It's getting colder and with the cost of living rising, how best to heat our homes in the most efficient way possible has become a big question.

Listener Ken got in touch about a new kind of portable ceramic heater he's seen advertised, promising to heat your room using 30% less energy.

Greg Foot teams up with Octopus Energy to run it through the evidence mill and test it against three other types of portable heater: a convection heater, a fan heater and an oil-filled radiator to find out which gives the most heat for the lowest energy used. The aim is to find out which portable heater is best for heating you, and the room you're in. And how does all that compare to using gas central heating?

This series, we’re testing and investigating your suggested wonder-products. If you’ve seen an ad, trend or fad and wonder if there’s any evidence to back up a claim, drop us an email to sliced.bread@bbc.co.uk or you can send us a voice note to our new WhatsApp number: 07543 306807.

PRESENTER: GREG FOOT PRODUCER: SIMON HOBAN