Sexier than a space heater — and certainly safer — these glass-panel heaters from London company Prefit supposedly install in minutes and are super-simple to use. You can get them in multiple sizes, and there's a mirror version for those who can't stand a cold bathroom floor in the morning. They cost about $1,750 to $2,600 — kind of proving that if you have the type of home where a large glass panel blends with the décor, then you'd probably be able to afford turning up the thermostat a few degrees. The panels heat up a room via an electrically conductive layer; when you pump some current through it, the high resistance generates heat. Since waste energy is defined as heat, the company can claim its heaters are 100% efficient. Fair enough, but don't let them convince you their mirror heater will make you look hotter.