Welcome to Back Morning返晨!Strengthen your supply chain!

Will IES data change after the LED lights work a long time?

IES parameter is different from Lumen.It includes more data for LED light,include:Light Distribution,Light Intensity,Beam angle,UGR,etc.These are very useful for lighting project designers.

And We already know:for good quality LED Lights, the Lumen reduction is very small after working for years.

So,a question come:After the LED lights working for a long time, will these IES parameters change?

  1. Beam Angle
  2. UGR
  3. X、Y Value
  4. CRI

Because the Diodes packaging material may change some physical properties during the long time working(heat),as well as the lense and reflector material.

To study this,we(FCS) prepared 3 pcs of LED Downlight,build below test model:

1.Use Gonio photometer and Integrating Sphere to test these lights,get the original data:IES Data and Spectrum Data.

2.Let these lights working under a high temp (65~70℃) for 1 week.

3.Retest these lights to get data.

Now the test finished, we can see:

There is no obvious change on these data!

The data include: Power, Power factor, UGR, Beam Angle,Lumen Efficiency,Ra,X&Y Valume,etc.

See below Summary for Beam Angle:

IES testing

See below Summary for X&Y Value:

0 (1)

See below summary for other data:

0 (2)


1.We used very good quality components and procedure to assemble these lights samples.

2.High Temperature testing is very helpful for us to get some reference data, but it's not 100% same as long time testing.

3.Duiring our testing,we used reflector, but not lense.These 2 items may offer different physical properties


We provide below professional service to LED Lighting importers, buyers, traders, project owners:

1.LED Lighting Sample testing

LED lighting testing  ,The spectrum test

2.Chinese lighting supplier's Evaluation/Audit

3.Inspect LED Lighting during production, and before shipment.


Hank Wang


Wechat: LNY0539

Whatsapp:+86 18616827523

The measured data of the following products has been approved by the supplier, and will be uploaded and released by Back Morning independently!

Test product category