While ethical questions can be raised in regards to ad-blocking, the advantages seem obvious. All those ads clutter up the page, slow down load times and eat up battery life, say proponents of ad-blocking software. Over four days, staffers from The New York Times tested ad-blocking apps Crystal, Purify and 1Blocker on their iPhones, and “measured how much the programs cut down on Web page data sizes and improved loading times, and also how much they increased the smartphone’s battery life.” The results favored ad-blockers for mobile devices.

Arguments against ad-blocking comes, not surprisingly, from the advertising industry, which notes that blocking online ads puts the existence of those advertisers in peril, including small companies like home town newspapers. But no one has measured if ad-blockers actually work and if so, by how much. Until now.

NYT ran two specific tests with all three apps: “In the first test, we recorded the data sizes of the 50 most popular news websites with and without ad-blockers enabled. We used those figures to calculate approximate page load times on a 4G mobile network. In the second test, which was designed to measure battery life, we compiled a custom iPhone app to cycle through dozens of popular websites in an endless loop. We then timed how long it took the battery to completely drain from our phone with and without ads.”

The results proved that ad-blockers — which work on mobile websites but not apps — help mobile devices. When loading the Boston.com site, says NYT, the homepage measured 19.4 megabytes with ads, and four megabytes without, translating to 39 seconds load time with ads and eight seconds without.

NYT measured its own website: the home page “measured 3.7 megabytes when loaded with ads and took seven seconds to load; Purify shaved the size down to 2.1 megabytes and cut the loading time to four seconds.”

In addition to slowing page loads and draining battery life, ads can also push data rates beyond users’ limits, resulting in higher phone bills. Crystal developer Dean Murphy hopes that blocking might “encourage publishers to create better ads that are less taxing on mobile gadgets.” If ad-blocking on mobile devices takes off, they’ll have to.