This year I got inspired to start seedlings again from Gardenfork with the videos on this post:
Last year I tried putting them in the garage window (south facing) but they ended up not doing so well and through the videos I learned why - not enough light.
I started in March with a setup in the furnace room.* I used adjustable shelving so that I can set the height and change easily when needed. For next year I can put a shelf on top of the hanger that hold the lights and put some more hanger higher up for another light.
(* actually I initially started on the kitchen counter with one tray under the counter light. But that soon got crowded. However it did serve the purpose of getting my son interested in starting his own seeds.)
A few weeks ago I decided to move them to the garage to start acclimatizing them to cooler nights and cooler day temps. The garage is not heated but it only goes below 0C when the outside temp is below -10C. So with some freezing nights on the way I wasn't too concerned until I realized that when I open the garage door they could be hit with a momentary blast of freezing air! Then I got an idea ...
I had some auto shades left over that I cut to fit behind and then ...
Not only are they protected from a blast of cold air much more of the light is reflected back in!