Basics: ALWAYS Get a Cover FIRST!!!! 

        75% of all heat loss is due to evaporation. (See "Pool Covers" in this section.) You can add up to 3 months of swim time just by adding a "good" cover. The FIRST thing anyone who wants to heat their pool should do is install a "good" pool cover. Any method of "Attempting" to heat a pool, without a "good quality" cover, is going to be EXTREEMLY expensive, and, without a bottomless supply of cash, doomed to failure. (No I don't "sell" covers. That's just the way it is. Note: A "good cover" is one that you will always open only when you want to swim, and you will always close when you are done. For this reason, "bubble covers" are not considered "good" Covers. They are a pain in the butt to put on and take off, and can take upwards of 15 minutes both ways, or 30 minutes total, of your time to do so. Automated pool covers are "good" covers. ) If you aren't going to get a cover that you are always going to "Use", don't bother the a heater for your pool. It will be too expensive for 99% of you to ever run. ($1000 plus a month in most cases.)

Heater Types:

1.) Solar Pool Heaters

            I have had a number of problems with people's claims on solar heaters. First Problem: I have never had one heat water warm enough for normal spa usage and keep that temperature maintained. Second Problem: without a good cover, I have never had one heat a pool to a temperature that is comfortable to swim in when the normal air temperature is cooler than 80 degrees. Using solar with a regular heater, for example, with a spa will result in the solar system "COOLING" the water coming from the heater, and will prevent it from ever reaching normal spa operating temperatures, regardless of how long it runs. (This assumes that you want your spa warmer than body temp, of course. ) Solar will not heat a spa to proper operating temperatures. Don't hook one up to a spa, period, EVER!

            Again, I am going to repeat myself: If your goal is to heat pool water to swimmable, and you want to keep it that way as long as possible, again, GET A GOOD COVER, FIRST!

            Some important things to consider: 

    1.) A solar heater that is run after dark will ALWAYS cool your water.

    2.) A solar heater that is exposed to freezing temperatures when it has water in it is about to become a sprinkler system that will soak your roof and drain your pool and/or spa.  (The solution: either completely drain all of the pipes and panels of water before anything freezes, or run your equipment from 10 pm till 9 am using the panels to cool your pool and spa, but to keep them from freezing.) Keep in mind, ONE MISTAKE, forgetting to run the equipment all night and early morning, or not draining everything completely will probably cost you thousands of dollars t repair. 

         Most solar systems I have run across in the last 20 years have been, at best, only moderately successful at heating the water, and have completely broken down within 5 years. If you actually have had a system that reliably heated your pool, and kept it heated, for over 5 years, and it's "solar", get me the information on it, and I will include it here. I am not a big fan of solar, and since this web site has been up for years, and no one has ever sent me an e-mail telling me about how great solar is, I assume no one else has had great results (After 5 years) either.

            That said, I made my own "solar" heating system. I used some 1" Copper plumbed with 1" copper offshoots, down to 1/4"copper, made grids, painted them flat black, and the wall black, attaching them to a wall that received sunlight from 9 am till 7 pm. Then put on a low volume circulating pump with a separate time clock. WITH A POOL COVER, it did a pretty decent job of consistently keeping the pool water about 10 degrees warmer than with the cover alone. Also, in the middle of the summer, when the water got too hot, I ran the pump from about midnight till about 9 am, through the pipes, attached to the cold block wall, and took 10 degrees “from” the water temperature. (Note: In the winter months, I drained all of the copper pipes to prevent freeze damage. And yes, If I had forgotten to drain it before it froze, the expense, time, labor ... would have been excessive. ) Yes, this system was simple, reliable, and EXPENSIVE! Soldering all the individual little copper fittings and pipes, attaching the assemblies to the walls, tying in with existing plumbing ... was a royal pain, but yes I got it done, and yes, I was happy with the results. Do I recommend that you do this? Nope. Here's the deal. When I did this, I was home anyway. I was injured and couldn't do regular pool work as I was on pain killers. I already had most of the plumbing supplies needed to do the work (i.e. copper fittings and pipe), handy, and I had all the time in the world. To reproduce the same system and custom build it would probably cost someone 8-10 THOUSAND dollars now. Copper isn't cheap, and I spent over 80 hours on the project. 

            Again, get a good cover. (I think I might have mentioned that somewhere before. LOL)  That, by itself, will add a month and a half on either end of your swimming season (As long as you only remove it when you actually swim, and put it back immediately after finishing your swim.) Also, when it is too cold to be "wet" and "outside", you aren't EVER going to swim, even if your pool water is close to spa temperatures anyway. For most, considering the cost, the cover alone is enough.

2.) Natural Gas or Propane Heaters

            These are great for Spa's, and "Natural Gas" is great, but EXPENSIVE for "occasional" pool use. AVOID HEATERS THAT USE PROPANE ON POOLS. You will never be able to keep enough gas on hand to heat a pool (Yes, you can sink a 5000 gallon propane tank into the ground, but why, when there are other options that are cheaper . For example, Heat Pumps. )

            Before you consider a Natural Gas heater FOR YOUR POOL, understand that it may cost you well in excess of $300.00 a month to keep even the smallest pool heated in the middle of an Arizona winter. (With a cover) It will probably cost $1000.00 a month, or more(Without a cover). Yes, you may be able to cut whatever that bill would be in half with a “good cover. Keep in mind, propane or standard electric heaters are inadequate or too expensive for pool heating. (See "Pool Covers")

            Note: All gas heaters should have no trees, bushes, overhangs from buildings ... anywhere near them. I know code specifies about 2 Feet of clearance (On all sides) in most areas, but I have seen heaters 3 feet away from trees go up in flames because they got debris blown into them (From trees considered a "safe" distance away), because the owners "forget" to do the "annual heater clean" PRIOR to firing up their heater. Dried leaves, and even green leaves attached to trees will go up in flames if they are “in”, or “over” the heater. The resulting sparks, have even set houses on fire, not to mention burning the equipment to the ground. Don't play with gas (Natural or Propane) pool and spa heaters. Get them cleaned EVERY YEAR prior to use, by a pool professional that will completely pull the top off and remove all the debris from every part of the inside of the filter, and will also get all the debris out from the bottom tray.

            MAKE SURE ALL TREES ARE CLEARED BACK 5 FEET FROM THE HEATER, AND 1 EXTRA FOOT FOR EVERY 5’ OF TREE HEIGHT, MINAMUM. I have had 40’ tall ponderosa pine trees completely cover a heater 20’ away. Starting the heater up without proper cleaning is a great way to get to know your local firemen better , and the trees do make pretty torches at night, it is far cheaper, and less dangerous to go to your nearest fire station and offer to bring the firemen Thanksgiving Dinner instead. They really do appreciate the gesture.

3.) Electric Heaters

        A.) Heat Pumps

            FIRST, YOU CANNOT USE A HEAT PUMP TO HEAT A SPA. YOU WILL NEED A SEPERATE "Gas" (Propane, Natural Gas or Electric) HEATER FOR THAT. And if you are going to do that, get completely separate equipment for the spa as well. A heat pump will only heat a pool up to "comfortable enough to swim in", for the times when the weather is, "comfortable enough to swim in". in other words, if it is 75 degrees out side, it will probably get your pool water up in the low-mid 80's. (With a "good" cover, with operating it all day, ...) That's the BEST it will do. Most spas are kept at 100 degrees or so. A heat pump is ONLY good for the pool. If you try to use it "with" a spa heater it will only "COOL THE WATER" AND PREVENT THE HEATER FROM HEATING THE SPA TO NORMAL SPA OPERATION TEMPERATURES. Again, do not operate a heat pump with a spa. This is for pools only!

             Electric Heat Pumps are my favorites for pool heating, unless you have tons of cash you want to "burn" to heat your pool. AGAIN, GET A COVER FIRST! Buy a "GOOD" Heat Pump. Get one with a lifetime warrantee on all the important parts. (Get them made of titanium if you can. Yes there are companies that make most of their "Critical" parts out of it, and offer 5, or even 10 times the warrantee of other heat pumps.). Also, while you are at it, if you live in Arizona, spend the money to get the reverse function. This reverse function allows you to cool your water during the summer as well as heat it in the winter. How does $3-$4 dollars a day to heat your pool sound? Nice, compared to $30 plus dollars a day with a gas heater, right? With that "GOOD" cover I keep talking about, that's about what you should pay to heat your pool.

          Again, all heaters, heat pumps ... are only for during the months MOST people are ever going to swim. The way I look at it is this: If the air temperature is so cold I would wear a jacket, only a spa will be hot enough for me to want to want to jump in. If it requires a heavy jacket and a hat, even that will not be warm enough. I still have to get in and out, of the spa, walk on that cold decking ... right? A heat pump cannot heat the water to spa temperatures. Look at it this way: If you would be reasonably comfortable outside in nothing but a "dry" swimsuit, and you have a good heat pump, and, you have a "good" cover on your pool (All the time you are not swimming), then a heat pump will heat your pool to "comfortable", for, "most", people. For those 1-2 months in Phoenix, that are outside of this temperature range, only a natural gas heater, or a propane heater with a "huge tank, will heat a pool to comfortable swimming temperatures. But if you do this, you had best have the Thousand Plus dollars a month, extra,   that it will take to keep it at that temperature. (And the good cover. LOL)

              THE PROBLEM WITH HEAT PUMPS: First they use Electricity. Running 8 Gauge or bigger wire (100 ft. run or less) to the equipment area, and putting in a sub panel, is not cheap. It is possible that you might spend 2 grand, or more, on a hundred foot run because, at that point, you might need 6 gauge wire. (Get firm prices for wiring and hookups, IN WRITING.) The heat pump, a good one, might easily run 6 - 7 thousand. (Or more.) But here is the thing, when compared with a thousand plus a month to heat a pool with gas, or a solar system that won't work, and getting the added benefit of cooling your pool during the summer months, what's the real cost? Verses gas, how long before you pay the difference? 7 months, right? That’s 2 years for complete payback, even if you got the gas heater for free. Plus for a couple of hundred dollars more, you can use it to cool your pool in summer. (You have to have this capability in the heat pump unit at the time of purchase. As far as I know cannot add it later.)

Forget solar. It won't do the job, and has less than a 5 year lifespan, regardless, all the money spent is gone, and you will get no greater return than with a good cover by itself.

        With a good heat pump, after 2 years, you will be paying 3-4 dollars a day to have a heated, "swimmable" pool (All but 2 months a year in the Phoenix area.). If the system you are planning on buying isn't going to do the job, or if the cost to operate is so great that you can't afford to use it, then ANY money you spend on something "ELSE" is wasted. If you aren't willing to spend this kind of money, (6-8 Thousand dollars), then why are you spending the money on ANY "pool heater" at all? Why not just rent a room at the local hotel. At a hundred a night, you can spend an entire month of weekends at a decent hotel for the same price you would have paid to heat your pool for a full month with gas, and you do not have to come out of pocket to buy the heater in the first place.

        And no, those selling pool heaters or solar ... and the manufacturers of the equipment, are not going to tell you these things. They would rather have you hand them money and let you figure it all out for yourselves later on.

          Again, as with ALL "Heating" methods, start with a good pool cover FIRST. Then, if you still find that there are a lot of days where you "Would Swim Outside", but can't because the water, even with the good cover, still isn't warm enough, THEN consider some "Other" heating method.  

       B.) Electric heaters (Using the same type of elements used on a household electric water heater.)

            Most spa's have smaller electric heaters with the same type of elements used on electric home water heaters. Again, if you are going to heat "anything", EVEN A SPA, GET A COVER. It will take long enough, and cost enough, for the spa to heat up with an electric heater. Do not double the time, and cost, by not installing a cover as well.

 HEATER OR HEAT PUMP PLUMBING: Side Note: Regardless of the heater type you get, for a pool and/or spa, see if you can get your installer to put in enough Never Lube Jandy valves to completely close off all water flow AND PRESSURE to the heater, so you can drain the water out of it at the end of the season. This requires at least three valves. (1) To shut off the Heater Intake (1) to shut off the heater return and (1) as a heater bypass valve.

          Water is a corrosive. If you add chlorine, pool acid ... and you put the equipment under pressure, you can take years of life off your heat exchanger/heater by not completely shutting off all water flow to heaters and heat pumps when you are not using them. At current prices, two extra valves will add 10 years of life to a normal heater/heat pump and save you at least $1500 - $2000 over 10 years, and triple that with a heat pump. That’s a lot of savings for spending the money on an extra valve or two.

        Life span on a heater is usually about 10-15 years. At that point in time, if you have any sort of major repair, if you are using it a lot, the technologies have usually been updated so much that it is cheaper to replace it. If you are only occasionally using it, just repair what you have, or scrap it. If you repair it, in most cases you can get another 5-10 years out of it.

OPERATING TIMES: Solar: From time sun hits panels till about an hour afterwards. Non-Solar(Sand or Cartridge Filters): For pools, especially when first heating up the pool to swimming temperature, you want to run the equipment as long as is possible. For Cartridge filters (Which I consider the worst for the home owner. See "Equipment" "Filters" for the reasons.) and Sand Filters, (You can operate them 24 hours a day with no bad effects.) D.E. or Diatomaceous Earth filters will be destroyed in a day or two if you run them this long. For D.E. filters, maximum heating, with no damage to the D.E. filter, requires that you will run the equipment 4 Hrs. On, 2 Hrs. Off,  4 Hrs. On, 2 Hrs. Off, 4 Hrs. On, 2 Hrs. Off, 4 Hrs. On, 2 Hrs. Off. That's (4) sets of on and off trippers. Read up on D.E. filters if you want to understand why. This said, in my opinion, even with this limitation, D.E. filters are, by far, the best filters if properly maintained.

            AGAIN, I CAN’T SAY THIS ENOUGH, FOR ALL HEATING EQUIPMENT, RULE #1 IS TO GET A GOOD POOL COVER. THEN, PAY ATTENTION TO ALL THE DAYS WHERE YOU THINK TO YOURSELF, IF THE WATER WERE 5 DEGREES WARMER, I'D SWIM. AFTER YOU HAVE USED, "JUST THE COVER", FOR A YEAR, AND CALCULATED THE NUMBER OF DAYS YOU MISSED BY "ONLY HAVING A COVER", LOOK AT THE NUMBER OF DAYS, AND FIGURE OUT IF THE ADITTIONAL THOUSANDS OF DOLLARS IT WILL TAKE TO BE ABLE TO SWIM THOSE ADDITIONAL DAYS (And heat the pool to comfortable.) IS WORTH IT.

          In case you are wondering, I do sell heaters, heat pumps, ... but not pool covers. I have nothing to gain by telling you not to spend the money on heaters and heat pumps. But the truth is more important to me. If you EVER find someone that has owned the equipment above, that has had that equipment for 5 years or longer, that disagrees with what is listed here, have them send me an e-mail. I will show up at their house and document the "Facts", and then alter what I have written here to fit the truth.