HVAC Error Code H5 — What It Means & How to Fix It

What Does This Error Mean?

H5 means the IPM module — the Intelligent Power Module — has failed or detected a critical fault. The IPM is the power electronics component that drives the variable-speed compressor in inverter systems. When the IPM fails, the compressor stops completely and the entire system shuts down. H5 is a critical fault that requires professional repair — the IPM is a high-voltage electronic component. Do not attempt to inspect or replace this component yourself.

Affected Models

Inverter mini-split systems
Variable-speed heat pumps
Inverter-driven central HVAC systems
Multi-zone inverter systems

Common Causes

The IPM module has overheated because its heatsink fan has failed or airflow to the outdoor unit is blocked
A power surge or electrical transient has blown internal components of the IPM module
The compressor has developed an internal short circuit that has caused overcurrent through the IPM
The IPM module has failed due to age — these components have a finite lifespan in high-use systems
Moisture intrusion into the outdoor unit's control board area has caused a short circuit on the IPM

How to Fix It

Turn off the system at the thermostat and immediately cut power at the outdoor disconnect box. Do not attempt to restart the system.

Unlike some faults that clear after a reset, H5 typically indicates actual hardware failure. Restarting will not fix it and can cause additional damage.
Do not open the outdoor unit's control panel. HVAC capacitors store lethal charge for several minutes after power is disconnected. Only trained technicians should access these components.

This is not a fear-based caution — HVAC capacitors run at 370 to 440 volts AC and store significant charge. Several people are injured each year from improper HVAC work.
Note the system's age and whether any power events — outages, storms, or electrical work at your home — preceded the H5 error. This information helps the technician diagnose the cause.

If H5 appeared right after a storm or power outage, a surge is a likely cause. If it appeared gradually or after reduced performance, the IPM may have been failing for some time.
Check whether your HVAC system is still under warranty. Many inverter systems have 5 to 10 year parts warranties. An IPM replacement under warranty covers the part cost entirely.

Find your installation date and the warranty card that came with the unit. The model and serial number on the outdoor unit label is needed for a warranty claim.
Call a licensed HVAC technician who has experience with inverter systems. Not all technicians are familiar with IPM replacement — ask specifically when booking.

IPM module replacement requires the correct part number for your specific unit. A good technician will order the part before arriving if you describe the H5 fault when you call.

When to Call a Professional

H5 is a critical fault that always requires a professional HVAC technician. The IPM module is a high-voltage component — capacitors in the circuit hold dangerous charge even after power is cut. IPM module replacement typically costs $300 to $800 for the part, plus $100 to $200 in labor. If the compressor caused the IPM failure, the compressor also needs replacement — significantly increasing costs. Call immediately — H5 is not a fault that clears on its own or gets better with time.

Frequently Asked Questions

What is the difference between H5 and F9?

Both relate to the IPM module, but they indicate different stages of the problem. F9 typically means the IPM's protection circuit triggered — it shut itself down before being destroyed. H5 typically means the IPM module has actually failed and can no longer operate. F9 may be recoverable with a restart and root cause fix. H5 usually means the module needs replacement.

How long does IPM module replacement take?

An experienced technician familiar with your system can typically complete an IPM replacement in 1 to 3 hours. The time varies based on how accessible the control board is and whether the correct part is on hand. Most technicians order the part first and then schedule the repair visit — same-day parts availability depends on your location and the brand.

Will the compressor be damaged after an H5 fault?

That depends on what caused the H5 fault. If a power surge damaged the IPM, the compressor may be fine — surge damage tends to destroy electronics first. If the compressor itself failed and caused overcurrent through the IPM, then both components need replacement. A technician can test the compressor's winding resistance with a multimeter to determine if it has been damaged.