Hayward 400K BTU Pool Heater Review

Step into a world of poolside luxury and endless relaxation with the Hayward Universal H-Series 400,000 BTU Natural Gas Pool & Spa Heater. Dive into a review where reliability meets unparalleled performance, offering you the ultimate comfort for pools and spas up to 1,200 sq. ft.

It’s not just about the quick warm-up—this heater is built to last, armed with a resilient cupro nickel heat exchanger that battles corrosion, ensuring season after season of top-tier heating performance. And let’s talk eco-friendly: with low NOx emissions meeting air quality standards, your comfort doesn’t come at the cost of the environment.

So, what are you waiting for? Let’s explore the Hayward 400K BTU pool heater review, and turn every swim into a luxurious escape.

Top Features of Hayward NOx Pool Heater BTU

The most important thing about a heater is what is its heating capacity? The more capacity a heater has, the more heat it will produce and the larger the pool it will be able to heat.

If you want to enjoy your pool time with this innovative polymerized pool heat pump which comes with such exceptional features. It comes with a cool and unique design to provide the best service while it pumps and heats the pool or spa.

Lin the Hayward 400K BTU pool heater review let’s jump into the main points to ensure its workability.

Here is some splendid features and benefits of this Hayward universal h-series low NOx pool heater BTU natural w3h pool heat pump.

  1. It comes with an anti-combustion system and pilot ignition model that ensures to set up a combustion area.
  2. More energy-efficient and economical as it comes to a gas heater.
  3. Made with a copper heat exchanger that ensures the flow of the heat naturally and freely.
  4. The innovative copper heat exchanger and flow-thru baffles for smooth heat transfer.
  5. It has a unique system that lowers the excessive heat and balances the heat properly.
  6. It is easy to use as it comes with an on and off button. You just need to press the on and off buttons to control and set the temperature as you need.
  7. Comes with BTU 400k natural gas polymerized cabinet that ensures rigidity and efficiency.
  8. As it comes with 400k BTU, it can cool the pool water effortlessly within a very short time and it also helps cool the pool or spa quickly even if the pool water is very hot.
  9. Hayward 400k BTU natural gas pool heater is user-friendly and more convenient as well as durable enough to last more years.
  10. The weight of this unit is 214 Pounds and dimensions are 39.6 x 32.8 x 30.6 inches.

Where Do You Use Hayward 400k BTU Natural Gas Pool Heater?

The Hayward 400,000 BTU Natural Gas Pool Heater is designed for use in both residential and commercial settings where natural gas is available. It’s ideal for heating pools and spas with a surface area of up to 1,200 square feet.

Whether it’s for a backyard pool, a hotel or resort spa, community pool, or any other setting requiring efficient and powerful heating, this heater provides reliable and fast heating performance. Its versatility makes it a popular choice wherever there’s a need for quick, efficient, and consistent pool or spa heating.

How Do You Use Hayward 400k BTU Natural Gas Pool Heater?

Operating the Hayward W3H400FDN H-Series 400,000 BTU Natural Gas Pool Heater involves several steps:

  1. Gas Connection: Ensure the gas line is properly connected to the heater. Follow the manufacturer’s instructions and safety guidelines precisely during installation.
  2. Water Flow: The heater needs a consistent flow of water to operate effectively. Verify that the pool pump is running and there’s adequate water circulation through the heater.
  3. Power On: Power up the heater by using the control panel or switch. The specific location and design of the controls may vary, but typically, there will be an interface panel where you can adjust settings.
  4. Thermostat Setting: Set the desired temperature on the heater’s control panel. Most heaters have a thermostat or temperature control knob that allows you to select the desired water temperature.
  5. Monitor Operation: Watch the heater for a few minutes to ensure it ignites properly and that there are no unusual sounds or smells. Also, monitor the temperature gauge to see if the water temperature starts rising.
  6. Regular Maintenance: Perform routine maintenance as recommended by Hayward. This might include periodic cleaning of the heat exchanger, checking for any blockages or debris, and ensuring all components are functioning properly.
  7. Safety Precautions: Always follow safety precautions outlined in the user manual. This includes keeping the area around the heater clear, ensuring proper ventilation, and regularly inspecting for gas leaks or other potential hazards.

What Makes Hayward 400k BTU Natural Gas Pool Heater Stand Out?

Hayward 400k btu natural gas pool heater

Enjoy in the swimming pool or spa even in the worst weather or condition with this pool heater spontaneously. Hayward 400k BTU natural gas pool heater comes with numerous beneficial features. It also adds more beauty in outdoor and handy equipment for any pool owner that saves extra energy and effort.

Here are some praiseworthy matters that make it a real heater for any pool.

1. Specialty

Magically, it comes with innovative and upgradable technology that makes this Hayward pool heater exceptional right now in the market. In addition, polymerized outside coating design makes it adorable and appealing.

Additionally, it is designed with copper heat exchanger function and flow-thru baffles to provide exceptional and effective heat transfer.

Also, it helps to reduce extra energy and is capable of heating the pool whenever you want to heat it.

2. Durability

Without a doubt, every pool heater or pool heat pump is a durable product because these units are made of rigid material and anti-corrosion metal.

Unlike all the pool heaters Hayward 400k BTU natural gas pool heater is durable enough to last up to 15 years and provides the best operation till the end. If you maintain and use it properly you don’t need to worry about the damage of this unit after many years.

3. User-friendly

Not all the pool heater is easily handheld material but this pool heater is easy to use and control. You don’t need to put extra force or require extra labor to set it up and install.

Also, it uses like a breeze because it comes with an on and off button system.

You can control and set the temperature as you need by pressing this button. Moreover, its automatic thermostat system helps you to set the pool’s temperatures easily.

Hayward Vs Puri Tech Pool Heater

There are lots of unique and innovative featured pool heat pump available that are good for a specific reason. Here are the two products comparison to understand more sharply why the Hayward pool heat pump is best.

In the Hayward 400k BTU pool heater review now let’s compare the unit with the Puri Tech.

  1. Hayward comes with 400k BTU that is capable of warm up the pool quickly whereas Puri tech comes with lower BTU than Hayward.
  2. Requires less energy than the Puri tech pool heater that helps you to keep your extra money saved.
  3. The Hayward pool heater comes with a polymer header. But the Puri tech pool heat pump comes with commercial-grade titanium.

Is Hayward Spa Heat Pump Suitable for Your Needs?

 Is Hayward Spa Heat Pump Suitable for Your Needs?

The suitability of a Hayward spa heat pump depends on various factors such as the size of your spa, your climate, energy efficiency preferences, and budget.

Hayward offers a range of spa heat pumps designed to efficiently heat spas and pools. These pumps utilize ambient air to heat the water, making them environmentally friendly and cost-effective in the long run. They work well in moderate to warm climates where the ambient air temperature is consistently above 50-60°F (10-15°C).

Factors to consider:

  1. Size of Spa: Ensure the heat pump’s capacity matches the size of your spa. Hayward offers different sizes and capacities to accommodate various spa dimensions.
  2. Climate: Heat pumps work more efficiently in warmer climates. If you live in a region with colder temperatures, a heat pump might not be as effective in heating the spa.
  3. Energy Efficiency: Heat pumps generally offer good energy efficiency compared to some other heating options. However, assess the energy efficiency ratings and consider factors like insulation, spa cover quality, and operating costs.
  4. Budget: Hayward’s spa heat pumps vary in price. Evaluate the initial cost, installation expenses, and potential long-term savings in energy costs to determine if it fits your budget.
  5. Installation and Maintenance: Consider installation requirements and ongoing maintenance. Heat pumps require proper installation and periodic maintenance to ensure optimal performance.

Ultimately, if you seek an environmentally friendly and cost-effective solution for heating your spa, and your climate is suitable, a Hayward spa heat pump could be a good fit. However, it’s essential to assess your specific needs, consider your climate conditions, and review product specifications before making a decision.


  • More convenient and user-friendly.
  • It is a more energy-efficient and long-lasting unit.
  • Easy on and off system and copper heat exchanger.
  • Comes at the best price.
  • Ideal for pool up to 1,200 ft.


  • Slightly heavy to carry and exchange.