HVAC Maintenance Schedule: What to Do Each Season

Most HVAC emergencies are not sudden. They are the visible end of a slow problem — a restricted filter, a dirty coil, a loose electrical connection, a drifting refrigerant charge — that would have been obvious to a technician months earlier. A professional tune-up costs $75-$200 and takes about an hour. Here is the year, divided into what you do and what you book.

Spring (April-May): prepare the air conditioner

• Replace the air filter and reset your rotation for the cooling season.
• Clean the outdoor condenser coil with a garden hose from the inside out. Never use a pressure washer — it bends the fins closed and permanently reduces heat transfer.
• Clear at least two feet around the outdoor unit: shrubs, fence panels, stored items, anything blocking airflow.
• Pour a cup of distilled vinegar or a cleaning tablet down the condensate drain line to head off clogs.
• Book the professional tune-up: refrigerant charge check, electrical inspection, capacitor and contactor test, coil condition, and blower amperage.

Run the system for an hour on the first mild day rather than the first hot one. A fault you discover in April gets a routine appointment; the same fault discovered in July gets emergency pricing and a wait.

Summer (June-August): monitor

• Replace the filter every one to two months. Pollen and dust load filters much faster in season.
• Listen for changes. New rattles, screeches or repeated clicking are the cheapest warnings you will ever get.
• Check the indoor coil and refrigerant line for ice. Ice means low refrigerant or restricted airflow, and running the system while it is frozen risks the compressor.
• Look for water around the indoor unit, which usually means a blocked condensate drain.
• Keep supply and return vents open and unobstructed. Closing vents to "save energy" raises system pressure and usually costs more.

Autumn (September-October): prepare the furnace

• Replace the filter. Consider a higher-MERV filter for the sealed-up winter months, but only if your system can handle the pressure drop — ask your technician.
• Book the furnace tune-up: combustion analysis, heat exchanger inspection, gas pressure check, flame sensor cleaning, igniter test and safety control verification.
• Test every smoke and carbon monoxide alarm and replace batteries. Do this before the heating season, not during it.
• Clear the flue and intake terminations outdoors of nests, debris and vegetation.
• Run the heat for fifteen minutes on a mild day. Expect a brief burning-dust smell; anything that persists needs attention.

The heat exchanger inspection is the item to insist on. A cracked heat exchanger can put combustion products into the air you breathe, and it is not something a homeowner can check.

Winter (November-March): stay alert

• Filter every one to two months, same as the rest of the year.
• Keep the outdoor unit of a heat pump clear of snow and ice, and never chip ice off the coil. Let a defrost cycle do it.
• Watch for short-cycling — the furnace starting and stopping every few minutes. It usually means a restricted filter or an overheating limit switch, and it is worth a call early.
• Keep vents clear of furniture, rugs and holiday decorations.
• Note any room that never gets warm, and mention it at the spring visit.

How often should you really change the filter?

The printed interval on the packaging assumes an average house. Yours is not average. A one-inch filter in a home with pets and heavy use may need replacing monthly; a four-inch media filter in a low-dust home can run several months. The reliable method is to look: hold it up to a light, and if you cannot see light through it, replace it regardless of the date.

Filter choice matters as much as timing. A very high-MERV filter in a system not designed for it restricts airflow, which can freeze an evaporator coil in summer and trip a limit switch in winter. MERV 11-13 suits most residential systems, but confirm with your technician for your specific equipment.

What should a professional tune-up include?

1. Refrigerant charge verified against manufacturer specification, not topped up by feel.
2. Static pressure and temperature split measured and recorded, so you have a baseline to compare next year.
3. Electrical connections tightened and amperage draw checked on motors and compressor.
4. Capacitors tested against rated capacitance, since a weak capacitor is a cheap part and a common cause of summer failure.
5. Coils and drain line inspected and cleaned.
6. Combustion analysis and heat exchanger inspection on the heating visit.
7. A written report with the readings, not just an invoice marked "tune-up performed".

That written report is what turns maintenance into information. Two years of readings will show a charge drifting or a motor drawing more current long before either becomes a failure.

Schedule a seasonal tune-up with a vetted local pro.