December 11, 2007

Light Reflectance Value

The exterior of our home is stucco. As we are going to try to get our home certified green by the FGBC, beyond being Low-VOC or no-VOC they also require an exterior paint with at least a 50% reflectance value. What does this mean? "Light Reflectance Value (LRV) is the total quantity of useable and visible light reflected by a surface in all directions and at all wavelengths when illuminated by a light source.

LRV is a measurement that tells you how much light a color reflects, and conversely how much it absorbs. LRV runs on a scale from 0% to 100%. Zero assumed to be an absolute black and 100% being an assumed perfectly reflective white. An absolute black or perfectly reflecting white do not exist in our everyday terms. The average blackest black has a LRV of approximately 5% and the whitest white is approximately 85%. Some yellows can measure up into the 80's or 90's as well." (from colorstratagies.net)"

I am going to start small on this one and go to the home depot and see what is already mainstream. All paints have a LRV rating right on the container apparently.

Labels: ,


posted by Mrs Gottfried at 10:52 AM 0 Comments

June 28, 2006

Q: What is R-value?

A: R-value relates to thermal resistance. Thermal resistance is the measure of a material's ability to retard heat flow. An R-value represents the amount of time (in hours) that is required for one Btu to be transmitted through one square foot of a material (or structure) when there is a temperature difference of one degree Fahrenheit between the two surfaces of the insulation. Since R-values are a measurement of the ability to retard heat flow, the higher the R-value, the higher the insulation value. Materials which have the same R-value, regardless of thickness, weight, or appearance, are equal in insulation value.

Labels:

Link
posted by Mrs Gottfried at 3:44 PM 0 Comments