A cold frame will ALWAYS be warmer inside than outside. Don't need a lot of sun shining on it. What a cold frame is about is transparent insulation. It allows sunlight to come in, heat the soil, and the cold frame prevents that heat from escaping. So as long as it gets any sun, it's going to work. Yes, an east-facing cold frame won't be quite as warm as a south-facing one, but it'll help.

Well, that's what I thought, something better than nothing. But since hubs has to build it, not sure it is worth the trouble. I have a big glass door storm window that I have been saving to use for it . . . But that makes for a big heavy footprint. Maybe I'll try something temporary in that spot this year and see how it goes before committing to such a large yard item . . .

I would just love a cold frame to grow seedlings in. If you don't do it this spring try to build it this summer for next spring. I bet you will just love it. Can you make it portable so you can move it out of the way if not being used? I wished I knew more about building one for myself. I have seedlings now that I have to drag in and out to get some bright shade. I started them under florescent lights and they need to strengthen up and grow more. If I had a cold frame I would have it loaded with things that I have winter sowed.