Four energy engineers walked into a bar...
Actually, it wasn’t a bar. It was a dinner party. After the second local, sustainable micro-brew the truth came out. Shanti Pless from the National Renewable Energy Lab said he enjoyed Seventhwave's case study of our "Living Lab" headquarters. But he had only one question—are we sure about those Lighting Power Density numbers?
Scott replied: “.08.” (Hint: that LPD is really low─almost half of NREL’s new net-zero energy office.)
This led to some very civilized looks of disbelief from Shanti and Brendan. And, that’s how Shanti and Brendan ended up on a lighting tour of Seventhwave’s headquarters.
How we did it
First, Seventhwave started with a strong yet cost-effective daylighting strategy. With a window-to-wall ratio of just 39%, strategic window placement on the north side of the building proves that a space full of natural light does not need to sacrifice energy savings. Skylighting and cost-effective interior design strategies also bounce natural light where it’s needed.
Second, Seventhwave used—and thoroughly commissioned—lighting controls that included simple but effective wireless photosensors and more occupancy sensors than many designers specify. This allowed us to tune the lighting in each type of space in the office for maximum savings without compromising the comfort and productivity of the space.
During the tour, Shanti made a good point. If facility management resources are too constrained to allow for advanced lighting controls, some building owners—like schools—are beginning to rely on an all LED lighting strategies since the cost of LEDs have been coming down over time. Something to consider as control sophistication and LED costs are both constantly changing.
This very low LPD is one of the many drivers behind Seventhwave’s low energy use intensity, shown below. Our current EUI is 33 while the average office building in the region sports an EUI of 86.
Moral of the story
Don’t challenge Seventhwave’s energy performance, unless you want a tour of our building. But do enjoy a local, sustainable micro-brew responsibly. Especially if it’s brewed by Seventhwave’s Adam McMillen.