How to Make Portable Air Conditioner Quiet

Aircon - Title

We live in London.

City not exactly well known for its hot weather.

But, it can get hot real quick!

Usually, we have about two weeks of hot waves, therefore investment to a split air conditioning unit for a house or flat is hard to justify. Especially if you spend the day in the well-cooled office or outside.

Facing The Problem

Nevertheless, if the hot wave comes, your flat is facing all it’s windows to the West, and you would like to have at least half decent sleep, you are forced to act.

That was my case in the Summer of 2013.

I’ve bought a portable air conditioner.

My portable air conditioner
My portable air conditioner

In my case, it was the Amcor 10000 BTU (affiliate link) unit, and I’ve immediately faced a noise issue. Sleeping next to it is no go even with earplugs.

What now?

Finding The Solution

Well, I’ve got inspired by the aircon solution at my work, where cold air is brought to the vents by ducting.

Industrial ducting - my inspiration
My inspiration

So, I’ve fired up an Amazon and went for shopping. As I am Amazon Prime subscriber (affiliate link), I was looking not just for the right items, but also for things which can be delivered within the Amazon Prime next day delivery service.

I only needed two items: Duct reducer and flexible duct hose. Only requirements were for the bigger diameter of the reducer to cover the cold air vent on the portable air conditioner and hose to fit the smaller diameter of the reducer. As a result, I’ve opted for duct reducer (affiliate link), and 10-metre long flexible hose (affiliate link). In my case that was 250mm to 125mm (10” to 5”) for reducer and 125mm (5”) hose, but it may vary by the availability in your country.

All the components together
All the components together

I’ve also prepared a small video to illustrate how to install it and how it works.

By using duct tape, I attach the reducer to the portable air conditioner and seal all the holes around. The cold air is forced through the funnel, and consequently to the hose. Then I lie down the hose and take it to the room I would like to cool. I place the aircon near a window so the hot air hose can

We use this solution every summer since 2013, and I am so happy with it, I’ve decided to put together this article. I am aware the solution isn’t perfect, but it does what I wanted it to do.

Pros and Cons of This Hack


  • Cheap – once you have portable air conditioner it is a matter of about £30
  • Quiet – at least in the room you are cooling
  • Works – I am successfully using it for several summers
  • Quick deployment – can be assembled within a minutes
  • Flexible – you can cool almost any room; aircon can be used without the hose


  • Noisy – in the room with the portable air conditioner
  • Efficiency – lose air pressure over the distance; longer the hose lesser the pressure
  • Bodge – not a replacement for proper split wall mounted aircon system
Duct hose to Timmy's bedroom
Duct hose to Timmy’s bedroom

The air pressure issue can be tackled with an in-line fan such as MANROSE MF125T (affiliate link) I sometimes use, but it also brings complexity and additional cost.

In-line fan
My in-line fan


I am only cooling one room. And the setup does a decent job. It is possible to cool more than one room by using duct Y splitter (affiliate link). In my opinion, you would need a powerful aircon (12000BTU+) and probably an in-line fan as well, as the air would have to be pushed even longer distance.

Duct Y splitter
Duct Y splitter

If the room windows are facing West (even roughly), and the sun is scorching everything inside, you have to help your portable air conditioner a bit. I use emergency foil blankets (affiliate link) as a temporary solution to tape them on the inside of the window – I know, yet another bodge, but works, and it is on a budget.

Emergency blanket
Emergency blanket

As a permanent solution can be used reflective window film, but I have no experience with this solution – when I try it, I will post it on the blog.

Reflective window film
Reflective window film can also help

I can happily live with all the Pros and Cons – as I said we usually have just about two weeks of hot waves here, but if Summer 2018 would repeat, I will consider a proper, permanent solution.

Please let me know what your solution is to keep cool.