Tumble dryers are not very eco-friendly by the very nature of their function. There are only a few electric models with an A rating and these use expensive heat pump technology, such as the V-ZUG Adora. Gas tumble dryers are rapidly gaining popularity because of their energy saving benefit. Around 25% of tumble dryers in the USA are gas models, and most tumble dryers in UK launderettes are gas. White Knight's own tests show their gas dryers produce 50% less carbon than a typical electric dryer, with 60% lower annual running costs! Electric tumble dryers currently account for a massive 4.3% of the entire UK domestic energy consumption, so gas powered are both more environmentally friendly and much cheaper to run.