Haven't got me new greenhouse set up yet here at this house

This is a forum for backyard hobby greenhouse enthusiast wanting to share their green house experiences with like minded people.
Guest

Post by Guest »

I see many people say it's difficult to keep a glass house warm.

It seems to me if I framed out a shed with newer windows and sealed it up like you would on a house that it would retain more heat. What am I missing about this conversation.?
Elizabeth

Post by Elizabeth »

Even in your house windows are one of the least insulated areas of the dwelling. The R value is heat resistance of a window and is an assessment of the material effectiveness. The U value of a window measures the amount of heat transfer through the actual glass.

A single pane window has an r value of 1. A standard double pane has an r value of 2. A good r value range for a window is 5; a good u value is .20 to 1.20. Polycarbonate panels generally have higher r values and lower u values than glass.

I have double hung, double panes windows I plan to use for a greenhouse and want to buy polycarbonate panels for the roof.
Tricia

Post by Tricia »

I think it depends on how cold it gets. There are more natural ways to heat if you live up north. The problem too is greenhouses can also get extremely hot on coolish days. There is a lot to know. Some greenhouses can actually get colder inside than outside in extreme cold because it traps cold air in until the sun comes up. You can heat with water tanks or build a partial in ground if you don't want to down tons on heating.
Ken

Post by Ken »

It really depends on many factors. What zone are you in? What's your goal? Extended growing season or a tropical rainforest?

To simply answer your question you can build a insulated building with plenty of south windows and grow plants. Especially if you plan on over wintering tender tropicals and houseplants.
Delisa

Post by Delisa »

The use of double paned new windows can be cost prohibitive and surrounded frames and supportive structure cut down on light. Purchased greenhouses are single pane and metal famed so the cold transmits in faster. The double and triple layered plastic panels tend to insulate better with its layers of air. Just depends on what looking for in finished product. If use wood framing be sure to use pretreated or seal well since will be high humidity.
Keren

Post by Keren »

not sure if this will help or not, but just in case- I have a plastic cold frame - clear plastic sheeting over a metal frame, that I use in winter. It will cook the plants on a sunny day if I don't open it up, but at night, there is pretty minimal difference in temp between inside and out. I've done the black jugs, its up against a brick wall, etc. Still not great at night. Until. I put a big ikea-type plastic tarp over it at night - I drag it forward at night and scrunch it back during the day. It has been a game changer. Significant heat hold even at night. Now, when it gets down into the mid 20's and lower, I still run an oil heater (low) because I have mostly tropicals in there. And this is a very ugly solution (I am the reason HOAs exist) but its a trick I wish I'd discovered years ago - it really helps
Scott

Post by Scott »

The R-value of your glass, is all that matters it’s the air space filled with gas that will help glass hold a little heat single wall glass isn’t any different than single layer plastic but if you double it and add argon you can get 2-3 R’s out of it
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