The first home energy drain to spring to mind is likely drafts and lack of insulation, so it's crucial to seal the home's "envelope."
First and foremost, be sure the attic is insulated and sealed. An attic's points of weakness include improperly sealed steps, trapdoors and vents. According to the New York State Public Service Commission and the New York State Energy Research and Development Authority (NYSPSC/NYSERDA), attics are the easiest place to insulate and yield the greatest energy savings.
"You can also test to see if crevices between doors and door frames need better sealing by trying to slip a sheet of paper through," according to NRG Residential Solutions, a new energy provider in the Northeast and mid-Atlantic. "If the paper goes through, it means cold air is seeping in and the hot air you paid to heat is going out."
Drafty windows can be another major point of weakness, and should be replaced with double-pane, low-emissivity windows, which can help reduce outside noise, drafts, heating and cooling costs, according to Jonathan Bass, green living expert and director of communications for SolarCity.
Two other major culprits to check out are the garage and the front door. Amy Matthews, home improvement expert with HomeAdvisor.com, recommended checking the gasket seal of garage doors (both the car door and the house door) and installing a new steel entry door for the highest ROI.
"Consider buying a Energy Star-qualified door, and if it has glass, they should be double or triple paned," she said.