Tracking down my high electricity usage with a new pool

[Vinoveritas]

We filled our pool Easter Weekend for the first time ever and ran the pump at about 1800 rpms for about 12 hours a day for the first month. This amounted to about 1000w per hour and our electricity bill wasn't that bad (we pay about $.116 per kWh). After that first month, I started using the Legend pressure side cleaner daily and jiggered with the pump schedule and we started using the spa regularly.

This month's bill was for over 2500 kWh which is double what last month's was and while we turned on the AC, we had lots of energy efficient items added (window film, duct repair, radiant barrier and tons of blown insulation) which should have reduced our AC use significantly. To put it in perspective, the use last month was as high as it was last summer when we had 100+ days of 100 degree weather. I am wondering if I am not calculating the pool energy use correctly or if I was sold a bill of goods by the efficiency folks (or both).

Would someone mind checking my math?

Here is a breakdown of my pumping schedule and costs (I used the wattage reflected in the "Status" window of my panel for the Intelliflo for the low, high and spa speeds and the booster is just amps*volts from the badge on the booster pump):

Low Speed 9hrs/day * 300w/hr = 2700w/day * $.116 per kWh /1000 = $.3132/day
High Speed 3hrs/day * 1000w/hr = 3000w/day * $.116 /1000 = $.348/day
Booster 3hrs/day * 1495w/hr = 4485w/day * $.116/1000 = $.52026/day

Total daily cost is $1.18146 * 365 /12 = $35.94 and 310 monthly kWh

Spa runs at 3450w and a 2 hour session is 6900w * $.116/1000 = $.80. Let's say we had 15 days of use so $12.

I am no math magician but it still seems we should be using less than $50/mth in electricity. Can I get some confirmation or someone tell me where I went wrong?

Thanks!

 

[Melt In The Sun]

Math looks OK to me, but I hate math :eye:

I bet it's your AC. If you've never paid close attention to your electric usage before, it is shocking how much it uses! In the heat of summer, our AC is 90% (yep) of our total power usage.

 

[chrisexv6]

How efficient is your A/C unit? Have you had a checkup done on it lately? Do you notice it running the same, longer, or shorter than normal? Its quite possible energy efficiency improvement have the OPPOSITE effect you are expecting. A/C uses the most power starting up, so if you cause it to run in shorter cycles (since it might cool the house faster with insulation improvements) there is more on/off than without the insulation improvements.

I know its TX so its probably hard to try, but the best way to figure it out is run without A/C (or pool pump) to get a baseline. Obviously not the ideal situation in TX.

Another option is to try a clamp on ammeter to determine how much current the pool pump (and possibly the A/C, if you have access to the power whip to it) are drawing. Convert current (amperage) to wattage (watts = current in amps * source voltage) and then factor that into your calculations. At minimum it would give you a more accurate idea of the pool pump, and might even show you if your A/C isnt running efficiently.

 

[CraigMW]

Is that a flat rate for your electricity or is it tiered? Here in California, going over baseline tier results in a significant increase in kW/h.

 

[SteveK]

Lots of variable at work here......more likely its not related to the pump/pool....your calcs look fine on a per day basis.
But adding them all up for the month, your pool & spa usage alone will cost almost $50 ($47.45 to be exact) and consumes a little over 409Kwh. So, another 2100 Kwh for the A/C and the rest of your household electric use doesn't seem to be out of line considering the heat of your locale.

"Improvements" that you'd think would cut down on A/C usage/electricity consumption usually don't deliver all that is promised or expected.

That intelliflo is the real-deal, though. My electric consumption is noticeably lower since I installed an Intelliflo about 4 weeks ago.

As mentioned by others...you need to establish a baseline, then identify the contribution to electric consumption for each variable.

 

[oldpoolboy]

the water pressure will affect the performance of the pump. a high pressure will increase power demand. so you could be using more than the rated watts.

 

[Bama Rambler]

You are correct that pressure will affect the performance of the pump. You however, are not correct about higher pressure increasing power demand. The higher head (pressure) a pump has to pump into the lower the power demand. I know that's counter-intuitive but that's how it works.

 

[Vinoveritas]

Thanks for checking my math. I just checked my use last May for the same period and subtracting out the 409kWh leaves me with a difference of about $22.45 in "savings." It will only take a decade or two to pay for the "upgrades" at that rate! :grrrr:

 

[harleysilo]

When was the last time your condensing unit was cleaned? Last time i had mine serviced i talked to the service man, he said i can just spray it down with simple green and hose it off with a nozzle on my garden hose (not super high pressure as you don't want to bend all the fins)......he said do it every 6 months or more often if i wanted too (remembered too).