The short answer
When the bill jumps and the weather did not, the system is working harder than it needs to. A dirty coil and filter, a low refrigerant charge, leaking duct in a crawlspace or attic, or an old unit are the usual reasons. A tune-up comes first.
What you can check yourself
- Check and replace the filter.
- Check the thermostat schedule and set point.
- Look at the outdoor coil: is it caked with dirt or covered with leaves?
- Compare with the same month last year, and note whether the weather was different.
What gets checked first
- Refrigerant charge
- Dirty coil and filter
- Duct leaks in the crawlspace or attic
- The age and efficiency of the unit
Repair or replace?
A tune-up first. If the unit is old, the numbers on a new one with $0 down are worth a look.
When to call now
No emergency. A system that works harder will fail on the hottest or coldest day.
Maintenance and tune-ups: how we help