Clean Your Air Conditioner & Heat Pump Coils Before Summer

When summer arrives, your air conditioner or heat pump needs clean coils to move heat efficiently. Over time, dust, pet hair, cooking residue and outdoor debris can collect on the coils, restricting airflow and coating the surfaces that transfer heat.

Blocked or dirty coils make the system work harder for less cooling. You may notice weak airflow, longer run times, uneven temperatures, higher power use, unusual smells or the unit struggling on hot days. In some cases, restricted airflow across a dirty indoor coil can also contribute to icing and water leaks.

What do the coils do?

Coils are the heat-transfer surfaces inside your system. The indoor coil helps absorb heat from your home when cooling, while the outdoor coil releases that heat outside. When dirt builds up, air cannot move freely across the coil and heat transfer becomes less effective.

Signs your coils may be blocked

• The unit is running but the room is not cooling properly
• Airflow from the indoor unit feels weak
• The system runs for longer than usual
• Ice forms on the indoor coil or nearby pipework
• Water drips from the indoor unit
• There is a musty or dirty smell when the system starts
• The outdoor unit is covered in dust, leaves or grass clippings

These symptoms can also point to electrical, refrigerant or mechanical faults. Coil cleaning is a sensible maintenance step, but it is not a replacement for professional diagnosis when problems continue.

How blocked coils affect summer cooling

A dirty coil reduces the amount of air and heat that can pass through the system. That means your air conditioner or heat pump may need to run longer to reach the set temperature, while the compressor and fan work harder. Restricted airflow can also make the indoor coil too cold, increasing the risk of icing.

Cleaning before the first hot spell helps your system start summer with better airflow and cleaner heat-transfer surfaces. It can also help you spot a problem before you are relying on the unit every day.

Two DIY cleaning options

Option 1: DIY Home Heat Pump & Air Conditioner Cleaner

For routine indoor-unit maintenance, use the DIY Home Heat Pump & Air Conditioner Cleaner. It is a practical option for cleaning accessible indoor coils, fins and fan components as part of your regular summer preparation.

Option 2: 5L Coil Cleaner and Degreaser with Extended Trigger Attachment

For outdoor units, food-fat or greasy residue, and extremely badly blocked coils, choose the 5L Coil, Duct & Filter Disinfectant Cleaner. The larger format gives you more product for heavy-duty cleaning, while the extended trigger attachment makes application easier in awkward areas and across outdoor coil surfaces.

Always follow the product label, protect electrical components, and rinse or remove loosened grime as directed. For heavy outdoor buildup, make sure the power is isolated before cleaning and keep spray away from motors, wiring and control boxes.

Safe DIY coil-cleaning steps

1. Switch off the power

Turn the unit off with the remote, then isolate it at the wall switch or breaker. Wait until the fan has stopped before opening the cover or starting work.

2. Protect the wall and floor

Use a heat pump cleaning cover, towel and bucket to catch runoff. Keep liquid away from electrical controls, wiring, sensors and the remote-control receiver.

3. Remove and clean the filters

Follow the manufacturer’s instructions to remove the filters. Vacuum loose dust and wash them if they are designed to be washable. Allow them to dry completely before refitting.

4. Apply the coil cleaner

Apply the cleaner to accessible coil and fin surfaces as directed on the product label. Do not use harsh household chemicals, bend the fins or force liquid into electrical areas. Allow the product to work for the recommended time.

5. Rinse, dry and check the airflow

Rinse or remove loosened grime exactly as directed by the cleaner instructions. Refit the dry filters, close the cover and restore power only when the unit and surrounding area are safe and dry. Run the system and check for improved airflow, leaks, unusual noises or persistent smells.

When to call a professional

Stop using the system and arrange a qualified technician if ice quickly returns, cooling remains poor after cleaning, the unit is leaking heavily, there is a burning smell, the outdoor fan is not running, or you suspect a refrigerant or electrical fault. Never chip ice off with a sharp object, and never attempt refrigerant or electrical repairs yourself.

Get ready before the heat arrives

Clean coils and clean filters give your heat pump or air conditioner a better chance of keeping up when summer temperatures climb. Choose the DIY home heat pump cleaner for regular indoor maintenance, or the 5L coil cleaner and degreaser with extended trigger attachment for outdoor units and heavier buildup.