I have a 1000gal above ground pool (10X7.5X.36).I opted for the 2000w for redundancy.Very basic instructions to follow.* 1 heater per socket. Do not share with any other appliance (LED etc. Are Okay).* Fully submerged.* if using an extension cord. Must be 12G.* Must be unplugged when using pool.I plugged in the 1st one. Let it sit for about 3hrs. Overall temperature went from 76° to 79°.I then plugged it in the second one.After five hours or so, it was above the 86° mark.Woke up in the morning and it was 88°, A little too warm lolTo reach the desired temperature would be dependent on your personal preference.This works very well for the price paid.

I bought (2) 2000w heaters for my 1000 gallon above ground pool. I ran them on separate circuits for about 16 hours and managed to raise the temperature about a degree an hour. Went from mid 70s to low 90s overnight. Definitely a great way to heat a small pool inexpensively.

Absolute trash! One worked for about 3 hours, seemed hopeful, stopped working. Used the other thinking maybe I did something incorrectly(not at all the case). Second worked for maybe a day running on a timer as not to overload the device and DEAD. Also, the fact there is no type of indicator light to let you know it's powered or 'running' is a safety hazard as well, because when the worked for the insanely short time they were dangerously hot! Do not buy!!!!!

The plug was hot off the outlet, so this needs a twelve k or ten cage extension cord.

I tryed in big pool. 2 of them. Didn’t work. I even tryed it with the smallest pool I could buy. And guess what. It did not work. So, I tryed one in a regular size storage container and it failed. Wow, these are bad. Will not buy again.

Item has cracked open and died. We have them in an above ground pool and they’re fully submerged. Worked well at heating for two weeks and then died. Not sure what happened, but I wouldn’t buy them again. Waste of money.

Bought to heat a 10ft x 5ft x 2ft inflatable pool. From ice cold well water out of our hose, to appx 90 deg feeing like warm bath water took about 5 hours with 2 heaters. Instructions explicitly state not to use heaters while in pool and use outlets that are on different breakers if using more than 1. Couldn’t run my pellet grill and 1 heater at the same time without tripping the breaker so I’d say that’s accurate. Left both heaters on the bottom of the pool 5+ hours and no damage to pool. Cord attached to heater is only 3 ft, instructions say not to use extension cord but this seems impossible for most applications of this tool. Highly recommend 14 ga or larger cord and as short as possible. Used 16ga orange outdoor rated cord first and it becameUncomfortably hot after only an hour of use, before I upsized.

Summary:Good - Heaters get hotBad - Heaters caused an extension cord rated for the heater amps to also get hotBad - Product does not appear to be UL listedBad - Product lacks safety devices to be used near water (GFCI)Summary - seem to be good heaters, but be careful how you power them!My use experience:Each heater is (per specs) about 12.5 Amps. This is the capacity of many standard home circuit breakers (after a standard derating for a 15 amp breaker). I figured, ok, I'll just run one of them at a time to heat up a small 10'x2' pool. I first tested the heater in a smaller plastic tub, which covered half way up the top yellow cap, but wasn't deep enough to touch the cord. I used a section of plastic pipe to hold the heater in place and plugged the heater into a long heavy duty extension cord, with an added GFCI adapter (the heater doesn't have one integrated and water + electricity makes me nervous).I saw the heat output from the unit creating small waves in the water and the top of the heater reached 90 degrees per a laser thermometer (15 higher than air temperature that day). The water temperature was slowly rising. More importantly, no discoloration or residue noticed in the water from the heater.I purchased this heater because it specifically advertised that it could be used for small above ground pools, which seemed like a stretch that a small electric heater could raise the temperature of 900-1200 gallons in a reasonable time, but I decided to give it a try.After my bucket test, I scaled up to the pool, and repeated the process with a long section of plastic pipe dangled the heater off the pipe and wrapped the cord loosly a couple times around the pipe, which was enough to hold it in place and still keep the plug end of the cord not over the water and the heater away from the vinyl pool wall/floor. I followed the directions and ensured the ENTIRE unit was in the water, including an inch or two after the cord exit. The heater ran for maybe 20 minutes and very slowly I was seeing the temperature was rising in the pool (don't put hands in the water with the electric heaters - use floating thermometer) just enough to take the chill off it. When I went to touch the extension cord it was HOT at the plug and 9-12" down the length of the cable jacket. The GFCI cord between the heater and the extension cord seemed ok. No melting visible on the plug or outer jacket of the extension cord, but the cord was limp compared to its normal rigid behavior where it was hot. This unit I suspect could have easily melted the extension cord if given enough time (far less than the 3 hours max duration per usage). This is the same cord which I have used to run large appliances (fridges), construction tools (compressors, table saws), apartment sized air conditioners, etc. all without issues and it rated for 18 amps (higher than I calculated the heater's amps, based on wattage = 12.5 amps).I ended up pulling out our home's backup generator which can run multiple circuits and a much heavier extension cord and ran both heaters (hanging from a pvc pipe support) on different circuits. Both heaters running at the same time were able to pull up the water temperature several degrees. None of the cords were warm/hot to the touch with the 10 AWG extension cord (rated at 30 amps per plug).In summary, the heaters seem to work well. Heating anything large might be a struggle. Be very careful that all of the wiring supplying power to the heater is more than adequately sized.