The word “audit” doesn’t exactly conjure pleasant emotions for a small business owner. When it comes to a pool’s energy consumption, though, an energy audit provides a way to show customers how much they could save every month with upgrades like power-conserving lights, a more efficient heater and filter, and a variable-speed pump or motor.
Pool service people agree that once consumers see the numbers, many jump at the chance to purchase new technology equipment.
Performing a pool energy audit doesn’t take a math degree — all that’s needed is a little patience, some knowledge of what to look for, and access to a computer that can crunch the numbers. Here, we walk through the main steps of the process.
Peek in the pool
The ideal place to start an energy audit isn’t on the equipment pad, but inside the pool itself. The three main areas to focus on are lights, jets and the automatic cleaner.
Turn on the lights and determine what kind of bulbs are being used — incandescent, fiber-optic, LED or halogen. This will provide a rough estimate of how much power those lights are consuming.
“Incandescent lights typically use 400 to 500 watts per hour,” says Michael Orr, executive director of the Foundation for Pool & Spa Industry Education located in Sacramento, Calif. “In many parts of California, that’s about 15 to 30 cents an hour.”
Halogen lights are a bit more efficient — they use approximately half the energy of incandescent bulbs — while more cutting-edge technologies like fiberoptics and LEDs can use as little as one-eighth the power. For now, just note the type(s) of lights in the pool — this will come in handy later as part of the analysis of the audit.
Next, check what kinds of jets are installed — newer directional venturi jets can provide a turnover rate as high as 80 percent of current unfiltered water in an average six-hour turnover cycle, but many older “straight-into-the-pool” jets provide a turnover rate closer to 40 percent.
“This is one of the most overlooked things in an energy audit,” Orr says. “Most swimming pools are very inefficient at turning over the unfiltered water in the pool — a good part of the same just filtered water keeps going back through the filter.”
Finally, if the pool uses an automatic cleaner, check if it’s pressure-side, suction-side or robotic. If it’s a pressure-side cleaner, check to see if it’s powered by a booster pump. A suction-side or robotic cleaner isn’t a major consumer of energy, but a booster pump can be — especially if the customer likes to leave the cleaner running throughout the day. It’s important to note that each type of cleaner must fit the individual pool’s work load — that is, the surrounding environment — to be at its most effective in that particular pool.
These three factors — lights, jets and cleaner type — will provide some crucial clues for later stages of the energy audit and potential energy savings.
Patrol the pad
The next stop is the equipment pad itself. Though discussions of energy efficiency tend to focus on pumps and motors, heaters and filters are crucial components as well. Things can get a bit tricky here, because an accurate audit depends on an accurate assessment of the equipment’s name plate information, or on the technician’s skill in recognizing that equipment — even if a previous technician has mislabeled something or modified the equipment.
Labeling errors tend to happen most frequently on cartridge filters that accommodate several different sizes of cartridge elements. “The installer has to check off on the label exactly which cartridges are installed — and most of the time, this seems to be overlooked,” says Orr.
Thus, it’s a smart idea to open up the filter and check the inscription on the cartridge itself. A word of caution: This procedure may involve replacing the filter’s body “O-ring” for reassembly. Sand and D.E. filters, on the other hand, are more likely to be labeled correctly — as long as the filter media is the same as the original filter owner’s manual has specified — so for these filters, the only important number to note is their square footage.
On the heater, BTUs are the main number to note and are typically found on the heater’s label. It’s also worthwhile to open the heater and take a peek inside, because rust, blockages and other wear and tear can seriously reduce efficiency. Age is another major factor — many heaters lose their capacity to function at maximum efficiency after seven or eight years, and older heaters often weren’t designed to operate at today’s standards. So note any traits of the heater that could reduce its performance.
The heater’s efficiency can be determined by dividing the heater’s output BTUs by the input BTUs located on the nameplate inside the heater. For example, 320 kBTU output ÷ 400 kBTU input = 80 percent efficiency.
Now, at last, it’s time to examine the pump. Note the horsepower and service factor of the motor, the current (amps) and the voltage — all of which should be listed on the pump’s label. Next, take the service factor and multiply it by the horsepower, which will reveal the true potential horsepower — known as the “brake horsepower” — of that particular pump. Then, use a volt meter, an ammeter and an RMS power meter to validate and record the findings with the equipment operating.
Find the flow
After noting the vital statistics of the major equipment, the next step is to determine the system’s flow rate. Though many pools incorporate a pressure gauge — usually located atop the filter on the influent side — this often provides an inaccurate measurement of flow, because debris passing into the filter tends to get jammed inside the gauge. To obtain an accurate measurement of the system’s flow, it’ll be necessary to either install a flow meter, or to complete a vacuum measurement and a pressure measurement of the water coming into and out of the pump.
A vacuum measurement can be performed by screwing a vacuum gauge in to the drain port at the bottom of the lint pot of the pump, and a pressure measurement can be taken either by installing a pressure gauge in to the volute chamber drain of the pump, or by unscrewing the pressure gauge from atop the filter and screwing in a new pressure gauge to take an accurate reading.
The flow rate is a crucial reference point for the pump, because a pump cost assessment requires an apples-to-apples comparison of units generating the same flow rate. “For instance,” Orr explains, “if you have a pressure-side pool sweep without a booster pump, you will need to ramp a future VS pump up — but if you don’t have that situation, then you can leave it at a lower money-saving flow rate.”
To learn the system’s flow rate, the simplest option may be to attach a flow meter — but it’s crucial to install it in the right place — and exactly where, that depends on the type of meter. The three types of flow meters are the venturi-type, which is relatively cheap, the check valve flow meter, which is approximately 50 percent more expensive, and the electronic flow meter, which costs approximately 2.5 times as much as the venturi-type, but is the most precise of the three.
For a venturi-type meter, it’s essential to install the meter after the filter and at least 10 times the diameter of the pipe after the nearest 90-degree angle pipe fitting in the piping located on the inlet (influent) side of the flow meter, and four times the pipe diameter before the next 90-degree angle on the outlet (effluent) side of the meter. For a check valve meter, follow the manufacturer’s instructions for placement. An electronic meter can be installed just about anywhere after the filter.
Another option for finding the system’s flow rate is to take the pressure gauge reading and multiply this number by 2.31, take the vacuum gauge reading and multiply this number by 1.133, then add those two resulting numbers together — this will give you the total dynamic head (TDH) of the system. Next, visit the Website of the manufacturer of that particular pump, and download the manual on that pump, or the pump flow curve chart, to find a graph that plots TDH on the vertical axis versus gallons per minute on the horizontal axis. Take the TDH from your calculations for this specific pump and come across the graph to where it intersects the pump curve, then follow a line straight down from this point to learn the corresponding flow rate.
Crunch the numbers
Once all the essential numbers are recorded, it’s time to plug them into an efficiency calculation — which, surprisingly, is one of the easiest parts of the audit. That’s because many pump manufacturers’ Websites offer free calculation tools that will crunch the numbers plugged into an easy-to-use online form.
Because these calculation tools are so convenient, many successful service companies recommend filling out the form right in front of the customer — perhaps on a laptop or electronic tablet — and letting the numbers help close the sale. “I carry my iPad with me every time I go visit a customer,” says Tom Cucinotta, owner of Cucinotta’s Pool Service in Lake Worth, Fla. “Once I show them how much they could be saving with a more efficient pump and lights, the upgrades practically sell themselves.”
Just what kinds of upgrades are ideal for a particular pool depends as much on the customer’s expectations as on the existing equipment. Though many customers will see the benefits a variable-speed pump can bring, some will resist the price, but that doesn’t mean they can’t still save money on power bills.
Some customers may prefer to keep their current pump but upgrade to a multi-speed or variable-speed motor — an option that saves more money in the short term. If the pool uses a pressure-side cleaner with a booster pump, another possibility is to swap out the booster pump or its motor with a more efficient one — or to replace the cleaner with a robotic model. Upgrading lights and jets can also return significant energy savings on a low initial investment.
No matter what kind of upgrade the customer is considering, experts agree that the most reliable sales tactic is to keep pointing to the numbers. Show the customer how much lower their monthly bills could be and the pay back period, and even the most cost-conscious consumers are likely to come around eventually.