Product Information
Description
Hayward W3HP21105T HeatPro 110,000 BTU Heat Only Pool Heat Pump
Extend your swim season for less.
The Hayward W3HP21105T HeatPro Heat Pump (SKU PST-W3HP21105T) delivers 110,000 BTU of heat-only output for inground pools up to roughly 20,000 gallons, using ambient air instead of gas to push your water to swim-ready temperatures. Hayward's microchannel heat exchanger (MCHX) cuts braze joints by 85%, drops the cabinet weight to 230 lbs, and lets the unit pull heat from outside air down to 40F. You get gas-pump heating without a gas bill, on a 230V single-phase circuit you already have at the equipment pad.
Microchannel Efficiency , Built for the Pad
The HeatPro MCHX heat exchanger replaces traditional tube-and-fin coils with a microchannel design that cuts braze joints by 85% and trims cabinet weight by up to 50 lbs. Less metal, less refrigerant charge, more surface area in contact with the air. The result is a quieter, lighter unit that pulls more heat out of every cubic foot of air the fan moves, while staying tough enough to survive years on a sunbaked equipment pad.
Patented Defrost Algorithm Stretches the Season
Most heat pumps fall off a cliff once outside air drops below 50F. The W3HP21105T's patent-pending defrost algorithm keeps capacity up where competitors stall, with rated operation all the way down to 40F ambient. That means real heating in early spring and late fall, not a unit that runs all day and barely budges the thermometer. You add weeks of swim time on both ends of the calendar without touching your gas line.
TCP Coating Survives Harsh Climates
Hayward's Titanium Coating Protection (TCP) was developed for Naval Air Command to resist salt air, pool chemistry overspray, and UV. The whole cabinet, fan grille, and exposed cabinet fasteners are treated, so a HeatPro sitting eight feet from a saltwater pool in coastal Florida looks the same in year five as it did on day one. Pair that with the corrosion-resistant MCHX coil and you get a heat pump that ages like equipment is supposed to.
Who It's For
Residential Inground Pools
Sized for typical 15,000 to 20,000 gallon backyard pools that want a 5 to 10 degree lift over normal swim season ambient temps.
Vinyl, Gunite, Fiberglass
The 2 inch plumbing union connections drop straight into any standard inground equipment pad, no shell type restrictions.
Solar Backup or Replacement
Pairs well with solar panels as a backup heater for cloudy stretches, or replaces aging solar entirely with predictable, on-demand heat.
Season Extension
Ideal for owners who want March to November swim time in transitional climates without the running cost of a gas heater.
Why PST Customers Pick This
110,000 BTU Output
Enough capacity for ~20,000 gallon pools, with a typical 1 to 1.5 degree per hour rise on a 20,000 gallon pool in 75F ambient.
5.7 Heating COP
You get about 5.7 units of heat for every unit of electricity, which is roughly 5x more efficient than electric resistance heating.
2 in Union Plumbing
Standard 2 inch threaded unions make swaps and winterizations straightforward for any pool tech.
Compact Square Footprint
30.5 in W x 33.6 in D cabinet with a 44 in height fits the same pad space as competing 100K class heat pumps.
TCP Cabinet Coating
Naval-grade Titanium Coating Protection resists salt air and pool chemistry, ideal for coastal and saltwater pool installs.
Quiet Single-Speed Fan
Top-discharge fan and MCHX coil move air efficiently, with sound levels low enough for backyards close to patios and neighbors.
Installation Notice
The W3HP21105T requires a dedicated 230V single-phase circuit with a 40 amp maximum breaker, wired per NEC Article 680 for pool equipment, with proper bonding to the equipotential grid. Maintain 12 in side and rear clearance and 72 in vertical clearance for airflow. Installation by a licensed electrician and pool professional is required to keep the Hayward warranty valid.
Full Specifications
Frequently Asked Questions
What size pool does the W3HP21105T heat?
At 110,000 BTU/hr, this heat pump comfortably maintains pools up to about 20,000 gallons in most climates. For larger pools or aggressive temperature targets, step up to the 140K BTU HP21404T or 140K square-platform model. Pool cover use can effectively double the gallons this unit holds at temperature.
What is the difference between the W3HP21105T and the HP21105T?
Functionally they are the same unit. The W3 prefix identifies the model as sold through Hayward's authorized residential distribution channel, which is the channel that carries the full warranty. The HP21105T (without W3) is the open-line or pro-only version sold through wholesale-only channels.
What is the difference between Heat Only and Heat / Chill models?
The W3HP21105T is heat only, designed to raise pool temperature. The HP31105T Heat/Chill version reverses the cycle to also cool the pool a few degrees in extreme summer heat. If you only need warming, the heat-only model costs less and uses fewer internal components.
Can I install this heat pump myself?
Most local codes require a licensed electrician for the 230V single-phase 40A circuit (NEC Article 680 bonding rules apply). The 2 in plumbing connections are straightforward for a handy owner or pool pro. We strongly recommend a professional install to keep the Hayward 5-year parts warranty valid.
How fast will it heat my pool?
A typical 20,000 gallon pool gains 1 to 1.5 F per hour with this unit at 75F ambient air. Cooler outside air slows the rate. A solar or thermal pool cover at night is the single biggest improvement you can make, often cutting runtime in half.
Does it work in cold weather?
The HeatPro is rated for operation down to 40F ambient air. Below that the patented defrost algorithm protects the coil but capacity drops sharply. For climates with winters below freezing, the unit must be winterized and the water side drained at the end of swim season.
How much will it cost to run?
With a 5.7 COP, the W3HP21105T uses roughly 4-5 kW when running. At an average US electric rate, that is a few dollars per hour of runtime, dramatically less than a gas heater hitting the same temperature target. Pool covers and only heating when you are using the pool will keep monthly costs sane.
Order the Hayward W3HP21105T From PST
PST Pool Supplies is an authorized Hayward dealer. Every HeatPro ships with the full 5-year Hayward parts warranty, backed by our in-house service team.
Additional Info
| Category | Pool Products Pool Heaters |
| SKU | PST-W3HP21105T |
| MPN | W3HP21105T |
| Manufacturer | Hayward |
| Weight | 230.0 lb |
Let customers speak for us
Easy to order - received the next day!
Beautiful!!
The valve fit perfectly and works great.
Fast shipping and great price!
Does what a small weed- eater would do it minutes versus an hour
Great product does exactly what was advertised to do.
I ordered the wrong part. Customer service was very helpful. I returned it and within the week my credit card was credited back. Excellent customer service policy.
There was a delay in shipping due to postal service. They sent another part right away.
New model 59303 works great, but too bad the last generation Balboa WiFi module 50350 became un-useable.
Exactly as advertised and super fast shipping and delivery
