Skip to content

Pool Heater Buying Guide

Have you been thinking about adding a heater to your pool but you’re not sure which option is best? Every pool owner wants to get the most out of their swimming pools, it was a big investment, requires a lot of maintenance, and you should get to use it as much as possible. One of the best ways to do that is by extending your pool’s swimming season. If the perfect temperature at any hour sound inviting, a pool heater can be a worthwhile investment. To help you make a well-informed decision, we’ve put together some information to make it easier to decide which choice is best for you. The information provided to you will help select the right option for your pool heating needs.


Pool heaters are made to raise and maintain the water temperature so that you can enjoy the pool longer. While all pool heaters can make pool water more comfortable and lengthen the swimming season, they do not all operate in the same manner. 


Which option is the best? 

There are three different types of heaters, each with their own features, finding the right heater is extremely important. The choice should be based on a combination of your climate, initial cost and operating cost; usage may also play a part.


Climate: Gas heaters and Solar heating will operate in any climate. Heat pumps require the air temperature to be around 45 degrees or higher to work properly. Heat pumps draw in outside air and convert it to heat; if you live in a higher climate you could technically have an 80-90 degree pool at all times. 


Initial Cost: Gas heaters are usually a lower price than a heat pump but often cost more to properly install. Heat pumps have a much higher upfront cost but often pay for themselves due to the operating costs. Solar heating may seem high at the start, especially for larger pools that require a large number of panels; but they have zero operating cost and quickly pay for themselves.


Operating Cost: Gas heaters cost more to operate as they run on either Natural Gas or Propane Gas. Models with 85% efficiency for instance only use $0.84 of each $1.00 spent. Heat pumps use about 1/2 as much gas to produce the same amount of BTU output as a gas heater allowing you to get a lower BTU model. Solar heating has no operating cost and is a great additional to any pool, with or without an existing heater.


Usage: Gas heaters are better for people that want “heat on demand”. They can raise the temperature 5-7 degree in about 2 hours on average.  Heat pumps are intended to have a continuous run cycle; they will keep the pool at a set temperature. Solar heating is great for any type of swimmer, it doesn’t cost anything to run; it uses your pool pump for power and just requires some sun.


When selecting a pool heater, you should consider the availability of fuels, fuel economy, emission requirements, and the general cost of the unit. Don’t forget to account for professional installation and maintenance costs when comparing models.


The Three Types of Heaters



Solar Pool Heaters are overall the most effective, provide the best value and are the best environmental choice for heating your pool - no matter what climate your pool is in. Before you buy a solar heating system, you should remember that solar heaters are not effective during inclement weather; they are better suited for more sun-filled climates. Keep in mind, after only a few days of warm weather your system can return the pool to a comfortable and pleasant swimming temperature. Solar pool heaters are becoming increasingly popular with pool owners, particularly those who want to be extra friendly to the environment and those that want to use a renewable energy resource for their pool heating needs. Larger pools do require more panels and will therefore also require a greater initial start up price.


Solar heaters provide a great alternative to both gas pool heaters and heat pumps. Solar heating is a passive system that consists of one or more black, flexible, plastic panels that contain hundreds of feet of tubing. The pool water gets pumped from the filter, through the solar panels (where it absorbs heat from the sun), and is then returned to the pool 10 to 15 degrees hotter. Solar heaters have no moving parts, and the force of the existing pool pump circulates the water. The greatest benefit of solar vs gas heaters or heat pumps is obviously cost; the panels themselves can run around $200 per panel, but the actual cost to heat the water is zero. They are not only a great way to save money, but many power companies provide tax write-offs, or discounts on your bills. Check with the local and state departments to find out if you qualify for any additional discounts for switching to solar. Solar heaters will typically last for 10 to 20 years, and therefore present an excellent investment.


The major drawbacks to solar heating systems are the space required for the panels (they may be roof mounted if space is not available), and the fact that weather so greatly affects their results. While solar heating will usually not extend the swim season as long other heating options will, they are a good alternative for us buyers on a budget. Many people often will use a solar heating in conjunction with another heater option; this way you can use the free heat source for as much as possible. Solar heaters have a variety of accessory options, from solar controllers to mounting kits.


Heat Pumps do require electricity to run, however they also incorporate elements of solar heating. Heat pumps collect heat from the surrounding air usually down to the 45 to 50 degree range; that means tropic and sub tropic climates can normally maintain a pool at 80 to 90 degrees under almost all conditions all year round. In the northern climates, a heat pump can greatly extend your swimming season. Heat pumps differ from gas heaters due to the fact that they run on electricity versus natural/propane gas and do not make any heat; they draw heat in from surrounding area and move it to where you want the heat to be, your pool water. Due to the fact that a heat pumps use depends on the outside temperature being warmer (and that is when you want normally want to swim anyways) they are very efficient to use. Heat pumps will provide the best results when used in the spring, summer and fall.


Heat pumps are electrically powered heaters, eliminating the need for large propane tanks.  Because of their efficiency, most heat pump models are intended to operate continuously so your pool is always at the temperature that you desire.  This means you won’t have to worry about remembering to turn your heater on Wednesday for the weekend party, just set it and forget it!  Heat pumps allow you to choose a model with less BTU’s than a Gas Heater because a heat pump is used to keep the pool’s temperature at a set level, rather than cycling through on and off periods.


While a heat pump is priced higher than many gas pool heaters, you should keep in mind that heat pumps have a much lower cost of operation than gas heaters. Many pool owners tend view the purchase of a heat pump as an excellent long-term investment. The additional cost will normally be recovered in only 3-4 seasons of use due to energy bill savings alone.  For example, a typical propane heater used from May to September in New Jersey costs approximately $2050 to run, natural gas approximately $1050, and the heat pump, $401.


Another benefit that heat pumps have over other heaters is that some models have a Heat AND Chill setting. These units basically just run in reverse and take heat out of the pool and release it back into the surrounding area. If you have ever jumped in your pool in July and said, "Wow, that is actually too warm", than this is what you need. This is a great option for areas where the air temperature can hit the triple digits; your pool can be refreshingly cool. 


The one drawback for a heat pump is they tend not to work at all if the outside temperature is around 45 degrees or below.


 Gas Heaters have the highest operating cost and are therefore the least effective method to heating your pool. If you require rapid heat up, constant temperature regardless of outside temperature, or you are heating a spa or hot tub, then a gas heater may still be the best fit for you. Gas heaters do not depend upon the weather and can therefore raise and maintain the temperature of swimming pool water at any hour of the day and at any time of the year. As a result, gas pool heaters are particularly suitable for pools that often need to be heated in a short amount of time, such as pools that are used only on weekends or during vacations.


Gas heaters are fueled by either natural gas or propane and are generally the most affordable type of pool heater to purchase. The type of fuel you select would normally be based on the availability and the price of each in your area. The price of the heater model itself is normally unaffected by the fuel type. Gas pool heaters do have a higher operating cost than heat pump heaters or solar heaters. In order to reduce operating costs, you should look for a model with a high efficiency rating. Units with a rating of close to 80 percent will provide both good efficiency and effective heating.


Gas heaters have a very simple installation process: a plumber will run a gas line to the heater (somewhere by your pool equipment), the return line from the filter is connected to the input of the heater, and then the output from the heater is attached to the pool’s return fitting. In the case of propane, a separate tank is required; depending on your local codes and regulations, the tank may be buried. For indoor installations, many codes require a Vent or Drafthood.


Gas heaters do have more options than a standard heat pump. Millivolt heaters use a standing pilot light that must constantly stay lit in order to initiate the pool heating process; you may find yourself having to re-light the pilot if it ever goes out. The electronic ignition heater models eliminate the need for this pilot light by electronically initiating the heating process. Most electronic ignition models also feature digital displays which will show you the temperature of the water and the temperature setting of the heater. Low NOx options mean the heater is designed to release fewer emissions than a regular pool heater; recently, California mandated the use of Low NOx heaters in certain counties. Due to their designs, most Low NOx heaters are larger and therefore more efficient than traditional pool heaters; higher efficiency means a higher heat transfer and therefore faster heating of your pool water. Be sure to check your local codes and regulations, some areas do not allow the use of Millivolt heaters, others require Low NOx.


If you live at an altitude 2,000 feet or more above sea level, I am sure you are used to looking for special instructions. And yes, you will need a special model pool heater designed for that altitude. The difference in the oxygen level in the air necessitates this special model. Just one more thing to think about before purchasing a swimming pool heater! Contact us for special information.


Sizing Your Heater


Sizing your heater depends on your location, swim season, pool size and even pipe size. Each manufacturer has a slightly different recommendation for BTU’s. Once you know the type of heater you are looking for please contact us for any further assistance in properly sizing your heater.

View All Our Swimming Pool Buyers Guides.