Top 3 Hot Tub Heater Reviews for 2021

Without a heater, a hot tub is just a tub. That is why the heater is so important. It is among the essential features of your hot tub. Although all hot tubs come with heaters, some don’t have very efficient ones, and in some cases, even the most efficient heater breaks down and needs to be replaced.


The need for a hot tub heater replacement sends many hot tub owners on a daunting hunt for the best replacement for their heater. Anyone who has replaced a hot tub heater could tell you how hard it is to find a quality product among hundreds of choices. That statement might sound discouraging but, on the contrary, we’re here to help you pick the right one.


Here is what to expect on this guide.


How Hot Tub Heaters Work

When heating a hot tub, a few components are at play. The exterior parts i.e., the cabinet, and shell and the heater itself along with the pumps and jets.


The shell is the external component of a hot tub and houses all other parts. The cabinet is under the shell, and it houses the heater, pump, and a series of tubes.


The pump pushes water through the tubes and into the pump. The water gets heated up as it is passing through the heater and gets mixed up with cold water within the hot tub as it leaves the tubes. This process continues until the water in the hot tub reaches the desired temperature, which is pre-set on the thermostat.


Types of Hot Tub Heaters

There are two types of hot tub heaters. They are categorized according to their mode of functionality as follows:

  • Gas heaters
  • Electric heaters

We are going to differentiate the two in terms of functionality and give some advantages and disadvantages for each to provide you with a better understanding.


Gas Heaters

Gas heaters are powered by either natural or propane gas. The gas is supplied to the heater through a gas line. The gas is then ignited within the heater to produce heat energy needed to heat the water.


  1. Low operational cost

The price of natural gas is lower than the price of electricity; hence a gas heater is cheaper to operate than an electric heater.

  1. Fast heating ability

Gas heaters heat water faster than electric heaters. A gas heater can raise the water temperature of the hot tub by 1-2 degrees per minute, while an electric heater takes up to an hour to raise the water temperature by a few degrees.


  1. High initial cost

The price of a gas heater is generally higher than that of an electric heater. In addition to its high price, it requires a gas line connection, which can cost almost as much or even more than the heater itself. Simply, when installing a gas heater, it will cost you a substantial amount of money.

  1. They are installed externally

Gas heaters need to be connected externally so that they have access to fresh air for combustion. They also have an exhaust shaft; hence they cannot be placed in the shell.

Electric Heaters

Electric heaters work by use of a heating element within stainless steel tubes. Water gets heated up as it passes through these tubes.


  1. Low cost of operation

If you have a well-insulated spa or hot tub and you live in a mild-hot climate area, then you don’t expect to spend much on heating. Although, if you have a poorly insulated hot tub or live in a cold climate area, then you can incur significant electricity charges.

  1. Low initial cost

Electric heaters usually don’t cost that much, at least not as much as gas heaters. Their cost of installation is also low, as all they need is a little wiring and a socket to plug into.


  1. They are slow to heat

Electric heaters heat the water very slowly. The heat gain when using electric heaters is about 2-3 degrees per hour.

If your hot tub is poorly insulated and the temperatures of the surrounding is cold, it can even do one degree per hour. Their slow heating speeds require you to heat your hot tub several hours before you start bathing.

  1. Might get damaged or cause an accident

Water and electricity wreak havoc when in contact. They may cause the electrical heater to get damaged or even shock the occupants of the hot tub. Luckily, such accidents rarely happen because they are protected by several safety components as well as a GFCI.

Factors to Consider Before Purchasing a Hot Tub Heater

  1. The type

When it comes to hot tub heaters, you have two primary choices to choose from. Gas or Electric. You should consider the climate of the area you live in, how long you are willing to wait for your tub to heat as well as your hot tubs energy efficiency.

Gas heaters heat water very fast, but their initial cost of installation is high. They are suitable for cold areas and hot tubs with low energy efficiency because they can supply the heat needed on demand.

Electric heaters heat water very slowly. They are suitable for medium-hot climate areas, and their initial cost of installation is not that high.

  1. Size and specifications

It is essential to consider the size of the appliance because once you buy it, you’ll need to put it somewhere. Electric heaters are smaller than gas heaters.

The size of your hot tub is also a factor you need to consider. For a large hot tub, it is better to buy a gas heater to meet its heating requirements. Smaller hot tubs can do well even with electric heaters.

  1. Your budget

You should go for a heater that you can buy, install and run without straining your budget. Gas heaters cost a lot and have a higher cost of installation but cost less to run than electric heaters, which cost less to buy and install but have a high price of maintenance.

Review of 3 of the Best Hot Tub Heaters on the Market

American Standard Safe-T-Heater



This is an electrical heater designed to maintain the temperature of the water in your hot tub at a set level when it is in use. It is compatible with all American standard whirlpool tubs.

To use, you just need to fill your hot tub with water and connect it. It then maintains the temperature of the water at that level. Although it is quite easy to install, it comes with a significant disadvantage as it does not heat the water, it only maintains it at a particular temperature.

  1. Raypak Electric Spa Heaters


This 11Kw electric heater is made of corrosion-resistant bronze and copper materials for enhanced durability. It is also fitted with a pressure switch that automatically turns it off when there is no water flow.

It is quite easy to install, and its compact design enables it to be placed in tight spaces. It also comes equipped with a thermostat and a high limit pressure control to prevent overheating. Its maximum flow rate while heating is 60 GPM.

  1. Hayward Universal BTU Pool and Spa Heater


This heater produces low NOx emissions; hence it is environmentally friendly. It is made of corrosion-resistant cupro-nickel; therefore, it is very durable. It comes with an LED control panel that you can use to check and set the hot tub temperature.

It heats water pretty fast. It can raise a volume of 800 gallons of water to 30 degrees in thirty minutes. It has a forced-draft system that moves air through its combustion chamber, thus ensuring that the outside temperatures don’t affect its operation.

The downside to using this heater is that it is pretty noisy and there have been complaints by some users of the company failing to honor its warranty.

Our Top Pick


We take the American Standard 9075.120 Safe-T-Heater as our top pic. Even though it does not heat the water well, its efficiency, ease of installation, and its plug and play mechanism make it stand out from other heaters.

Its ability to maintain hot tub water temperatures at a constant level means that you can jump into your hot tub at any time, and the water will be just as warm as you left it. It also has a compact design, meaning you can place it in a pretty tight space problem-free.


The Bottom Line

Heaters are essential in all hot tubs. When choosing a heater, take factors such as the climate of the place you live and the size and energy efficiency of your hot tub.

With these factors in mind, choosing between a gas and an electric heater is not hard. If you live in a hot area and your hot tub is well insulated, an electric heater will work great for you. If the climate of the area you live in is cold or your hot tub has poor energy efficiency, then you’ll have to go for the more expensive option, a gas heater.

Frequently Asked Questions (FAQs)

  1. Question: What is a hot tub heater?

Answer: A hot tub heater is like any other water heater. The only difference is that a hot tub heater warms up the water from your pump, thus feeding your hot tub with warm water until it reaches your desired temperature.

  1. Question: Can I use a pool heater to heat my hot tub?

Answer: Many pool heaters are also compatible with hot tubs. However, if you plan on using the same heater to heat both of them, then you will need a specialist to install it. It is probably easier to buy separate heaters.

  1. Question: How safe are hot tub heaters?

Answer: Hot tub heaters come with a lot of safety features to prevent accidents and over-heating. The cases of hot tub accidents resulting from a faulty heater are very few. It is best to follow all the safety instructions that come with it and regularly maintain your hot tub.


Hot tubs are neither fun nor relaxing when you just sit there in cold water. In fact, a hot tub that is not heated is not technically a hot tub. It’s just a tub. This shows how essential they are. We hope that this guide on hot tub heaters has enlightened you on everything you needed to know about hot tub heaters.

When shopping for a new heater for your hot tub, you must consider the factors that we had given earlier in the guide. Also, you can purchase any of the three heaters that we have listed or use their features as a guide when purchasing a hot tub heater.