Hi I'm trying to replace my old pump which is a Hayward 1HP pump for a dual speed energy efficient pump, so far my choices are a Hayward Super Pump 1 HP, Whisperflo Dual Speed 1 HP and the Pentair SuperFlo 1 HP, I will like to know any pros and cons on any of this, and which one do you think is better?

A 2 speed Superflo will line up exactly. It comes with unions. It's that simple.

Scott

Was the old pump a SuperPump? As Scott metioned, if it is a SuperPump, then the SuperFlo will line up which can be a big plus.

But as for a comparison between the three:

Assuming the Whisperflo is the up rated version, SuperPump and SuperFlo are both up rated, then the only real difference between them is flow rate. Efficiency wise, they are all pretty close but the Whisperflo will have a higher flow rate and faster turnover on the same plumbing than the other two. For larger pools and pools with larger plumbing, the Whisperflo may be a better choice but it usually costs more than the other two. In terms of pump size, they line up this way from smallest to largest and the CEC Curve-A high/low speed flow rate is shown in parentheses.

SuperFlo 3/4 HP Up Rated (GPM:47/24)
SuperPump 1 HP Up Rated (GPM:51/26)
SuperFlo 1 HP Up Rated (GPM:56/28)
WhisperFlo 1 HP Up Rated (GPM:61/31)

What is the size of your pool?

thanks for the answers, I should have started with my pool description, the old pump don't know what it is, since the label is all worn out, but I believe is a Hayward 1 HP.

The pool is a 26,000 gallons pool, with 5 returns, I have a solar heating system on a 2nd story house, sand filter and a polaris booster pump

Does the dual speed pumps have a switch to change the speed from low to high, so I can manually change it when I want to use the heater or the polaris?

Yes, some of the pumps come with a switch but you can also purchase a two speed timer to control both speeds. Can you post a picture of your
old pump? If is is not a SuperPump, that may alter your choice of pump. Note too that if your wet end is in good condition, you could just replace the motor with a two speed.


Also, can you answer the following questions:

Height of pump relative to the pool water level
Diameter and number of individual suction pipes from the equipment to the pool
Diameter and number of individual return pipes from the equipment to the pool
Diameter and number of return eyeballs
Filter type and backwash valve model if known
Filter PSI reading at the desired valve settings and pump's highest speed setting.
Heater - yes or no
Pool/Spa Valve - yes or no (If there is a spa, the number of jets and size)
Check Valves - Number and locations

no other heater, only the solar system.
no spa
the filter psi normally is 20 when the panels are on

Your current pump is a SuperPump so you would be ok replacing it with either another SuperPump or a SuperFlo. However, as I mentioned before you could just replace the motor of your current pump and save about half the cost of a new pump. But if the wet end is not in very good condition, then you should probably replace the entire pump. If you replace the pump, I would go with either of these two pumps as they are close to your current pump:

SuperPump 1 HP Up Rated SP2607X102S
SuperFlo 1 HP Up Rated SF-N2-1A