Reducing Energy Use with Daylighting: See why Polycarbonate beats FRP

Posted in Construction & Architecture
Reducing Energy Use with Daylighting: See why Polycarbonate beats FRP
By Jeramy Albert, Business Unit Manager - Construction Products

Case Study Purpose:

Senergy Consultants executed this case study to compare lifecycle energy savings & lumen depreciation of both standard FRP sheets and Palram’s SUNSKY polycarbonate.


A pair of near-identical machine shop sheds (approximately 12,910 sq ft) were chosen for the test. The units operated for 24 hours per day/300 days per year and were illuminated by 200 watt metal halide lamps.

By installing an energy meter in the main lighting distribution board of the respective units, power consumption was able to be measured over a week before sheets were added to the roof covering to provide daylight for the shed. An identical set of measurements were taken to record the illuminance level at different times of day at various places. The SUNSKY sheets were installed on the roof of the other shed. A timer was installed to monitor the period during which the lamps were actually switched off.

Both energy consumption and lamp off-time were monitored by noting the requisite data on a day-to-day basis. The illuminance levels were measured once per week at different times of the day in both sheds at the same time intervals. After five years of testing, there was virtually no savings in the unit with the FRP, mainly due to reduced light transmission of the sheets over time. Keep reading below to see findings made during the case study:

Observations & Findings:


  • SUNSKY provided a higher and more uniform illuminance level than standard FRP sheets over the entire period of five years. The illuminance level of SUNSKY reached a 450 lux average whereas FRP sheets averaged only 125 lux during the same period.
  • The unit with FRP Sheets saw lumen depreciation of 66% vs only 5% for the unit with SUNSKY over 5 years.
  • The unit with FRP sheets was forced to switch on the artificial light during daytime on rainy/cloudy days right from day one, switching on the artificial light kept increasing over the test period.
  • The unit with SUNSKY never switched on the artificial light during day time at any point within the 5 years.
  • The unit with FRP sheets required switching to artificial lighting in twilight zones – evening as well as morning; but no such concern was felt by the unit with SunSky. The “Lamp on Period” kept on increasing during the twilight period as the days passed by.
  • At the end of third year/beginning of fourth year, the unit with FRP sheets switched on lamps throughout the day to illuminate critical areas and the requirement of artificial illuminance increased as days passed. The unit with SUNSKY required no artificial illumination to supplement the lighting.
  • At the end of fifth year the unit with FRP sheets had to switch on all the lamps since the sheets became practically opaque, whereas the unit with SunSky could easily rely on natural daylight.

As the results show, Palram’s SUNSKY corrugated sheets vastly outperform FRP and can help yield extra savings. See specs and more product info here.

About Palram Americas

Palram Americas is an end-to-end, state-of-the-art thermoplastics manufacturer based in the Lehigh Valley, PA. For 60 years, Palram has provided high-quality polycarbonate & PVC solutions used in countless markets spanning construction and architecture, sign and display, agriculture, safety & security, transportation, DIY and outdoor living.

Whether you’re a contractor, fabricator, designer, architect, printer, or even a homeowner interested in DIY projects, Palram’s range of polycarbonate and PVC solutions will help transform your vision into reality. Together, we will build on.

Learn more about Palram’s skylight/sidelight solutions here.

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