I put my brooder in the coop. I set up a light where I can keep one small area the right temperature and let the far corners cool off as they will. It is often 30 degrees cooler in the far corners. The chicks play alll over the brooder and come back to the heat when they need to. That is a surprisingly small amount of the time. I'd go bonkers trying to keep the entire brooder the right temperature. I let them determine their comfort zone.
I do have a good draft guard so they do not have a breeze blowing on them and I can keep that one area in the right temperature range. With the temperatres you are talking about, I'd suggest a cardboard ring or some way to keep them near the heat for the first few days, but by the time they are a couple of day sold, they should know to come back to the heat. Your danger period is at night when it gets that cold.
For your specific question about the room in your house. Initially, say for the first week, I'd probably try to keep the temperature in there same as the rest of the house. Just keep one area in the brooder warm for them. After that first week they will be very active and mobile. You can lower the temperature in the room if you wish, as long as they have a warm spot to go to. I think they do feather out faster and acclimate themselves better if they are given that chance to play in cooler temperatures. It does not have to be all day long. Just a half hour a day will help acclimate them.
If they get cold, they will tell you. They'll huddle under the light to try to keep warm and huddle together to keep each other warm. But it is normal for them to sleep in a bunch anyway for the comfort of having their buddies close. Them huddling when they sleep does not mean they are cold. If they are cold, you will hear a distress peeping. You'll recognize something is wrong when you hear it. It is a loud piercing peep.
Good luck!
