Here is what chicks need. A safe, dry, clean place with proper ventilation, food and water.
The also need an environment that mimics the under side of Mother Hen who would brood them, in nature. To achieve that environment, regardless of whether one broods in the basement, the laundry room, the garage or the shed, the temperature needs to be proper. Not too hot as to cook them, not too cool that they pile up and smother themselves under the pile.
A basement works well because the temps are rather constant, allowing you to use a wattage bulb, hung in the right height, to provide a good, comfortable environment. They'll want that temp at 85-90 the first week, and then a wee bit cooler in subsequent weeks. I don't bother with a thermometer. The chick's body language is far, far more accurate. The brooder needs to be big enough for the chicks to "self adjust". If they pile up under the heat circle, it is too cool. If they avoid the heat circle and stand panting? You're cooking them. It's really that basic. Watch them and respond appropriately.
Big brooder are always better, for a host of reasons, than small, cramped brooders.
If you brood in the garage, you may find your daytime temps are warm enough out there to put the lamp on a timer. Maybe not the first week, but in subsequent weeks. If your garage is 90F during hot days? No heat is needed. If it falls to 70F in the earning morning hours before sunrise? They'd need a bit of added warmth.
It just doesn't take much supplemental heat to raise ambient air that is already 80F. Hope this makes sense.