Installation quality is one of the biggest factors in how well a heat pump performs, and unfortunately, some mistakes don't show up immediately. Here's what to watch for.

The System Runs Constantly

A heat pump that rarely, if ever, switches off is often a sign it's undersized for the property, or that flow temperatures have been set too high during commissioning.

Rooms Never Quite Reach Temperature

If certain rooms consistently underperform, this often points to radiators or underfloor loops that weren't resized for heat pump operation, a common oversight when upgrading from a gas boiler.

Unusual Noise from the Outdoor Unit

Some operational noise is normal, but persistent buzzing, rattling, or vibration can indicate poor mounting, incorrect refrigerant charge, or airflow obstruction.

Short Cycling

Frequent starting and stopping, rather than steady, longer running periods, usually points to oversizing or a design that doesn't match the property's actual heat loss.

No Weather Compensation Set Up

If your installer never discussed weather compensation with you, there's a reasonable chance it was left at a factory default rather than configured for your home, one of the most common shortcuts we come across.

Missing or Incomplete Documentation

A properly commissioned system should come with a heat loss calculation, design documentation, and commissioning records. If you were never given these, it's worth asking for them, their absence is often a sign steps were skipped.

Hot Water Recovery Feels Slow

If your hot water takes noticeably longer to reheat than expected, this can point to an incorrectly sized cylinder or heat pump output that wasn't matched to your household's usage.

If several of these sound familiar, it doesn't necessarily mean anything needs to be ripped out and redone, but it's worth getting an independent opinion before assuming it's simply "how heat pumps are."