Summer is in full swing. For many, that means resorting to air conditioning to maintain a comfortable indoor temperature. But how many of us know what we need to do to maintain our AC units’ functionality and efficiency? The Focus spoke to Peter Duncanson, vice president of training and development at ServiceMaster, a global home and business restoration services company, about at-home AC unit maintenance, and Bobby Lynn, the owner of Charlotte-based electrical firm LiveWire Electrical. Unsurprisingly, both recommend cleaning and replacing AC filters. Duncanson also recommends replacing your u…