What is the difference between a 1HP and a 0.5HP water pump?

Finding the right water pump can be a bit confusing for the uninitiated, especially with the huge variety of well pumps on the market today. The difference between a 1HP and a 0.5HP water pump comes down to the type of motor used. A 1HP water pump uses a larger motor than a 0.5HP pump motor, and that 1HP motor will consume twice as much power. A 1HP water pump will therefore be able to pump from deeper wells and pump higher flow rates than the 0.5HP water pump could. 

Let's look at the approximate power consumption between the two pumps.

1HP = 746 watts 

0.5HP = 373 watts

If you use a 1HP water pump over a .5HP water pump, expect higher electrical power usage, and in turn, the electricity bill will cost more. 

1/2 HP vs 1 HP Well Pump

Your well depth and intended pump application will determine what size of pump you use, whether it's a submersible pump or not. A submersible well pump is sized using a total dynamic head calculation. For deeper wells, deep well pumps are often necessary.

Well depth + vertical lift + frictional loss + head from use of a water pressure tank

A 1HP pump is used in situations with total dynamic heads up to 500 feet. 

A .5HP pump is used in situations with total dynamic heads up to 250 feet. 

Let's take a look at a couple of examples of 1HP and 05.HP RPS model water pumps. You’ll notice that the 05RPS05, a .5HP water pump, and the 05RPS10, a 1HP water pump, are from the same model line of pumps that produce up to 2-8GPM. 

However, a 1HP water pump will outperform the .5HP by producing more pressure and more water flow at every level of total dynamic head, and provide a higher total head that's double the .5HP.

Depending on the water depth, you may need a higher horsepower pump to draw efficiently, particularly if using a storage tank in your system. In some cases, a shallow well jet pump may be appropriate for low-depth applications. There are various residential water pumps available for different needs. Additionally, ensure your drop pipe is rated for the total head pressure required and is compatible with your existing well pump. Don't forget to check if you need a new well pump pressure switch for optimal performance.

For a deeper dive into the key differences and how to choose the right option, see our detailed guide on the difference between 1hp and 1.5hp water pump.

Let's take a look at another comparison of a 0.5HP water pump and a 1HP from the same model line, this time 3-13GPM. Again, unsurprisingly, the 1HP 07RPS10 outperforms the .5HP 07RPS05. For applications requiring additional pressure, a booster pump might be necessary. 

Filed in: 0.5 HP water pump, House well system, Submersible well pump, Water pump