As sweltering heatwaves become more common, many people have turned to portable air conditioners to keep cool. However, these units often suffer from a major design flaw that makes them inefficient. Michael Le Page, senior reporter at New Scientist, has shared a simple DIY hack that can dramatically improve their performance.
The Design Flaw
In a TikTok video, Le Page explained that single-hose portable air conditioners are problematic because they pull in hot, humid air from outside through gaps around the hose, forcing the unit to constantly cool that air. This wastes energy and reduces efficiency, especially as outdoor temperatures rise. He compared it to "mixing mud into laundry detergent."
Additionally, the hose itself gets very hot during operation, and if it runs inside the room, that heat radiates back into the space, further diminishing cooling effectiveness.
DIY Fix: Converting to Dual-Hose
Le Page recommends using a dual-hose portable air conditioner, which has an extra hose to draw in outside air for cooling the condenser, then expels it outside. This prevents the unit from pulling in warm air from the room. Some manufacturers sell conversion kits to turn single-hose units into dual-hose systems, with one manufacturer claiming the conversion can triple cooling power.
If no conversion kit is available, Le Page demonstrated a DIY solution: using cardboard to seal off the back of the air conditioner where hot air is taken in, effectively creating a barrier that forces the unit to draw air from outside rather than the room. He also suggested covering the hose with a towel or blanket to minimize heat loss.
Dramatic Results
Le Page reported that this hack dramatically increased his machine's performance. "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," he said.
Call for Regulatory Change
LePage urged the UK government to revise energy labeling rules to make the inefficiency of single-hose units clearer and to mandate dual-hose designs. He also noted that split-unit air conditioners, with an outdoor compressor and indoor air handler, are "much more efficient" and may save money long-term despite higher upfront costs.
