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A pool heater for an inground pool is a device that is used to heat the water in the pool. The pool heater is usually a gas or oil-fired boiler that is used to heat the water in the pool. The pool heater is usually placed in the pool area and is connected to the pool pump.
The pool heater is used to maintain the temperature of the water in the pool and to keep the water from freezing.
20 Best Pool Heater For Inground Pool
Product Image
Product Name
Features
Price
Hayward H-Series Universal Low Nox Pool Heater 250,000 BTU Natural GAS
The Universal H-Series Heater is an energy efficient, high performance, installation adaptable commitment to the pool service professional. An industry leading hydraulic design reduces circulation pump run time.
The energy efficiency of the Universal H-Series gas heater combines with environmentally friendly low NOx emissions, a standard cupro nickel heat exchanger and ultimate installation flexibility on new or existing equipment pads to responsibly heat a pool or spa today and for years to come.
The forced draft system in the Universal H-Series constantly moves air through the combustion chamber at a precise flow rate eliminating outside weather variables that can affect heating performance.
Wind conditions are eliminated and there is no install a high-wind stack. Patented bypass design for superior hydraulic performance. 2 in. x 2-1/2 in. CPVC union plumbing connections are perfect for todays larger plumbing systems.
Easy to read LED control panel. For indoor/outdoor use note: HAYWARD Universal H-Series heaters meet or exceed the SCAQMD and the SJAPCD low NOx emissions standards in all low NOx areas that apply the SCAQMD standard.
This is a great product at a great price. I decided to buy an entire pool system. I saved a ton of money but guess what, no one will install because I didn’t buy it from them. I found one pool company that was willing but clearly I was being penalized because the price was through the roof.
So, I will do it myself except for the gas connection. When ordering items like these one gets a much shorter warrantee and the hassle of paying out those savings to a pool company for installation. I’m determined to get it done.
Here is an opportunity for someone to start an install only business and with the help of these online retailers, it is sorely needed. I recommend buying online but do be aware of installation difficulties.
Additionally, do inspect the equipment when it arrives since heavy freight is not easy in residential areas and everything I have ordered had damaged packaging in one way or another. Lucky for me the contents survived the rough handling.
That last mile is a problem for heavy, large items.
The Universal H-Series Heater is an energy efficient, high performance, installation adaptable commitment to the pool service professional. An industry leading hydraulic design reduces circulation pump run time.
The energy efficiency of the Universal H-Series gas heater combines with environmentally friendly low NOx emissions, a standard cupro nickel heat exchanger and ultimate installation flexibility on new or existing equipment pads to responsibly heat a pool or spa today and for years to come.
The forced draft system in the Universal H-Series constantly moves air through the combustion chamber at a precise flow rate eliminating outside weather variables that can affect heating performance.
Wind conditions are eliminated and there is no install a high-wind stack. Patented bypass design for superior hydraulic performance. 2 in. x 2-1/2 in. CPVC union plumbing connections are perfect for todays larger plumbing systems.
Easy to read LED control panel. For indoor/outdoor use note: HAYWARD Universal H-Series heaters meet or exceed the SCAQMD and the SJAPCD low NOx emissions standards in all low NOx areas that apply the SCAQMD standard.
Warm your pool with the powerful and economic HeatPro 140,000 BTU In-Ground Pool Heat Pump by Hayward. Featuring a strong, corrosion-resisting titanium heating element and requiring no propane or fuel, the heat pump is a great way to maintain a comfortable temperature in your pool.
The heater functions by drawing in exterior air and uses that to warm your pool, removing the need for propane or natural gas. This makes for an economical, easy-to-use heater that functions efficiently, always keeping your pool warm and comfortable.
Ultra Gold technology resists corrosion and withstands even harsh coastal environments, and the titanium heat exchanger encourages maximum heat transfer while stopping degradation from saltwater or pool chemicals.
The system operates quietly so you can enjoy the sounds of summer poolside without interruption. A compact design makes the heater easy to move and install, fitting on a square equipment pad. Perfect for your backyard pool, stay warm and comfortable this summer using the HeatPro 140,000 BTU In-Ground Pool Heat Pump by Hayward.
Heat pump got here quick, easy to install, and is running great. Raised temp on my 20 by 40 pool 9 degrees in less than 2 days, and keeping it there despite nights of 50-60 F and less, and days in 70’s to low 80’s.
Runs very quiet, and very satisfied with it. Would certainly recommend!.
This heater is a heat pump so it ducks the hot air out of the atmospheres and transfers it to the heater coils then into the pool. It can also send cold water into the pool if pool too warm. Very efficient because it uses air as the catalyst for the heat.
Less than 55 degrees and it doesn’t work but I don’t plan on swimming in temperatures less than 55.
Awesome pool heater. Installation instructions were well written and install was easy with the supplied quick disconnect for the pool lines. Heater is quieter than my 1hp pool pumps which I didn’t expect.
Unit only requires 20amp breaker. Would recommend.
MasterTemp Heaters offer all the efficiency convenience and reliability features you want in a pool heater plus a lot more. As easy to use as your home heating system plus user-friendly indicator lights make system operation and monitoring a snap.
The compact design and super-quiet operation won’t intrude on your poolside leisure time. MasterTemp’s easy-to-read controls make system operation and monitoring simple. Pool and spa temperatures can be pre-set and controlled with the push of a button.
A digital display indicates the water temperature and five LED lights give you system status and let you know if the heater needs service. No matter what you re seeking in your swimming pool heater MasterTemp measures up.
Compare this list of features to any other and you ll see why MasterTemp is setting a new standard for total value.
Purchased a bundle of screenlogic and several other Pentair products. The 400k master temp, natural gas…. Junk since out of the box. Had service call after service call over the warranty period and as soon as the warranty was out, catastrophic failure Internally.
We have the pool service bi-weekly, so water was maintained and ph levels monitored regularly. Life space was less than half expected, and Pentair did not want to even speak to us about it. Stay away from this and consider Jandy or Heyward for your pool heater needs.
I assure you! I build homes and have seen constant issues after committing business to Pentair for my home, as well as others…. I spoke to a pool professional that says 13 months on several of his projects, same thing with life-span, but an array of reasons of this failure of a product.
The heater came with box damage and scratch on front of heater. The heater didn’t come with the high temp unions shown in the picture with the heater. Had several conversations with the seller about getting these parts that were suppose to come originally.
The sellers answer was sorry we don’t have the parts and you can return the 120 lb heater if you want. Also they were no help in helping me to figure out what parts were missing. After researching myself I had to order the $60 unions to make hooking up my heater possible.
Also the heater didn’t come with a 3/4 inch zinc plug you will need. The heater was a pretty easy to install. Seems to heat my 15000 gallon pool up around 2 degrees an hour.
I bought my first Pentair in 2007, a MiniMax 100. It went 10 years then needed a few parts to get to 15. This new MasterTemp 125 is awesome. No more pilot and fire to blow out in wind. Operating on millivolts, it was very sensitive to electrical connections integrity.
I feel like I’ve joined the 21st century with my capacitive discharge ignition and digital control panel.
The forced draft system in the Universal H-Series constantly moves air through the combustion chamber at a precise flow rate eliminating outside weather variables that can affect heating performance.
Wind conditions are eliminated and there is no need to install a high-wind stack. Presenting Hayward ‘s world-class heater with an Earth-friendly conscience the Universal H-Series heater! The Universal H-Series Low NOx heater has an 84 percent industry-leading thermal efficiency and complies with all current California air quality emission standards.
The low NOx emission makes it a perfect choice for the environmentally concerned pool owner. Enjoy a warmer pool this season without your fuel costs skyrocketing. Hayward’s Universal H-Series heaters represent innovative heating technology for pools and spas.
Its hydraulic performance also saves energy by reducing the circulation time of the pump.
The Universal H-Series 200,000 BTU Propane Heater is an energy efficient, high performance, installation adaptable commitment to the pool service professional. An industry leading hydraulic design reduces circulation pump run time.
The energy efficiency of the Universal H-Series gas heater combines with environmentally friendly low NOx emissions, a standard cupro nickel heat exchanger and ultimate installation flexibility on new or existing equipment pads to responsibly heat a pool or spa today and for years to come.
The forced draft system in the Universal H-Series constantly moves air through the combustion chamber at a precise flow rate eliminating outside weather variables that can affect heating performance.
Wind conditions are eliminated and there is no install a high-wind stack. Patented bypass design for superior hydraulic performance. 2 in. x 2-1/2 in. CPVC union plumbing connections are perfect for today’s larger plumbing systems.
Easy to read LED control panel. For indoor/outdoor use note: Hayward Universal H-Series heaters meet or exceed the SCAQMD and the SJAPCD low NOx emissions standards in all low NOx areas that apply the SCAQMD standard.
The Raypak 014779 106A Natural Gas Pool Heater for 0-4999ft Elevation is an Analog Gas Heater that has a polyester-coated, non-corrosive cabinet that is more durable than solvent-borne and waterborne-coated metal cabinets.
The circular manual thermostat that can be easily used provides accurate and precise performance since it is considered as the nerve center of your pool heating system. This model unit, Raypak Model P-R106A-AN-C, uses Natural Gas for its operations and it comes with a three-prong 120V 3-feet electrical cord but it can also be removed with the voltage transformer rewired for 240V operation.
Its stainless steel burner has the capability to self-adjust to compensate for gas pressure fluctuations for a cleaner and safer burning. A soft-opening gas valve is installed so you can easily turn on the unit.
Plus, its burner tray and pilot assembly are easily removable for more convenient maintenance of the unit. It also uses a robust spark-to-pilot ignition system which is the most current and reliable ignition system.
It has a copper fin tube for a more efficient transfer of heat and there is a controlled water flow rate inside the heater to minimize condensation, sooting, and scale buildup. The waterways are also designed with rust-free polymer header design with integral copper finned-tube heat exchanger and stainless steel tube sheets.
It has a 105,000 BTU input and also has a 2-inch flange connection.
I owned the 105K unit for five years. The heat exchanger failed twice. The copper tube heat exchanger on the original unit was so thin was like paper. Manufacture would not honor warrantee claiming chemicals.
Replacement heat exchanger much thicker copper but a problem with manufacturing the tubes are crushed in assembly in high stress areas of the exchanger. Two years later the second heat exchanger failed.
Not going to spend another $400 plus to replace the heat exchanger instead I went to Hayward for cupronickel unit. The Rheem product is built very basic. It’s corrosion resistance is poor. I covered my heater every year and after five years it looked like it was 50 years old.
I would not recommend the Rheem product although I love their furnaces and air conditioners for the home. Look before you buy don’t be led My price like I was. Spend the money do it right the first time! I feel I threw away $1300 on the Rheem unit.
Overall, this was a great replacement for our above-ground 15×26′ pool. It replaced a Hayward H100i that was probably 15 years old. My only complaint is that the unit came pretty dinged up – likely FedEx’s fault and not InTheSwim’s.
I’m a pretty handy DIY-er, so installing it wasn’t that difficult. We dug up the lines because the inlet/outlet are on the back of the unit, as opposed to the side on the Hayward. We then poured a new concrete pad based on the clearance specs given in the manual.
Once everything was re-plumbed, it fired up the first time and heats noticeably quicker than the old unit. I really like the digital control better than the old analog Hayward. As a note, the outlet we have this on is timer controlled along with the pump for the pool filter.
I was worried that the heater would reset every time its power was cut, but it seems to save its settings. Saved me from having to do some re-wiring as well!.
MasterTemp works fast and efficiently without taking away from your pool’s aesthetics. Design ensures safety and reliability with a tough exterior and easy to use digital controls. A fully pre-mixed system with a highly efficient air and gas mixture lets MasterTemp heat up fast; no long waits before enjoying your pool or spa! Compare energy efficiency ratings and you’ll find MasterTemp at the top of the list.
With a hot surface ignition (no pilot light) and pushbutton, digital controls, MasterTemp is as easy to operate as your home heating system. Plus, user-friendly indicator lights make system operation and monitoring a snap.
The easy-to-view, rotating digital display places controls front and center, no matter how MasterTemp is positioned on your equipment pad.
I tried to use my heater for the first time since last spring (maybe 4 months of not using it) and it would not work. It was installed less than a year ago. I contacted the Pentair warranty department and was told it was still covered.
It has been over three months and they still have not been able to get a repair company to come fix it. They have given a “work order” to a company that keeps denying anything and pentair has yes to resolve the problem.
Raypak Digital heaters come standard with intermittent spark ignition pilot safety controls. What this means is that the pilot only comes on when there is a call for heat. This is a more energy efficient way to control you heaters gas usage by not having a standing pilot.
Raypak has been using the same reliable electronic pilot ignition design for over 20 years. The Raypak Digital gas heater comes with a microprocessor based thermostat control. This control allows you to set your pool or spa temperature precisely at your favorite setting just by pressing an up or down temperature control button.
The Digital display gives you a constant read out of your pool water temperature. Just set it and forget it! Truly simple.
Having worked in the swimming pool business for over 13 years I can say this is the best heater you can buy. I’ve worked on many heaters including ones made by Teledyne Laars, Pentair, Sta-rite, Jandy, and Hayward.
These are the reasons why I recommend this heater in my business: it has a simplistic, easy-to-work-on design with less wiring and moving parts. This is important because mice and insects destroy all of the heaters I mentioned at a faster rate.
Raypak actually seals the computer board in a compartment that is almost impregnable. When something does go wrong the diagnosis is much simpler because there are fewer wires and parts. Frankly just about every other heater I work on is a complete nightmare in the wiring department.
Over the years Raypak is the only company I’ve seen make meaningful changes to their product namely, protecting the delicate computer board and decreasing the size of the power supply. Furthermore, this is one of the only brands I’ve never seen catch on fire, because it is vented properly.
Older Purex and Hayward heaters were notorious for burning up but luckily the wires would melt and shut the heater down so it never became an inferno. Newer Hayward and Sta-Rite heaters use a power vent, which is a cool idea although unnecessary for outdoor use.
However these fans crap out all the time as mice seem to love them more than computer boards. It’s just an unnecessary part unless you’re setting your heater up indoors and if you do, Raypak sells a more robust vent separately.
By far this is the easiest heater to install and integrate with the Comp Pool and Aqualink computer management systems. I also feel the need to address some of the negative reviews for this product, namely that you are buying this product on-line at wholesale price.
You assume the risk for it’s installation. When I buy it from my supplier there is a mark-up and a warranty that extends to professional people who install these things professionally. If you don’t check your pH in four years and your heat exchanger disintegrates Raypak shouldn’t have to replace it because you’re an idiot.
The extra money you pay for a professional installation is the peace of mind you get from knowing the job was done right.
The MaterTemp EC 125NA Residential Pool and Spa Heater with cord is 125,000 BTUs, fueled by natural gas and offers 82% thermal efficiency. The MasterTemp 125 has 1-1/2 inch plumbing connections and is ideal for smaller aboveground or inground pools or spas up to 15,000 gallons.
This E-Commerce pool heater offers advanced operating features that were only available previously from much larger heaters. The advanced LCD display/controller provides more information and better control.
With its state-of-the-art pre-mixed gas combustion technology, the MasterTemp 125 Heater offers 82% thermal efficiency, the highest in its class. That keeps your operating costs low throughout the year.
The MasterTemp 125 is lightweight and has a compact design that makes the heater easier to install than any other heater in its class. It is rated for outdoor placement. To place this heater indoors, please order the appropriate indoor draft hood.
The MasterTemp 125 offers all the efficiency, convenience and reliability you want in a pool heater. Plus there are no long waits to heat up your pool to a comfortable temperature. You can extend your pool season with the right swimming pool heater.
For an economical, eco-friendly, reliable gas pool heater, MasterTemp 125 is an excellent choice.
Raypak 014786 – 156A Propane Pool Heater is 150,000 BTU and uses 120V or 240V for installation. This unit is rated for 0-1999ft Elevation and uses corrosion Polymer Headers. The Raypak 156A is the perfect choice for above-ground pools and spas.
Raypak is the only manufacturer of this size heater to use all the engineering and components utilized in our bigger gas heaters. The unit is fully serviceable and built for years of operation. This may be our smaller sized pool and spa heater, but it’s built to the same exacting standards as the rest of our products.
Extend your swim season, open your pool earlier and close it later. Your pool is always ready when you have a Raypak on duty. Size: 27. 5 H x 12 W x 27 L. Color: Multicolor. Gender: male.
The Raypak 106A heater is an electronic ignition heater with analog control designed for hot tubs and above-ground pools. By adding a pool heater to your above ground pool you can extend your swim season by being able to open your pool earlier and keep it open later into the year.
Don’t dread entering your pool or hot tub: the Pentair 460736 MasterTemp High Performance Pool Heater makes sure your water is always at a comfortable temperature. This pool heater has an unobtrusive, compact design that’s easy to install or retrofit to replace an existing unit.
Digital controls and a push-button ignition make adjustments quick and easy. The unit uses a mixture of warm gas and air that heats up quicker than other units. Overheating sensors help keep your safe.
Hayward Universal H-Series Low NOx heater has an industry-leading thermal efficiency and complies with all current California air quality emission standards. The low NOx emission makes it a perfect choice for the environmentally concerned pool owner.
Its hydraulic performance also saves energy by reducing the circulation time of the pump and it can raise the temperature of an 800 gallon pool 30 degrees in less than an hour. Other advances the Hayward Universal H-Series heater include are stainless steel burners, corrosion-resistant heat exchangers and insulated Fire Tile combustion chambers.
This traps the heat unlike other forms of insulation delivering the highest degree of performance from every BTU. Equipped with an LED control panel, it monitors heater performance for added convenience and maximum comfort with minimum effort.
The ignition system delivers dependable lighting and reliable operations with just a touch of a button. The forced draft system constantly moves air through the combustion chamber to eliminate all outside weather variables affecting heating performance, such as wind conditions, eliminating the need to install a high-wind stack.
MasterTemp Heaters offer all the efficiency convenience and reliability features you want in a pool heater plus a lot more. As easy to use as your home heating system plus user-friendly indicator lights make system operation and monitoring a snap.
The compact design and super-quiet operation won’t intrude on your poolside leisure time. MasterTemp’s easy-to-read controls make system operation and monitoring simple. Pool and spa temperatures can be pre-set and controlled with the push of a button.
A digital display indicates the water temperature and five LED lights give you system status and let you know if the heater needs service. No matter what you re seeking in your swimming pool heater MasterTemp measures up.
Compare this list of features to any other and you ll see why MasterTemp is setting a new standard for total value.
The Pentair 460736/EC-462028 MasterTemp 400,000 BTU Natural Gas Pool Heaters come standard with a rotating digital display so you can position your controls where you need them. The digital controls are very simple to operate and there is no pilot light to deal with.
Pentair heaters feature a pre-mixed system with a very efficient gas and air mixture that allow the heater to heat up quickly and heat your pool faster. MasterTemp offers all the efficiency, convenience and reliability you want in a pool heater, plus a lot more.
As easy to use as your home heating system, plus, user-friendly indicator lights make system operation and monitoring a snap. The compact design and super quiet operation won’t intrude on your poolside leisure time.
It easily stands up to the elements with its tough, corrosion proof composite exterior. Its compact design is an added bonus, requiring a smaller equipment pad and taking up less of your poolscape!.
MasterTemp Heaters offer all the efficiency convenience and reliability features you want in a pool heater plus a lot more. As easy to use as your home heating system plus user-friendly indicator lights make system operation and monitoring a snap.
The compact design and super-quiet operation won’t intrude on your poolside leisure time. MasterTemp’s easy-to-read controls make system operation and monitoring simple. Pool and spa temperatures can be pre-set and controlled with the push of a button.
A digital display indicates the water temperature and five LED lights give you system status and let you know if the heater needs service. No matter what you re seeking in your swimming pool heater MasterTemp measures up.
Compare this list of features to any other and you ll see why MasterTemp is setting a new standard for total value.
The MasterTemp High Performance Heaters offer all the efficiency, convenience, and reliability features you want in a pool heater, plus a lot more. As easy to use as your home heating system, plus, user-friendly indicator lights and troubleshoot icons makes system operations and monitoring a snap.
The compact design and super-quiet operation won’t intrude on your poolside leisure time. Features: Superior “Best-in-Class” energy-efficiency Rotating digital display allows for easy viewing, rotate to 3 positions so there’s no need to reverse the header, simplifying installation Quick-change orifice allows easy conversion of gas sources Compact design (21″ L x 21″ W x 28″ H) is easy to retrofit, no matter what the space challenges Tough, rustproof exterior handles the heat and weathers the elements Built-in carrying handles for easy transport Certified for outdoor and indoor installation Certified for Low NOx emissions Standard copper heat exchanger 84% efficient.
For indoor or outdoor installations on pools and spas. Features include an LED temperature readout with dual thermostat controls, temperature safety lockout, and 6-position control panel. PMG burner technology requires no outdoor draft hood.
Proven Dura-Glas Resin provides rust-proof construction. Heavy-duty (HD) unit with cupro-nickel exchanger stands up to the harshest of applications, like low pH, high flow or heavy use. Features Rust-Proof Enclosure – Unlike conventional metal enclosures, th.
Shipped well and arrived as expected. Had small issues with the voltage plug not being set up for 120 volts, it was plugged in for the 240 and just had to be swapped around. must’ve been that way in case you hooked it to 240 and it would’ve fried the whole system.
Other than that had a little issue with a limit switch connection. Once these 2 items were found, it worked properly, so far. just been 2 wks since installation. Advice: if your not experienced in some manner of heating and cooling, get someone who is to install this.
Heater has been installed for 3 months now. wanted to delay a review until I was comfortable with the operation of this unit. It is extremely efficient with the use of natural gas. I had a Teledyne-Larrs, 20 years old, that never worked as good as this at any point.
Heating the spa is about 15 to 20 minutes max. The pool used to take overnight to heat and now it’s about 4 to 5 hours! LOVE IT!!! Would never buy any other heater in the future! 16,000 gallon with 9 ft.
The MasterTemp High Performance Heaters offer all the efficiency, convenience, and reliability features you want in a pool heater, plus a lot more. As easy to use as your home heating system, plus, user-friendly indicator lights and troubleshoot icons makes system operations and monitoring a snap.
The compact design and super-quiet operation won’t intrude on your poolside leisure time. Heavy-Duty (HD) unit with cupro-nickel exchanger stands up to the harshest of applications, like low pH, high flow or heavy use.
Features: Superior “Best-in-Class” energy-efficiency Rotating digital display allows for easy viewing, rotate to 3 positions so there’s no need to reverse the header, simplifying installation Quick-change orifice allows easy conversion of gas sources Compact design (21″ L x 21″ W x 28″ H) is easy to retrofit, no matter what the space challenges Tough, rustproof exterior handles the heat and weathers the elements Built-in carrying handles for easy transport Certified for outdoor and indoor installation Certified for Low NOx emissions Standard copper heat exchanger 84% efficient.
Inground pool heaters – what to look for when choosing
When choosing an inground pool heater, there are several things to take into account. The first is the size of the pool. The heater must be large enough to heat the entire pool. The second is the climate.
In a colder climate, the heater will need to be larger to heat the pool. The third is the type of pool. An inground pool can be either a saltwater or fresh water pool. The type of pool will determine the type of heater needed.
The different types of inground pool heaters
There are three main types of heaters used for inground pools: gas, electric, and solar. Gas heaters use either natural gas or propane to heat the water, while electric heaters use electricity to heat the water.
Solar heaters use the sun’s energy to heat the water.
The benefits of an inground pool heater
There are many benefits to having a pool heater for an inground pool. A pool heater can extend the swimming season by allowing the pool to be used during cooler months. A pool heater can also make the pool more comfortable to swim in by heating the water to a comfortable temperature.
The cost of an inground pool heater
The cost of a pool heater for an inground pool can range from $500 to $3,000. The type of pool heater, the size of the pool, and the climate will all affect the cost of the pool heater.
How to install an inground pool heater
If you want to install a pool heater for your inground pool, you will need to purchase a heater and have it installed by a professional.
How to maintain an inground pool heater
To maintain an inground pool heater, you will need to:
– Keep the area around the heater clean and free of debris
– Check the heater regularly for any signs of damage or leaks
– Make sure the gas or electricity supply to the heater is turned off when not in use
– Follow the manufacturer’s instructions for any maintenance or servicing that is required
The pros and cons of inground pool heaters
There are several pros and cons to using a pool heater for an inground pool. Some of the pros include being able to extend the swimming season, being able to use the pool at night, and heating the pool to a comfortable temperature.
Some of the cons include the cost of running the heater, the potential for the heater to break, and the fact that the pool will cool down quickly once the heater is turned off.
FAQs about inground pool heaters
How do I know if my pool heater is working properly
If your pool heater is not working properly, you may notice that the water in your pool is not as warm as it should be. You may also notice that the heater is not running as often as it should be. If you have an electric pool heater, you may notice that the electricity bill is higher than usual.
Conclusion
Your conclusion should be based on the information given in the question.
Based on the information given, the pool heater for inground pool is most likely not working properly. The pool heater may need to be replaced.
