The concept of a swimming pool heater might sound strange at first. Because swimming pool activities should help you to cope up with the scorching summer heat and in that case, cold water is more desirable. But it turns out that you need to regulate the temperature of the pool water for truly enjoying the poolside activities. To make your swimming and pool hours more enjoyable, the portable pool water heater is necessary if you live in cold weather.
There are varieties of pool heaters available in the market utilizing different types of fuels and price tags. Also capacity and models are different and you have to consider a lot of factors to buy a suitable portable pool water heater which is cost-effective and efficient as well. Lots of people get hung up in those issues and bounce back and forth between options. This article is to guide you purchase a suitable swimming pool heater.
Why You Need Heating Your Pool
As mentioned earlier, pool heaters are a controversial issue and some people don’t consider it worth investing. However, there are counter-arguments hard to ignore. The pool water temperature is crucial for an enjoyable pool experience. The optimum pool water temperature would be at least 26 °C but normal pool water will not get any warmer than 22 °C, or perhaps 25 °C on very hot days.
On top of that, during nighttime, temperature normally even dips lower and makes it uncomfortable for nighttime pool parties. The warm swimming pool in autumn, when the summer heat has faded is quite an excellent experience. You can extend your swimming season up to earlier in the late spring by installing a pool heater.
If you live in chill weather, a pool heater is a must-have for comfortable swimming inside your pool. People living in a warmer climate can take advantage of solar energy and by installing solar heaters which store energy during day time, they can have warm pool water at night.
Best Method For Heating Your Pool Water
Mostly, there are two major categories of portable swimming pool water heating methods. One is an active method that involves heater generating heat burning fuel or using renewable energy. These swimming pool heaters can run on electricity, natural gas or propane, or solar energy. The heat pump type heaters transfer heat from the surrounding to the pool water. Heat pumps run on electricity and they are very efficient in terms of heating the pool water.
The other method is passive one and it deals with design to reduce the amount of heat a pool loses and thus keeping the pool water relatively warm. Combining both active and passive methods yields the best result for heating your portable pool.
1. Active methods
above the ground pool heaters have different designs and fuel types. Most common types of pool heaters are given below
Electrical heater:
The electrical heat pump utilizes electricity to capture heat and move it from one place to another. Heat pumps don’t generate heat rather transfer heat from the surrounding.

The evaporating coil holds liquid refrigerant which absorbs the heat from the outside air as a fan draws in the outside air and directs it over the evaporator coil. As a result, refrigerant within the evaporator coil absorbs the heat from the outside air and becomes a gas. This warm gas then passes through the compressor that increases the heat, creating a very hot gas. As the hot gas from the compressor passes through the condenser, it transfers the heat from the hot gas to the cooler pool water circulating through the heater.
The pool pump circulates the swimming pool’s water through a filter and the heat pump heater to get warm. The cold pool water is returned as heated and the hot gas in the condenser returns to liquid form and back to the evaporator, where the whole process begins again.
Since the function of the heat pump is dependent on the outside environment, the heat pump works efficiently as long as the outside temperature remains above the 45ºF–50ºF range. Apart from the heat pump, there are conventional electric water heaters for portable pools which are less expensive than heat pumps but they lack efficiency.
Gas heater:
For portable above the ground pools, gas operated heaters are very common and they can heat up the water pretty quickly. Gas fired portable pool heaters draw water from the portable pool and circulate through a filter and then to the heater. The heater burns natural gas or propane inside the combustion chamber to generate heat. This heat is transferred to the water while circulating inside the heater and it gets heated.
The heater is controlled with a thermostat (ranging from a simple analog device to the state of the art digital controlling device) and when the temperature reaches the preset level, the burner is turned off. If the temperature level goes down, the burner is started again. A modern gas heater can be 89% to 95% efficient based on the Btu (British thermal unit) output. An efficient heater may be expensive to buy, but it has low fuel consumption and thus minimum operating cost. So, you will be able to save a handsome amount annually. The gas heater for a portable pool can heat up the water more quickly than any other type of heaters.
Solar heater:
If you are more inclined towards renewable energy, then you can try solar heaters or solar panels with an electric heater. With the solar panels, you will be able to generate your own electricity to run an electric portable pool heater without paying the utility bill.
Another option is the solar collector which generates heat by concentrating sunlight over a small space.


On average, these solar heaters can raise temperature upto 6 -10℉ and they don’t cost any electricity bill. But they are completely dependent on the weather condition and they must be installed in a place where plenty of sunlight is available. They work efficiently with small portable pools and a good amount of energy is required to pump and circulate the water inside the solar heater.
2. Passive methods
if you can reduce the amount of heat a pool loses, you will need less energy to heat up your portable pool in the first place. Passive solar designs help to cut cost and energy requirements. There are plenty of schemes you can apply to prevent heat loss of your above the ground pool. Some of the strategies are:

- Pool location in the yard: you should place your pool in an area shielded from the wind. As wind on the surface of a pool creates ripples or small waves, it increases the water surface of the pool and hence accelerates the heat losses from evaporation. So, a less windy and shielded area is more suitable to erect your portable pool.
- Pool insulation: In the USA or Canada, the ground temperature is quite constant regardless where you live in particular and it is less than the ambient temperature. So, putting some insulation outside the thermal mass of the water-retaining structure is advisable to prevent heat loss of pool water. You should place rigid panel insulation under and around the structure of the pool to prevent heat transfer from pool water to ground.
- Color of the pool: the brighter color reflects greater amount of heat radiation and darker colors absorb more. So by choosing appropriate color of your above the ground pool, you can save a lot of energy.
- Solar pool blanket: 70% of energy loss of pool water occurs due to evaporation. Solar blanket is designed to reduce the evaporation rate near to zero and trap the heat from the sun by greenhouse effect. These blankets are transparent and allow the sunlight to enter the pool water. They have air bubbles on the surface which acts as an insulator and retain heat for a long time.
Top 6 Best Portable Water Heater For Pools
Freezing temperature of your pool shouldn’t spoil all fun you could have and to prevent this from happening, we have covered electric, gas and solar portable water pool heater for your in-ground or an above ground pool to control the swim season with these wonderful pieces of equipment.
1. Hayward W3H150FDN Universal H-Series pool and spa heater
For more than 80 years, Hayward is a renowned brand producing cutting-edge, technologically advanced pool equipment worldwide. The W3H150FDN model of Hayward Universal H-series pool heater can control your swim season and provides luxurious comfort that fits your lifestyle. The heat output of this natural gas heater 150,000 BTU which provides reliable, long-lasting comfort. The fast pace heating capacity cuts the heating time so that you can spend more time in the water and less time waiting.
The resilient Cupro Nickel heat exchanger’s extraordinary protection against corrosion resulting from salt-based, high flow or aggressive water chemistry conditions ensures long-lasting performances. The low NOx emission is compatible with the air quality standards in all low-NOx areas which also impact your environment at minimum level.
Forced draft combustion system always circulates air through the combustion chamber at a precise flow rate, eliminating all outside weather variables that can affect heating performance, such as high wind conditions. The thermal efficiency of this unit is 83%. Digital LED control panel helps to maintain the water temperature accurately. The panel also provides digital temperature readout, diagnostics and electronic ‘lock-out’ of temperature set-point.
- Forced draft combustion system for precise combustion control in all weather type
- Corrosion proof Cupro Nickel heat exchanger
- Doesn’t get damaged by salty or acidic water
- Low nitrous oxide emission and air standard compatibility
- Durable natural gas pool heater
- Efficiency up to 83%
- High maintenance cost
- Installation process is complicated, trained professional is needed.
2. SunHeater S120U Universal Solar Pool Heater
This eco friendly yet cost effective portable pool heater utilizes nothing but the sun to heat up your pool water. Your annual fuel cost is zero as well as the emission of harmful pollutants. This solar collector is designed to circulate the pool water through the heat exchanger using the pool pump without adding any extra cost.
SunHeater collectors are manufactured using special mold and polymer material to ensure maximum efficiency along with durability. A properly sized unit can raise the water temperature upto 100 F during the season. Using the pool pump, the cold pool water is pushed through the solar collector automatically and the water is then heated by the sun as it moves through the collectors.
The installation of the SunHeater solar heater is quite easy and requires only a few tools and PVC pipes. This unit should be installed in a place where sunlight is available for at least 6 hours and the collector should be faced south. The tube and web design of the collector perform efficiently to collect heat from the sun. Tough polypropylene piping of SunHeater collectors won’t rust or scale easily.
- Eco friendly
- Corrosion proof
- Efficient design
- Minimum maintenance
- DIY installation
- Doesn’t require extra pump
- Requires at least 6 hours of sunlight
- Doesn’t perform on cloudy days
3. IIS 220V 240V 3KW Premium Quality Heat Pump Water Heater
B-M3 model swimming pool and spa heater is a heat pump of 3KW capacity. The flow temperature sensor technology is quite advanced and a single chip micro-computer accurately regulates the water temperature with the help of this sensor. The computer also timely monitors the temperature status of the entire heating system. The temperature range maintained by the heat pump is 22 – 500 C.
The safety measures of B-M3 heat pump includes protection against overcurrent, ultra-high temperature, short circuit to the power supply line, and water flow protection. The liner material inside the heat pump is 316# stainless steel which is corrosion-resistant, especially chlorine-related corrosion.
This model is suitable for small pools less than 5 CBM. The modern state-of-the-art temperature sensor replaces the traditional magnetic flow switch which improves reliability and ensures trouble-free operation. The micro-computer control system displays the operation status and alarms to assist the user or maintenance personnel in troubleshooting. The controlling system is quite easy to operate.
- Cutting edge temperature sensor
- Computer controlled system
- Easy to use control system
- Corrosion proof
- High efficiency
- Constant water temperature
- Suitable for small pools only
4. Pentair 460736 MasterTemp Pool Heater
MasterTemp natural gas pool heater offers quick operation, efficiency, convenience and reliability of a high performance natural gas pool heater. This heater is also eco friendly and certified for low NOx emission. The compactly designed heater features a tough, rust-proof exterior.

The heater is fashioned with the cupro-nickel exchanger capable of withstanding the harshest of applications, like low pH, high flow or heavy use. For easy operation and troubleshooting, MasterTemp natural gas pool heater is fashioned with an LCD monitor which can rotate to view the monitor easily from different angles. There is a manual shut-off valve for servicing the heater.
- High performance natural gas pool heater
- Quick operation
- Digital control system for accurate temperature control
- Rotating display
- Tough and corrosion proof heat exchanger
- Manual shut off valve
- Low NOx emission outperforms the industry standard
- Several complains about the unit not being very durable
5. ZMM 18KW Electric Pool Water Heater
The intelligent control system of ZMM electric pool heater is fashioned with a single chip microcomputer which control the pool water temperature very precisely as well as monitor the status of the entire heating system and the flow of water, ensuring that the user sets the water temperature while the heating element works reliably under the proper flow conditions. During non heating conditions, the water flow is reduced to save energy which ensures low utility bills and prolonged service life.
The liner of the thermostat is made of 316# stainless steel and the electric heating tube provided by Duan Baker Company which has good corrosion resistance (chlorine corrosion). Specially designed liner ensures good circulation and no slag accumulation. The liner can be removed easily if needed.
The temperature sensor is state of the art which has no moving parts avoiding mechanical failure. The sensor is impervious to accumulation of calcium (scale), magnetic substances, hair and suspended matter in water. The capacity of the heater is 18 KW and has a heat rate of 60,000 Btu/Hr for a pool of 5000 gallons capacity in coastal climate.
- High capacity electric pool heater
- Specially designed thermostat liner is easy to remove
- Corrosion proof liner
- Advanced technology temperature sensor has no mechanical issue
- Intelligent control and monitoring system
- For electric connection, a plug can’t be used.
6. ZZP 240V 3KW Electric Water Heater Thermostat SPA Bath Heater Pump
Suitable small portable pool or hot tub, ZZP 3 KW thermostat is specially designed to automatically control the water temperature of your pool and keep it warm. This heater is fashioned with a single chip microcontroller along with flow temperature sensor which replaces the traditional magnetic flow switch improving smooth operation without mechanical trouble, adaptability of water environment and stability.
The thermostat timely monitors the temperature status of the entire heating system and the flow maintaining the bath temperature at 22 – 500 C. the inner lining of ZZP thermostat is made of 316# stainless steel which does not corrode by chlorine. Also this electric heater is equipped with protection schemes such as over-current, ultra-high temperature, short circuit to the power supply line, and water flow protection.
- Efficient electric portable pool heater
- Rust proof thermostat liner
- Minimum maintenance pool heater
- Modern flow temperature sensor without any mechanical failure
- Automatic control system
- Fit for small pools less than 5CBM only
See more : How To Raise pH In Pool Water ?
Features to Look Before Buying Portable Water Heater For Pool
Before purchasing a heater for your portable swimming pool, there are some basic features to be considered in general.
Sizing of the heater
Foremost important thing before buying a heater for your above the ground pool is to perform a proper sizing analysis for your specific swimming pool to determine pool heater size.
Many elements are associated with the sizing of your pool heater. The first thing to consider is the surface area of the pool and difference between the desired pool water temperature and the average air temperatures in the coldest month. Now calculate the surface area of your pool in square feet. The formula to determine the Btu/hour output requirement of the heater is:
Pool Area x Temperature Rise x 12
In this formula, the rate of temperature rise is 1º to 1-1/4ºF per hour at 3-1/2 mile per hour average wind at the pool surface. If a higher rate is desired, then multiply the result by 1.5 for 1-1/2ºF rise and multiply by 2.0 for a 2ºF rise. It is very important to calculate the required capacity of the heater accurately and you should consult an expert for this matter.
Efficiency
The efficiency of the heater for your portable pool greatly affects your operating cost. The annual fuel cost difference between a 55% and 95% efficient gas heater is $420. The efficiency figure is the ratio of usable output to energy input. To simply put, an 80%-efficient heater uses $80 worth of useful heat for every $100 worth of fuel. So a heater with higher energy efficiency is desirable. But the price tag also goes high as the efficiency of the heater increases. You have to find a sweet spot between these two conflicting facts.
Estimating The Operating Cost
It is possible to estimate the annual cost of using a gas or electric heater by calculating COP (coefficient of performance) of the heater, square-feet area of the pool, water temperature, location and per unit fuel cost
For example, in Miami, the average electricity cost for a heat pump running round a year is $1100 (for water temperature of 780 F) and $1845 (820F). To calculate the cost, the area of the pool is assumed to be 1,000 square foot and a heat pump with an average COP of 5.0 at $.085/kwh. For the full chart go here.
As for a gas heater, this cost is around $2136 (780 F water) and $3600 (820F water) in the same location and same size pool. The efficiency of the pool heater is 80% efficient natural gas heater at $.80 per therm and the pool remains uncovered for 8 hours per day. For the full chart go here.
Fuel Types
The above ground pool heaters can run on gas, electricity or solar energy and different fuels have different characteristics. Before selecting a particular type of portable pool heater, you have to ensure the availability.
For example, a solar collector heater is the cheapest to run and it is recommended if you live in a sunny state like California. But if you live in a state like Portland, a solar heater may not be a good choice. Besides, the solar heater takes a long time to warm the pool water
Electric heaters are quite efficient and cheap to run. But they are suitable for small pools. For a portable pool of suitable size, electric heaters can be used to heat the pool year round.
Natural gas or propane heaters will be expensive to run. But they can heat up the water very quickly and maintain the optimum temperature for a long time. Based on these facts and how fast you want your pool to be swim ready, you should decide the type of fuel best suit your purpose.
Control Panel
Electric or gas heaters have control panels to control the water temperature and you have to check them before buying one. The digital control panel is very easy to operate and you will be able to control the pool water temperature very precisely. Some cheaper models don’t have one and you may have to buy an extra thermometer to check the pool water temperature.
Installation And Maintenance
Some portable pool heaters are quite easy to install and you can do it yourself without any extra cost. While other heaters, such as gas heaters, need to be professionally installed and you have to hire a professional tradesperson to do the job. Eventually, your primary cost depends on the nature of the installation of your heater and you have to take it into account.
Maintenance is an equally important issue to consider before purchasing. Proper maintenance ensures the longevity of your heater. Scaling in the burner or heat exchanger decreases efficiency over time. You have to calibrate the thermostat annually, too. If you have to hire a professional for maintenance every time, it will definitely raise your annual cost.
Safety Tips
Although modern heaters are quite reliable and safe devices, it takes just one service slip-up — a failure to fully clean out the heater’s interior, or to leave the ventilation open — to turn a trusted piece of equipment into a major liability. To avoid catastrophic disasters, proper installation by following local safety codes and regulation is mandatory. In addition to that, here are some useful safety tips:
- Indoor installation of gas heaters without proper ventilation can produce carbon monoxide which is lethal and extremely difficult to detect it. Venting and chimney codes; ventilation air, combustion air — all these codes have to be strictly followed. If a carbon monoxide leakage is suspected the user must contact the emergency services immediately.
- Chemicals and the heater unit have to be stored separately. It will prevent any accidental combustion from growing into a full-blown chemical fire.
- To prevent leakage and mechanical failure, many heaters have internal safety mechanisms. You have to test them occasionally by consulting the heater’s manual as a guide.
- Preventive maintenance and regular inspections for blockage or any other malfunction will prevent severe accidents. Biological blockages such as twigs, dry leaves, and small animals pose threats for fire hazards.
- Proper electrical installations are extremely important for ensuring safety. Issues like underground power cables, connections not protected with plastic wire nuts, grounding of the equipment have to be examined with great care. Otherwise, the heater’s electronic component might get damaged or even worse- can cause an electrical fire.
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FAQs – Frequently Ask Questions
Is a portable pool heater worth buying?
For a pleasant swimming pool activity, the water temperature is crucial. If you live in hot weather and you have decided to use your pool only in the hottest days of summer, you probably don’t need one. The desired pool water temperature is around 27o C.
But if your environment is cold and lacks sunlight, a pool heater would be necessary for both residential or commercial pool owners. The modern pool heaters work with great efficiency, versatility, and reliability to keep the pool temperatures maintained as per requirement. A pool heater has the potential to be an incredibly worthwhile investment if a family wants to utilize its new pool year ‘round, or even just well into school starting in the fall or at night
Is it safe to use a heater with a portable swimming pool?
Yes. pool heaters don’t heat up the water to a dangerous level. Besides, they have a thermostat to control the temperature and fuel consumption. Also, basic protective devices are incorporated with gas or electric heaters.
What is the annual maintenance cost of a portable pool heater?
Most of the pool heater repairing costs range from $161 and $730. Apart from that, some sudden breakdown may occur. The solar pool heaters are most cost effective in terms of maintenance and the electric heaters are in the second position. Basically, the maintenance cost is highly dependent on the capacity of the heater. Check the warranty of the pool to learn about the frequency of the maintenance.
Is it possible to convert a natural gas heater to a propane heater?
Some natural gas heaters can be converted to a propane heater. Basically, a natural gas burner is a low pressure device where a propane burner operates at higher pressure and the heaters capable of handling high pressure can be converted.
Can I install the heater under the deck?
Gas heaters must be installed in an open space and under no circumstances they should be placed in a confined space. The gas fumes and exhaust gas are harmful for health and they should be kept in space with proper ventilation.
Does a pool heater pollute the environment?
Apart from solar heaters, the gas or electric pool heaters are not very environmentally friendly. The gas heaters emit greenhouse gases and electric heaters use electricity which is produced by burning fossil fuel or coal, again the major source of greenhouse gas. But if you use solar panels to generate your own electricity, then it will not pollute the environment.