Sterile bins can come in practiacaly any size within reason however the bare minimum is 24" x 24". Like any other cage, the term"The bigger the better." applies. There are a variety of options for heating as sterile bins are great for holding in heat. Some options include, a human foot warmer set on low, a heating pad, and a Ceramic Heat Emitter. With the ceramic heat emitter you will need a thermostat. There is another thread in this section that has info on thermostats if you would like to use that. The CHE should NEVER come in direct contact with the plastic bins as they can melt or atleast get extremely hot. Connecting two seperate bins is a great idea and provides your hedgie with more space but also requires some modifications. For one, you will need to drill holes in the connectors so as to provide ventilation. Also, controlling the heat in both sections could be a problem unless you intend to use a space heater or have two heat sources. On a last note, I would get a bin with tall sides otherwise you may be forced to use a lid which then must reqire holes drilled in the sides and many other challenges. i'm sure someone else will come and pitch in some more ideas but this is my recomendation. Here is a thread that has some of Cimredopyh's awsome and creative sterile bin mansions-http://www.chins-n-hedgies.com/forums/showthread.php?t=77&page=2
What I did for my hedgie's cage was drilled holes in the upper sides of the bin and all along the lid of the bin. I need a lid because I have curious cats, but many people use no lids at all. Then I had to slice a rectangular hole in the lid to fit her large wheel, which was just too big by a few cms.
