Florida’s HVAC
contractors have always worked in one of the nation’s toughest climates. But as prolonged periods of extreme heat become more common, many are facing a new challenge—not failing equipment but changing customer expectations.
Most residential air conditioning systems installed over the past decade were properly sized using ACCA Manual J load calculations based on ASHRAE climatic design data. Those standards use statistically derived outdoor design temperatures—not record-breaking highs—to determine the equipment needed to maintain indoor comfort. In other words, systems are engineered to perform under the vast majority of summer conditions, but not necessarily during the hottest hours ever experienced.
As a result, homeowners may increasingly find that a system maintaining 75 or 76 degrees on an exceptionally hot afternoon isn’t malfunctioning at all. Contractors often respond to “my AC isn’t keeping up” service calls only to verify that refrigerant charge, airflow, ductwork, and controls are all operating within specifications. The equipment is simply working at the limits of its designed capacity under weather conditions that exceed its original design assumptions.
Perhaps the larger question is whether today’s design assumptions should evolve. If prolonged periods of above-design temperatures become the new normal, should the climatic data used to size residential systems be updated? That discussion belongs to organizations such as ASHRAE, ACCA, manufacturers, and code officials, but it is one worth having.
In the meantime, contractors can best serve their customers by explaining that a properly operating air conditioner is not always capable of overcoming unprecedented weather. Emphasize the importance of keeping shades closed, filters changed, and closing doors when going outside for short periods of time. Ensuring that there is proper insulation in the attics is another factor to check.
What are you seeing in the field? We’d like to hear from Florida contractors about the challenges they’re encountering and the conversations they’re having with customers.
Warm regards,
Peter Montana, Managing Director, ACprosite
pmontana@acprosite.com
