Heat pumps provide both heating and cooling — when they fail, they take both functions offline. Get connected with technicians who diagnose and repair heat pump systems across Mount Juliet and Wilson County year-round.

Mount Juliet sits in Wilson County east of Nashville near Percy Priest Lake, and it has been one of the fastest-growing communities in Tennessee for more than a decade, transforming from a small rural crossroads into a dense band of new subdivisions built almost entirely within the last twenty years. That rapid, concentrated growth means Mount Juliet's HVAC service needs skew heavily toward newer systems — installation quality issues, undersized equipment in larger new-construction homes, and warranty-period repairs are a bigger share of the workload here than the aging-equipment failures more common in older Tennessee towns. Middle Tennessee's hot, humid summers and cold winter snaps apply fully, and the sheer pace of Mount Juliet's growth has occasionally outstripped how quickly local HVAC capacity has been able to keep up with new-home demand.

Heat Pump Problems

Common heat pump failures include reversing valve problems that prevent the system from switching between heating and cooling modes, refrigerant leaks, defrost board failures that cause ice buildup on the outdoor unit, compressor issues, and auxiliary heat problems. Heat pump diagnostics require specialized knowledge of the refrigerant cycle in both directions.

System runs constantly but never quite reaches the set temperature

This often points to a refrigerant or airflow issue rather than a thermostat problem — a technician can check charge levels and airflow before assuming the system itself is undersized.

Outdoor unit is covered in ice, even when it's not especially cold out

Some frost during a normal defrost cycle is expected, but heavy ongoing ice buildup usually means the defrost cycle isn't completing correctly or airflow is restricted.

Noticeably higher electric bills with no change in usage habits

A system working harder than it should to hit the same comfort level is a common early sign of a developing mechanical issue, often before anything sounds or feels obviously wrong.

Heat Pump vs. Furnace in Middle Tennessee

In Middle Tennessee's climate, heat pumps are efficient down to certain outdoor temperatures, after which auxiliary or emergency heat takes over. If your heat pump is running but not keeping up in cold weather, the issue may be with the auxiliary heat source rather than the heat pump itself. Technicians check the full system.

  • Auxiliary heat running during genuinely cold weather. That is the system doing what it was designed to do, and no repair removes the cost of it.
  • A bill driven by rate changes, occupancy, or water heating rather than the heat pump. Comparing against the same month a year earlier is the cheapest first check and costs nothing.
  • Building heat loss from thin insulation or leaky ducts. A repair restores equipment performance; it does not reduce how much heat the house loses.
  • A thermostat simply set higher than it used to be, since each degree of setpoint raises runtime regardless of equipment condition.
  • Comfort problems in a house where the equipment was undersized at installation, which no component-level repair will change.

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This content is reviewed by the Tennessee HVAC Repair editorial team and informed by licensed-contractor sourcing, manufacturer documentation, and established industry standards for hvac repair. Read our editorial standards.