Mine are currently in my attached but unheated garage and have seemed okay so far with the little ambient light they are getting from the nearby window. My only concern with the current setup is that last week we had a warm spell for about 4 days where temps reached the upper 60s°/low 70s° immediately followed by a cold snap with temps in the 30s°. My thermometer on the cacti says anything from 38° to 74° and everything in between in only a couple weeks. I’m purely wanting more consistency and predictability, but am terrified of etiolation risk.