Why Your Heat Pump Works Harder During Central Virginia Cold Snaps

In Central Virginia, we are accustomed to a relatively mild climate, but every resident from Charlottesville to Albemarle County knows that winter can bring sudden, sharp drops in temperature. When a cold snap hits the Blue Ridge foothills, your home’s heat pump undergoes a dramatic shift in how it operates. You might notice that the fan runs longer, the outdoor unit makes unfamiliar noises, or the air coming from the vents does not feel as “toasty” as it did in November. These changes often lead homeowners to worry that their system is failing, but in most cases, your heat pump is simply working harder to overcome the laws of physics.

At Albemarle Heating & Air, we want our neighbors to understand the mechanics of their home comfort. A heat pump is an incredibly efficient tool for our region, but it has a specific set of operational “gears” that it must shift into when the mercury drops below freezing. This blog explores why your heat pump works harder during a Virginia cold snap and how to ensure it remains reliable through the coldest nights of the year.

The Science of Heat Extraction in the Cold

To understand why your system is working overtime, you must first understand that a heat pump does not create heat in the way a gas furnace does. Instead, it is a “heat mover.” Even when it is 20 degrees outside in Charlottesville, there is still a significant amount of thermal energy present in the outdoor air.

Increasing the Compression Load

The heat pump uses refrigerant to absorb that outdoor heat and bring it inside. As the outdoor temperature drops, the “density” of the heat in the air decreases.

• Lower Efficiency Window: As it gets colder, the system has to move more refrigerant and run the compressor at a higher intensity to “squeeze” the available heat out of the air.
• The Balancing Act: When the outdoor temperature is 45 degrees, the heat pump can easily find enough thermal energy to warm your home. When it drops to 25 degrees, the system must work twice as hard to extract the same amount of warmth.
• Continuous Operation: It is perfectly normal for a heat pump to run almost continuously during a cold snap. Unlike a furnace that cycles on and off, a heat pump is designed to provide a steady, lower-intensity stream of heat to maintain a consistent indoor environment.

The “Cool” Air Sensation

Homeowners often complain that their heat pump is blowing “cold” air when it is freezing outside. In reality, the air is likely around 85 to 90 degrees. Because your body temperature is 98.6 degrees, air that is 90 degrees can feel cool to the touch even though it is effectively warming your room. During a cold snap, this temperature difference is more noticeable because the system is running longer to keep up with the heat loss through your windows and walls.

The Defrost Cycle: A Necessary Winter Chore

One of the most common reasons for a “hard-working” heat pump is the accumulation of frost. In Central Virginia, our winter cold is often accompanied by high humidity or dampness from the mountains. This creates the perfect conditions for ice to form on the outdoor coils.

Why the Unit “Reverses” Itself

If ice is allowed to coat the outdoor unit, it blocks the airflow and prevents the refrigerant from absorbing heat. To fix this, the heat pump enters a “Defrost Cycle.”

• Temporary AC Mode: The system essentially turns into an air conditioner for a few minutes. It sends hot refrigerant to the outdoor coils to melt the ice.
• Steam and Noises: During this process, you may see steam rising from the unit or hear a loud “whooshing” sound as the reversing valve shifts. This is a sign of a healthy, functioning system.
• The Fan Shutdown: The outdoor fan will often stop spinning during defrost to allow the coils to heat up as quickly as possible. Once the ice is gone, the system will shift back into heating mode and resume its normal operation.

Auxiliary Heat: The Backup “Boost”

When the outdoor temperature falls below what is known as the “balance point” (usually between 30 and 35 degrees for most Virginia homes), the heat pump alone can no longer provide enough heat to offset the heat loss of the structure. This is when your auxiliary heat, or “heat strips,” kick on.

The Role of Electric Resistance

Most heat pumps in Albemarle County are equipped with electric resistance heating elements inside the indoor air handler.

• The Emergency Backup: These strips act like a giant toaster, providing a blast of intense heat to help the heat pump reach the target temperature on your thermostat.
• During Defrost: Auxiliary heat also turns on during the defrost cycle to ensure that the “cooling” effect of the defrost process does not chill your home.
• Energy Consumption: While auxiliary heat is effective, it is much more expensive to run than the heat pump itself. If you notice your electric bill spiking during a cold snap, it is likely because your system is relying heavily on these backup strips to fight off the Virginia chill.

Avoid the “Emergency Heat” Trap

Many thermostats have an “Emergency Heat” setting. You should only use this if your outdoor unit is physically broken or encased in a thick shell of ice that the defrost cycle cannot handle. Manually switching to emergency heat turns off the efficient heat pump entirely and uses only the expensive electric strips, which can cause your utility bill to double or triple.

Maintenance Strategies for a Virginia Winter

Because your heat pump works so much harder in the winter than in the spring or fall, it requires specific attention to prevent a breakdown in the middle of a snowstorm.

Keep the Outdoor Unit Clear

After a Central Virginia snowfall, it is important to check on your outdoor unit. A heat pump needs a constant supply of air to function.

• Clearance: Ensure that snow is not piled up against the sides of the unit. Gently brush away any snow from the top and sides, but never use a sharp shovel that could damage the delicate fins.
• Gutter Leaks: If your gutters are leaking directly onto the heat pump, that water will freeze into a solid block of ice that the defrost cycle cannot melt. Ensure your drainage is directed away from the HVAC equipment.

Filter Health and Airflow

Because the system runs for longer durations in the winter, it pulls much more air through the filter. A clogged filter restricts airflow, forcing the compressor to work even harder and potentially leading to a system “trip” or failure. We recommend checking your filter every 30 days during the peak of winter.

Ensure Your Winter Reliability with Albemarle Heating & Air

Is your heat pump struggling to keep up with the latest cold snap? Do not wait for a total system failure to get an expert opinion. The team at Albemarle Heating & Air is ready to provide a comprehensive winter diagnostic for your home. From testing your defrost controls to ensuring your refrigerant levels are perfect for the cold, we provide the professional service you deserve.

Contact us today to schedule your maintenance and stay cozy no matter what the Virginia winter brings.