and how that will affect everyday nevadans, like pat and craig carrell. >> the day we moved here, the temperature was 115 degrees, so that was a welcome to nevada. >> reporter: former academics, the carrells moved to a retirement community outside of las vegas in 2002. what did you notice about the energy bills as it crept towards summer? >> they crept higher and the air conditioning kicks in, and our bills, over time rose to over $450. >> reporter: a month? >> yeah. >> reporter: to reduce their electric bill, the carrells added insulation to the attic and sunblocking ultraviolet film to the windows. then in 2014, they decided to go solar. >> so we've got panels up there and there. >> reporter: the carrells spent $45,000 dollars on roof solar panels for their two-bedroom home. federal government rebates and credits from the energy company reduced their out-of-pocket cost by more than 40%, and they expected the rest of the investment to pay for itself through lower electric bills. on average, their bills dropped by about 95%. so in the hottest days of the summer, what you had been payi