For anyone looking to lower their energy bills, I’d look to your attic. We moved a little over a year ago, and the new house didn’t have sufficient insulation in the attic. Stuffed it full and the bill dropped immediately, and should recoup that cost in pretty short order.
Agreed 100%^. If you do access an attic and move anything in it, be sure you do not disturb the blown-in insulation to the best of your ability. It’s real easy to kick it or move it around thinning it out in places. Also if you have any tray ceilings, often times blown-in insulation “falls off” these over time. There either needs to be correct blocking to hold appropriate amounts or some blanketing to hold the blown in cellulose in place near these.
Another place energy is often wasted is in garages. Jamb seals could/should be replaced much more often than they are in our extreme climates. They’re subject to cracking, bowing, wearing down on the edges, and so on. It’s crazy the number of homes I’ve been in where there’s a noticeable gap near garage doors. You cannot get a perfect seal with something that large that moves, but every millimeter makes a distinct difference. Keeping a garage just a few degrees cooler can make a substantial difference with heating costs. For us, we avoid opening the large doors at all when we can. If it can fit out the side door without too much hassle that’s what you use. Fans help also. The higher the ceilings, the more crucial they are as your money in heat is sitting near the top of the ceiling.
Fiberglass doors have a higher R-Value than wood or steel. For those who want beautiful custom wood doors on their homes, newer fiberglass designs are worth a look. In my opinion the look is still there with the new technologies, but you get a higher R-Value for sometimes a better price point as well (These can still costs thousands of dollars though too)