This is what has worked very well for me -
The smallest bedroom in my house (about the size of a large walk-in closet) is my puppy room. The room is heated with a small electric heater with a temp control. The floor has a plastic tarp over the carpet to protect it, then a huge quilt on top of the plastic. The door to the room has a good fit to the floor so there are no drafts. I also block off the room register so the furnace or A/C kicking on doesn't change the room temp. There is a small work table that holds a scale, phone, radio and supplies. Lights in the room are on a dimmer switch and a light-blocking shade is on the window.
In the room is an indoor/outdoor thermometer with the probe tucked in under the blankets in the pool so I can quickly check both the room temp and the pool temp. There is also a small gauge that tells the room humidity and if it is too dry, I have a cool water humidifier to run. Also in the room is a nice digital scale (like the post office uses) to weigh pups and an oxygen generator if needed.
Pups are kept in a kiddie pool with a kennel heater (12" x 18" 'Lectro Kennel) that is temp programmable. The kennel heater is covered with a crib pad, then towels and blankets line the pool. There are a couple of huge fluffy stuffed animals in the pool for the pups to snuggle into, then a sheet is draped over the pool. I prefer a pool to an incubator because it gives the pups room to move around to a cooler or warmer spot that suits them, and since my cat likes to nap with the pups, she can get in and out by herself.
I covered a 2' x 3' x 4" piece of 'egg crate' foam with a big towel and use this to lay the dam on when the pups nurse. If she gets too warm in the room I put a 'cool collar' on her and can also drape a 'cool cloth' over her body, just keeping it away from the pups. The foam pad also makes a comfy spot for her to sleep if she doesn't want to leave her pups.