CoolCowl

A cooler idea for portable AC

Stop throwing your cool air out the window.

CoolCowl helps turn a single-hose portable air conditioner into a dual-hose system, reducing the hot outside air pulled back into your room.

Check your AC See how it works
  • No permanent modification
  • Made to fit your AC
  • UK pilot coming soon
CoolCowl dual-hose airflow illustration
Fresh air in
Hot air out
Room temperature 23.5°C and holding steady

The hidden problem

One hose out.
Hot air sneaks back in.

A standard portable AC uses room air to cool its hot condenser, then blows that air outside. The room is left under negative pressure, so warm air is drawn back through gaps around doors and windows.

CoolCowl supplies the condenser with outside air instead. Your AC can spend more of its effort cooling the room—not replacing air it just cooled.

Single hose

Warm air pulled back in

With CoolCowl

A balanced airflow loop

Simple by design

Upgrade the AC you already own.

CoolCowl fits over the condenser intake on the back of your portable air conditioner and adds a dedicated outside-air hose.

  1. 01

    Made to fit

    Send us your model details and rear photos. We identify or create the correct cowl shape.

  2. 02

    Strap it on

    A soft perimeter seal and removable straps secure the cowl without modifying your machine.

  3. 03

    Feel the difference

    Connect the second hose to your window kit and let outside air carry the condenser heat away.

Tested in a real room

It reached the target. Then it eased off.

In our early comparison, the unmodified AC ran continuously but stalled above the chosen setpoint. With CoolCowl fitted, it reached the target and the compressor began cycling off.

~50%compressor duty after reaching target
23–24°Ctarget range reached in testing

Early prototype result from one room and machine. Performance varies with AC model, room, weather and installation.

Room temperature Illustrative trace of prototype testing
Single hose CoolCowl

See the test unfold

Same AC. Same room.
One important change.

Test A

Standard single-hose setup

Compressor stays on as the room temperature levels out above target.

Test B

Dual-hose CoolCowl setup

Temperature reaches target and the compressor begins cycling.

Video placeholders are ready for your original time-lapse files.

Help shape the pilot

Will CoolCowl fit your AC?

Tell us what you own and upload a clear photo of the back. We’re building our supported-model list now.

  • Be among the first to hear when the pilot opens
  • Help us prioritise the most common models
  • No obligation to buy

Prototype form: submission is demonstrated in your browser but is not stored yet.

Questions, answered

The useful details.

Does CoolCowl modify my air conditioner?

No permanent modification is intended. The cowl seals over an existing condenser intake and is held with removable straps.

Will it fit every portable AC?

Not immediately. Rear layouts vary, so we are creating model-specific lower sections around a standard hose connection. Your photos help us expand compatibility.

Do I need a window kit?

Yes. Both hoses need to connect to the outdoors while the window opening is sealed. We’re exploring options for common UK casement and sash windows.

When can I buy one?

CoolCowl is in prototype testing. Register your model above and we’ll contact you when a suitable pilot kit is available.