Best Natural Gas Pool Heaters: 
Review and Buying Guide

what type of electric pool heater to use for heating the swimming pool?photo: pixabay

Statistics show that most people rely on gas heaters to heat water in their pools. According to plumbers and customers, if you have decided to join them, here is a buyer's guide and a short review of the best natural gas pool heaters available. In the end, we have added some vital info to clarify the differences between the models.

Natural gas pool heaters: Benefits and considerations

How do gas pool heaters work?

Swimming pool gas heaters work by burning natural or propane gas to heat the pool water. The system uses a pump to circulate the water from the pool through a filter, heater, and back.

They provide the quickest heating solution for many homeowners, and because of their high BTU power and quick response, they are used for any pool size and in most climates.

How long do natural gas pool heaters last?

When properly (professionally) installed and maintain regularly, natural gas pool heaters typically last from 5 to 10 years, having the shortest lifespan.

In addition to the above, there are many other factors that can affect the life expectancy of your heater, including:

  • Water quality (chemistry)
  • Usage
  • Weather (local climate)
  • Location

Signs it is time to repair or replace your gas pool heater

Here are the common signs of a broken pool heater that might require you to replace it:

  • Pool water doesn't get warm enough
  • Your gas heater makes strange noises
  • The efficiency is very low, and your gas bill is very high
  • Corrosion
  • Leakage
  • Damaged heat exchanger

Are electric or gas pool heaters better?

  • Natural gas pool heaters have higher purchase and operating costs.
  • Electric models are more affordable but are also expensive to run due to higher energy prices. Electric heat pumps are a better choice because they have the highest efficiency, offering the greatest savings. 
  • Gas models require professional installation, which make them cost more than the electric installation. The electric type is easy to install and maintain and can be a DIY project.
  • Since gas powered pool heaters can deliver more BTU than electric kW, water is heated much faster.
  • When properly sized, gas models won't have any problems heating any pool size, while electric models are mostly effective on smaller pools and spas.
  • Electric models can run up to 15-20 years while gas 5-10 years.

Are natural gas pool heaters expensive to run?

Natural gas pool heaters are a popular option for many homeowners because they heat water quickly and are not expensive to run.

They cost less to operate than electric and propane types but more than heat pumps and solar types.

Expect to pay between $200 and $400 per month to run (depending on the fuel prices) or more for propane.

When talking about costs, note that they can cost you between $1000 and $4500 to buy and up to $1500 to install.

How efficient are gas pool heaters?

Gas pool heaters use energy efficiency, or output/input ratio, to determine how much of useful heat is used or wasted.

For example, if the heater is 90% efficient, 10% is waste, and the rest goes toward water heating.

Today's advanced pool heaters are designed with an efficiency between 90 and 95%.

You can find the efficiency on the unit label or manufacturer's specs.

What size gas pool heater do I need?

Sizing a swimming pool gas heater is very important to buy a suitable model and have comfortable swimming. So, consider the following:

  • Size of the pool that has to be heated.
  • Location and climate.
  • The efficiency of the gas pool heater - choose one with over 90% efficiency.
  • Costs - this includes the initial price of the unit and installation.
  • As with most heaters, the heater's warranty and lifespan last an average of 5-10 years but require proper maintenance and replacement of parts worn out.

The best of the best list is extremely simple. There are two of the most popular manufacturers – Hayward and Pentair, both specialized in pool equipment.

Just to mention a few of their models.

Gas pool heater sizing chart

Pool Size Gas Heater Size
15' Round 100,000 - 150,000 BTU
18' Round 100,000 - 200,000 BTU
21' Round 100,000 - 200,000 BTU
24' Round 150,000 - 250,000 BTU
27' Round 200,000 - 300,000 BTU
12' x 24' 100,000 - 200,000 BTU
14' x 28' 150,000 - 250,000 BTU
16' x 32' 200,000 - 300,000 BTU
18' x 36' 200,000 - 300,000 BTU
20' x 40' 250,000 - 350,000 BTU

What is the best gas pool heater?

Best of Pentair

Sta-Rite SR400HD Max-E-Therm from Pentair

Sta-Rite SR400HD Max-E-Therm from Pentair is on the top of many experts' lists. The unit is robust and lightweight at the same time. The highest efficiency in its class (84% efficiency rating), durability, innovative technology and protection, LED controls... are the most important pros of this 400,000 BTU water heater. Natural gas and propane options are available, also in 200K BTU and 333K BTU versions.

Pentair MasterTemp 460737 stands with an 84% efficiency rating alongside the previous water heater, representing the high efficient 400,000 BTU units. Users like its superior performance, quality housing, and customizable digital panel with various settings.

The previous two are highly recommended if you are ready to pay about $2200. They are the best choice if you have an inground pool.

Pentair MasterTemp product line consists of several propane and natural gas models from 125K to 400K BTUs. Let's mention the highest efficient smallest 125K Pentair 461059 MasterTemp, with $1140 price, which is an excellent pick.

Best of Hayward

Hayward H200FDN

The best Hayward pool water heaters are those from the H-Series.

Hayward H200FDN is an excellent choice if you are looking for superior quality for a price unit, cheaper ($1600) and weaker (200,000 BTU) than the most powerful ones.

Powered by natural gas and suitable for all weather conditions, this water heater is equipped with an innovative airflow design and heat exchangers to raise its effectiveness.

The most affordable unit we recommend is 100,000 BTUs Hayward H100ID1 – the water heater for above-the-ground pools that also utilizes one-of-a-kind Hayward heating technology. High performance and efficiency, quick installation, and an innovative built-in heating chamber come in a pack at the $800 price.

Hayward H-Series water heaters include propane and natural gas-fueled models from 100K to 500K BTUs. More about Hayward here.

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Other manufacturers

Besides the manufacturers mentioned above, you may consider Raypak (a Rheem company) or Jandy gas water heaters for pools, still good choices.

Before starting the search for your best-fit gas water heater, read short answers to the questions buyers usually ask.

Other things to consider

How many BTUs is enough?

More BTUs heat faster, with quicker gas consumption. There will never be too much BTU energy. Talking about gas water heaters for pools, plumbers advise a simplified formula (pool volume in gallons + 10%) x 10 = BTU energy needed to increase the temperature by 1 degree F in an hour.

Propane vs. natural gas

If the natural gas line is in your backyard or very near, this fuel looks like the best and a budget-friendlier choice. The alternative is a propane tank. Compare propane and natural gas prices in your region, consider the cost of the construction work you have to do and keep in mind that propane gas may be more expensive, but it contains more energy than natural gas.

What does HD mean?

HD stands for heavy-duty, which means the heat exchanger is made of cupro-nickel, a material of high conductivity and durability.

Millivolt vs. Electronic (digital) pool heaters

Without diving into details – electric heaters are based on modern technology; they need the power to ignite the pilot, but the pilot does not burn all the time. Millivolt heaters slowly become obsolete.

As an addition – do not neglect the importance of the control panel and its helpful features: temperature adjustment or even automatic temperature control, quickly available commands, safety alerts...

Advantages of the gas pool heaters

Natural gas pool heaters heat pool water very fast, faster than electric, solar, or heat pumps, so this type is ideal if you don't use a pool daily but occasionally. These units are considered "green" due to their environment-friendly operation and are reliable when used in any region, from warm to cold northern parts.

Average efficiency is between 80 % and 85%, but still lower than what heat pumps can produce. These are recommended due to their ability to maintain the water temperature easily in any climate and due to their lower operating costs.