kyerie1
"without spending huge amounts of money"

That will be the hard part, lol.

Visit the greenhouse forum on gardenweb. They are extremely knowledgable about this stuff.

Depends on what you want to grow. Greenhouses can help get a jump on the season. Using it year round could get expensive.
Do you have a large enough growing space so that you can grow alot to freeze or can to supply you throughout the winter.- potatoes- in a root cellar, canned tomato sauce, frozen green beans, canned pickles, etc..
Cold frames are good for some greens which can be harvested late into the season. One of my favorite TV shows used to be Gardening Naturally. They built plastic greenhouses over cold frames. Supposedly each layer of insulation raised the temperature to the next growing zone. So if their area was a zone four it would be a zone 7 inside the coldframe which was inside the greenhouse.

If you can attach the green house to the south side of the house that may help hold the heat. I would think that you would have to intstall heat cables because you solar panels may not be able to collect enough sunlight to keep it heated. Grey winter days and snow covering the greenhouse aren't going to provide much sunshine.
Penny