Actual savings of variable speed pump

[Rasterman]

I have a 3/4 hp pump that runs 6 hrs a day, 5000 gal pool. I measured it at 121V at 10.4A, 1260W, or $25/day or $300/yr. The pentair website says I'm using $373 per year and if switching to the intelliflow variable speed I would save $300/year. This doesn't seem very likely to me. But even if I "only" saved $200 I would switch, do you think that's possible?

 

[JoyfulNoise]

If your pool is fairly simple then a VSP is overkill. You could easily switch to a 2-speed pump, which is a lot cheaper than a VSP, and yield enough energy savings to pay for it after a year or two.

Can you add more details to your signature as it helps us to help you.

 

[Teald024]

Hello and Welcome to TFP.

Based on the numbers you have provided, the best option is likely a 2spd motor. From your other thread, it doesn't seem like you have a complicated setup.
At $25/month electric, it's not realistic to save $300 a year. That would make your bill almost $0. However attractive that seams, it's not realistic. You could probably cut that in half and still save $150 a year with the 2spd. Payback will be much shorter than a VS pump. Run it on LS most of the time and HS when you need to.

 

[pooldv]

I run my Intelliflo 3hp VS pump at 1100 rpm for skimming, filtering and making chlorine with the SWG and it uses 150 watts. I can run it 24x7 during spring and fall for less than 12 bucks a month at 10.25c/kWh. It usually runs 12 hours a day the rest of the time for less than 6 bucks a month.

 

[Rasterman]

I found this 3/4hp 2 speed, since I currently run 6 hours and am probably getting about 5 water changes per day, I could run this at half speed and still get 2 changes. Are there any others you would suggest?

https://www.amazon.com/Energy-Effic...&qid=1507846635&sr=8-26&keywords=2+speed+pump

Also found this 3/4hp 2 speed, seems to use a little less power, one guy says 2.6 amps on low
https://www.amazon.com/gp/product/B002FQIYI2/ref=ox_sc_act_title_1?smid=A3SQ9YFE6CSCS0&psc=1

The variable speed I'm looking at is
https://www.amazon.com/gp/product/B00PKHX2BM/ref=ox_sc_act_title_2?smid=ATVPDKIKX0DER&psc=1

 

[pooldv]

A 2 speed pump will move 1/2 the water volume and use 1/4 of the electricity on low speed as it does on high speed.

 

[jmastron]

A 2 speed pump will move 1/2 the water volume and use 1/4 of the electricity on low speed as it does on high speed.

Actually 1/8 the electricity (HP varies by the cube of the speed), roughly.

So an exact turnover equivalent would be 1/2 speed for twice the time -- 160 watts * 12 hours/day = 1.92 kWh/day * 360 = 691 kWh/year * .11/kWh = $76. That's $225 right there. But you're likely to find that you don't really need to run 12 hours a day; 6-8 may very well still be plenty to skim properly and keep the water circulating well (in a residential low use pool, turning over the water volume every day isn't really necessary), so over $200 a year savings is quite achievable.

The advantage to a variable speed pump vs a 2-speed is being able to tweak as needed -- if you find that proper skimming, or solar, or a salt cell etc, requires a bit higher speed, you can just dial it in instead of having to run at full speed.

However, I notice you have a 120V pump -- is there 240V available at the pad? I don't know if any of the variable speed pumps (like the Pentair IntelliFlo) can operate at 120V. Some of the 2-speed WhisperFlo pumps can be wired for 120V, it seems. That might impact your decision.

 

[CJadamec]

Actually 1/8 the electricity (HP varies by the cube of the speed), roughly.

However, I notice you have a 120V pump -- is there 240V available at the pad? I don't know if any of the variable speed pumps (like the Pentair IntelliFlo) can operate at 120V. Some of the 2-speed WhisperFlo pumps can be wired for 120V, it seems. That might impact your decision.

The Superflo VS will operate on either 110/220 volt the drive electronics automatically adjust to the voltage supplied to the unit. That said unless there is a rebate from your utility company for going to a VS pump a 2-speed is a much better choice for this application from an economics stand point.

 

[Gecrabill]

I recently switched from a 3/4 Whisperflo single speed to the Superflo VS. I too struggled with getting a 2speed vs VS. in the end, I got the Superflo VS from my local pool store. They had rebates and it ended up being about the same as amazon price. Plus they gave me a 3 year warranty even with self install. My pool is only 11k gallon. I am spending about $7/month vs $45/month. It is so quiet that sometimes I go check to make sure its on. It has 3 time frames you can use, plus a quick clean mode and you can adjust rpm to whatever works best. I run it around 1400rpm. I could not be happier with my decision to go with the superflo VS.

 

[needsajet]

If you need 6 hrs for skimming, that's a good reason for 2-spd or VS.

If not, 2-3 hrs per day would be plenty for filtration, and would save you money with no outlay.

 

[mas985]

Actually 1/8 the electricity (HP varies by the cube of the speed), roughly.

Actually, not true. The affinity laws only apply to pumps and not motors. Also, the power law applies to the power delivered to the water and not to the motor.

Low speed on a two speed motor uses a separate thinner gauge winding that is 1/2 as efficient as the primary winding so the net result would be only a 1/4th reduction in energy use.