When your house is lit up like Blackpool Tower it’s pretty easy to tell you’re wasting energy. But what if someone accidentally leaves the fridge door open? Not only is that a massive waste of electricity, it’s a recipe for disaster when dinner time comes. You’d been saving those sausages since Wednesday. Glow (from US$149) has a sensor that measures the inductive magnetic fields created by energy flowing through the meter, using a traffic light system on the device itself to tell you how much you’re using. If there’s a sudden spike, suggesting those sausages are at risk, it’ll send a notification to your phone so you can make sure those delicious pork cylinders make it to the dinner table.