This Epson is a light canon. (That translates to "really bright".) Even for 3D viewing, I can't see the need for a really high gain screen. This simplifies and lets you pick the screen that best suits the room you are in, the varying levels of ambient light you might deal with, and also how big a screen you choose.
The Epson Home Cinema 3020 fills my 124" Studiotek 130 screen (1.3 gain, 2.35:1), even with lamp on ECO, without even trying. Or, if you want some lights on, try to have the ambient lights coming from the sides, look for a screen that's high contrast and gray, for rejecting a lot of side ambient light. Most manufacturers have them.
If your room has ambient light but not from the sides, rather straight back, those HC gray's aren't going to help that much, so you might be better off with a nice "plus gain" screen - say 1.3 to 1.6, to brighten the image. That won't help though if your ambient light is back where the projector is. Some HC gray screens are better at rejecting light coming from above, than others.
Whatever your room for the Epson Home Cinema 3020, I offer some advice, if you have the option to try to improve the room. Fortunately:
Should you be able to pull it off, darken your walls and ceiling, and if possible, also the floor of your room, to dramatically improve your experience. Keep in mind with a bright projector like this Epson, however, you can cut through quite a bit of ambient light when you want to watch sports, regardless of walls... 2000 lumens can go a long way.
If you can't really redo the room, do what you can. But, if you can do nothing else, and can manage to darken the wall your screen is on, that alone will make a real difference. If you have the usual off white ceilings, you can, as I did, darken them several shades - They will likely still seem as bright to everyone, since the ceiling will likely still be the brightest surface. That worked in my old great room. I darkened the ceiling several shades, and the result - well less than half the reflected light getting back to the screen. - And no one noticed the ceiling change.
My new theater, with its black ceiling and dark blue walls and floor, just about any projector now seems bright. The Home Cinema 3020 is downright brilliant, and is the first 3D capable home projector in here for review that is actually fairly bright on 3D on screens over 100". Wow!
Even the testing room with about half of its wall surfaces set to off-white, the projector easily handles my 110" screen (2.35) when filling the full width with a widescreen movie in 3D.
Most likely you should chose a white surface with gain up to 1.5 for this Epson, or a high contrast gray surface, if your layout benefits from it.
Image below taken using 128" screen, an old (2007) Sony VW60. A projector that we measured at a max of under 700 lumens. This room at that time, was "watch football during the day, everything else, at night only." (My other theater room in that house was far darker.)
same setup, the old Epson 1080UB - several generation forerunner to the Epson 5020, and twice as bright as the Sony. The 1080UB at its brightest was very bright for its day (2008). This HC3020 however, is still a few hundred lumens brighter
My presumption is, you care about good movie performance, and having good blacks, since you are considering, or own this projector. Rooms with a fair amount of light are often just fine for almost all HDTV and definitely sports. They won't be significantly impacted by reflected light from the original image.
Family room image.This image shows the difference after darkening ceiling several shades below the original off-white, and taking the walls to a dark rust color: Even with the door shades partially open, the JVC used in this picture had almost identical brightness as the Sony in the first image. The moral to the story - darker walls can easily offset having fewer lumens.
That's pretty impressive, is it not? with the Medium rust walls, a bit darker ceiling (everyone still thought it was white - as it was the lightest surface in the room), the shades opened a bit, yet thanks to the darker surfaces, the image is far better looking than the first image above.
I loved having that Stewart Firehawk G3 (in the images above) in my last home for handling a light surfaced room. As I said, it was 128" diagonal in a room with a cathedral celing. When I started out there, all the walls were off white, as was ceiling, and carpet was gold. Lots of windows, which I covered with pleated shades - but with no channels. The Firehawk allowed me to have a good picture even with a moderate amount of light (when the room is "you can read a newspaper easily" bright)
That HC gray screen rejects most of the side lighting. This allowed me to even have my slide window shades open a few inches on sunny days, and still have a large, great football image. If your ambient is coming from straight back near the projector, like rear windows, the HC gray won't help you.
Ultimately, an HC gray is going to be the best choice for most folks with lighter rooms, and especially if the lights are on the sides. Consider the especially the Firehawk G3, and the various Screen Innovations Black Diamond screens (different gains, etc.) which are especially good, but also relatively pricey. More affordable: Elite's HC Gray, Da-lite's HC-Da-Mat, possibly Stewart's new Cima series I haven't worked with any of them yet.. Typically we're talking screens with gains of 0.8 to 1.1 gain. The Epson's inherently pretty bright on all but the very largest screens or if doing 3D, so trading a little brightness for some ambient light rejection is a plus. (Note HC screens are a touch darker in the corners/sides.)
Don't get me wrong, you can go with a standard white surface, but in a light surfaced room, you'll also appreciate the gray surface's ability to lower the overall black levels, in addition to helping "reject" much of the ambient light that isn't coming from where the projector is (straight back).
One alternative to the HC gray, might be a "high power" screen, one with lots of gain - such as 2.0 or higher. Like the HC gray screen there are tradeoffs. I find the roll off from the very high gain screens to be much worse than the less than perfect edge to edge brightness of an HC gray screen. I avoid hi-power screens, but I know some very serious projector owners who swear by them, for the right situation
OK, what about 3D? In a room like my old one above, the HC gray type screens although a little less bright, are still your ticket if you have side ambient light to deal with. Otherwise, go with the higher gain whites.
Bottom line: The projector has the brightness. Now find the right surface screen to deal with the room. All that brightness gives you a good deal of leeway, and it means you can tackle a room a bit worse, lighting wise, than the competition is able to handle.
