Energy Detective: The Case of the Bothersome Booster

Lately I’ve been seeing lots of energy and money waste hiding in basements in plain sight. No, I’m not talking about the boiler or the water heater – they are another sad story entirely. I’m talking about the water booster.

You may not have a water booster in your building, in which case you’ll have to look a bit harder for the proverbial low-hanging fruit. But if you do have one, well, put it this way, most water boosters I see are fruit hanging so low that they virtually touch the ground.

Working Nonstop

Street water pressure in New York City is usually adequate up to about six stories; taller buildings either have a roof tank or a booster, or sometimes both. A booster is basically a pump that keeps the water pressure in the building above a certain minimum; the taller the building, generally the more powerful the pump.

In its most basic form, a booster consists of one, two, or three pumps controlled by a pressure sensor. If the pressure is above a certain point, the pumps shut off; when it drops below that point, the pumps come on in sequence as the pressure drops further. So what’s the problem?

The problem is that in the real world, a booster of this type is almost always “on,” because as soon as the pump shuts off, the pressure drops and the pump comes right back on. In fact, in many buildings, the pump is just left on manual (“hand”) and runs 24/7/365 without a break. I was at a five-story building recently where the booster pump was set to hand operation and was going full blast all the time. The piping was insane; it ran up through the basement ceiling to the first floor, came back down, went through the booster, and then went up and down a second time. Worst of all, the piping bypass was wide open, so the pump was probably just sending the same water around and around the same short loop. Even if the booster was needed, which it probably wasn’t, it was wasting a lot of energy.

Not all boosters have this basic format – some add a buffer tank or a variable frequency drive to reduce full-on pump run time. Theoretically, they should operate much more economically – but often they don’t because the control settings are incorrect, the unit has been poorly maintained, or a key part has failed without anyone knowing.

Small Tweak, Big Payback

As the table at left shows, a one-horsepower (1-HP) pump running 24/7 will use about $1,300 in electricity in a year (in Con Edison service territory). If the booster could be adjusted so that it ran only 18 hours a day, you would save about $340 annually. For larger pumps, the savings are even greater.

Frankly, it should be possible to cut back to even less than 18 hours a day. In fact, in some smaller buildings, it may be possible to simply shut the booster off; I’ve seen many that should never have been installed in the first place.

Generally speaking, it should not be expensive to have a booster technician come in and tune up the unit for more efficient operation, so payback should be fairly quick even for a small 1-HP model. But make sure whoever comes in knows what he or she is doing – guesswork on the part of the technician could result in either unnecessary repairs or no reduction in energy use.