{"id":2361,"date":"2026-08-27T09:05:16","date_gmt":"2026-08-27T09:05:16","guid":{"rendered":"https:\/\/chineseledlight.com\/?p=2361"},"modified":"2026-08-27T09:07:23","modified_gmt":"2026-08-27T09:07:23","slug":"led-efficacy-project-roi","status":"publish","type":"post","link":"https:\/\/chineseledlight.com\/it\/led-efficacy-project-roi\/","title":{"rendered":"Why Higher LED Efficacy Does Not Always Deliver Better Project ROI"},"content":{"rendered":"

LED efficacy is the amount of visible light a luminaire produces for each watt of electrical power it consumes, normally expressed in lumens per watt (lm\/W), but a higher efficacy rating does not automatically produce lower project cost, better illumination or stronger LED lighting ROI.<\/strong><\/p>\n\n\n\n

A quotation lands on the desk.<\/p>\n\n\n\n

Supplier A: 125 lm\/W<\/strong> Supplier B: 145 lm\/W<\/strong> Supplier C: 165 lm\/W<\/strong><\/p>\n\n\n\n

Easy decision?<\/p>\n\n\n\n

Buy C.<\/p>\n\n\n\n

At least, that’s what the spreadsheet seems to say.<\/p>\n\n\n\n

But if the 165 lm\/W fixture throws too much light outside the useful zone, creates uncomfortable glare, needs a lower-CRI LED package to hit the number, costs substantially more, requires the same fixture count and saves only a few watts per luminaire, that apparently superior efficacy number can have surprisingly little financial value.<\/p>\n\n\n\n

It happens.<\/p>\n\n\n\n

And the longer I look at commercial-lighting specifications, the less interested I am in asking which luminaire has the highest lm\/W?<\/em> before asking where are those lumens going?<\/em><\/p>\n\n\n\n

Because watts cost money.<\/p>\n\n\n\n

Lumens don’t pay bills either.<\/p>\n\n\n\n

Useful lighting performance does.<\/strong><\/p>\n\n\n\n

LED Efficacy Is Simple. Project Efficiency Isn’t.<\/h2>\n\n\n\n

The basic calculation couldn’t be easier:<\/p>\n\n\n\n

LED Efficacy = Luminaire Lumens \u00f7 Luminaire Input Watts<\/strong><\/p>\n\n\n\n

A 3,000-lumen fixture consuming 20W:<\/p>\n\n\n\n

3,000 \u00f7 20 = 150 lm\/W<\/strong><\/p>\n\n\n\n

Another fixture produces 3,000 lm at 24W:<\/p>\n\n\n\n

3,000 \u00f7 24 = 125 lm\/W<\/strong><\/p>\n\n\n\n

On paper, the first fixture is 20% more efficacious<\/strong>.<\/p>\n\n\n\n

Fine.<\/p>\n\n\n\n

Now put both into an actual ceiling.<\/p>\n\n\n\n

If Fixture 1 sends 900 lumens somewhere the project doesn’t need them while Fixture 2 controls more of its output onto shelves, task planes, walls or vertical merchandise, the nice-looking lm\/W ranking starts wobbling.<\/p>\n\n\n\n

And this isn’t some philosophical argument about lighting quality.<\/p>\n\n\n\n

The U.S. Department of Energy’s 2023 commercial LED procurement guidance specifically warns buyers to compare efficacy only between like products<\/strong>, because luminaire style, size and light distribution affect application suitability; DOE notes that comparing unlike products by efficacy can lead to selection of the wrong luminaire. (DOE Commercial and Industrial LED Luminaire Guidance<\/a>) (The Department of Energy’s Energy.gov<\/a>)<\/p>\n\n\n\n

That’s a sentence procurement teams should probably print above the quotation spreadsheet.<\/p>\n\n\n\n

\"Commercial
Commercial LED lighting comparison showing how optical distribution affects useful light<\/figcaption><\/figure>\n\n\n\n

First, Understand What lm\/W Actually Tells You<\/h2>\n\n\n\n

It tells you:<\/p>\n\n\n\n

how efficiently the complete luminaire converts electrical input into measured luminous flux.<\/strong><\/p>\n\n\n\n

Useful metric.<\/p>\n\n\n\n

Absolutely.<\/p>\n\n\n\n

DOE’s June 2023 FEMP requirements, for example, specified minimum efficacy levels of:<\/p>\n\n\n\n