Are new electric clothes dryers more efficient than older models?
What ENERGY STAR dryers are available to replace an old electric dryer? I’ve looked for efficiency information on electric clothes dryers but can’t find any. I have an electric clothes dryer that’s over 10 years old and I’ve been thinking of replacing it with a more energy efficient model, but I can’t find any from any of the big name brands. Are newer electric clothes dryers more efficient than something 10 or more years old?
Answer from Green Energy Efficient Homes
You won’t find ENERGY STAR dryers because there should not be any significant difference in efficiency between older and newer electric clothes dryers.
Electric clothes dryers use an electric resistance heating element, which is always 100% efficient at converting electricity into heat. By far the biggest share of energy used by an electric dryer is for the heat, so improvements to the fan motor won’t make much difference in dryer efficiency. Fan motors are inductive loads, which means you can actually improve the power factor efficiency of them by using a built-in capacitor in the motor assembly, but assuming this makes the motor 5-10% more efficient it will only effect the overall efficiency of the dryer by 0.5 to 1%.
ENERGY STAR dryers would need to be at least 10% more efficient than the current minimum efficiency standard for electric clothes dryers, as typically the ENERGY STAR standard for an appliance type starts with what is easily achievable with current technology, and tries to push for a higher efficiency. But there’s really not much you can do to make an electric dryer more efficient, so I don’t think you’ll ever see ENERGY STAR dryers being offered because there would be no way for manufacturers to improve on existing efficiency, and therefore no point in ENERGY STAR setting a new standard.
To give an example of how hard it is to boost dryer efficiency, and why there are no ENERGY STAR dryers, consider this: The US office of Energy Efficiency and Renewable Energy (EERE) does not rate electric dryers at all, while the Canadian Office of Energy Efficiency does rate electric dryers on efficiency, but for example, their electric dryer ratings vary only between 950 kWh/year (least efficient) and 898 kWh/year (most efficient), which is only a difference of 52 kWh a year, or about $5-10 worth of electricity depending on what you pay. Compare that to washing machines, where the differences between lowest and highest energy use range from 100 to 500 kWh per year. That means the most efficient is 400% more efficient than the least efficient. That’s why there are plenty of ENERGY STAR washers and no ENERGY STAR dryers.
The best way to save energy on drying your clothes is to upgrade your washer to a front-loading, ENERGY STAR rated washer. Front loaders use less water and less electricity to wash, but above all they spin much faster than top-loaders so they extract far more water than a top loader could. As a result, the clothes you put into the dryer from a front-loader are much dryer to start with than those from a top-loader, so take much less energy to dry.
Of course, even better are clothes lines and clothes racks. We have a dryer but almost never use it, except for towels, which get to feel like prickly boards when you dry them on the line, and some permapress or cotton shirts that get too wrinkled when line dried.