Investing in energy efficiency upgrades for your home is not only one of the easiest ways to decrease your carbon footprint; it’s also one of the best ways to save money on utility bills. However, despite the clear benefits, some homeowners hesitate to install air source heat pumps, add insulation to their home, or switch to solar hot water technologies because of anticipated upfront costs. Fortunately, this isn’t much of an obstacle in the Bay State: thanks to Mass Save, homeowners throughout Massachusetts can finance these projects at 0 percent interest with the HEAT Loan Program.