Today’s Patio and Spa at Cactus and Tatum (they’re awesome) had this Pentair IntelliFlow Variable Speed 3HP on display with a computer program to estimate your electricity bill saving’s per month. The knowledgeable and helpful salesman showed me something like this on the fancy computer screen:
Hours per day: 10
kWh charge: $0.13
Old 2HP pump cost per month: $97.50
New pump cost per month: $12.48
(NOTE: The picture above depicts $55/mo savings b/c I went back and put in my actual kWh rate, $0.09 and snapped this photo after I wrote this article.)
The screen was animated to look pretty, but the calculation was pretty simple. The way this pump saves so much is it only runs at high speed cleaning mode for 2 hours a day at about 1 kWh and then very low speed for 10 hours a day at about 150 Wh (that’s 0.15 kWh). My old pump only had one high speed and consumed about 2500 Wh for the full 10 hours a day it ran.
My old motor burned out and I needed to buy a new one. My decision to buy this Pentair IntelliFlow Variable Speed unit for $1250 (grand total out the door, with pro certified install and sales tax) over the $450 (grand total out the door, w/ sales tax, but self install) was based on long term cost savings. At $85/mo in electric bill savings, I’ll break even on the cost difference in 10 months, and the unit will pay for itself after 15 months. After that, it’ll be $85/mo in my pocket. Sounds like a wise investment…..
BUT, will it really save me $85/mo? REALLY REALLY?
First off, I have one of those OnPeak/OffPeak plans with APS, and my electricity is not $0.13/kWh! It’s about that during onPeak, but we run our pool pump during offPeak! My offpeak rate is closer to $0.03/kWh. But, there are more factors to consider when looking at your APS power bill.
There is the “Delivery service charge”, “Federal transmission and ancillary services”, and “Federal transmission cost adjustment”. These charges are based on the number of kWh’s you consume and don’t consider onPeak/offPeak time. And then there are about 10 more nickel and dime line items. I may write another article on how insanely confusing this is, but that’s not the point of this article. Even taxes and fees are to be considered, because based on cost of electricity, if you consume less, then charge is less and taxes are less too.
I took all of this into account, even the nickel and dime items and taxes, and now have a high level of confidence the new pump will actually save me $55 / mo. Let me show you how I came to this conclusion.
First, lets look at two APS bills and figure some stuff out. I picked September and March, representing most expensive and least expensive monthly bills. Both of these bills are from BEFORE I had the Pentair variable speed pump installed.
- Delivery service charge – this is the sum of the onPeak/offPeak kWh’s * $0.03
- Federal transmission and ancillary services – this is the sum of the onPeak/offPeak kWh’s * $0.0052
- Federal transmission cost adjustment – this is the sum of the onPeak/offPeak kWh’s * $0.0070
- Generation of electricity on-peak – went from $0.21/kWh to $0.16/kWh. Either my electricity got cheaper or APS charges more in the summer. I suspect the latter.
- Generation of electricity off-peak – remained the same at $0.03/kWh.
- Other – This is my way of simplifying this a tad. It’s total charges minus sum of the 5 above. It ranged from 24 to 33% of the above 5.
The digital read out on the Pentair IntelliFlow Variable Speed pool pump shows the number of Watt hours it’s consuming. You can change the speed and see the Wh’s change. That’s pretty cool. You can easily calculate almost exactly how many kWh’s per month the pump will consume.
My pump is consuming about 150 Watts/hour at the lower speed that runs for 10 hours a day.
My pump is consuming about 1000 Watts/hour at the higher speed that runs for 2 hours a day.
Savings: 645 kWh/mo
Now, if I subtract 645 kWh from my off peak bill from March, the new grand total is $256.32, a savings of $55.76.
If I had only considered the $0.03 / kWh for offpeak consumption, I’d only be saving 645 kWh * $0.03 = $19.35. When considering “Delivery service charge”, “Federal transmission and ancillary services”, “Federal transmission cost adjustment” and “Other”, my cost savings is actually $55.76.
Because it’s interesting, if I take $55.76 / 645 kWh = $0.09 / kWh, much closer to my true offPeak energy rate, all things considered. This is close enough to $0.10/kWh to use for quick estimation. Figure out how many kWh/mo the new pump will save and multiply by $0.10 (easy to do in your head). In my example, a 645 kWh/mo savings would be $64.50. Slightly bloated, but close.
At $55/mo cost savings, I’ll make up the $800 difference in price between the two units in 14 months, the unit will pay for itself in 2 years and be money in my pocket every year after. If it lives 5 years, it’ll save me $3300 over it’s life. Considering I had to replace the pump, I see this as an $800 investment that will pay out $3300 over 5 years. 413% return over 5 years or 82.5% APR. I wish all my investments had this level of return! I’d be rich.