- Figure out the difference in annual energy consumption between my old and new water heaters:
Old Water Heater (4,992 kWh/yr) - New Water Heater (1,856 kWh/yr) = 3,136 kWh/yr
- Figure out the daily savings in kWh/day:
3136 kWh ÷ 365 days = 8.6 kWh/day
- Multiply daily energy savings in kWh/day by the number of days remaining in 2011:
8.6 kWh/day × 358 days = 3,078 kWh
Why get so specific regarding the number of days left in 2011? As you see in the upper right hand corner of the blog, I've added a counter that I will use to track my estimated energy savings over the course of the year-- including those resulting from improvements made during subsequent months. I'll be using a similar formula to prorate these savings to achieve a conservative, but accurate, estimate.
Whew! If I had known there'd be math involved, I might not have made this resolution to begin with!