Smitty has a good idea as long as there is space left in the panel. Some research was done 10 to 15 years back that showed that if a house was wired one size wire larger than called for by breaker size (10 awg on 20 amp; 12 awg on 15 amp,ect) the savings in lost power from voltage drop in the wiring would pay for the added cost in under 18 months. That did not factor in the added cost of air conditioning to remove the excess heat from the structure. This was published in Electrical Contractor. I have long since thrown away that copy so please do not ask for exact dates.
Yes, Minotbob is correct in his info. Also, the old large fluorescent tubes we are so used to will be a thing of the past shortly too. Same legeslation.
Charles