Home › Common Problems › High Electric Bills From AC
High Electric Bills From AC
in Tempe, AZ
Tempe summers mean AC systems run almost continuously from May through September, and an inefficient system makes that expensive. Most homeowners notice bills creeping up year over year rather than spiking overnight. In areas like McClintock and Southern neighborhoods with older ranch homes built in the 1960s, leaky ducts and aging equipment are the most common culprits. Ignoring it means the system runs harder, wears faster, and costs more every month.
Quick Answer
High electric bills from AC in Tempe usually mean the system is working harder than it should because of a dirty coil, duct leaks, or failing capacitors. APS customers in Tempe can see bills climb well above average in June and July when the system runs nearly 24 hours a day. A technician can find the cause in one visit. Call (928) 564-6468 before the next billing cycle — the problem does not fix itself.
Telltale Signs
Warning Signs to Watch For
- Monthly electric bill is significantly higher than the same month last year
- The AC runs for hours without reaching the set temperature
- Some rooms cool fine while others stay 5 or more degrees warmer
- The outdoor unit runs constantly even during mild evenings
- The system is over 12 years old and has never had a tune-up
Root Causes
What Causes High Electric Bills From AC?
Leaking or Uninsulated Ductwork
Ducts that run through Tempe attics regularly reach 150 degrees in summer. If the duct joints are not sealed or the insulation has thinned out over the years, cooled air leaks into the attic before it ever reaches the living space. Homes built before 1990 in central Tempe often have original flex duct that has cracked or separated at the connections.
The Fix
Duct Sealing and Insulation
A technician pressurizes the duct system to find leaks, seals them with mastic or metal tape, and adds insulation where needed. Properly sealed ducts in a Tempe attic can cut cooling costs noticeably.
Failing Run Capacitor
The run capacitor helps the compressor and fan motors start and run efficiently. A weak capacitor causes the motor to draw more current than it should on every cycle. In Tempe, capacitors degrade faster than in cooler climates because they sit in outdoor units exposed to temperatures above 100 degrees for months at a time.
The Fix
Capacitor Testing and Replacement
A technician tests the capacitor's microfarad rating against the rated spec. A capacitor reading more than 10 percent below spec gets replaced. It is a small part, but it affects how hard every other electrical component in the system works.
Dirty Evaporator Coil
The evaporator coil sits inside the air handler and is where the actual cooling happens. When the coil builds up a layer of dust and debris over years without service, it acts like insulation and slows heat transfer. In Tempe, fine desert dust gets past even decent filters and coats the coil slowly enough that homeowners don't notice until the efficiency loss shows up on the bill.
The Fix
Evaporator Coil Cleaning
A technician applies a no-rinse coil cleaner to the evaporator coil and lets it break down the buildup. A clean coil transfers heat the way the manufacturer designed it to, bringing efficiency back to normal.
Self-Diagnosis
Which Cause Applies to You?
Check the signs you're observing to narrow down the likely root cause before your inspection.
| What You're Seeing | Leaking or Uninsulated Ductwork | Failing Run Capacitor | Dirty Evaporator Coil |
|---|---|---|---|
| Uneven cooling with some rooms much warmer than others | |||
| System runs constantly but efficiency has dropped slowly over time | |||
| Compressor hums louder than usual at startup | |||
| Dusty buildup visible on the indoor coil surface | |||
| Air pressure noticeably weak at far vents from the air handler | |||
| Bill increase started over the last one or two summers gradually |
Free Inspection
Get a Diagnosis in Tempe
An on-site inspection is the only way to confirm which cause applies to your property. Free, no obligation.
(928) 564-6468Free on-site inspection
Written estimate before work starts
Serving Tempe & surrounding areas
Other Problems
Services That Fix This
Also Helpful