The Swedish start-up that's worked out how to use hot fumes from kitchens to heat restaurants.

Hear from the entrepreneurs who've developed this new technology. They tell us how it works and how it can help restaurants lower bills and carbon emissions.

However this technology is expensive for restaurant owners, especially at a time when hiring workers and buying ingredients has got a lot more costly. One small business tells us about the benefits and challenges of investing in new equipment.

Producer / presenter: Maddy Savage Image: Annika Lyndfors; Credit: BBC