How Hurricane Force Winds Impact HVAC Systems
The 2017 hurricane season has proven to be one for the record books, reminding everyone of the importance of being prepared to handle catastrophic losses. As demonstrated by Irma, the most dangerous aspect of a catastrophic hurricane is the accompanying storm surge along the coastline.
Equally important, the sheer wind speeds (and tornadoes spawned by the remnants of the storm) can wreak havoc hundreds of miles inland. These high winds can prove particularly damaging to roofs, siding, fences and HVAC systems.
Extensive damage caused by a hurricane-spawned tornado
And while many adjusters are experienced in assessing and estimating the costs to repair structural damage, diagnosing wind-driven damage to HVAC units can be particularly difficult.
A visual assessment of the extent of damages to an HVAC system is the first of many critical steps in reaching an appropriate scope of repairs (and associated settlement) to return the insured to pre-loss condition.
Condenser coil clogged with dirt and debris following high winds of a storm
Dust and debris-clogged condenser coils
High winds that accompany a hurricane often lead to excessive airborne dust and debris that will easily (in the best-case scenario) clog the aluminum fins of an HVAC system’s condenser coil. When the storm passes, property owners will often find the fins of the condenser coil packed with dirt, dust, grass, leaves and other small, lightweight objects from the surrounding environment.
When a condenser coil becomes clogged, the airflow through the unit is likewise restricted. This restriction reduces the potential heat transfer from the refrigerant to the ambient air, and in turn inhibits the HVAC system’s ability to adequately cool the conditioned space. It also causes the unit to work harder than under normal conditions, and slightly increases the system’s power consumption.
Fortunately, a clogged condenser coil is relatively easy to repair. Coils can be cleaned using condenser coil cleaner and a standard garden hose (a pressure washer should never be used to clean the condenser coil, as this can flatten the coil’s malleable aluminum fins). If performed correctly, this repair action can sufficiently restore a condensing unit to normal operation.
Microchannel coil damaged by wind-blown debris
Coil fins damaged by windblown debris
The condenser coil’s aluminum fins that surround the copper refrigerant tubing can be easily bent and flattened. If the strong winds of a hurricane or other storm send objects flying, they can easily dent the fins of the coil, similar to the effect of hailstones.
Once the fins are flattened, the airflow through the unit is restricted. As mentioned earlier, this condition can impact the system’s cooling capabilities, efficiency, and eventually, if left unrepaired for an extended period of time, the useful life of the system.
The potential repair actions for condenser coil fins flattened by wind-blown debris is similar to those used for repairing hail-damaged coils. Combing the coil’s fins should be considered as the first and most likely remedy. However, if the fins are torn, exceptionally brittle, or if the system utilizes a microchannel condenser coil (see example photo above), combing may not possible. In this scenario, the next repair action for wind-blown debris is the replacement of the condenser coil, an often ignored or forgotten repair option.
If the fins cannot be combed and the coil is no longer commercially available, the condensing unit may need to be replaced. Finally, if the replacement of the outdoor condensing unit leads to a technical or regulatory mismatch with the remaining equipment, full system replacement may be required.
The fins of this condensing unit were protected from the wind-blown debris; however, the corner panel was dented. The system was repaired by replacing the individual panel
Large foreign object impact to the condenser coil
Unlike smaller debris that simply clogs or dents the condenser coil, large, heavy objects picked up by strong winds can cause significant damage to an outdoor condensing unit. Hurricane force winds can send objects such as large branches, shallow-rooted trees or heavy building materials flying. If these objects make contact with the condensing unit, they may penetrate the refrigerant lines, damage multiple system components or even crush the system in its entirety.
The extent to which a system is damaged depends not only on the weight and speed of the flying object, but also on the construction of the condensing unit. Of course, the severity of system damage and availability of replacement parts will dictate if the unit is repairable.
Condensing unit damaged by heavy, wind-blown object
During a hurricane, 160-mile-per-hour winds can take a toll on HVAC equipment. While the typical residential condensing unit weighs between 150 and 200 pounds, it can still be easily blown askew from its position on the rooftop or ground pad. Following tornadoes and hurricanes, it is common to see equipment displacement ranging from minor shifts to those that are completely blown over.
Condensing unit blown off of pad by high winds
Once a condensing unit has shifted on the pad, it is important to assess whether or not the refrigerant lineset has been breached. If so, moisture and contaminants may have entered the refrigerant loop and can cause significant damage to the compressor. If the unit was blown over, the condenser coil and the fan assembly may also be damaged. Depending on the extent of the damage, repairs may still be possible, up to and including the replacement of the condensing unit.
Fortunately, in hurricane-prone areas such as Florida, building code regulations often require that all outdoor mechanical equipment exposed to wind be able to withstand wind pressures, or be securely fastened to the ground/rooftop (Florida Building Code, Mechanical Sec 301.15).
The required wind resistance depends on both the specific county and usually, the zone within that county. As an example, in Miami-Dade County Risk I, mechanical equipment is required to be able to withstand gusts of wind for three seconds at speeds of up to 165 mph (Florida Building Code, Sec 1620.2).
Significant damage to a condensing unit during a hurricane
As with any property claim, it is important for adjusters to consider all options before coming to a settlement decision following a hurricane or tropical storm, and a thorough visual inspection is the first critical step along the settlement path.
Although devastating, wind-damaged HVAC systems are often repairable, if objectively evaluated by a licensed professional. Most HVAC configurations include both outdoor and indoor equipment, offering frequent opportunities to return the system to pre-loss condition via simple and straightforward repairs.
For information on water and lightning damage accompanying hurricane claims, you can access our adjuster toolkit for hurricane claims. You can also review a labeled split system diagram and a labeled packaged unit diagram, to assist in identifying components and their susceptibility to wind and foreign object impact damage.