NREL Technical Daylighting Report

A Literature Review of the Effects of Natural Light on Building Occupants

Daylighting report on the effects of daylighting in offices, schools, retail and industrial locations.

…A three-year payback, typical in lighting retrofits, is equal to an internal rate of return in excess of 30%. This type of return is well beyond the “hurdle rate” of most financial managers. In addition, the same retrofit may cut energy use by $0.50 or more per square foot, which has significant positive effects on the Net Operating Income of a building. However, the energy and operating costs of a building are small when compared to the cost of employees.

Based on a national survey of the stock of offices for 1990…electricity typically costs ~$1.53 [per square foot] (85% of the total energy bill); repairs and maintenance typically add another ~$1.37 [per square foot]; both contribute to the gross office-space rent (including all utilities and support services) of $21 per square foot. Yet paying the office workers costs ~$130 [per square foot]. Thus the office workers’ salaries cost ~72 times as much as the energy costs. Or, an approximately 1% gain in productivity is equivalent to the entire annual energy cost.

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NREL Technical Report

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