REDUCE YOUR POOL'S ENERGY USE!

Yes, I know, I’ve heard it before.  How can we be creating a simpler life and have a backyard pool?  And it's a heated pool too!  Well of course for us it’s simple!  This is our BIG family vacation.  You know that big vacation some families take? The one that costs upwards of a few thousand dollars for a family of four?  Well, this is our BIG vacation and so far it has lasted us 10 years! 

Having backyard animals and a garden it is hard to get away for anything more than a few days at a time so we invested our 'vacation' money into a backyard heated pool that we have never regretted, especially when we jump right in after weeding the garden on a hot day!  And despite the initial investment, the pool does NOT have to break the piggy bank every summer, especially when it comes to the amount of energy it uses.  After extensive research I have learned that by making a few simple changes we should be able to save approximately 600 kWh this summer alone!

So what did we change that will save both energy and money?

HOW LONG DOES THE PUMP OPERATE EACH DAY?
In my research to find ways to decrease the cost of running our pool I learned that most people are running their pool filter far too long every day. The goal is to pump all of the water in your pool through your filter once every 24 hours.   In order to figure out how long that would take I needed to answer a few questions first:

• How many gallons of water does the pool hold?  Pool Volume Calculator
  
• What is the residential flow rate of the filter in gpm (gallons per minute)?
  
• What is the flow discharge rate in gpm of the pump?

OUR POOL AS AN EXAMPLE:

Our pool holds 23,000 gallons (Pool Volume Calculator).

Our 1.5 HP pump and our filter both have a flow rate of 120 gpm (We had to use the Jandy Model PHPU1.5 manual to figure out the flow rate for the pump.).  Note that if your pump and filter do not have the same flow rate, then use the lower of the two, however they should be perfectly matched if the system was properly designed.

Math:  
23,000 gallons/120 gpm = 192 minutes, or 3 hrs 12 minutes minimum run time per day

Our pump was set to run from 8 AM to 4 PM every day.  Yes, it was set at 8 hours a day as advised by our pool installer! So now we are running it 4 hours instead of 8 hours per day.  

Why 4 hours and not 3.2 as calculated?  Because the California Energy Commission recommends the following:

"Reduce filter operating times to no less than 4 to 5 hours per day during the summer and 2 to 3 hours per day during the winter period. This will reduce annual electrical consumption by 40 to 50 percent. Normal and heavier swimming use may require as much as eight or more hours filtration per day. Should water clarity or chemical imbalance indicate inadequate filtration, immediately operate the filter until acceptable water clarity has again been established.

If additional filtration is still indicated, increase filter operating time in one-half hour increments until the water remains clear and properly balanced chemically. When the pool is being heavily used, it is recommended that the pool be operated manually and that the filtration system be run under such conditions. Under no circumstances should the water quality of any swimming pool be so poor that the main drain cover is not clearly visible from the deck."

HOW MUCH ENERGY CAN BE SAVED?
Saving money by using less electricity was the goal so of course I have to know exactly how much will be saved!

How many horsepower (HP) is the pump?

1 HP uses the equivalent of 745.7 Watts

Example: 
Our pump is 1.5 HP so it will use  1.5 HP x 745.7 W = 1,118.55 Watts

To convert this to kW, we just divide by 1,000:  1,118.55/1000 = 1.12 kW used every hour

Amount used in 8 hours:  1.12 kW x 8 hours = 8.96 kWh

By simply decreasing our pumping time from 8 hours to 4 hours a day, we have cut our pool energy use in HALF (saving 4.48 kWh every day)!

WHAT ABOUT THE HEATER?
We have a heat pump which is actually a very energy efficient way to heat the pool.  However it works most  efficiently when the air is warmer.  For this reason we set our pump to run between the hours of 11 AM and 3 PM (generally the warmest time of the day).  Of course there are times that we will override the system and keep it running longer if we want to get the temperature of the pool water higher or if we have a lot of people swimming.  Note that if the pool is at the desired temperature the heater automatically shuts off which is part of what makes it so efficient.

WHAT ABOUT THE ELECTRIC BILL?
Since the heat pump is connected to the same timer as the filter system, the amount of time the heater runs was also decreased by four hours saving an additional 1.5 kWh per day. That brought our savings to an average of 6 kWh/day. Multiply that by how many days the pool is open (about 100 days) and we are saving about 600 kWh’s over the course of the entire summer season.  At a total annual  electricity usage of approximately 12,750 kWh last year, that is a savings of 4.7%!  Definitely worth it J

A FEW MORE TIPS ON SAVING $:

• If you do not have your pool pump set on a timer, get one now!  This makes life so easy!
  
• If you are using the pool more, you will need to filter more (common sense).
  
• It is cheaper to have your pump run at ‘off’ times for electricity use.  The early morning is usually best, unless you are like us and need to take advantage of the outdoor temperatures to heat the pool using a heat pump.
  
• If you have a heater, keep the temperature reasonable (we keep our temperature set at about 85°F).

• Additional ways to decrease your pool expenses can be found at Conserve101.