Many years ago some bright spark suggested that putting a tennis ball into a dryer would help soften clothes and save you money by reducing drying time. Marketing gurus have cottoned onto this idea and introduced plastic or woollen balls claiming to do the same thing. But do they truly work?
In short, not really. There are marginal differences, but in most cases they increase your costs by a very small percentage. We tested with a conventional electric vented dryer and an upmarket condenser dryer both with and without the balls and compared the two – none made much impact on performance.
So by all means if you want to throw your money towards this product, go ahead, but don't be under any illusion that they'll save you any money with regards to reducing drying time.
We compared each of the products with a separate run without dryer balls in each dryer type. We used identical loads and program types. We measured against the final mass and energy usage for the conventional electric vented dryer and we compared against mass, time and electricity with regards to the condenser dryer. We've only displayed energy usage because this is the difference you'll see in your energy bill. We used a 3.5kg IEC cotton load that we use for all our dryer (and washing machine) tests. We based the energy cost calculation on $0.30/kWh.
Electric vented dryer: Simpson 39P400M
Condenser dryer: Miele T8929WP
Don't bother buying these products to save you money by speeding up your drying times and using less energy. Quite simply, they don't work.
Dryer balls also make the claim to make clothes softer, which we haven't tested – but as per our fabric softeners article, you can just give your clothes a flick when they come out of the wash and that should add some air to the fabric.