America’s most unpopular way of saving energy…is one of Europe’s favorites

Last week, we drew upon 2.7 million survey responses in Opower’s energy data storehouse to reveal America’s most popular ways to lower household utility bills in summer.

Popularity is, of course, a contest. And while every contest has its winners, it also has its losers. In our analysis, one summertime energy saving practice in particular emerged as catastrophically unpopular: hang drying laundry.

Among the 150+ efficiency tips in our interactive energy-information web portal, hang drying laundry was the only high-traffic tip (i.e. clicked more than 50,000 times) that garnered more detractors than adopters. In our data sample, for every 20 American utility customers who indicated that they do hang dry their laundry, 21 indicated that they don’t.

Perhaps it’s not surprising that a relatively toilsome energy saving behavior like hang drying laundry would get less love than other piece-of-cake practices, like drawing the curtains to keep out the summer sun (#3 in our most popular tips list) or adjusting the thermostat (#1).

More surprising, however, may be the sizable implications of America’s preference to use the tumble dryer instead of the clothesline. With approximately 85% of US households owning tumble dryers and the vast majority of them toasting up 2+ loads of sopping wet laundry per week, clothes dryers account for a big chunk of home energy use. Joining water heaters and refrigerators among the top three electricity-hogging appliances in US homes, dryers account for 6% of the country’s residential electricity consumption and each year add $9 billion to American families’ utility bills.

Europe beats out US on energy-efficient clothes drying (a.k.a. why Europeans’ clothing probably lasts longer)

So why are American households so committed to their tumble dryers, when they could save upwards of $100 per year (not to mention extend the lifetime of their threads) by using clothespins, a string, and some extra time?

Granted, nearly 27,000 US homes in our data sample (consisting of around 220,000 utility customers who have made personalized energy saving plans) report that they do already hang dry. But they are outnumbered by their tumble-drying counterparts (approximately 29,000 of them in our sample).

To find the real leaders of air drying, one must look beyond North America. Whereas 85% of US homes own energy-gulping dryers, the UK gets by on a 57% dryer ownership rate. And survey data from Opower’s UK-based customers reinforces their relative comfort with surviving sans tumble dryer: in our data sample, UK customers who embrace hang drying far outnumber those who don’t — by a ratio of 14:1.

Most western European countries, in fact, have tumble dryer ownership rates below 50%. The most ambitious case of line drying on the continent is Italy, where clotheslines are famously ubiquitous and 95% of homes reportedly live without dryers.

Meanwhile, in the Southern Hemisphere, New Zealanders are another shining example of a people who regularly makes use of their clotheslines: 90% of Kiwi households assert that they hang dry their laundry all the time (67%) or some of the time (23%).

One major explanation for the US’s low rate of hang drying can be traced to rules and regulations. Tens of millions of Americans live in community associations or landlord-managed properties that impose restrictions on the use of outdoor clotheslines, citing aesthetic concerns. In the past few years, however, a growing number of states and jurisdictions have begun to assess the drying-related energy impact of these ordinances.

If hang drying is not for you…

For families who simply can’t imagine hang drying (whether they’re restricted from using outdoor clotheslines, are too busy, or live in a frigid climate and are sensitive to the ambient moisture buildup associated with indoor air-drying), there are several ways to reduce the energy consumption of tumble dryers.

A few energy-saving best practices include: running the washer’s “spin cycle” to remove excess water from clothes before they go into the dryer (washers are 10 times less power-hungry than dryers); activating the dryer’s moisture sensor, which prevents energy waste by automatically powering down the machine once clothes are dry; and cleaning the lint filter after every load to improve air circulation.

And for those in the market for a brand new dryer, it’s worth shopping around for cutting-edge technology like heat-pump dryers, which are up to 40-50% more efficient than conventional North American models, and have already been embraced by consumers in Europe and Australia.

If you’ve never hang dried your laundry, summer is the best time to try it out (or should we say, “dry it out”). See what life is like without the tumble dryer for a week, and you’re bound to see your summer energy bill tumble downwards.

Barry Fischer is Head Writer at Opower. Nate Kaufman leads Opower’s energy efficiency content team and is a Certified Building Analyst

Special thanks to: Arjun Dasgupta, Ashley Sudney, Erin Sherman, Dylan Lewis, Aaron Tinjum, and Brett Foreman.

Follow @OpowerOutlier on Twitter


Data analysis is based on an anonymous, geographically diverse sample of energy saving plans from 222,607 unique utility customers — constructed via their visits to and engagement with Opower’s energy information web portal. Tip popularity is inferred from an aggregate pool of 2.77 million clicks that convey users’ preferences on how to save energy.

To determine popularity rankings of each tip category (see Part 1 of our Summer Tips Analysis for more details), we computed adoption-to-rejection ratios, defined as: (# of customers who report adopting a given tip) / (# of customers who report not being interested in a given tip). Adoption is defined as the sum of unique customers who report having done or planning to pursue a given tip. Rejection is defined as the number of customers clicking “No Thanks” in response to a given tip.

Adoption-to-rejection ratios for each category of savings actions (among US-based utility customers) were as follows: Set Thermostat Wisely (22), Let AC Breathe (18), Keep out Sun (12), Structural Improvements (6), Peak Savings (3), Hang Dry Laundry (1). Given that relatively few homes own pools but they are responsible for a disproportionate fraction of home energy use, the pool savings category was included based on the authors’ judgment, rather than for its specific adoption-to-rejection ratio.

Dryer-versus-CFLs comparison is based on 15 watt CFL bulbs, a dryer with a power draw of 3400 W (the midpoint of the US Department of Energy’s sample wattage range of 1800-5000 W), and an hour-long dryer cycle.

Data Privacy: All data analyzed here are anonymous and treated in strict adherence to Opower’s Data Principles.

Author’s note: The analysis and commentary presented above solely reflect the views of the author(s) and do not reflect the views of Opower’s utility partners.

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Barry Fischer and Nate Kaufman /