Most heat pump failures give warning signs weeks before they happen completely. Here's what to watch for.
Written by the March Technology Technical Team · Last Updated: July 2026 · 5 min read
Lukewarm rather than properly hot water is usually the first and clearest sign something's wrong — it can point to a refrigerant issue, a failing compressor, or simply the wrong thermostat setting. A unit that cycles on and off frequently, makes unusual noises, or shows visible icing on the outdoor unit outside of a normal defrost cycle are all worth investigating rather than waiting out.
A less obvious sign is a gradual rise in your electricity bill with no change in usage — an underperforming heat pump often works harder for less output, quietly costing you more each month. Catching any of these early is almost always cheaper than waiting for a complete breakdown; see our troubleshooting service if you're not sure what's causing the symptom, or our repair service once the cause is known.
Most common sign: Lukewarm rather than hot water
Don't ignore: Visible ice on the outdoor unit
Cost-saving tip: Early repair is cheaper than a full breakdown
Next step: Book a troubleshooting or repair visit
Noticed any of these signs? Book a diagnostic visit and we'll identify the exact cause before recommending any work.
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Lukewarm rather than properly hot water is usually the first sign most people notice, often before any other symptom appears.
For minor issues like reduced output, it's usually fine to keep using it while you book a diagnostic visit, but stop use and call us immediately if you notice a burning smell, sparking, or a refrigerant leak.
Yes — a small refrigerant leak or loose electrical connection left unaddressed can lead to compressor damage, turning an affordable repair into a much more expensive one.
If you have zero hot water at a commercial property, or suspect a refrigerant leak or electrical safety issue, our emergency repair service is the faster option.