From Cold Air to Full Power: Common Heat Pump Problems & How to Fix Them

• Cleaning your heat pump's filter every few months is the most important thing you can do yourself to maintain efficiency.
• Strange noises, unpleasant smells, or a unit that won’t turn on are clear signs you need a professional technician.
• An annual professional service can significantly improve your unit's efficiency and save you money on your power bills.
• If your heat pump is leaking water inside your home, it often means you have a blocked drainpipe that needs to be cleared.

It’s a familiar story for us. A chilly Auckland evening sets in, you reach for the heat pump remote, and… nothing. Or maybe it’s a strange rattling noise that’s suddenly started, or a mysterious drip from the indoor unit. When your home’s main source of comfort decides to act up, it’s frustrating. But before you panic, we’re here to tell you that not all problems mean a costly disaster.

As technicians on the ground across Auckland, we’ve seen every issue imaginable. The good news is that many of them have simple solutions you can handle yourself. The key is knowing what to look for and when to pick up the phone.

And here’s a powerful reason to pay attention to your heat pump’s health: regular maintenance keeps your power bills down. In fact, a clean, well-serviced unit runs so much more efficiently that an annual service can save you up to $250 a year on your energy bills. That’s because dust and grime can increase power consumption by a whopping 10-35%.

This guide is our first-hand advice, straight from the field, to help you diagnose what’s going on with your heat pump.

Over the years, we’ve noticed the same issues pop up time and again in homes from the North Shore to South Auckland. Here are the most common culprits and what they usually mean.

1. My Heat Pump Isn't Heating or Cooling Properly

This is easily the number one call-out we get. Your heat pump is running, but the air coming out is lukewarm at best. Before assuming the worst, check the simple things.

First, grab the remote. Has it been accidentally switched to ‘Fan’ or ‘Dry’ mode instead of ‘Heat’ or ‘Cool’? Or is the temperature set too low or too high? It happens more often than you’d think. Another common mistake we observe is setting the fan to 'Auto', which can cause the unit to cycle on and off, making it feel ineffective. Try setting it to a constant low or medium speed.

If the settings are correct, the next suspect is a dirty filter. According to the government’s energy advice site, Genless, cleaning your filter is the most important thing you can do to keep your heat pump running efficiently. A clogged filter suffocates your unit, restricting airflow and dramatically reducing its ability to heat or cool your room.

2. Why Is My Heat Pump Making Strange Noises?

A heat pump should operate with a gentle hum. So when it starts making new and unusual sounds, it’s right to be concerned. The type of noise is a big clue for us.

• Rattling or buzzing:  This often points to something being loose. It could be the front cover of the indoor unit, debris like leaves or twigs in the outdoor unit, or a loose component that just needs tightening.
• Grinding or squealing:  These are more serious sounds. A grinding noise often suggests a problem with the fan motor’s bearings, which can fail due to wear and tear. This isn't a DIY fix and needs professional attention before it causes more damage.

3. There's a Bad Smell Coming From My Unit

That musty, "stale sock" smell when you turn on your heat pump is a sure sign of mould and bacteria buildup. The dark, damp environment of the indoor unit's coils and fan is a perfect breeding ground. Not only is the smell unpleasant, but it also means your heat pump is circulating mould spores around your home, which isn't great for air quality or your family's health.

This is a problem that a simple filter clean won't fix. It requires a deep, professional clean to properly sanitise the internal components.

4. Help! My Heat Pump is Leaking Water

A leaking heat pump can be alarming, but it’s crucial to know where the leak is coming from. As Consumer NZ points out, if your heat pump is leaking water outside, this is usually normal. It's just condensation being drained away as the unit does its job.

However, if you see water dripping from the indoor unit, you have a problem. In our experience, this is almost always caused by a blocked drainpipe. Dust, slime, and other gunk can clog the pipe that’s meant to carry condensation outside, causing it to back up and overflow into your home. This needs to be fixed promptly to prevent water damage to your walls and floors.

Before calling for a repair, running through these simple checks can sometimes solve the problem and save you a call-out fee. It takes just a few minutes.

1. Check the Remote:  Make sure it’s on the right mode (Heat/Cool) and temperature. Replace the batteries if the screen is faint.
2. Clean the Filters:  Turn the unit off. Open the front panel of the indoor unit, slide the mesh filters out, and wash them gently in warm water. Let them dry completely before putting them back in. You should do this every few months.
3. Inspect the Outdoor Unit:  Check that there are no leaves, branches, or weeds blocking the airflow around the unit. Clear away any debris.
4. Reset the Power:  Sometimes, a simple reset is all that’s needed. Turn the heat pump off at the wall isolator switch (the dedicated switch usually near the outdoor unit) or at your home’s main switchboard. Leave it off for 15 minutes, then turn it back on.

When to Call the Professionals: Signs You Need an Expert

1. If you've tried the DIY steps and your heat pump is still on the fritz, it’s time to call in a technician. Trying to fix complex issues yourself can be dangerous and often leads to bigger, more expensive problems.
2. Call us if you notice:

• The unit won't turn on at all (and you've checked the power).
• The system is blowing warm air in cooling mode, or vice versa.
• You hear grinding, squealing, or loud banging noises.
• The unit is icing up, either inside or outside.
• Your power bills have spiked unexpectedly.

1. These symptoms often point to issues like refrigerant leaks, thermostat failure, or electrical faults that require specialised tools and knowledge. A professional service involves much more than a quick clean. For instance, an expert will clean and disinfect the coils, check refrigerant levels, test the thermostat, and inspect all electrical components to ensure peak performance. When you book with us, we run through a comprehensive 20-point checklist to diagnose and resolve the root cause of the problem. You can see exactly what's involved in a professional heat pump service on our website.

Repair or Replace? Making the Smart Financial Choice

1. This is a question we get a lot. Is it worth spending money to fix an older unit? Generally, if your heat pump is less than 10-12 years old, a repair is almost always the more economical choice. A professional service to fix a common issue is a fraction of the cost of a brand new installation.
2. Our comprehensive service costs just $130 + GST, with any additional units at the same property costing only $65 + GST each. If we find an electrical fault, our qualified electrician's hourly rate is $90 + GST. When you compare that to the cost of a new unit, a repair often makes the most sense. We always provide a clear quote before starting any work, so you're in complete control. Feel free to check our competitive repair and servicing prices , which are backed by a price match guarantee.
3. If your unit is very old, inefficient, or requires a major, expensive part like a new compressor, we’ll give you an honest assessment of whether replacement might be the better long-term investment.

Don't Suffer in Discomfort, We're Here to Help

1. A faulty heat pump can disrupt your entire household, but it doesn't have to be a major drama. By following these simple troubleshooting steps, you can often get things running smoothly again yourself. And for those bigger problems, you know who to call.
2. Our team at Auckland Heatpump Services is here to get your home's comfort back on track quickly and efficiently. We pride ourselves on honest advice and expert work.
3. Ready to get your heat pump sorted? Book Your Heat Pump Repair today or call us on 0221758992 for a free quote and friendly advice.