Your heat pump used to make the lounge warm in 15 minutes. Now it seems to run constantly, the air doesn't feel as hot, and you're wondering whether it's time to replace it.
The good news is that most heat pumps don't suddenly lose performance because they've worn out. More often, there's a simple reason they're no longer heating as well as they once did.
Here are the most common causes we see across Northland.
1. Dirty Filters Restrict Airflow
The most common reason a heat pump loses performance is also the easiest to fix.
As your heat pump runs, the filters collect dust, pet hair and pollen. Eventually the airflow becomes restricted, meaning less warm air can circulate through your home.
Signs your filters need cleaning include:
- Weak airflow from the indoor unit.
- The room takes much longer to heat.
- The fan seems louder than normal.
- Your electricity bill has slowly increased.
Most manufacturers recommend cleaning the filters every 1–2 months during periods of regular use.
Remove the filters, wash them with warm water, allow them to dry completely, then reinstall them.
2. The Outdoor Unit Is Blocked
Your outdoor unit needs plenty of airflow to operate efficiently.
Leaves, grass, weeds, cobwebs and dirt can gradually block the coil, forcing the heat pump to work much harder for the same amount of heating.
Take a quick look outside.
Check that:
- Nothing is stacked against the unit.
- Plants aren't growing around it.
- Leaves haven't collected underneath.
- The coil isn't clogged with dirt.
Avoid using a water blaster, as the high pressure can bend the delicate aluminium fins and reduce performance.
3. Damaged Pipe Insulation Can Reduce Efficiency
Many homeowners don't realise the insulated copper pipes between the indoor and outdoor units are an important part of the system.
One of these refrigerant pipes is covered with thick foam insulation. Over time, sunlight, weather and even birds can damage this insulation, leaving sections of copper exposed.
When the insulation deteriorates, the refrigerant can gain or lose heat before it reaches the indoor or outdoor unit. The heat pump still works, but it has to work harder to produce the same result, reducing its overall efficiency.
Check the pipework outside your home.
If you notice:
- Bare copper pipe exposed
- Cracked or brittle insulation
- Birds have pecked sections away
- Foam insulation falling apart
it's worth having it replaced. It's a relatively inexpensive repair that helps keep your heat pump operating efficiently.
4. Your Heat Pump Needs a Professional Service
Cleaning the filters is only part of the maintenance.
Inside every indoor unit is a fan wheel and heat exchanger that gradually collect dust, mould and grime. These components aren't accessible without dismantling the unit, and even a small build-up can significantly reduce airflow.
A professional heat pump service normally includes:
- Deep cleaning of the indoor coil and fan.
- Cleaning the outdoor coil.
- Checking refrigerant performance.
- Testing operating temperatures.
- Inspecting electrical connections.
- Clearing the condensate drain.
Many customers are surprised how much stronger the airflow feels after a proper service.
We recommend having your heat pump professionally serviced every 12 months to keep it operating efficiently and extend its lifespan.
5. It May Simply Be Set Incorrectly
Every winter we visit homes where the heat pump is working perfectly—it just isn't being used in the most effective way.
For heating:
- Select HEAT mode (☀️).
- Set the temperature between 21°C and 23°C.
- Leave the fan speed on Auto.
- Keep internal doors closed where practical.
Many people think turning the temperature up to 30°C will heat the room faster. It won't. The heat pump simply runs at full capacity until the target temperature is reached.
6. Low Refrigerant Usually Means There's a Leak
Unlike petrol in a car, refrigerant doesn't get "used up."
If refrigerant levels are low, there's almost always a leak somewhere in the system.
Common symptoms include:
- Air that feels only slightly warm.
- Ice forming where it shouldn't.
- The outdoor unit running almost constantly.
- Much poorer heating than previous winters.
If you suspect a refrigerant issue, it's best to have the system inspected rather than simply topped up.
7. Your Home May Have Changed
Sometimes the heat pump hasn't changed—your house has.
Perhaps you've:
- Opened up living spaces.
- Added an extension.
- Removed heavy curtains.
- Left more rooms open.
- Changed insulation levels.
A heat pump that was perfectly sized ten years ago may now be heating a much larger space.
8. It Might Be Nearing the End of Its Life
Most quality heat pumps last around 10–15 years, particularly when they're serviced regularly.
As components age, efficiency gradually declines and repairs become more common.
If your system is older and beginning to require regular repairs, replacing it with a modern high-efficiency model can often reduce running costs while providing noticeably better comfort.
How Often Should a Heat Pump Be Serviced?
As a general guide:
- Clean the filters every 1–2 months during winter.
- Have the entire system professionally serviced once every year.
Regular servicing helps maintain efficiency, improve airflow, reduce mould build-up and identify small problems before they become expensive repairs.
When Should You Call a Technician?
It's worth arranging an inspection if:
- Your heat pump isn't heating properly.
- Airflow is much weaker than it used to be.
- It smells musty.
- Water is leaking inside.
- It's making unusual noises.
- Your electricity bills have increased unexpectedly.
- It hasn't been professionally serviced for more than a year.
Many issues can be fixed quickly when caught early.
Heat Pump Servicing in Whangārei and Kerikeri
Gibson Electric services, repairs and installs heat pumps throughout Whangārei, Kerikeri and the wider Northland region.
Whether your heat pump simply needs a thorough clean, damaged insulation replaced, a refrigerant leak repaired or you're wondering if it's time for a replacement, our experienced technicians can inspect your system and explain the most cost-effective option.
If your heat pump isn't performing like it used to, get in touch with our team. Often, a professional service is all that's needed to have it heating efficiently again. Gibson Electric recommends annual servicing to keep systems operating at their best.