Sounds like to me your wiring and service may be undersized to meet your power demands now...What size is your main breaker??, how many square foot of living space does the home have? Are most of your circuts protected with 15 amp breakers? I think you may need to have your wiring and maybe your circuit breaker panel updated to new sheathed electrical cable wire with a bare copper ground--12 gauge circuitss protected with 20 amp circuit breakers. You probably currently have mostly 15 amp circuits with 14 gauge 2 wire with no safety ground wire. Post up with more info on the state of your breaker panel and wiring.