Thermostat
Swapping out the old-school thermostat for one that warms up the kitchen before I get out of bed and saves on my oil bill.
Oh, the little things... like a thermostat that still has a tiny bead of mercury in it. And changing it out for one that actually controls the temperature in my house. I didn't get anything fancy... just a simple 5/2 Programmable Honeywell. Maybe someday I'll go for a super-fancy smartphone kind, but for now this works.
