Rainsing my greenhouse

[Shiva]

This is my greenhouse in back of the house as it is still looking a few years after construction. It's built on cinder blocks raised three feet high. It's 16 feet or so in lenght and width. Double polycarbonate glazing.

My problem is despite everything I've done to save energy, it stills cost a fortune to heat. Since the price of heating keeps going up, every improvement I make is consumed by the higher prices.
My idea is to raise the g/h four more feet with cinder blocks. That would allow me to install two sliding windows on each sides for ventilation in summer. I could also replace the flimsy aluminium door with a stronger double glass door, which I have already. Raising the g/h would also allow me to get sunlight inside everyday of the year. Right now, the g/h doesn't get any sun for part of the day for about eight weeks in winter. Finally, raising it another four feet would allow me to install a thermal barrier over my head that would keep most of the heat where I grow my plants. In summer, the thermal barrier could be removed creating a chimney effect for the heat that would then be dispersed outside by a fan (I have) a couple of feet over the door.

I would first detach the g/h from it's sill and raise it alternatively in the back and in the front in small increments then fill the void by cinder blocks and the new windows until I get it up to four feet high. I could also rent a small crane to raise it completely and lay it on the ground while the work is done.

I'd like to know what you think of this project? And if you have any suggestions to help in its completion. And also, what would you recommend for a thermal barrier. Of course it would have to let the light through.

 

[etex]

So this is where you grow your beautiful plants and blooms. Very nice greenhouse. I've wondered how folks in the north handle the heating costs with all the snow and cold weather you get.

 

[Bob in Albany N.Y.]

I hate to admit this but the way I handle the cost of the heat in the greenhouse is to just take it. It costs as much to heat my greenhouse as it does to heat my home. I look at it this way. Everyone has so much spendable income. Some people like to gamble, others like women and I just stay at home and play with my plants. Donna, agrees, that this is the way to go.

 

[NYEric]

Do you add bubble insulation sheets inside during the winter? The added R value should help.

 

[Shiva]

Do you add bubble insulation sheets inside during the winter? The added R value should help.

I tried it all but the problem remains the same with the ever rising cost of energy. Putting bubble sheets is difficult with all the structural parts in the way and the top of the roof is already 11 feet high. To make a reasonnable job, I'd have to take all the plants out and dismantle all the benches to allow for stepladders movement. That's a lot of hassle and I'm not getting any younger. Raising the whole g/h four feet would simplify everything. I could put a thermal barrier on top of my head at about eight feet level, which would make a significant air space between the roof and the thermal barrier. Four sliding windows would cost me about $800 including taxes. The rest would be cinder blocks, mortar and manpower. My brother has already offered to put the blocks if I mix the mortar. One more thing, with good crossed ventilation and the thermal barrier removed in late spring plus a lot of paint shading outside, I may keep most of the plants inside instead of moving them out for the summer.
The cost of heating that greenhouse this last winter is well over $3000.

 

[NYEric]

The cost of heating that greenhouse this last winter is well over $3000.

In Florida they only have to heat for one month! oke:
BTW, don't you live in Southern Canada!?

 

[Erythrone]

Wonderful greenhouse...

I would be concern too about energy saving!! That is why we don't have one yet...

We were looking for a solar passive gh many years ago.

 

[Shiva]

In Florida they only have to heat for one month! oke:
BTW, don't you live in Southern Canada!?

Southern Canada is in Ontario, around Niagara Falls or Hamilton, where JohnM lives. It doesn't look like it, but the more you go south, the more sun you have in winter and that makes a lot of difference. JohnM is in Zone 6-7 while I'm in Zone 4-5, if I remember my zones well.

 

[Shiva]

Wonderful greenhouse...

I would be concern too about energy saving!! That is why we don't have one yet...

We were looking for a solar passive gh many years ago.

If I were to start over, I would build a ''greenhouse'' with a solid, well insulated roof and large double glass insulated windows exposed to the sun South and East. The North and West walls would be fully insulated with vapour barriers. I'd also have HID lamps on the ceiling to help light the plants in winter. The sun being low in winter, you'd have good light inside and when the sun is high and spends a lot of time in the South and West, in summer, the roof would help prevent overheating. My conclusion about greenhouses like the one I have is that they're not made for my climate. I've even thought of removing the greenhouse and selling it and use what money I get to build the kind of structure I mentioned above. I just don't think I would get enough money to pay for the new structure. :wink:

 

[ohio-guy]

wouldn't rising the green house just give you more interior space in need of holding heat? The heat would rise to the top and you would be stuck with a cool underneath area. And if you raise the walls 4 feet, will you need to raise the plants too? if so, all your work space will be over head.
Finally I am not sure it would look aestetically pleasing to my eye.
I am not sue what the solution is. Is your idea a common configuration for green houses in your area?

 

[tim]

a double-poly, winter-only hoop house costs less than your window idea and is much less work than raising the entire thing...put it up over your existing gh...

 

[Marc]

If and when I build a greenhouse I'm going to make the floor below ground level. But seeing that your house is allready standing I don't think it's an option to lower it.

 

[Shiva]

wouldn't rising the green house just give you more interior space in need of holding heat? The heat would rise to the top and you would be stuck with a cool underneath area. And if you rais the walls 4 feet, will you need to raise the plants too? if so, all your work space will be over head.
Finally I am not sure it would look aestetically pleasing to my eye.
I am not sue what the solution is. Is your idea a common configuration for green houses in your area?

Yes, but the upper part of the greenhouse would be separated in the winter from the lower level by a thick sheet of transparent plastic. The plants would stay where they are since a lot of light would still ge coming from the clear roof and sides. The large volume of air between the roof and the plastic shield would tend to remain at the same temperature, which should help the lower portion to stay warm. The principle is the same as a double pane insulated window but with a lot more air in between. In summer, removing the plastic sheet would allow hot air to rise to the top, making the lower part cooler.

As for the idea, it's totally original as far as I know. I live in a farming area and the neighbours have lots of other things to do then build greenhouses for orchids.

Thanks for your comments Ohio-Guy. I don't want to make mistakes this time and that's why the contributions of ST members are helpful. If my reasonning is wrong or if someone has a better idea, now is the time to talk. I might even scrap this project and modify the structure for something on the line of what I explained in my response to Erythrone.

 

[Shiva]

If and when I build a greenhouse I'm going to make the floor below ground level. But seeing that your house is allready standing I don't think it's an option to lower it.

Unfortunately, I'm located in a spring flood area.

 

[Shiva]

a double-poly, winter-only hoop house costs less than your window idea and is much less work than raising the entire thing...put it up over your existing gh...

I have one of those and it nearly crashed under the weight of snow one winter. I actually had to puncture the poly with a shovel to prevent this outcome. Now I use it as a shade house in summer.

 

[tim]

others i know in snowy areas deflate the bubble and increase the heat during snow, which decreases the insulative value and allows the snow to melt.

what do other greenhouse owners (commercial especially) do to deal with snow and cold?

 

[Shiva]

others i know in snowy areas deflate the bubble and increase the heat during snow, which decreases the insulative value and allows the snow to melt.

what do other greenhouse owners (commercial especially) do to deal with snow and cold?

They close shop for the winter and remove the poly sheets until early spring. (That's also an option for me. I could bring all the plants inside the house.)

 

[Clark]

Perhaps you could drill a mile and go geothermal. oke:

Must be the paint fumes. :crazy:

 

[Shiva]

Perhaps you could drill a mile and go geothermal. oke:

Must be the paint fumes. :crazy:

Or I could use some of these spent nuclear fuel rods from Japan and build my own covered water pool to put them in. The steam could go into pipes warm the greenhouse and go back to the pool. I bet my municipality doesn't have any bylaw against that kind of system. :rollhappy:

 

[Erythrone]

With solar passive GH, you can use heat storage from water or rock to heat the GH.


http://www.attra.org/attra-pub/solar-gh.html