Occupant Experience Matters

In MEP, we are often expected to be out of sight, out of mind. There are obviously some examples where this isn't true, but the majority of buildings require interaction with occupants and to some degree facility staff at a minimum. This is a good thing, our systems should work, tirelessly, behind the scenes, for many years. One could argue that plumbing sees the most occupant interaction, then probably electrical and finally mechanical.

When portions of our systems do interact with the occupant, it is critical we get it right. Sensors and control devices are the dominant form of interaction between mechanical and electrical systems. Plumbing, well we all know how we interact with plumbing; no one likes a backed-up kitchen sink, or worse. I'll leave that there :).

Light switches, occupancy sensors, thermostats, window sensors, and many other devices interact with our occupants. A few weeks ago, I was at a retirement community and walked into the restroom in one of the suites. I searched around for the light. Most of us would expect it to be on the inside wall adjacent to the door handle. No such luck. I walked into the restroom and searched the other wall in darkness until I finally found the switch; minimal illumination occurred from the room light behind me, but it was still really dark. As you can see above, it's pretty far from the door handle.

I'd like to think there were good reasons for this switch location but if I had to guess it was cost. Another conduit drop, another junction box, another switch plate and all the labor associated with it adds up in a large community project. I can see that in a standard apartment/condo (maybe) this makes sense, but in a retirement community, the occupants cannot afford to be walking around in darkness. Many are not steady on their feet, many don't have the best vision, some may not remember that there is a towel on the floor. There are plenty of examples as to why an older occupant should not be hunting around in the dark for a switch.

The switch on this wall is a vacancy sensor. You may recall that vacancy sensors are manual-ON, auto-OFF. As opposed to occupancy sensors which are auto-ON, auto-OFF. An occupancy sensor would likely have solved this issue. There was a portion of time when the code said occupancy sensors were not allowed, vacancy sensors were the only option in single occupant restrooms (technically high efficacy lighting was an allowed path of compliance). However, at least in the 2022 CA Building Energy Efficiency Standards, the multi-family section (160.5(a) 2E iv) now allows occupancy sensors or vacancy sensors in single occupant restrooms.

In spaces where light means safety for vulnerable occupants, let's remember to design and install occupancy sensors. For spaces that serve the rest of the population, I'll leave that up to you.

Lastly, if your grandma (like mine), lives in a community that has vacancy sensors, many of the older switches can be converted to occupancy sensors by changing the dip switches. Some of these switches have the dip switches on the face, typically behind the ON button plate, so you don't have to work on the 120V side. If you have to get to the backside of the switch, remember to turn power off to the breaker before you work back there or look to a professional if it really needs to be changed.