Caution should be exercised when buying older kilns. I recently turned down an op to get a free Knight kiln. Now I'm not a rich potter, living on my studio and craft show sales. It was tempting, but....
My reasons for not opting was this:
1. New elements would have to be ordered. And if Knight isn't around anymore then you have to go to an after market manufacturer.
2. The odds of being able to "break loose the old connections to the firing bar without breaking is remote. I rewired an old Crusader, and had to build connector "packs" of stainless screws, washers, locnuts to hold the wires to elements. Many of the old posts snapped off as I was trying to disconnect. The kiln is alive and working for another potter in my area. So it can be done, but hey, what is more cost effective. I figure time at my wheel is better spent than chasing down hardware.
this is just my opinion based on personal experience. Do you have the option with your electric company to go to a "time of day" use? I bought a computer kiln, and fire after 8pm til 9am and anytime on weekends/holidays. The savings on that will help convince you to buy a new computer kiln. Whatever you decide to do, good luck!!