How to Build Safe DIY Radiator Heat Reflectors (And Why Foil-Wrapped Cardboard Is a Risky Choice)
The viral version of this hack is everywhere: wrap a flattened cardboard box in kitchen foil, wedge it behind the radiator, and watch your heating bill drop. It’s cheap, it reuses an Amazon box, and it sounds too good to pass up. Here’s the problem nobody mentions in those videos: plain kitchen foil and cardboard…