought in our place it would be great!! for the keeping the prices down!! LOL
hope this helps any.

medonto:

Thank you for the compliment, but I posted what you quoted as an explanation of how I got cheap heating. However, my elaborate system was intended for a year-round use GH that primarially houses valuable tropical fish, in an area that can experience zero temps for days on end.

What someone would need for only seasonal use is another matter altogether, but as another poster so wisely noted: Insulation doesn't cost- it pays, and I'd add- the cost of energy to heat or cool any structure, GH or otherwise is never going to get cheaper.

The more insulation, the faster it will pay back- every month the cost of energy to heat/cool rises.

Thanks for all the feedback. I've not had a chance to get back here for a couple of days. Here's a little more info.

Technically, I am now in zone 6b, maybe 7. But since we are out in the country, I am being conservative.

Not a horse barn. At least there are no horses.

The tree line is a concern, but I don't think it will be a huge issue for my purposes. And they will certainly help during the summer. Not that I'll be using it during the summer.

My desire is to be able to store semi-tropical plants over the winter, as well as a place to start seeds in the spring. Currently I keep the plants in my basement, which does get pretty chilly, but stays above about 45. So this may be a challenge.

My thoughts at this point are to find some double pane, triple track windows if possible and frame up the outside wall for those, keeping a 4" thick wall. In between the windows I want to frame up the dead air spaces with clear poly on the outside and black poly on the inside. Spring loaded flappers in the top and botom of these spaces would allow for natural convection heating during the day. (Cooler air enters at the bottom and hot air leaves at the top.) This would also keep the air stirred.

The back and side walls I will insulate with some type of insulating board, preferably with silver backing to reflect light back into the GH. My original plan was to use a thick layer of gravel on the floor and paint it black. Someone elesewhere suggested using paving stones instead. I may use both. I don't think heat losses through the floor will be a major issue either.

I also like the idea of putting black painted barrels of water inside to absorb heat during the day and radiate it back out at night. What else could be used for this sort of passive heating?

If worse come to worst, I can always fire up a kerosene heater for the extremely cold nights. Luckily, we haven't had many of those in the past few years.

No matter what, I probably won't keep too much out there this coming winter. Not until I have some idea of how this will all work out.

Keep the ideas coming!

Any other ideas?