How to size a water pump and calculate installation costs

The primary two things that matter are first size a water pump correctly and then evaluate the exact water pump installation cost. It is essential for all project types whether you are working on new construction, renovation, or remodelling projects. If you consider massive structures like commercial and industrial buildings, their plumbing or water systems work is also very huge. That means, even a single issue in one system can affect the other one! 

For this reason, accurately sizing the water pump is important for efficient operation. As a property owner or a manager, you will not have to face over- or under-sizing issues and the overall energy consumption will also be reduced. If you feel to have professional opinions or calculations to deal with your ambiguities, you can rely on professional plumbing estimating services. You will get precise calculations in the quickest time possible with a detailed explanation of its types and all! 

READ OUR BLOG TO LEARN HOW TO ESTIMATE WATER PUMP INSTALLATION COST AND DISCOVER WHICH FACTORS AFFECT THE OVERALL COST AND TIPS FOR SELECTING THE RIGHT PUMP FOR GOOD PERFORMANCE!

Explaining how to size a Water Pump!

Now we will show you how you can size a water pump but wait first you must know the factors on which the sizes depend. 

• The first one is named Flow Rate (GPM) Gallons per minute, it is the rate at which the pump moves the water. 
• The second most important factor is Head Height (ft), it is the distance coverage of water that needs to be pumped vertically and horizontally, including friction losses.

These two factors are the main elements that tell you the exact size of a water pump. However, the ideal situation is when flow rate and head height are met which also helps in maximizing the life of a pump and less energy is consumed. 

 How to Calculate the Flow Rate (GPM)

Before calculating the flow rate, let us show you what are the key terms:

• First, the amount of water that needs to be pumped per minute – GPM.
• Second is the height and the friction loss – Total Dynamic Head (TDH)
• The third term is for measuring the power which is required to drive the pump – Horsepower (HP)

To calculate the flow rate (GPM), you must be fully aware of the water demand and for what type of application you are working on because different applications have various flow rate needs!

Use an Approximation Formula: Flow Rate = Number of Fixtures × Fixture Flow Rate.

For instance, if a home has 8 fixtures and each requires 2 GPM, 

the required flow rate is 8×2=16 GPM.

 How to Calculate Head Height

Step-by-Step Calculation of Total Dynamic Head (TDH)

First, you need to calculate the static head which is the vertical distance from the pump to the highest point.

Then you need to know about the friction loss that increases with the pipe length. Generally, friction loss is considered 5-10% of the static head.

The third step is to calculate the pressure requirement because few systems work at some pressure levels such as 50 psi for sprinklers. To convert psi to feet, multiply by 2.31.

With the help of this formula, you can calculate TDH:

TDH=Static Head + Friction Loss+ (Pressure Requirement × 2.31)

Let’s Assume:

• Static head is 20 feet
• Friction loss is 10 feet

The pressure requirement is 40 psi, then:

• TDH = 20 + 10 + ( 40 × 2.31) = 122.4 feet

Selecting the Right Pump Horsepower (HP)

Now you have the right flow rate (GPM) and head height (TDH), the next thing you need to calculate is the correct horsepower. Use the Pump Power Formula:

Horsepower (HP)=  Flow Rate (GPM)×TDH (ft) / 3960×Pump Efficiency

Let’s do some calculations for you!

• Flow rate = 16 GPM, 
• TDH = 122.4 feet,

Pump efficiency is 65% (or 0.65), then:

• HP = 16 × 122.4 / 3960 × 0.65 ≈ 0.76  HP

This means you have almost 1 HP pump for an efficient, long-lasting solution.

Estimating Installation Costs for a Water Pump

Now you know how to size a water pump comprehensively. In addition to that, you must also know how to estimate the installation cost and which factors to consider while evaluating the cost. 

Factors in Installation Cost Calculation

• Labour expenses cover the maximum budget of the project. Nowadays the rate for professional pump installation ranges from $300 to $700. This cost depends on the building’s location, complexity, and size. 
• The next thing is to estimate the material cost which can add another $100 to $300.
• Based on the calculated horsepower and brand, water pumps can range from $200 to $800.

NOW WITH OUR DETAILED EXPLANATION, YOU HAVE COME TO KNOW HOW TO SIZE A WATER PUMP AND ESTIMATE INSTALLATION COSTS! MAKE SURE YOU ARE DOING THE CALCULATIONS RIGHT BASED ON THE EXACT WATER PUMP SIZE!

Conclusion

In short, we have discussed all possible formulas and factors that help to size a water pump and calculate the installation cost. By following our guidelines you can select the perfect pump that aligns with the demands of the system. Additionally, make sure to select the right one because you have to manage energy consumption cost-effectively. Only accurate sizing helps to increase the life of a pump. However, you can also contact a reliable partner for cost estimating services, they will provide more insights with detailed explanations.