The number of return air vents a house should have depends on its overall square footage. You'll need one supply vent and one return vent for every 100 to 150 square feet of living space. This means that, ideally, there should be at least one return air vent in every room. However, if the room is 100 square feet or larger, it's better to have two or three. A 2,000-square-foot home should have between 13 and 20 return air vents, in total.

You should plan to change your AC unit's filter every one to three months, depending on the manufacturer's recommendations. You should also clean the coils at least once per year, but if you have pets or someone in your household has allergies, you might need to clean them more often. Fortunately, many pros will clean the coils and change the filter for you during an inspection, which you should schedule once or twice per year.

To extend your HVAC system’s lifespan, it’s crucial to keep up with maintenance. This includes changing filters and thermostat batteries, keeping the outside unit clean and clear of clutter, and lubricating moving parts. Watch out for leaks, mold buildup, and blockages to ensure your unit stays in good working order. Spotting these issues early can be the difference between a simple, wallet-friendly repair and an expensive replacement.

HVAC companies may charge an hourly rate or a flat fee. Hourly rates typically range from $100 to $250 per hour, with an average around $175. Some contractors charge a flat fee for specific services, such as an inspection, which can cost between $150 and $500. The total cost of an HVAC service is influenced by several factors, including: the urgency of the service (emergency repairs after hours or on holidays cost more), the time of year, the type, size, and brand of your HVAC system, the specific repair needed, and whether you have a service contract.