One Tiny Setting. One Big Billing Problem

Recently, a client asked us to reference-test all 98 meters in a particular NYC building as part of a new initiative for their properties. We started on the top floor and are working our way down, checking each and every submeter and documenting its performance. We're also updating the documentation about actual serial numbers and locations (because Dunkin’ moved out 10 years ago but the doc didn’t get updated).

Everything was going well initially. We tested each meter, both its instantaneous load and its cumulative usage, against our calibrated power analyzer to see how much usage the power analyzer was recording vs. how much the meter was recording. The first few meters looked good.

Then we got to meter 148. Instant disagreement. The power analyzer was reading half the kW the meter was showing. But why?

This particular problem was discovered by applications engineer Anthony Elia. Anthony has worked for utiliVisor for almost seven years now, and before that he worked as a subcontractor electrician. So he knows what he’s looking at when he’s testing meters.

So what did this programming error do to the tenant's electric bill?

In this building, on this floor, the submeters have an unusual setup. Meter 147 (the "tenant" meter) reads the mains electricity for more than half the floor, not just the tenant space. In other words, meter 147 was reading the electricity for the tenant space as well as the floor's common areas – the bathrooms and hallways – consumption that’s not the tenant’s direct responsibility.

Meter 148 is what's known as a deduct meter. It reads the power for just the bathrooms and the hallway – the common area spaces. So to create an accurate tenant bill, the consumption from 148 has to be deducted from 147 every month. But because 148 was reading twice as much kW as it should have been, more was being deducted from the tenant's bill than should have been. In other words, the tenant was being undercharged.

If thinking about deduct meters gives you a headache, try it this way:

• If the tenant meter reads $100 a month in electrical consumption and the deduct meter reads $20, the tenant is billed $80.
• But if the tenant meter reads $100 a month and the deduct meter reads $10 instead of $20, the tenant is billed $90.

As the property, you'd rather recoup $90 than $80, right?

Yes, meter 148 is tracking a low load, but it likely has been misreading for a very long time. We don't know how long this problem has existed, but clearly it's been there for a while. That monthly loss in recovery adds up!