I did a simple indirect light (~1 lux) test between a halogen and led with a SNB-5004 set to AGC off and shutter of 1/4.
- the Halogen Mono image is clearly brighter than the LED Mono pic.
- the Halogen Color image is slightly brighter than the LED Color pic.
The first statement, taken without any IR filter, is easily explained since camera sensors are typically sensitive to IR and the infrared component of a halogen lamp has a significant IR component to it, as shown here:
In the second case, though one might argue that the IR filter should eliminate the IR reaching the sensor, so they should be the same. IMHO, optical sensors are not hard-pass filters, they taper and so rather than reduce any visible light, they err on the side of letting a little of the shorter-wave IR thru. Not much, but detectable in the case of halogens.
A unscientific but convincing way of demonstrating the sensitivity to IR even with the cut-on is is to take a remote control and fire it at a security camera in color mode. I did:
In the OP's case though, since he intends to use low-light cameras in color mode, the extra IR illumination lost would be minimal, and most likely made up by even a small increase from the new lights.
On the other hand, when replacing incadescent or halogen with LED's, and in cases where one is switching to Night mode without any additional IR, the difference could be significant.
In either case the one thing to keep in mind is beam spread and CRI (color index) of the new fixtures vs. the old. LED's can be extremely directional, they have a "FOV" just like cameras but in reverse.
So even if brighter overall, you will likely find after the conversion spots that are better illuminated than before and vice versa.
My wife runs a small LED retrofitting company which I interfere with in my spare time. :)