Shedding Some Light on Daylighting
For all the attention that’s paid these days to energy efficiency, the mainstream still remains very much in the dark about daylighting, or daylight harvesting, as its also known.
Chances are, you’ve at least heard about it, since you’re reading this. But, for the sake of bringing us all onto the same page, it’s, basically, the practice of using windows and skylights to light a home’s (or a building’s) interior with natural light as much as possible during the day, which, in turn, limits the need for artificial lighting. Where once there may have been little to no upside—sure, you’re awash in sunlight, but you’re also baking in the summer and freezing in the winter—modern windows and skylights are highly energy-efficient, so they’re able to let the light in while also maintaining the space’s interior climate. (More on how exactly they do that in our next post.) The most energy-efficient skylight windows also block up to 85 percent of infrared light and 99.5 percent of ultraviolet light with minimal effect on how much visible light shines through.
A natural daylighting system is a design where the windows and skylights are positioned to optimize the sunlight. There’s no one-size-fits-all here. It’s going to depend on your home and your climate, foremost. The U.S. Department of Energy recommends basing the size and location of your windows on the cardinal directions rather than their street-side appearance. In other words, this is a decision borne from practicality, not aesthetics. (But we can do a lot to minimize that gap.) South-facing windows admit the most sunlight in the winter and the least direct-sunlight in the summer. The sunlight that comes through north-facing windows is relatively even year-round. East- and west-facing windows provide healthy shots of sunlight in the morning and evening, naturally, but they may also cause glare and admit a lot of heat in the summer and contribute little to solar heating in the winter.
To discuss how to best outfit your home, contact us to schedule a free energy-efficiency consultation. In our next post, more on how skylights have become, simultaneously, more revealing and protective.