Looking for info abt backyrd greenhouses: heat, plumbing, electrical, yr round produce for family of 6, cost.?

I want to grow my own food so I know it's organic and fresh and I'm thinking of installing a greenhouse. How practical are they? Will I be able to grow fruits and vegetables year round if I keep the heat at 55 degrees or so? How does the quality of veggies grown in a greenhouse compare to non-greenhouse veggies? Are some vegetables and fruits more ideal than others in a greenhouse environment? What should I expect to pay for a greenhouse with water and heat? CAN A I PUT A GREENHOUSE ON A DECK?