Enter a typical monthly heating bill, how many degrees you set back, and how many hours a day you keep it there. The estimate uses about 1% of the bill per degree for an 8 hour setback.
| $180 | 1° for 8 h | 8 | $1.80 |
| $180 | 4° for 8 h | 8 | $7.20 |
| $180 | 8° for 8 h | 8 | $14.40 |
Four degrees of setback for 8 hours on a $180 heating bill is about $7 a month on this rule. Eight degrees for the same 8 hours is about $14. If the setback lasts only 4 hours, the estimate is cut in half. Use it to compare settings, then check the next bill.