A packaged rooftop unit puts everything in one cabinet: compressor, condenser, evaporator, blower and often the heat, all sitting on a curb over a roof penetration with duct running down into the building. It is an efficient way to condition commercial space, and it has one significant drawback, which is that it lives outdoors in full weather for its entire life.

Out of sight is the real issue. An RTU on a flat roof gets no attention because nobody walks past it. The filters do not get changed on the schedule the office equipment does, the drain pan does not get looked at, and the corrosion happening on the coil is invisible from the parking lot. So the first symptom of most rooftop problems is the space getting hot, which by then means a component has already failed.

We service, repair and replace packaged units across the Emerald Coast, and a good share of that work is preventing the failure rather than responding to it. Getting on the roof twice a year to clean coils, check the drain, read the electrical and look at the cabinet is what keeps an RTU from becoming an emergency during your busiest month.

Salt is the defining factor near the Gulf. Salt-laden air settles on the condenser coil and the cabinet, and it does two separate kinds of damage. It corrodes aluminum fins and copper tubing, which is how pinhole refrigerant leaks start, and it builds a fouling layer that blocks heat transfer so the unit runs longer and hotter to do the same work. Units in Miramar Beach, Seagrove Beach, Inlet Beach and Panama City Beach take this constantly, from every direction, with nothing shading them.

Water is the second. The curb, its flashing, and the condensate path are all opportunities for water to get into the building. Wind-driven rain here comes sideways, and a curb that was adapted poorly during a previous changeout will let water past. Meanwhile the condensate side runs almost continuously through our long humid season, so the pan and drain never dry out and biological growth blocks them. Water on a ceiling tile under an RTU is usually one of those two things.

Then there is heat and runtime. A dark flat roof in July is a brutal place for a condenser to reject heat, and the unit is asked to do it for twelve or more hours a day for most of the year. Contactors, capacitors, belts and bearings all wear on a runtime clock, and rooftop equipment runs that clock harder than anything at ground level.