Here’s How Different Weather Conditions Affect Your HVAC System

Woman In The Cold in Kirkland, WA

From storms to extreme temperatures, there are a number of ways that inclement weather can impact your HVAC system. These changes can be felt in every season, and they can sometimes build up over time and carry over into subsequent seasons. Here are just a few common problems that Mother Nature can cause for heating and cooling systems.

High Winds

High-speed winds can be present at any time of the year, and they can cause numerous issues with your HVAC system. Outdoors, they can cause parts of your unit to become loose and damaged; they might even lift away parts that aren’t securely attached. They can also blow all kinds of leaves, branches, and other debris around your pumps and vents.

Indoors, the dust and other debris that winds sweep over your unit can impact your air quality, especially if they create a blockage. This is particularly common with air conditioner units that get clogged with dirt on their filters or evaporation coils. Not only do small contaminates get mixed in with your clean air, but less of that air reaches your home overall, making you fiddle with the thermostat and putting extra demands on your HVAC system.


Lightning strikes can be a major source of harm to HVAC systems. They can be expensive, too. In fact, they cost insurance companies more than $2 billion per year because of homeowners filing claims for damages. The damage from a lightning strike is easy to spot when it causes charring to external HVAC components such as contactors, compressors, and fan motors. You might also see black spots on the casing and wiring of your equipment boxes.

However, it’s worth noting that lightning doesn’t have to directly strike your unit to break it. Power surges can also fry the electronic parts of your HVAC system, and that damage won’t necessarily look scorched; it can be mistaken for general wear and tear. You might want to check on your HVAC system after a heavy lightning storm to see if you notice anything amiss.


April showers might bring May flowers, but they can also bring water damage to your air conditioner. While exterior AC units are designed to withstand the elements, including rain, there can be issues when there’s enough of a storm or a flood to create standing water. Prolonged, non-evaporating puddles can cause moisture to seep into the cracks and crevices of your air conditioner and destroy its electrical components.

It can also cause mold, attract insects, and lead to the deterioration of internal wiring. Similar effects can be seen when a basement gets flooded and a furnace or water heater is soaked for an extended period of time. Ultimately, rain is a potential hazard to cooling and heating systems alike, so it’s something to keep an eye on year-round.

Snow, Sleet, And Ice

Winter is one of the harshest seasons on your HVAC system, and this includes your air conditioner as well as your heater. Even if you aren’t using it, your outdoor AC unit can be piled with snow and impacted by a constant freeze-thaw cycle that leads to standing water and therefore water damage.

Another thing to beware of is your furnace and its connections to the outside world, including its heat pump and exhaust vent. They can be blocked by snowfall, frozen over with ice, and backed up with fumes, all of which can lead to reduced efficiency thanks to poor ventilation. When the weather outside is frightful, you’ll want to pay particular attention to where snow is falling.

Excessively High or Low Temperatures

Are you sweating in the heat or shivering in the cold? Intense temperatures on either end of the spectrum can prompt you to run your HVAC system at maximum capacity. Even if you aren’t setting your thermostat to extremes, the fact that you’re running your unit at all hours of the day will force it to work harder and harder to deliver the same level of performance.

This efficiency is measured in something called the Seasonal Energy Efficiency Ratio (SEER), which can diminish over time as your HVAC unit gets older and more worn out. A lower SEER rating can also have consequences for your energy bill if you’re forced to run your unit full-time to stay warm or cool. This isn’t even getting into the physical damage that extreme temperatures can cause when they warp, melt, or freeze various components of your HVAC system.


Hail is another hazard that bad weather can bring to your HVAC system. Just like it can dent cars, roofs, and other structures, it can also crash into your exterior air conditioner units. Hailstones can reach several inches wide and strike at more than 100 miles per hour, so don’t underestimate the damage that they can do to your home and its HVAC units.

Another thing to keep in mind is that hail rarely comes alone; it’s usually accompanied by a storm that also sweeps in rain, lightning, and high winds. With all of this combined, a bad storm can be a disaster for your outdoor HVAC components.

Sandstorms and Dust Storms

While less common than other types of weather, these storms can impact homeowners living near beaches, bluffs, and deserts. Their main danger is the clogging that they cause when they stir up large volumes of airborne particles. These particles can range from dirt to dust to sand, and once they infiltrate your exterior HVAC units, they’re capable of causing all kinds of problems as they cake onto your fans and coils.

They might impact your air quality, or they might cause less air to cycle in and out of your home thanks to a blockage. This can force you to run your heating or cooling system at maximum capacity. In large quantities, dust and sand can accumulate so thickly that they might stop moving parts from being able to move at all, bringing your entire HVAC system to a standstill.


Frost damage is similar to cold and snow damage, but it’s also unique in the sense that it can impact your indoor HVAC system just as much as your exterior units and their components. Your water heater, for example, can be vulnerable to the expanding and contracting of its metal parts under a layer of frost. This can compromise its structure and lead to leaks.

Frost can also creep like a vine through furnace vents and exhaust pipes, and it doesn’t even have to be snowing outside; frost can be generated by the condensation created by exhaust gases meeting cold air. You’ll want to stay vigilant about frost during all winter months, even mild ones.

Ask the Experts for Help

If the weather has affected your heating and cooling systems, you’ll want to call in professional help for a damage assessment and plans for potential repairs. At Black Lion Heating & Air Conditioning, we can help you get your HVAC system back up and running after bad weather. Our team provides Heating repairs, maintenance, and installation to residents of Kirkland, Bellevue, Tacoma, and the surrounding areas. We also offer indoor air quality, duct cleaning, gas fireplace, water heater, and electrical services. Give us a call today to set up an appointment.