White, white walls, ceiling, floor for lighting efficiency 1

To light a building interior efficiently highly reflective walls are desired. I believe that newly painted white walls are only about 80% reflective to visible light - but this decreases as "dirt" accumulates on the surface.

What information is available on increasing the light level in a building independant of increasing the efficiency of the light source?

 

[EEJaime]

Hello,

Light colored finishes are a prime source of reflected light and increase the useable light. For the average light color pallette, we generally calculate it at 80%-walls, 60% ceiling, and 20%-floor reflectances. We do include LDD, (Luminaire Dirt Depreciation), LLD, (Lamp Lumen Depreciations) and MF, (Maintenace Factor) that take into account the aging of the lighting system and the loss of reflectances and translucence of the lighting media. That is why when we calculate the initial lighting levels, we are generally 30% to 40% above the maintained levels that are the targeted design levels. That is also why we use dimming and switching to lower the lighting levels when a building is new.

The only other way to increase lighting levels is to select lighting sources that are of high efficacy, give good Lumen-Watt ratios and provide good color rendition indeces.

Windows and skylights at least in California also help, but we must use daylight harvesting controls, and they increase the heat load on the HVAC systems.

Hope that helps a bit.
Regards,
EEJaime

 

[1gibson]

I saw an interesting article about a homemade projector screen that used white latex paint with I belive silica sand applied to the surface. Google can probably help find it, has comparison pictures, big difference.

Doubt this will help you very much other than considering additives to the paint...

 

[racookpe1978]

OK.

But be aware that - commercially - I do not go to Target stores specifically because of their color scheme and harsh, glaring white lights off of their red and white contrasting decor.

Tread carefully - There are reasonable causes to subdue lighting sometimes.