Why Is My Heat Pump Blowing Cold Air?

There’s nothing worse than switching on your heat pump expecting a blast of warmth, only to

be met with cold air. If you’ve found yourself asking, “Why is my heat pump blowing cold air?”,

you’re not alone. It’s a common issue for many Christchurch households, especially as we

transition into colder months. Thankfully, there are some common causes and easy

troubleshooting tips you can try before calling in the experts.

At ATL Electrical, we specialise in heat pump installation and servicing in Christchurch and

can help you get your system running efficiently again.

Common Reasons Your Heat Pump Might Be Blowing Cold Air

1. It’s in Defrost Mode

Heat pumps work by extracting heat from the outside air - even when it’s cold - and bringing

it indoors. When temperatures drop, moisture on the outdoor coil can freeze. To fix this, your

heat pump occasionally goes into “defrost mode.” During this time, it temporarily switches to

cooling mode to melt any ice buildup.

While this process is normal, it can blow cool air inside for a short time. If this is the cause,

the issue should resolve itself within 5–10 minutes. If it doesn’t, it might be time to book a

Christchurch heat pump expert to take a closer look.

2. The Thermostat Is Set Incorrectly

It might sound obvious, but double-check your settings. If your heat pump is set to "cool" or

"fan" instead of "heat" or "auto," it may be circulating cold air. Make sure your thermostat is

set to the desired temperature and mode.

Also, consider whether the room temperature is already close to your set point. In this case,

the pump might just be circulating air rather than heating it.

3. The Outdoor Unit Is Dirty or Blocked

Christchurch’s windy and sometimes dusty conditions can lead to blocked or dirty outdoor

units. If airflow is restricted due to leaves, dirt, or debris, your heat pump will struggle to work

efficiently and may end up blowing cold air.

Check around the unit and remove any obstructions. If it’s especially dirty, it might be time to

schedule a professional heat pump clean or service.

4. Refrigerant Levels Are Low

Refrigerant is the substance that allows your heat pump to transfer heat. If levels are low due

to a leak or gradual loss over time, your system won’t be able to generate warm air

effectively. This is not something you can fix yourself - refrigerant issues require a licensed heat pump technician. You might hear some strange noises coming from your heat pump

unit if the refrigerant is running low, and this can lead to poor performance and higher power

bills.

5. The System Needs a Service

Like any other appliance, your heat pump needs regular maintenance. A build-up of dust and

grime in the filters, coils, or fan can reduce performance and cause airflow problems. If your

heat pump hasn’t had a service in a while, this could be the reason it's not functioning

properly.

Routine heat pump servicing in Christchurch can help extend the life of your system and

keep your energy bills under control.

Quick Troubleshooting Tips

• Check your settings – Make sure your unit is in “heat” mode and the temperature is set higher than the current room temp.

• Inspect your filters – Dirty filters reduce airflow. Clean or replace them regularly.

• Clear the outdoor unit – Remove debris or anything blocking airflow.

• Observe the cycle – If your unit briefly blows cold, it could be in defrost mode—wait a few minutes to see if it returns to heating.

If none of these solve the problem, it’s best to book a service with a qualified electrician or

heat pump specialist.

When to Call the Christchurch & West Coast Heat Pump Experts

If your heat pump is still blowing cold air or not performing as well as you think it should be

after trying the basics, it’s time to call in the professionals. At ATL Electrical, we’ve helped

countless homeowners with reliable heat pump servicing and heat pump installation across

Canterbury and the West Coast. Whether it’s a quick repair or a full system upgrade, we’re

here to help you stay warm and comfortable.

We pride ourselves on being heat pump experts, offering efficient, honest, and affordable

service. From older systems to the latest models, our experienced electricians can diagnose

and fix a wide range of issues quickly and safely.

Need Help With Your Heat Pump?

Don’t wait for the chill to set in. Whether you need urgent repairs or are considering a new

heat pump installation, ATL Electrical has you covered. Get a free quote today.