Summer cooling bills can double your monthly electric payment, and the single biggest driver of those high bills is an HVAC system that's running with dirty coils, clogged filters, and low refrigerant. The good news: most of the culprits are things you can address in an afternoon without paying a technician.
Here's the spring checklist we recommend before the first 90-degree day.
Tasks a homeowner can do (about 1 hour total)
1. Replace the air filter
This is the single most important thing you can do. A clogged filter makes the blower work harder, reduces airflow across the evaporator coil, and can cause the coil to ice up. Use a pleated filter rated MERV 8-11 for most homes; anything higher can restrict airflow on older systems.
Replace Cadence: Every 30 days if you have pets or allergies, every 90 days otherwise. Set a phone reminder, not a calendar reminder — you'll forget by June.
2. Clear the outdoor condenser unit
Trim shrubs back at least 2 feet from the unit. Hose down the aluminum fins from the inside out (water going the same direction as the airflow) to push debris out, not deeper in. Don't use a pressure washer — the fins bend.
3. Straighten bent fins
A plastic fin comb (about $5 online) lets you comb bent fins back into alignment. Even a small number of bent fins reduces airflow by a surprising amount.
4. Vacuum the return vents
The return air vent in your hallway collects dust, pet hair, and dog fur. Vacuum the grille and the first few inches of ductwork. You'll be horrified.
5. Check all supply registers
Walk the house and confirm every supply register is open and not blocked by furniture or rugs. Closed registers don't save money — they create pressure imbalance and force the blower to work harder.
Tasks a professional should do (annual tune-up)
These tasks require gauges, a vacuum pump, or working with refrigerant. They're worth the $80-150 tune-up fee every spring.
6. Clean the indoor evaporator coil
Restricted airflow across this coil is the #1 cause of high cooling bills. The coil is buried in the indoor air handler and requires chemical coil cleaner and a rinse kit.
7. Check refrigerant charge
Low refrigerant means a leak — refrigerant doesn't get "used up." A tech will check subcooling and superheat, find the leak, and seal it. Running low on refrigerant can damage the compressor, which is a $2,000+ repair.
8. Inspect the capacitor and contactor
These two electrical parts are the most common failure points in summer. They're $15-30 parts that fail without warning and shut down the entire AC. A tune-up tech will test their capacitance and replace if marginal.
9. Verify thermostat operation
A tech will cycle the system through heating, cooling, and fan modes and confirm the staging works on multi-stage systems. A misconfigured thermostat on a two-stage system can run high stage constantly and double your bill.
Why this checklist matters
An unmaintained HVAC system can use 20-30% more electricity than a maintained one. On a $300 summer bill, that's $60-90 per month, every month, all summer. The maintenance pays for itself in the first two months.
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Do the homeowner tasks this weekend. Book the pro tune-up for the week after. Your summer bills will thank you.