I have a heated (and cooled) garage but no drain. I use the rinseless wash from Griot's. It is basically just a bucket wash with out a hose and works surprisingly well. You wipe once per face of your wash rag then back to the bucket to knock all the dirt out - then repeat. You do need to follow up with a drying cloth. I think it actually leaves a cleaner finish to the paint then when I use the hose. The wash solution has something in it that encapsulates the dirt and it falls below the grate in the bucket. I think that is why I do not get water spots because it precipitates out the minerals in the hard water. I sometimes use a bit of the rinseless wash in my normal bucket if I'm doing a hose wash to get the minerals in the hard water to precipitate out.
I also do this method when it is 105 degrees out and too hot or 8pm at night and too dark outside. When the car is particularly nasty in the winter, I will run it through a brushless wash to knock off most of the salt then bring the car into the garage and go over it with the rinseless wash bucket method.
This is the stuff I use. Griot's has some without wax now but I have not had a chance to try it yet.
I have to agree that it is a wonderful feeling to be washing your car in a 70 degree F garage when it is 10 degree F outside.