Keeping Your Greenhouse Warm In Winter

Whether you heat your greenhouse or not, you willl want to take steps to keep your greenhouse from losing its warmth in the Winter. Of course, that is assuming you actually use your greenhouse in the Winter.

Stopping Air Leaks in Your Greenhouse

Just like in your home, the first step is to find and stop the air leaks.

• Weatherstrip doors and windows.
• Caulk around any seams or joints that are leaking air.
• Make sure automatic vent openers and louvers are well lubricated and working properly.
• If your greenhouse is not on a solid foundation, check around the bottom for air leaks and seal them.

Insulation

There are a variety of options for insulating your greenhouse. If you have any unglazed walls or portions of the roof, they should have been insulated when the greenhouse was built. Also the foundation and perhaps under the floor should already be insulated.

For the glazed portions of your greenhouse, you can use insulating curtains, removable insulated panels, or some form of temporary, extra glazing. Good quality insulating curtains, alone, can improve your heat savings by 58%. Aluminized vinyl or aluminized fabric make the best curtains. They do a good job of insulating, without being too bulky. Make sure that they seal well to the greenhouse so that cool air does not leak around the edges.

A sometimes  simpler, but less effective method is to add another layer of glazing. You can put plastic film up on the inside of your greenhouse, again, making sure it is well sealed. The only advantage here is that you do not have to keep moving it every day. If you have a small greenhouse, you could use plastic bubble packing material. That will do a much better job of insulating than a single layer of plastic film.

Rigid, movable, insulating panels are only a reasonable option if you live in a very cold climate. They are much more time consuming, plus you need space to store the panels when they are not in use. If you are planning to put in your own curtains or insulating panels, the book, Movable Insulation, by William K Langdon, is a must read. It is written for homes, but the ideas apply to greenhouses, and it is an complete resource on the subject.

Improve Thermal Storage

Whether you have a solar greenhouse or not, thermal storage is important in the Winter. In your freezer, if you keep it full, it lowers cooling costs. In the same way, keeping your greenhouse full, keeps it warmer. Adding containers of water or potted plants in any available space will make it easier to keep your greenhouse warm. Also, if you have a lot of unused space in you greenhouse, you could isolate it. Put up insulated walls in you greenhouse, to shrink the amount of space you need to keep warm. A good way to do that is to wall off the north side of the greenhouse. A lot of heat gets lost to the north side, if your greenhouse is glazed on that side.

Greenhouse Heating Systems

Heating under planting benches, or heating the soil directly, is much more efficient than heating the air in general. Apart from that, regular maintenance of your heating systems, to keep them working efficiently is the best way to reduce heating costs.