Here are some findings I’ve been meaning to post for a while.
A bit over a year ago, I fulfilled a decade-long dream of owning a good projector for movies, instead of some silly monitor with a diagonal measured in “inches”. My lifestyle very rarely allows me to watch movies (or series*), so when I decide to watch something, it needs to have a rating over 90% on RottenTomatoes, it has to be watched with a bunch of friends, and it needs to be a top-notch audio-visual experience. I already had a surround sound system for over a decade, so the projector was the only missing part of the puzzle.
After about six months of research and agonizing over projector choices, I narrowed it down to the infamous BenQ W1070, which uses conventional projection lamps (Aaxa’s LED projectors were not competitively priced at that time, costing more for a lower resolution and less connectivity):
First power-on, with David Revoy‘s beautiful artwork as my wallpaper
In the process of picking up the BenQ W1070, I compared it to the Acer H6510BD and others, and this particular question came up: how realistic are manufacturers’ claims about their dynamic “lamp life saving” features?
The answer is:
For starters, I asked Acer to clarify what their “Extreme Eco” feature really did, and to their credit they answered truthfully (emphasis mine):
Acer ExtremeEco technology reduces the lamp power to 30% enabling up to 70% power savings when there is no input signal, extending the lifespan of the lamp up to 7000 hours and reducing operating costs. 4,000 Hours (Standard), 5,000 Hours (ECO), 7,000 Hours (ExtremeEco)*
*: Lamp Life of ExtremeEco mode is based on an average usage cycle of 45 minutes ECO mode plus 75 minutes ExtremeEco (30% lamp power) mode
Yeah. “When there’s no input signal”. What kind of fool leaves a home theater projector turned on while unused for extended periods of time and thinks it won’t destroy the lamp’s life?
Now you’re wondering if Acer is the only one trying to be clever about marketing and if other manufacturers actually have better technology for lamp savings. After all, BenQ is very proud to say this (direct quote from their website):
By detecting the input content to determine the amount of brightness required for optimum color and contrast performance, the SmartEco Mode is able to reduce lamp power while delivering the finest image quality. No compromise!
Bundled with this chart, no less:
Note: “LampSave” mode is a different thing, it’s either the manual screen blanking button, or when SmartEco detects no more input signal at all and turns down the lamp, like Acer’s “ExtremeEco”!
So, perhaps the widely acclaimed BenQ W1070 projector’s “SmartEco” mode is a truly smart psychovisual image analysis system that continously varies the intensity to make darker scenes go extra-dark, darker than the “constant” Eco Mode? Glad you asked, because I have the numbers to prove that’s not the case either.
I measured the BenQ W1070’s power consumption through a 3×6 conditions experiment:
Power scheme:
Normal mode
Eco mode
SmartEco mode
Content type:
A photo of the Hong Kong skyline at night
A static view of the TED.com website, split-screen at 50% of the width, on top of the Hong Kong image
A static view of the TED.com website, maximized
GIMP 2.10, maximized, with a pitch-black image and a minimum amount of UI controls (menubar, rulers, scrollbars, statusbar) as bright elements
That same 100% pitch-black static image, fullscreened
Playing Sintel and measuring the total electricity consumption over 15 minutes, in kWh
Here are some of the “content type” conditions above, so you have an idea what the static images looked like:
Here is a visual summary of the results for the “static images” conditions:
And here are the raw numbers:
Normal mode
Eco mode
SmartEco mode
Static H.K. night skyline photo
264 watts
198 watts
273 watts
Static TED.com split-screen
264 watts
198 watts
276 watts
Static TED.com maximized
264 watts
198 watts
276 watts
Static GIMP (almost pitch-black)
264 watts
198 watts
256 watts
Static pitch-black image (fullscreen)
264 watts
198 watts
198 watts
15 minutes movie (Sintel)
0.066 kWh
0.0495 kWh
0.06x kWh
Note: for the Sintel benchmark, the “0.06” figure lacks one decimal compared to the two other conditions (Normal and Eco modes). This is due to display limitations of my measurement instrument; other values were calculated (as they are constant) and confirmed with the measurement instrument (ex: Eco mode was measured to be at 0.04x kWh). It is thus possible that SmartEco’s 0.06 kWh was anywhere from 0.060 to 0.069 kWh.
As you can see, BenQ’s SmartEco provided no significant advantage:
With normal/bright still images, it increases consumption by as much as 3% compared to the full-blast “normal mode”; it reduces consumption by the same amount (3%) when displaying very dark images, and does not under any circumstances (even a 100% pitch black screen) fall below the constant power consumption value of the regular “Eco mode”.
In practice, while watching movies that combine light and dark scenes, “SmartEco” mode might (or might not) reduce energy consumption compared to “normal mode”, by a small amount.
SmartEco will always be outperformed by the regular “eco mode”, which yields a constant 25% power saving.
Out of curiosity, I also tested all the other manual image settings in addition to “eco mode”, including: brightness, contrast, color temperature, “Brilliant Color” (on/off); none of these settings had any effect on power consumption.
My conclusion and recommendation:
“Smart” eco modes are dumb and will eat your lamps.
With current technology, home theater projectors should be locked down to a constant lamp economy mode to maximize longevity and gain other benefits; after all, you’re supposed to be sitting in a pitch-black room to maximize contrast and quality with any projector anyway, and the lower lamp power setting will also reduce heat, and thus cooling fan noise.
Nonetheless, the W1070 is a very nice projector.
*: When I tell people I don’t watch any series at all, including [insert série-du-jour here], I typically get reactions like this: