A science expert has revealed that single-hose portable air conditioners have a major design flaw and demonstrated a simple DIY hack using cardboard that can dramatically improve their efficiency. Michael Le Page, senior reporter at New Scientist, shared the tip on TikTok, highlighting that these units waste energy by pulling in hot, humid air from the room and expelling heat through a hose that warms the indoor space.
The Design Flaw Explained
Le Page explained that single-hose air conditioners draw warm air from the room and blow hot air outside through a hose. However, the hose itself becomes hot, radiating heat back into the room. Additionally, the unit pulls in hot and humid air from the room, which it must constantly cool, wasting energy. He likened this to 'mixing mud into laundry detergent'—the hotter and more humid it gets, the less efficient the machine becomes.
The DIY Cardboard Fix
To address this, Le Page demonstrated a DIY conversion using cardboard to seal off the rear of the air conditioner, where warm air is drawn in, from the bottom. This forces the unit to pull air from outdoors instead of the room, similar to a dual-hose system. He noted that some manufacturers sell conversion kits that can increase cooling power by three times. 'If there is no conversion kit available, you can do a DIY job as I've done here,' he said.
Le Page added: 'Because the hose is outside, it's not warming up my room at all. If you do have a hose like this inside your room, I'd recommend covering it with a towel or blanket to minimise that heat loss. This hack has dramatically increased the performance of this machine. Before, when it got really hot during heatwaves, it was struggling to keep a single room cool. Now it's effectively cooling the entire house. It's a huge difference.'
Call for Regulatory Change
Le Page urged the UK Government to overhaul energy labelling regulations for portable air conditioners, making it transparent how they function and mandating dual-hose designs over single-hose ones. He also noted that split-unit air conditioners are 'much more efficient' and, while more expensive upfront, can save money in the long run by using less energy.
