Pool Pump Horsepower vs THP: What's the Difference

HP and THP in a Pump Listing

A pool pump listing can state both HP and THP. HP appears on the pump name and in the title, and THP, the abbreviation for total horsepower, shows as a separate figure. A buyer comparing pumps sees two numbers and needs to know what each one names before choosing.

The site reads both figures as words in the listing, not as measured results. A maker such as Pentair lists horsepower and THP as separate filter attributes on its product pages, which is one reason a listing can show a value for each. Hayward uses the wording "True 4.0 HP" on its site for the same purpose of naming output in plain terms.

When a listing states only one figure, the other is simply not stated by the seller. "Not stated" is a valid answer in a comparison, and the guide says so rather than guessing at a number. See pool pump horsepower explained for the term on its own.

• HP names the stated horsepower of the pump motor.
• THP names the stated total horsepower of the motor.
• A listing may show one figure, the other, or both.
• When one figure is absent, the guide records it as not stated.

What THP Means as a Listing Term

THP stands for total horsepower. As a listing word it describes the motor output in a single figure. Related terms appear in certification programs. The ENERGY STAR pool pump criteria use a related term, hydraulic horsepower (hhp), to sort pumps into size classes: self-priming inground pumps under 0.711 hhp fall in the small class, and non-self-priming aboveground pumps at or below 0.13 hhp fall in the extra small class.

The criteria express each class requirement as a wire-to-water efficiency (WEF) level. As a shopper, the useful move is to read THP as the maker's stated total output, not as a promise about how the pump performs in a particular pool. The site never turns a stated figure into a measured flow or head claim. See motor horsepower versus THP for the neighboring term.

Comparing Pumps on Stated Horsepower

The site compares pumps on the details a listing states: horsepower, speed type, voltage, and pool type. For horsepower, the stated HP and the stated THP are both listing details, and the guides sort pumps into horsepower bands from those stated figures.

A stated 1.5 HP does not become an energy figure, a flow figure, or a noise figure on this site. The best 2 HP and up guide sorts pumps the same way each pump's stated horsepower is one of the listed details, and the buyer decides from the stated words. The same approach applies to voltage, so a listing that says 115V or 230V is read as stated, as explained in 115V versus 230V.

What This Site Cannot Say About Horsepower

This site does not size a pump to a pool. No formula here turns pool gallons into horsepower, and no turnover, total dynamic head, or pressure drop calculation appears in the articles. The reason is simple: the site has no data beyond the stated details in a listing.

The site also converts no units. A stated gallon per minute or gallon per hour figure stays as stated, and no new figure is derived from it. Pool pump flow rate explains the units as terms without converting them.

For sizing, the maker's sizing page and an installer are the people to ask. The maker publishes manuals and sizing tools, and the installer knows the existing plumbing of the pool. Codes and standards vary between jurisdictions, as the Pool & Hot Tub Alliance notes, so the local building office is the place to check any installation question.

Any wiring decision, such as a pump whose listing names 115V or 230V, is made by a licensed electrician, the maker's manual, and the local building office.

ENERGY STAR and Horsepower

ENERGY STAR is a voluntary program that certifies pool pumps able to run at different speeds, according to its pages. The program's pool pump criteria sort pumps by hydraulic horsepower and express each class requirement as a wire-to-water efficiency level.

A pump that carries the ENERGY STAR mark is one the program has certified, and that mark is a program detail. This site does not translate the mark into a saving figure for a specific pump, and the articles do not repeat the program's savings wording as buying advice.

Questions for the Maker and Installer

A pump listing gives the maker's stated details, and the maker's own pages are the next place to look. The maker publishes sizing pages, manuals, and the meaning of the figures in its model names.

• What horsepower range does the maker's sizing page recommend for this pool and its plumbing?
• Does the listing state both HP and THP, and which figure does the maker say to use for comparison?
• What flow rate does the pump need at the existing plumbing, and does the listing state a flow figure?
• Does the installation need electrical work, and who handles it according to the local building office?
• What do the maker's warranty terms cover, and where does the maker publish them?

What to pick for your situation

Questions

Is THP the same as HP?

No. HP names the stated horsepower in the listing, and THP names the stated total horsepower. A listing may show both figures, and each is a separate stated detail.

Why do some pump listings show two horsepower figures?

Sellers and makers often state both the motor's common horsepower and a total horsepower figure. Pentair, for example, lists horsepower and THP as separate attributes on its product pages.

Which figure should a buyer use to compare pumps?

Compare the stated HP and stated THP as separate details. The site sorts pumps by stated horsepower and tells the reader what each listing states.

Can the site tell you what size pump your pool needs?

No. The articles do not size a pump to a pool. Ask the maker's sizing page and an installer, and check the local building office for any installation question.

Does a higher THP mean a better pump?

A higher stated figure is a stated figure, not a promise of performance. No measured claims are made here about flow, head, energy, or noise.

What does ENERGY STAR say about horsepower?

ENERGY STAR is a program that certifies pool pumps able to run at different speeds, and its criteria sort pumps by hydraulic horsepower size classes.