Pentair Heat Pump

The Pentair UltraTemp Heat Pump is a high performance pool heater with the distinction of being the first pool heat pump charged with a non-ozone depleting refrigerant (R410A).

To purchase a Pentair Heat Pump from Pool Supply World – Click Here.

The UltraTemp heat pump range includes models ranging from 75 – 140k BTU/hr two of which feature the option to reverse the system to cool the pool. Heat pumps are environmentally friendly as they are very efficient, do not create any emissions and this one is even environmentally friendly at the end of its working life. To see the UltraTemp product brochure – Click Here.

Unusually you have a choice of color (Black or Almond) for the casing, which is a nice touch but not a major factor in deciding to buy one. Some of the features of this Pentair Heat Pump that are more interesting are:

  • Titanium heat exchanger to resist corrosion and ensure long life.Pentair UltraTemp Heat Pump
  • Scroll compressor which has fewer moving parts and increases efficiency and reliability.
  • Thermostatic expansion valve controls the refrigerant flow to maintain optimum efficiency over a wider temperature range.
  • Automatic defrost feature which allows the heat pump to operate at lower temperatures than would otherwise be the case.
  • Long life plastic cabinet which is resistant to corrosion, pool chemicals and the weather.
  • Easy to use LCD control panel so you know exactly what is going on.
  • Performance certified by AHRI (Air-Conditioning, Heating and Refrigeration Institute).
  • Very high efficiency – The COP (Coefficient of Performance) varies slightly but the base model has a rating of 5.8*.
  • Digital controls with dual thermostats offer precise temperature control for pool/spa combinations.

* This means that for the heat pump outputs 5.8 units of energy (heat) for every one unit (electricity) consumed. This is because it is not using the electricity to generate heat but to transfer it from the surrounding air to the pool water. The COP will vary depending on the air temperature and water temperature here it is based on 80 degrees for both.

Of course we have to accept that a heat pump costs considerably more than a gas heater (which would also be more powerful) and that the performance of a heat pump drops when the air temperature gets colder. However, unless you only heat your pool occasionally the low running costs and environmental credentials of a heat pump cannot be ignored.

If you are looking for a heat pump this Pentair Heat Pump has much to commend it. It is designed for reliability and long life and its key selling point is its high efficiency. It has a limited lifetime warranty on the heat exchanger and a 10 year warranty on the compressor. Reviews seem to be in the 4/5 star range.

Our recommended supplier is Pool Supply World who offer good prices which include shipping (which is an extra with many other suppliers) together with good service.

CLICK HERE to see their prices.

Other Pentair Pool Heaters.

Raypak Pool Heaters

Raypak pool heaters are produced by Raypak inc. a California based company specializing in water heating systems including commercial boilers, water heaters and control systems, pool and spa heaters, and residential boilers. Founded in 1947 the company has grown rapidly and now supplies its products worldwide. Its goals have always been to achieve high quality, reliability and energy efficiency. The company was pleased to become the first boiler manufacturer to achieve ISO 9001 registration in 1996.

The current range includes:

  • Raypak Digital Heater – This is often referred to as the RP2100 although that is actually an older model. With models ranging from 200 to 399 BTU/hr, theRaypak Digital Heater Raypak digital heater is designed to minimize condensation and provide rust free waterways. It will provide years of trouble free use and be unaffected by all except the most extreme weather conditions. It is microprocessor controlled with electronic ignition and on-board diagnostic controls. Basically you just have to set the required temperature and the heater does the rest. There is also a low NOx version of this heater which exceeds all NOx emission requirements.
  • Raypak Millivolt Heater – This is very similar to the Digital heater except that it has a standing pilot light to provide ignition, uses a mechanical thermostat and has no diagnostics.raypakpool heaters
  • Raypak Heat Pumps – For 2019 Raypak have revised their lineup of heat pumps (details on the Raypak Heat Pump page) but most of those on sale are still the 2018 models – the Compact Series, the Classic Series, the Specialty Series and the Quiet Series. All feature a titanium heat exchanger to withstand corrosion. There is a choice of analog or digital controls but in both cases you can control pool and spa temperature separately. Some of the Specialty models can be switched into reverse to provide pool cooling in summer and also feature a defrost mode to prevent ice forming on the condenser.

Of these Raypak pool heaters which is best for you? Well the first thing to decide is whether you want a gas heater or a heat pump. Assuming that getting electricity to the pool location is not a problem, a heat pump will be best if you keep your pool heated most of the season. Although the purchase price is higher than a gas heater, a heat pump has much lower running costs. You might prefer a gas heater if you only heat your pool occasionally because gas heaters are more powerful and can get a pool up to the required temperature more quickly. They are also cheaper to buy and if they are not used a great deal then this advantage will not be wiped out by the higher running costs.

Assuming you are looking at a gas heater then you would go for the digital heater (or the low NOx version) if you can provide an electricity supply to the heater. If not you will have to go for the Millivolt heater.

Either way you will find that one of the Raypak pool heaters meets your needs.

Raypak Heat Pump

Raypak have updated their range of heat pumps for 2019 but these are very difficult to find at present, most of the Raypak heat pumps on sale are from the 2018 range below.  The new range comprises six heat only models, two with heat/cool and one with power defrost. Click Here to see the product brochure.

The three smaller models range from 48-80k BTUH with a COP of 5.7-6.2 at 80/80/80. The remaining models are of the larger design with a BTUH up to 140k and a COP of 5.6-6.0. All feature:

    • Exclusive DuraSteel™ Powder-Coated Cabinet – They claim that a plastic cabinet is no match for the all steel Raypak cabinet.
    • Quiet Operation – Special fan design mean more air over the coil which translates to greater efficiency all while being whisper quiet!
    • Extremely Tough Composite Base – Rust proof and ultra sound deading base material keeps your heat pump up and running while holding sound levels to an absolute minimum.
    • Scroll Compressor – The unique design of a scroll compressor actually wears in over time, not out!
    • Spiral Titanium Tube – The spiral titanium tube heat exchanger provides a corrosion-free waterway that can withstand the abuses of harsh pool chemistry.
    • Seperate Pool/Spa Controls
    • Remote Compatible – The digital heat pump pool heater can be easily controlled by most two-wire and three-wire remote systems.
    • On Board Diagnostics – Tells you if there is a problem.
    • Built-in Mini Automation – Includes ability to work with solar and/or gas heater.

Previously Raypak offered four ranges of Heat Pump. These are still on sale so I have left the information from 2018 below:

The Compact Series – Three models outputting 50k, 66k & 83k BTU/hr (at 80F air & water and 80% RH) available with analogue or digital controls. The top model is also available with a Power Defrost option. This enables the heater to defrost itself whilst still heating the pool.

The Classic Series – Three models outputting 95k, 117k & 133k BTU/hr (at 80F air & raypakpool heaterswater and 80% RH) available with analogue or digital controls.

The Specialty Series – Eight models based on the two higher Classic models offering options like digital power defrost and cooling as well as heating. Three phase models are also available. Raypak say that this range is intended to offer features “not as commonly required”.

The Quiet Series – Raypak’s latest heat pump has been specially designed for quiet operation at only 59db.  There are three models outputting 95k, 117k, and 133k BTU/hr (at 80F air & water and 80% RH). These feature digital control and several extra features to ensure quiet operation such as a slow rotation fan motor and a custom engineered four blade fan.

In terms of features, the Compact series do not have sound installation pads on the compressor nor internal bypass valving in the heater exchanger but other than that the basic features are the same.

A heat pump may cost more than a gas heater to buy but they are extremely efficient devices which can be 3 to 4 times cheaper to run than natural gas and 6 to 7 times cheaper than propane. They are not as powerful, so cannot heat a pool as quickly, so are ideal if you heat your pool constantly.

All these heat pumps are built to Raypak’s usual high standard to give “rock solid performance at an affordable price”.  All versions feature a titanium heat exchanger, to withstand pool chemistry and corrosion and use a Spiral Rifled design to maximize the surface area.

The cabinet is a polyester coated rugged steel construction. There are large air coils (made by Raypak themselves) to maximize the heating capability at low temperatures.

The standard Raypak heat pumps run of a single phase power supply but will need their own circuit which will require an electrician but it should cost less than a gas heater to install.

Raypak Analog Control PanelYou can opt for digital or analog controls on the cheaper models. Both allow you to set a separate pool and spa temperature and are compatible with remote controls. The analog control has 6 LEDs which tell you what is going on whilst the digital control has on board diagnostics which can provide detailed information to the owner or pool technician.  The Raypak documentation indicates that the digital version is superior but, strangely, the prices are similar.Raypak Digital Control Panel

If you are looking for a low cost, environmentally friendly way to heat your pool a heat pump is ideal. A Raypak heat pump is a great choice as it combines the latest technology with Raypak’s reliability at an attractive price. It should give you years of hassle free use of your pool.


These heat pumps are not as widely available as many pool heaters featured on this site but Pool Supply World offer a limited range and a wider range is available at INYO Pools.

Gas Pool Heaters – The Best Choice?

Gas pool heaters are very popular but these days might be considered environmentally unfriendly when there are more energy efficient ways of heating a pool.

However gas pool heaters are popular because they have a number of advantages:

  • Relatively cheap to buy and install – Obviously the cost depends on the size of your pool but gas pool heaters for above ground pools are available under $1000 and for in-ground pools under $1500. You will have to pay to have the gas and electric side of things professionally installed but the rest of the installation should be within the capability of someone who is reasonably handy.
  • Powerful – A key advantage of gas pool heaters is that they are powerful and can heat up a pool quickly (although we are still talking hours rather than minutes). Therefore they are ideal if you only heat your pool from time to time.
  • Energy Efficient – Gas heaters are much more efficient that they used to be with most falling in the 80-85% range. However you can buy gas heaters with an efficiency rating of 95% but they are expensive.
  • Reliable – Although gas heaters are improving all the time this is a tried and tested technology. A properly maintained heater should give you many years of worry free pool heating.
  • Not affected by the weather – A gas pool heater will operate in all weather conditions.

Gas heaters usually are available for either natural gas or propane. In terms of performance it does not matter which you use but in terms of cost there is a major difference. Propane is much more expensive and you would only use it if natural gas is not available.

Gas pool heaters are available in both electronic and millivolt versions. The former are more popular as they feature electronic ignition and electronic controls. However to power these functions they need an electricity connection. Millivolt heaters, on the other hand, use a pilot light ignition system (which wastes energy) and have more basic controls but have the advantage of not needing an electricity connection.Pool Heater

Popular heater ranges include the Raypak Digital Heater, Pentair MasterTemp and Hayward H Series.

The main competition these days comes from pool heat pumps. These cost considerably more, are less powerful, are electrically powered and don’t work in very low temperatures. However, they can be several hundred percent efficient so that they are cheaper to run than a gas heater.

If you heat your pool constantly during the season then you should certainly consider a heat pump. If you do not heat your pool all the time then a gas heater will be your best option giving you the best balance between purchase/installation costs, heating power and running costs.

The table on this page gives approximate running costs for a gas heater by city.

Hayward Pool Heaters

Hayward pool heaters are manufactured by Hayward Pool Products, a division of Hayward Industries, Inc., who have been manufacturing pool equipment for over 80 years. They are one of the large pool equipment producers and their range includes pumps, filters, pool cleaners, lighting, salt chlorine generators and pool heaters. The length of time they have been in the business indicates that they know what they are doing.

Their current range includes:

Hayward pool heaters for In ground pools

Hayward H SeriesUniversal H Series– A range of heaters powered by either natural gas or propane. Power levels range from 150K to 500K BTU/hr. The key benefit of these heaters is that they are energy efficient (84%) and produce emissions of NOx low enough to meet the most demanding local requirements including those of California and Texas. These heaters feature electronic ignition and a digital LED control panel, they are designed for ease of installation as connections can be made on either side.

Hayward H250H Series Millivolt – Again a range of heaters powered by either natural gas or propane. The available power levels range from 150 – 400k BTU/hr with the Hayward H250 being the most popular. Their energy efficiency is 81% and there is no claim as to low NOx. Millivolt heaters have a pilot light for ignition and to generate a small amount of electricity for the controls. The benefit is that they do not need an electricity supply so there is more flexibility in choosing a location.

HeatPro Heat Pump – A range of heat pumps rated at 95 – 140 BTU/hr. They all feature electronic temperature control and dual thermostat, so you can heat both a pool and spa. In addition they they are specially designed to operate quietly and reliably whilst being extremely energy Hayward Heatproefficient.

Which to choose – A gas heater will be cheaper to buy but will cost more to run. A gas heater will also warm the pool quicker. If you are going to heat the pool constantly during the season then a heat pump will be best, however if you are only going to heat it occasionally then a gas heater will be the better buy. If going for a gas heater you would go for the Universal H Series unless getting electricity to the heater is a problem. In this case the H Series Millivolt provides a good alternative.

Hayward pool heaters for above ground poolsHayward Swimming Pool Heaters

Above Ground H Series (Hayward H100) – A 100 BTU/hr gas heater available in 2 versions for either natural gas or propane. A simple plugin electricity connection is provided which provides direct-spark electronic ignition. Energy efficiency is 81%. Induced draft system means the heater is not affected by wind so it can be located where it is needed.

Hayward Heat Pump HP50TA – A 50 BTU/hr. heat pump specifically designed for above ground pools up to about 13k gallons. The features and benefits are much the same as the HeatPro shown above. This heater requires a 220 volt 30 amp electricity supply.Hayward Heat Pump

Which to choose – The same factors apply as for in ground pools above.

In general it is better to buy a more powerful heater than you think you need but if you choose correctly any of the above Hayward pool heaters will provide years of good service.

Hayward H Series (Universal H Series)

The Hayward Universal H Series is a series of pool and spa heaters ranging from 150K to 500K BTU/hr with versions for either natural gas or propane. The key benefit of these heaters is their energy efficiency and low NOx emission levels which comply with all current California and Texas air quality emission standards.

To purchase from the Hayward Universal H Series range at Pool Supply World – Click Here.

The Hayward Universal H-Series heaters feature an industry leading 83%-84% thermal efficiency and this plus the low NOx emissions make these heaters about as environmentally friendly as a gas heater can be (unless you pay considerably more). This energy efficiency is achieved through the use of an insulated fire tile combustion chamber which minimizes heat loss and maximizes the heat output for every BTU used.

These heaters also save energy through their industry leading hydraulic performance which reduces the time the pump needs to be running.

Hayward H series pool heater

In addition to their environmental credentials the Hayward H Series heaters also have a number of other significant benefits (see Hayward H Series Brochure):

  • Heat Exchanger – “Finn Plate” heat exchanger specially designed for fast heating and longer life. In addition the use of cupro nickel provides exceptional corrosion resistance even with salt based chlorination systems.
  • Exclusive Silicon Nitride ignition system – provides dependable lighting and reliable operation.
  • Digital LED Control Panel – which makes it easy to see the water temperature and  monitor heater performance.
  • Dual Voltage – Can be installed with a 110 or 220 volt electricity supply.

The Hayward Universal H Series heaters are easy to install thanks to their low profile, light weight and CPVC plumbing capability. In fact the electric, gas and water connections can be on either side and only front panel access is needed for servicing.

The Universal H-Series heater combines advanced technology with universal-fit, for easy installation. This together with the range of models available means that it is a good choice for just about any pool.

These heaters are widely available and get good user reviews. Our favorite supplier is Pool Supply World. They offer competitive prices, which include shipping, and feedback from their customers is very good.

See other Hayward Pool Heaters.

The Types Of Swimming Pool Heater You Can Choose From

Having decided that you want a heater for your swimming pool you then need to decide which type. The main types are gas, solar and electric (mainly heat pumps) but even within these there are a number of choices to be made.

Gas Powered Heaters
These are the most common type and they have the advantage of being able to provide heat faster than other options as they are more powerful. Units designed for above ground pools (such as the Pentair MasterTemp 125) typically supply around 100k BTU, on the other hand a heater designed for an in ground pool (such as the Hayward H series) can provide up to about 400k BTU. This is particularly useful if you heat the pool intermittently and therefore need to raise the temperature quickly.

Gas pool heaters are available to use natural gas or propane. Clearly natural gas would be the best choice if it is supplied on site or LPG might be a good option if you already store it for home heating. If there is no existing supply of gas it may be best to look at some other form of pool heater.

Gas pool heaters also come in Electronic or Millivolt versions. Electronic versions are like a modern gas boiler and feature electronic spark ignition and micro processor control. Millivolt models use an older technology which uses a permanent pilot light and therefore is slightly less efficient. As well as being used as an ignition source the heat from the pilot light is used to produce a small voltage (where the name comes from) to power the controls. The former is the preferable option but it requires an electricity supply, if this is not possible a Millivolt heater is appropriate.

The major negative with gas heaters, especially those using LPG, is that they can be costly to operate.

Electric Heaters  
You can buy direct electric heaters but these are expensive to run and so are usually only appropriate when heating small above-ground pools.

These days the electric heat pump is becoming an increasing popular choice (such as the Hayward HeatPro range). Heat Pumps work by transferring heat from the surrounding air into the pool water, rather than generating heat themselves. This means that in terms of energy used to heat output they can be several hundred per cent efficient. As a result they are cheaper to run than gas heaters and are more environmentally friendly. They are also expected to have a longer lifetime than gas heaters.

Heat pumps do have some disadvantages. They are not as powerful as gas heaters and are best run continuously, to maintain the pool temperature. In addition the air temperature should be at least forty-five degrees if they are to work efficiently.

Solar Pool Heaters
In these systems the pool water is pumped through solar collectors which are designed to trap solar energy. Although each location is different, a good rule of thumb is that the area of solar collectors should be the same as the pool area. Solar heating will probably be more expensive to purchase and install than other types but should have a longer lifetime and be less costly to operate. It is certainly the best option if you want to be environmentally friendly.

There are more things that you need to address with a solar system if it is to work satisfactorily. These include the local climate, finding the best location, heeding local building codes and making sure the system is safe. Solar systems are dependent on the local climate so the most important thing is to ensure that the system will heat the pool for the period you wish to use it.

Spa Pool Heaters

Spa pools are mainly used for relaxation purposes and therefore it is common to have a heating system installed in them. Spa pool heaters not only provide a comfortable soothing experience that is perfect for unwinding after a long day, they also extend the season of the spa pool so that they can still be used during a cold weather.

The normal range to which a spa pool is heated is 97 to 102 degrees.  This is considerably higher than the normal temperature of a swimming pool but spa pools are much smaller, typically not more than eight square feet and less than four feet deep. As a result the requirements for a heating system are less than those of a swimming pool.

There are four main types of spa pool heaters that are available today. These are:

Small gas heaterhot tubs like the Hayward H100 or Pentair MasterTemp 125 which are designed for an above ground pool and/or spa. These are relatively cheap to buy and will be able to heat up a spa quickly. If you can use natural gas they are reasonably cost effective. Disadvantages are that they are not small and because of the need for ventilation and safety cannot be out of sight.

Direct Electric Heaters such as these made by Coates are small and effective. They can be installed out of sight and should offer trouble free operation for many years. However they cost more than a gas heater to buy and much more to run.

Lower capacity heat pumps like the Hayward HP50TA are another option. This model is designed specially for above ground pools and spas and has low running costs. You probably can’t hid it but there are less issues with installation than with a gas heater and it is the most environmentally friendly of these three options. The disadvantage is the purchase cost which is more than an electric heater and considerably more than a gas heater. Also a heat pump becomes less effective as the temperature goes down.

A solar heating system can also be considered. In the right location solar power is quite practical during the summer but is not much use on cold evenings at other times of year.

In the end it depends on how often you want to heat your spa. If it is only occasionally a gas heater is likely to be the best option but if it is used regularly it might be worth investing in a heat pump.

Above Ground Pools – Buying & Heating

Installing above ground pools is clearly cheaper and less work when compared to in ground pools however it requires considerable commitment (usually your site turns out not to be as level as you thought). The good news is that there is a large range of pools available for sale in varying sizes shapes and depths. To see what you can buy CLICK HERE. Tips on installing your pool can be found HERE.above ground pools

When it comes to heating your pool you have a number of models to choose from which are made specially for the purpose. These differ from in ground pool heaters as they are lower powered, and hence cheaper, as the volume of water to be heated is smaller.

When looking at above ground pool heaters there are a number of options. As the volume of water is relatively small it is possible to use an direct electric pool heater. These are cheaper than gas heaters and easier to install. However, they are not cheap to run as they use a significant amount of electricity which is more expensive than gas.

Gas heaters made for above ground pools (such as the Hayward H100) are lower powered than those for in-ground pools (such as the Raypak 2100). Since an above ground pool is usually relatively small you don’t use up that much energy as the heater only needs to maintain the temperature of a relatively small volume of water.

Another option when looking at above ground pool heaters is a solar pool heater. You can buy small cheap solar panels but it is generally agreed that the solar panels need to cover the same area as the surface of the pool to be heated. They also need to be sited at the right angle, facing south and in an unshaded position. Since most above ground swimming pools are not that big, you don’t need to have a very large space for the solar panels. However, proper solar pool heater systems can be expensive to buy and setup, do have running costs and of course depend on the weather – that’s why most people opt for gas or electric heaters.Above Ground Heat Pump

Today a good energy efficient way to heat a pool is to use an electric heat pump (like the Hayward Heat Pump). Heat Pumps are very efficient because they don’t produce heat they just “pump” heat from the air into the water.

When using a pool heater you can greatly increase its efficiency, and reduce your costs, by using a pool cover when the pool is not being used. Pool covers insulate the pool and minimize evaporation so limiting heat loss. As a result the pool heater will not use as much energy to keep the pool temperature steady.

If you are looking at above ground pool heaters keep the above points in mind so that you can maximize your enjoyment of the pool whilst minimizing the cost. Click this link to see the above ground pool heaters reviewed on this site

Pentair MiniMax 100 Review

Note: This heater was discontinued after the 2014 season and is no-longer available (although you can still get parts). The replacement is the Mastertemp 125 – click here for more information.

The Pentair MiniMax 100 is a high performance 100k BTU gas heater designed specifically for above ground pools and spas. There are four versions:

  • Natural gas with electronic ignition,
  • Natural gas with millivolt ignition,
  • Propane with electronic ignition,
  • Propane with millivolt ignition,

although prices are very similar for all models.

Pentair Minimax Pool HeaterIf you just want to heat a smaller above ground pool or a spa the heating capacity of the MiniMax is ideal, there is no point in paying more than you need. As a guide if you have a 500 gallon pool this heater can raise the temperature up to twenty degrees in an hour. So even if you only heat the pool intermittently, maybe just at weekends, it will soon be ready for use.

The Pentair MiniMax heater is a compact self contained unit which is easy to install and maintain. Its key features are:

  • High thermal efficiency means less heat lost into the air thereby keeping costs as low as possible.
  • Patented thermostatic bypass valve minimizes calcium scaling and corrosion thereby maintaining the efficiency and prolonging the life of the heater.
  • Uses a proven burner system for trouble free operation.
  • Flow valve senses water flow and controls this to maximize heating efficiency.
  • Durable weather proof housing protects the heater from the elements.

It is also service friendly, quiet in operation and has user friendly controls.

The MiniMax 100 is the ideal way to keep your spa or above ground pool at the optimum comfortable temperature so that the whole family can enjoy the pool throughout the day and outside the normal swimming season.


Other Pentair Pool Heaters.