Energy Vanguard blogger Allison Bailes reviews energy data collected by Danny Orlando, a manager in the EPA's Energy Star program, who has cut energy use at his home by about two-thirds since 1995.
The improvements Orlando made include installation of a sealed combustion furnace and new AC system, both of which were at the high-end of the energy efficiency scale in 1997, when they were installed. Next came work on the envelope, beginning in 2004 with attic air sealing and blown-in cellulose insulation to R-45. After that came window replacement, conversion to a tankless hot water heater, and switching to 100% LED lighting.
Bailes includes a chart that shows, among other things, data for energy savings from each of the upgrades.