Diagnostic guide
Heat pump blowing cold air in heat mode? Here is what is happening and what to do.
A heat pump blowing cold air in heat mode usually means the system is in defrost cycle (which is normal and self-resolves in 5-15 minutes), the reversing valve is stuck, or the system has lost refrigerant. If it persists for over an hour, turn off and call a pro.
Likely causes, ranked by probability
- 1
Defrost cycle (normal)
Self-resolves in 5-15 minutes.
Likelihood 50%
- 2
Stuck reversing valve
Valve stuck in cool mode.
Likelihood 25%
- 3
Low refrigerant
Reduced or no heat output.
Likelihood 25%
What you can try first
- · Wait 15 minutes to see if defrost cycle resolves it
When to call us: Cold air persists for more than 30 minutes.
Our diagnostic process
We arrive within a one-hour window, inspect the system end-to-end, read any active error codes, test temperatures and pressures, and identify the actual cause. You get a written quote before any repair work starts. The $129 diagnostic fee is applied to any repair you proceed with.
Frequently asked questions
Is heat pump blowing cold air in heat mode dangerous?
Most causes of "heat pump blowing cold air in heat mode" are not immediately dangerous, but ignoring them can damage the system or raise repair cost. Cold air persists for more than 30 minutes.
Can a cleaning fix this?
Sometimes. Biofilm, dirty coils, and clogged drain lines often resolve after a deep clean. Mechanical or electrical issues require a diagnostic visit instead.
How much does diagnosis cost?
Our diagnostic visit is $129 flat, applied to any repair you proceed with. We will quote any repair before starting work.
Need a tech to take a look?
$129 flat diagnostic. Same-week scheduling across Vermont. Credited toward any repair.