Recouping your Energy Management System (EMS) Investment: HVAC Type, and Occupancy Sensing

(Part 5 of 5)

What factors are used when calculating ROI on a new Energy Management System?

When you’re shopping for an energy management system, you want to be presented with a realistic ROI. There are many factors that go into the calculation. Some are weighted more heavily than others. We’ve discussed:

But there’s more to consider, and that’s what we’re talking about today.

Unitary PTACs vs. Central FCU’s

Generally speaking, PTACs are less efficient than fan coils. Analysis of the data collected by one EMS provider over the last decade (that’s a LOT of data) shows there were only 2 months difference between the project paybacks for PTAC/PTHP’s and those for FCU’s. PTAC/PTHPs had a slight advantage in payback.

Why is this? PTAC/PTHP’s are electric based and not boiler/chiller based, and since electricity is comparatively more expensive than natural gas, the project payback time is slightly better.  


Actual occupancy is one of the MAIN drivers of savings and payback. We say “actual” because the old-fashioned (but still relatively common) time-of-day thermostats are programmed to set back based on time of day. Smart thermostats, on the other hand, adjust heating and cooling based on whether a room is physically occupied.

In fact, the single most heavily weighted factor that affects project payback is incorporating smart thermostats with occupancy-based sensors into your energy management project. Smart thermostats put YOU in control of balancing guest/occupant comfort and energy savings—room by room, across climates, from economy living spaces to executive suites.

As you shop for an EMS, be sure to get a trustworthy ROI estimate for how long it will take to recoup the expenditure you make on your new energy management system…from whichever EMS company you work with.

If you’d like to get carefully calculated ROI that factors in details proven to be relevant, contact us at or 888-730-9398.