Why is calculating run-time for my new VS motor so difficult?

[duckcmmndr]

I'm doing research to determine if I should swap out my 1HP single speed Hayward Super Pump with a VS pump. You say you have a high electric rate, how much are you paying per kwh?

Currently I have a 1 HP Hayward Super Pump, according to the specs, it runs at 750 watts (compared to the VS pumps that's at lest 3x your rate) for 9 hours a day, at an electrical rate of .085 per kwh. I think if I did my math correctly:
.085x.75x9x30= $1721 per month

I know that when my current pump craps out, I will be forced to replace it with a multi speed or VS pump, but at this time it doesn't look like a good financial move to change the pump at this time.

You did not include the decimal (.75) when you multiplied. Another way is to deal with watts and then then convert to kilowatts.

750w * 9hours = 6,750 watts per 9 hour run cycle

6,750 * 30days = 202,500 watts per monthly run cycle

202,500/1,000 = 202.5 Kilowatts per monthly run cycle

So you would multiply 202.5 by your price per kwh, you stated .085, but that seems low. ($17.21)

You are also missing the point with the variable speed pumps. You will run them most of the time at a much lower setting. I never run mine full speed for normal operation. I have the Hayward Tri-Star VS950 2.7 hp pump. I run it 24 hours a day. The highest RPM that I run is 1,725 RPM which only draws 331 Watts of power...so roughly half of what your 1hp pump uses. Over the night time hours I run it at 900 RPM which only uses 46 Watts of power.

I only use 169.92 kwh running my pump 24/7 compared to your 202.5 kwh running yours only 9 hours a day.

 

[red-beard]

I'm doing research to determine if I should swap out my 1HP single speed Hayward Super Pump with a VS pump. You say you have a high electric rate, how much are you paying per kwh?

Currently I have a 1 HP Hayward Super Pump, according to the specs, it runs at 750 watts (compared to the VS pumps that's at lest 3x your rate) for 9 hours a day, at an electrical rate of .085 per kwh. I think if I did my math correctly:
.085x.75x9x30= $1721 per month

I know that when my current pump craps out, I will be forced to replace it with a multi speed or VS pump, but at this time it doesn't look like a good financial move to change the pump at this time.

The 1 HP super pump is rated at 9 amps @ 230 VAC, or 2,070 Watts or ~2kW

@9 hours per day, you are using 18kWh. This is 540 kWh/mth. At $0.085/kWh, $46/mth

I am running my VS pump at about 40 GPM @60 Watts 24 hours per day. I use 1.5 kWh/day or 45/mth. My monthly cost is $3.50. I run the pump 365 days a year, or about $45 per year at this speed. My real cost is around $130/yr when I include the skimming speed 4 hours a day (80 GPM), the SWG and the pool robot electric costs.

I had a 1HP Hayward Tristar pump that was 1776 Watts. I ran it about 16 hours per day (6AM to 10PM). 10372 kWh/year at $0.079/kWh = $820. Add in my pool cleaner pump and I was close to $900/year!

My VS pump was around $700. I saved enough to pay for my pump in one year. People with 4-5 month seasons it might take a little longer to pay for the pump. OTOH, Doheny's has a 2 hp VSP for around $450. And they have a 2 speed (300 Watts/1700 Watts) pump for around $350. Even a 2 speed pump will pay for itself quickly.