How do I calculate energy usage? 1HP single speed vs 1.65HP vs pump.

[Major_in_MS]

My current pump is a Hayward Super Pump with a 1HP single speed pump. I'm currently running my pump for 6 hours in the morning and 6 hours in the evening. My electric bill shows that I used 176.48 KWH/Day in August when I was running my pump 24/7, and 159.97 KWH/Day in September after I changed my pump to 12 hours per day and I also bumped up one of my thermostats in my home from 70 to 75 degrees.

I want to try to lower my electricity usage even more and I'm thinking of getting the PureLine PL2605 VS pump from INYOpools.com.

I'm paying $0.091/KWH. How do I figure out how much less electricity I will use if I switch my pump out? Will I have to run it for longer due to the lower GPM?

I'm sure my biggest energy hogs are my three central air units, but I'm willing to pay the $600 to change out my pump if it will pay for itself within a reasonable amount of time, I just don't know how to calculate the savings.

Thanks for helping

Major

 

[duraleigh]

but I'm willing to pay the $600 to change out my pump if it will pay for itself within a reasonable amount of time,

What's reasonable is a big variable......what do you think........3 years? 10 years? My bet is more like 10 years with that kw rate of .09

Far, far and away the best way to save energy is to cut pump run time. Drop back to 10 hours daily and see if your pool stays clean. If so, keep dropping back until you are no longer satisfied with the cleanliness of your pool. You might save 30-50% of your electricity without lifting a finger.

 

[Major_in_MS]

Ok, so I'm not looking at the variable speed pump being able to pay for itself in like 6 to 12 months? Looking at the advertised savings on some of the pump sales literature I thought I might be able to save up to $100/mo with a new pump/motor.

I'll cut my run time down a few hours at a time and see how my pool handles the reduced filtration as you suggest. I'll also be hoping for cooler weather so my AC can run less.

Thanks for the reply.

 

[scooperhsd]

As pointed out , the easiest way to save is to reduce your pump's runtime - don't go overboard on that and end up with a swampy mess either.

A VSP will save money , but how long will it take to pay for itself ? If you need a new pump anyway - sure.

With your electric rates that low, you may want to checkout 2 speed pumps - not too much more than single speeds, and about 50% of the power savings of the VSP's.

 

[GaryT58]

Hi Major,

You're in the same boat I was. I wanted to replace my 1hp single speed pump. Here is link to thread (see 2nd post) that shows a great table that compares cost of ownership for various pumps. You can download the excel spreadsheet from the 3rd posting, with link next to "Pool Pump Tools*". You can edit this worksheet (must enable macros) to change the various things to your case, like electric power cost, run times, product cost, run speeds, ....

There are other spreadsheets included which can provide some great info.

I used the "Energy Cost" sheer to verify in my case that the 5-year cost of ownership of the Pentair SuperFlo VS was much better than a 2-speed pump for how I plan to run (low speed 24/7). Also, with the "Energy Cost" worksheet, you can select the pumps you want to compare by entering the "Pump Model" value for the column and it will fill in the data for the pump from the "PumpData" sheet (where you can get the Pump Model values. I edited sheet with my local power $, run times, rates, current pump costs, and compared the couple models I was looking at (couple VS, one 2-speed) and compared to my original pump. Very helpful in selecting my new pump.

I am installing my new VS this weekend (would have been last weekend but original arrived with a crack).

[edit] From the sheet, I see I should save about $95/month running new pump. Will see for sure once installed, and find best RPM rate for my SWG.

Gary

 

[GaryT58]

I also recall that you are considering a SWG addition. For me the VS made the most sense as I want to be able to dial the speed to be meet the GPM that my SWG needs (Autopilot can run between 15-20). I have read on TFP for some users that the lower speed on some 2-speeds was not sufficient to allow their SWG to run, so had to run on high when chlorinating.

 

[CJadamec]

There are a lot of cost brake downs for VS pump floating around. At 9 cents a kW your payback on energy savings will take years when compared to the price of a single or two speed pump. An important thing to look at is any energy rebates your power company might provide for going to an energy efficient pump. That could change the math some what. Another cost to having a VS pump is adding surge suppression to the electrical panel feeding your pump. If your pump electronics get fried from a power line surge any saving you may have hoped to reap will go out the window in the blink of an eye. Single and 2 speed motors don't have any fancy electronics to worry about.

 

[GaryT58]

I would suggest adding a surge protector regardless if you go to VS pump. I added one to protect my whole sub-panel as I wanted to protect my SWG. As for return on investment, that will greatly depend on how you plan to use it, which is why the spreadsheet is such a great tool. In my case of running at low RPM at 24/7 it should save me $95/month compared to my single speed pump, and passes the savings of a 2 speed as well over time.

[edit] To be clear, from the spreadsheet I found that for 24/7, which is the way I want to run, return on investment (savings equal or exceed $ spent):

AO Smith 2 speed motor replacement - 4 months.
Pentair SuperFlo SF-N2-1A (2-speed) - 7 months.
Hayward SuperPump SP2300VSP - 8 months
Pentair SuperFlo VS 342001 - 8 months.

And I found because I should be able to run the VS even lower RPM to handle my SWG, the VS will pass the 2-speed in 20 months.

This can be much different depending on how you will use - # hours at which speed.

 

[pooldv]

Here is how to calculate energy usage and cost. This assumes your pump uses 1500 watts.

Pump watts x hours run per day / 1000 x 30 days x rate
1500×8 = 12000/1000 = 12.0×30 = 360 kWh × $0.09 = $32.40 per month to run your pump 8 hours per day
1500×24 = 36000/1000 = 36.0×30 = 1080 kWh × $0.09 = $97.20 per month to run your pump 24 hours per day

I run my VS pump at 1100 rpm to skim, filter and make chlorine with the SWG. It uses 150 watts at 1100 rpm.
150×24 = 3600/1000 = 3.6×30 = 108 kWh × $0.09 = $9.72 per month to run 24x7

 

[n240sxguy]

I replaced my single speed 1.5 hp pump motor this year with a 2 speed 1.5 hp. The service ratings are different, but 1.65 thp was what they both ended up at. My electric rates are right at $.10/kWh. I don't remember the watts on them, but I remember the $ figure attached to each based on the math. My old motor would cost $5/day to run 24/7, the new motor costs $4/day on high, and $1.47/day on low. I run it about 12 hours a day because I want to see the water moving when I look out there. So, I went from $2.50 a day to about $.75 a day with the motor swap. VS was never an option for me. My three A/C units are what's killing my electric bill. I'm on vacation now with the pool running exactly like it normally does. I bumped all my thermostats from 75-85. While I've been gone, my kWh/day has gone from 160-180 to 35-40. So, $16-18/day down to $3.50-4.00. It's almost cheaper not to live at my house.


Sent from my iPhone using Tapatalk

 

[duraleigh]

From the sheet, I see I should save about $95/month running new pump.

Holy Benoli!! My old single-speed 1.5 (full rated) pump running 24/7 only cost about $80/month.

If you are going to save 95, what in the heck is your current bill?

 

[GaryT58]

Holy Benoli!! My old single-speed 1.5 (full rated) pump running 24/7 only cost about $80/month.

If you are going to save 95, what in the heck is your current bill?

About $100/month. That is according to the excel worksheet for my pump running 24/7. That seems to match the increase on my electric bill. So using the same worksheet and new pump, with same KW cost, it drops to just under $5/month.

I plan to confirm this tomorrow using an amp meter to take true readings from existing pump and then new pump at various RPM values, down to the low RPM value that I end up selecting for 24/7 operation.

 

[Major_in_MS]

Here is how to calculate energy usage and cost. This assumes your pump uses 1500 watts.

Pump watts x hours run per day / 1000 x 30 days x rate
1500×8 = 12000/1000 = 12.0×30 = 360 kWh × $0.09 = $32.40 per month to run your pump 8 hours per day
1500×24 = 36000/1000 = 36.0×30 = 1080 kWh × $0.09 = $97.20 per month to run your pump 24 hours per day

I run my VS pump at 1100 rpm to skim, filter and make chlorine with the SWG. It uses 150 watts at 1100 rpm.
150×24 = 3600/1000 = 3.6×30 = 108 kWh × $0.09 = $9.72 per month to run 24x7

Best Answer Award!!


So I used the above formula to get some useful information.

My electric power association has two different rate plans available to me.

Residential rate A = 9.761 cents per kWh

and

Time of Use Rates

On Peak = 18.190 cents per kWh
Off Peak = 6.419 cents per kWh

Summer Period (May to Oct)
On Peak = 3pm to 8pm
Off Peak = all other hours

Winter Period (Nov to April)
On Peak = 6am to 8am, and 5pm to 8pm
Off Peak = all other hours

So aside from the hour differences between the summer and winter periods, on peak is 5 hours per day for both periods.

Please read through my thought process and let me know it there is a flaw in my plan.

So, if I enroll in the Time of Use rate plan, and run my pump year round for 19 hours per day during the off peak hours, then it will take me 12.14 months for the savings to pay for a $600.00 variable speed pump.

Current pump = (1500 x 19)/1000 = 28.5 kWh/day x 30 = 855 kWh x 0.06419 $/kWh = $54.88/mo
VS pump @1100rpm = (150 x 19)/1000 = 2.85 kWh/day x 30 = 85.5 kWh x 0.06419 $/kWh = $5.48/mo

Monthly savings = $49.40. New pump approx $600.00 / $49.40 = 12.14 months

The other extreme, running 24 hours/day year round at the residential rate A, the variable speed pump would pay for itself in 6.3 months.

Upon further breaking down my current usage from august of 176.48 kWh per day, assuming constant hourly consumption, if I switch to the Time of Use plan and make no other changes, then I will save almost $230.00 per month. My water heaters, cooking, clothes dryer, and heating are all natural gas, so the only electricity I'm using is small motors in the refrigerator and the freezer, pool pump, lighting, computers and other electronics, and the three central air units. All of these, except for the AC, pretty much use the same amount of electricity around the clock. If I install programmable thermostats to shift my AC usage away from the On Peak hours, then I can save even more.

So it seems to me that switching to the Time of Use plan is a no brainer.

If I can cut my bill almost in half just by changing rate plans and limiting use during the 5 hours/day On Peak, then I'm not gonna be in such a hurry to buy a new energy saving VS pump. I can just wait for my current pump to reach it's end of life and then replace it with a VS model.

So, anybody see any flaws in my thinking?

Thanks,
Major

 

[pooldv]

Good plan. Knowledge is power!

 

[cjpwalker]

Before you make the peak/off-peak rate decision, do yourself a favor, and shut your AC off every day for the next week, then don't turn it back on until 8:00 in the evening. See how that works for you. Most HVAC systems are (should) be designed to maintain a home at maximum design conditions (a published number usually a couple of degrees below your most extreme summer days). That said, if it's hot out, and really hot inside the system will have trouble pulling back down to a comfortable level unless it's oversized.

 

[Major_in_MS]

Before you make the peak/off-peak rate decision, do yourself a favor, and shut your AC off every day for the next week, then don't turn it back on until 8:00 in the evening. See how that works for you. Most HVAC systems are (should) be designed to maintain a home at maximum design conditions (a published number usually a couple of degrees below your most extreme summer days). That said, if it's hot out, and really hot inside the system will have trouble pulling back down to a comfortable level unless it's oversized.

Thanks for the advice, I do need to see how quickly my home heats up when the AC units are turned off and then how long it takes to get back to a comfortable level again after they are turned back on.

Currently I have all three of my thermostats set around 70 degrees F as near as I can tell with the old mercury switch style thermostats. I've just ordered three electronic and programmable thermostats on Amazon.com. White-Rodgers Emerson Sensi Wi-Fi Thermostat

I'm thinking if I just change them to 78 degrees F during the On Peak hours then I will still see a significant savings on my bill, and the AC will still be able to come on and cool as needed to keep the temp from rising too much.

I'm also going to try to figure out if it's worth the high price of those new LED light bulbs to replace my incandescent bulbs. I suspect however that lighting has very little effect on my monthly bill.

 

[GaryT58]

Currently I have all three of my thermostats set around 70 degrees F as near as I can tell with the old mercury switch style thermostats. I've just ordered three electronic and programmable thermostats on Amazon.com. White-Rodgers Emerson Sensi Wi-Fi Thermostat

I'm thinking if I just change them to 78 degrees F during the On Peak hours then I will still see a significant savings on my bill, and the AC will still be able to come on and cool as needed to keep the temp from rising too much.

This is a very good idea as simply shutting off in peak summer could let it get too hot and humid and risk chance of mold and/or humidity damage. I have programmable thermostats as well, and use them the opposite way in winter (temp lower when sleeping or no one home).

I'm also going to try to figure out if it's worth the high price of those new LED light bulbs to replace my incandescent bulbs. I suspect however that lighting has very little effect on my monthly bill.

A 100 W equivalent LED standard type bulb can be purchased for about $6.25 (in 4 pack). This bulb uses 14.5W, so a savings of 85.5W. So if use 5 hours (non-peak) a day, 85.5 *5 / 1000 * 30 * 0.06419 = $1.31 saving/month. So would take 5 months to pay for itself. Also, LED bulbs rated life is about 10,000 hours, so at 5 hours/day the life is about 5.5 years, so a savings of over $80 per bulb for its lifetime (and this is not considering the savings of replacing the existing bulbs over that time, which would burn out anyway). So while not huge savings per bulb, it does make a difference. I started by replacing the largest energy use bulbs first and worked my way around. I would say I have about 80% LED at this time.

Some things about some LEDs:

• The bulbs can be bigger than the ones they replace, so putting a 100W equivalent in place of a 100W may not fit in some lamps.
• If using light dimmers, you would need to purchase ones which say "dimmable" on the package. Not all can be dimmed. And most older dimmers may not dim them well - can dim for say about 1/2 or so, then it drops off.
• Like regular bulbs there are different types in term of light color - warm, cool, ...
• Because they use less power, you can increase the brightness. For example, use the 14.5W LED (100W equivalent) in lamp which was rated for 60W, and get more light (if it fits).

Since the major pump use is winding down now, you could make the other changes, and use those savings to save/pay for the new pump next spring and save even more.

 

[Major_in_MS]

A 100 W equivalent LED standard type bulb can be purchased for about $6.25 (in 4 pack). This bulb uses 14.5W, so a savings of 85.5W. So if use 5 hours (non-peak) a day, 85.5 *5 / 1000 * 30 * 0.06419 = $1.31 saving/month. So would take 5 months to pay for itself. Also, LED bulbs rated life is about 10,000 hours, so at 5 hours/day the life is about 5.5 years, so a savings of over $80 per bulb for its lifetime (and this is not considering the savings of replacing the existing bulbs over that time, which would burn out anyway). So while not huge savings per bulb, it does make a difference. I started by replacing the largest energy use bulbs first and worked my way around. I would say I have about 80% LED at this time.

That's actually a bigger savings than I expected. Hmm, I guess I'll get a few and start replacing my bulbs. I found some 60W equivalent Soft White in a 16 pack for about $2 per bulb on Amazon.

Thanks

 

[scooperhsd]

Thanks for the advice, I do need to see how quickly my home heats up when the AC units are turned off and then how long it takes to get back to a comfortable level again after they are turned back on.

Currently I have all three of my thermostats set around 70 degrees F as near as I can tell with the old mercury switch style thermostats. I've just ordered three electronic and programmable thermostats on Amazon.com. White-Rodgers Emerson Sensi Wi-Fi Thermostat

I'm thinking if I just change them to 78 degrees F during the On Peak hours then I will still see a significant savings on my bill, and the AC will still be able to come on and cool as needed to keep the temp from rising too much.

I'm also going to try to figure out if it's worth the high price of those new LED light bulbs to replace my incandescent bulbs. I suspect however that lighting has very little effect on my monthly bill.

Holy cow - 70 degrees inside in the summer where you live ?!?!?!?! Do you like living in a meat locker ?

Just setting your cool temps to 73-75 will save you dramatically.

I keep my 2400 sq feet house at 75 during the day, and 72 when we're sleeping.

I have a Honeywell 7600 programmable thermostat - It will also switch from heating to cooling or vice versa, and also does the same with my gas furnace.
It also has different setting for setting heating temoeratures - I usually run 70 when we are awake and 65 or so when sleeping.

 

[Major_in_MS]

Holy cow - 70 degrees inside in the summer where you live ?!?!?!?! Do you like living in a meat locker ?

Just setting your cool temps to 73-75 will save you dramatically.

I keep my 2400 sq feet house at 75 during the day, and 72 when we're sleeping.

I have a Honeywell 7600 programmable thermostat - It will also switch from heating to cooling or vice versa, and also does the same with my gas furnace.
It also has different setting for setting heating temoeratures - I usually run 70 when we are awake and 65 or so when sleeping.

No, actually a meat locker is much colder.

The meat hanging room must be temperature controlled from between 33 and 37 degrees Fahrenheit (1-3 degrees Celsius).
It is such a small window in temperature because the meat will spoil if the room is too hot and the process of dry
aging stops if the water in the meat freezes.
​

I work night shift, so I sleep during the day. I sleep best when the temp in my bedroom is between 65-68 degrees, makes no difference summer or winter.

Yes, all the exterior doorknobs and windows are constantly dripping from the condensation.
Yes, my AC units are oversized and run most of the day.