Today's issue leads with a story  about how some community colleges are going to four-day schedules (MW/TTh classes only) to help students avoid commuting costs. When I first read it, my first inclination was to take an unearned victory lap. A victory lap because I had suggested just such a strategem (OK, not for students and faculty, for staff -- but it's the thought that counts!) in a post  back on May Day. Unearned, because not even a community college could have read that idea and made a decision to implement it across the academic schedule in 2+ weeks (and "not even" isn't a slight; it's acknowledgement that decision-making at many community colleges is -- for better or worse -- more (shall we say) "expeditious" than at larger, or private, or 4-year institutions).
But the suggestion that staff work on a rotating schedule of "nine nines" or "four tens", rather than "five eights", presumes that the school as a whole is still on a five-day schedule, overall. The problem with cutting the academic schedule back to a four-day week is that it leaves all those buildings unoccupied and unused about 44% of the time, even when classes are "in session". A building that's not being utilized still consumes a significant amount of energy, especially if it needs to be kept ready to re-open in just a couple of days' time.
In fact, one of the reasons community colleges often consume less energy per student-hour than other categories of schools is that they utilize their physical plant more efficiently. Cutting classes back to four days a week is, in that regard, a step in the wrong direction.
A better idea, if it will fly in your market, might be to go to a six-day week(!). Each section of any class could still be offered only two days a week ( e.g., MTh, TF, WSa), and specific programs (majors, certificates, etc.) could be arranged to utilize only two of the three pairs of days. That way, any student would be able to pick a schedule that required that (s)he commute to campus only four days a week (or even only two), yet the overall physical plant utilization could still remain high.
For community colleges in strong markets, this would provide an opportunity to expand the range (or capacity) of course offerings without adding buildings. If your geographic location is less advantageous, spreading a fixed number of sections across a larger number of days might offer the possibility of "mothballing" a building, or at least a section of a building. (Buildings which are going to remain unused for long periods of time can have their energy utilization drastically reduced. Timing is everything.)
Saturday classes aren't likely to be popular with full-time faculty, but if accommodating students' work schedules is key to success and commuting costs are a legitimate concern, a six-day academic week might actually be an enrollment advantage. And it's certainly more likely to allow reduced energy use and reduced greenhouse gas emissions.