What a clothes dryer costs to run
Across 639 certified models ENERGY STAR currently lists in this category, the median uses 608 kWh/yr. The cheapest certified model to run costs about $23/year; the most expensive costs about $129/year, more than 6x the spread.
Efficient models versus the rest
Of the 639 certified clothes dryers tracked here, 109 use meaningfully less energy than the category average and 186 use meaningfully more, the rest are within about 8% of it either way. The most efficient certified model found is the Bosch WQB245AXUC at 122 kWh/yr; the least efficient is the Amana NGD5800H** at 687 kWh/yr.
Your state changes this more than you'd think
The figures above use the simple average of all 51 published state electricity rates (18.8¢/kWh). A median-efficiency clothes dryer costs about $74/year to run in North Dakota (12.19¢/kWh, the cheapest state rate this site tracks) and about $279/year in Hawaii (45.95¢/kWh, the most expensive), the identical appliance. Every model page on this site lets you pick your own state to see the real number. See the guide to why location matters this much.
Over its lifetime
NAHB's Study of Life Expectancy of Home Components puts a typical clothes dryer's service life at 12 years. At that span, a median-efficiency model costs about $1,372 in electricity over its lifetime; the least efficient certified model costs about $1,550, a $178 gap from the choice of model alone. See the guide to when replacing one actually pays off.
Shopping for a new one
If the clothes dryer you own is old enough to be well past ENERGY STAR's current efficiency baseline, a current certified model like the ones above can cost meaningfully less to run.
Compare current ENERGY STAR certified clothes dryers before buying.