When I was looking for the perfect projector for my home theater system, I dove right in. As with all my electronics, I knew to compare the specs. However, I found myself constantly questioning what these specifications actually meant to me. One of the most baffling specs, however, was the lumen or ANSI lumen measurement. If you are like me, you may find yourself wondering the same thing.
So what are projector lumens and what do they mean for your home theater set up? Lumens measure the brightness of the picture produced by your projector. ANSI lumens provide a more realistic brightness measurement, although is not always provided.
For most home theater projectors, lumens should measure between 2000 and 3500 lumens when moderate ambient light is present. However, if you are in a room filled with ambient light, you should look for a projector with at least 4000 lumens.
For a truly custom approach, understanding lumens and what factors affect the amount you need is vital. Depending on your content, resolution and ambient light – the lumens you need may fluctuate. Which is best for you? Keep reading to find out.
What Are Projector Lumens?
There are a lot of features and specifications you will want to evaluate prior to investing in a home theater projector. Contrast, throw ratio, light technology, and input capabilities are often listed in the specifications for all projectors.
(I will briefly go over the some of the other specs that affect image quality below, but you can find my in-depth explanations on my Ultimate Projector Buyer’s Guide.) However, one of the most commonly misunderstood specifications is actually one of the most important. This is the lumens quantity.
When you see a projector lumen listed, this refers to the level of brightness your device can produce. The brightness levels produced by your projector actually affect the quality of the images displayed by your device similar to how the digital zoom can affect the image quality as well which we explained in more detail in our guide.
Check out our recommended projectors to ease your worries about lumens and other projector specs.
Lumens vs ANSI Lumens
Some projectors list ANSI lumens instead of just lumens. To some, this may be a bit confusing. So let us start at the beginning. Lumens measure what is known as the “luminous flux”. This is the strength of light as observed by a viewer. A lumen observation is generic and somewhat subjective.
ANSI lumens, however, tend to be more accurate. This is because, in 1992, the American National Standards Institute (ANSI) standardized the way lumens are measured. (Projectors did not begin using the ANSI lumen measurements until much more recently.)
ANSI lumens are measured through more scrupulous methods that involve several variables. This includes measuring the white contrasts fields at specific spots located on the screen or medium you project onto.
These measurements are then averaged and multiplied to account for the total projected area. While the measurements are actually more complex than that, you can see that the ANSI lumens measurement method involves several components that help provide a more accurate total.
Older projectors typically include a lumen measurement. Unfortunately, they often reflect inaccurate measurements. The majority of newer home theater projectors, however, typically provide an ANSI lumen measurement. This reflects a more realistic and quantifiable lumen measurement that you can rely on.
A Brief Overview of Other Projector Specs that Affect Image Quality
Lumens and ANSI lumens for that matter are not the only specifications you should consider. This is because the lumens alone cannot account for screen materials, ambient light influence, or other issues that may affect the final image. Other specifications that may affect the projector’s image include:
- Contrast Ratio: Contrast ratio measures the difference between pure white and extreme black. Your projector’s contrast ratio will contribute to how vivid the final projected image is. As with lumens, ANSI contrast ratios provide a more accurate measurement due to more standardized test criteria. At a minimum, you will want a contrast ratio of 1000:1 for your home theater projector.
- Resolution: Often, the resolution is conveyed through pixel measurements. Pixels tell you how high your resolution, or image sharpness, can be. For most, a 1080p resolution, which is measured as 1920 x 1080 pixels, is ideal for a home theater projector. For those looking for Ultra High Definition (UHD), a 4K resolution of 3840 x 2160 pixels is best.
- Zoom & Throw Ratios: Zoom ratios tell you the range of screen sizes a projector will work with. The throw ratio, on the other hand, tells you how far or close your projector needs to be to the screen for optimal image quality. Both of these measurements are entirely personal choices based on the size of your screen and the room you plan to project in.
How Many Lumens Do You Need For a Projector?
There are three things you need to consider when determining how many ANSI lumens you need. These are content, resolution and ambient light.
- Ambient Light
The number of lumens you need should be a cumulative assessment of these three factors. Why? Certain content, resolutions and ambient lighting can provide you with a range of required lumens.
What you plan on projecting impacts the level of lumens you need. While it is unlikely you are purchasing your home theater projector to display presentations and business briefs, your content may still range.
- Home Theater: If you are primarily interested in using your projector for movies or television shows, a minimum of 2000 lumens is suggested.
- Gaming: Projectors should also start at 2000 lumens if you are planning on using it mostly for gaming purposes.
- Portable: Just for reference, presentations require fewer lumens. A minimum of 1500 lumens would suffice if you were looking for a portable projector you can take with you to the office yet still use for personal purposes as well.
The Bottom Line: Most home theater projectors should start at 2000 lumens at a minimum, regardless of other factors.
Projector Lumens and Resolution
I already briefly touched on resolutions. However, it warrants another mentioning here as it directly impacts the lumens you need. After you understand the type of content you want to primarily use your projector for, you should consider the resolution you will need to accurately project the images.
- Home Theater: Technology is constantly evolving. Right now, 1080P resolution (1920 x 1080 pixels) is still the reigning champion when it comes to television, video streaming, and movies. However, 4K (3840 x 2160 pixels) technology has been steadily gaining traction.
- Gaming: Almost all gaming platforms are built to work best with 1080P resolutions. A projector that supports this capability is ideal as 4K technology is not yet in sync with the flash bang of your PS4, Xbox or Nintendo Switch.
- Portable: Many portable projectors include only 840 x 480 resolutions. If you plan on using your projector both at home and at work, you will need to pay careful attention to the resolution capabilities for a quality movie display. Contrary to what some people think, projectors can be diverse in terms of how they work – like laser projectors, which we’ve explained before – which is why it’s important to pay attention to things like resolution capabilities among other specifications.
The Bottom Line: While your content, screen size and ambient light will likely push your lumens up, keeping your resolution in mind will ensure your image provides a clear image suited to your needs.
Projector Lumens: What Effect Does Ambient Light Have?
Ambient light is actually one of the biggest factors when you are looking to invest in a projector. Ambient light refers to the level of natural light that filters into the room where you intend to use your projector. Ambient light directly affects the brightness and, therefore, should be carefully considered when reviewing lumen specifications.
In order to determine the proper lumens as they relate to ambient light, you also need to consider the intended screen size. (Screen size is measured diagonally from the lower left corner to the upper right corner.)
- Home Theater: For home theaters, screen sizes that measure between 92 inches and 119 inches, rooms that include little to no ambient light, lumens could be as low as 1300. For rooms that have some ambient light, however, screens that measure between 90 inches and 119 inches would do best with lumens that range between 1500 and 3500 based on the level of light seeping into the area. If there is a lot of ambient light, you should start with a minimum of 4000 lumens regardless of screen size.
- Gaming: Gaming projectors needs in ambient light are actually quite similar to those used for a home theater. However, I recommend you look for a projector that includes a “Game Mode” should you be torn between usage.
- Portable: Most people opt for a portable projector because they are looking to use their device for several purposes, including business and travel. Because of this, screen sizes and ambient light are often widely ranging. For rooms with little to no ambient light, screen sizes that range between 72 inches and 150 inches, you should look for 2500 to 2700 lumens. For rooms with some ambient light, however, screens that measure between 72 inches and 100 inches should be between 3000 and 4500 lumens. Screens that measure between 120 inches and 150 inches in this same environment should actually have between 2700 and 4500 lumens. In rooms with a lot of ambient light and screen sizes that range between 120 and 150 inches, you should look for a projector with 5000 to 6000 lumens. These projectors are not recommended for screens smaller than 120 inches in areas with high ambient light.
The Bottom Line: Carefully evaluate the level of light coming into the area where you intend to use your projector. Buying a projector that does not take into account the ambient light and screen size can seriously affect your image quality.
What happens if I buy a projector with “too many” lumens? It is best that you invest in a projector that, at a minimum, meets with the highest estimated lumen need. In fact, having “too many” lumens is much better than having too few.
This is because having more than you need will not affect the image. But having too few? That will greatly reduce your image quality.
Sunday 6th of November 2022
Hi I wonder if you could help. I am keen to buy a projector with a budget of around £500. I want to use it fairly regularly during day and night in a couple of rooms one of which has a good amount of ambient light so needs lumens. The distance to wall will be around 3-4m in each max. I’d be using it to watch tv and film but sports too, so would want good usability and access eg hdmi for Amazon Netflix etc. I guess I’d need to get a speaker. Portability is a positive too. I believe I need 4,500 ansi but I’ve been searching the web and I must admit I’m confused as they range in spec massively and sometimes high cost projectors have worse spec than cheaper ones, and really keen for someone with experience to advise best projector at around the price tag mentioned so I can finally get one. Hope you can help! Thanks so much in advance. Ross
Leslie M Kruth
Friday 31st of July 2020
Hello Johna, I am trying to figure out what the ratio of height to width should be BEFORE I buy my projector because I have the opportunity to buy a 9'x6' canvas now. I am wondering if that might work. My projector will be 15 feet away. Thanks! Leslie (you might email me if possible) Where do you live?
Leslie M Kruth
Friday 31st of July 2020
When you say "screen size that measures between 72-150" is that a diagonal measurement? Your side is very clear otherwise! Thank you
Saturday 2nd of May 2020
Very useful content and well explained. I have to run a projector in a hall about 4m from a 345x216 cms screen. If curtains are closed then what lumens? 3,500? if ambient light then how much?
Raed Nazmi Mouanna
Monday 16th of March 2020
Hi am planning to buy: BYINTEK UFO R15 Android LED Mini HD DLP 3D Projector to watch movies in room with little ambient light to moderate one in like 200 inch
But it has only 600 Ansi lumen. This made me worry & not to buy. am i right?