by Mark Garcia December 30, 2014
That is a question that may have crossed your mind at one time or another - usually when it comes time to buy an expensive piece of pool equipment, you may wonder if they are interchangeable.
The answer is... it depends, or maybe yes, maybe no. The main difference in pool equipment for inground and aboveground pools is size - obviously, inground pool equipment is made to handle larger volumes of water, at higher flow rates.
Another obvious difference is price. I'm sure you noticed that aboveground pool equipment is priced much lower than inground pool equipment. Margins are smaller for aboveground equipment, due to a system of perfect pricing discrimination and product versioning, to create products that are more affordable for the aboveground market, which presumably has less discretionary income than inground pool owners.
Let's take a look at several product categories - pumps, filters, heaters and cleaners, and compare inground vs. aboveground!
The main difference between inground and aboveground pool pumps is that inground pumps are "self-priming", and aboveground pumps are not. This refers to the ability of the pump to lift water vertically, since most inground pumps are located above water level, and most aboveground pumps are situated below water level. Aboveground pumps have what's called "flooded suction" and gravity and atmospheric pressure is feeding the pump without requiring a lot of suction or vacuum pressure. In ground pumps are usually 2-3 feet above the water level, and sometimes higher.
The second main difference between a/g and i/g pumps is flowrate. A/G pumps are designed to produce flow rates of 30-60 gpm, whereas I/G pumps can produce 75-150 gpm. Ideally, a pool pump should turnover all of the water (send it all through the filter) every 8-10 hours. A smaller pool will need a smaller pump to accomplish this, and any more is just overkill and wasted energy. In addition, pump flow rate must match filter flow rates - if the water is moving too fast through the filter, filtration suffers and the filter media can be damaged.
Can you use an aboveground pool pump on an inground pool? Sure you can, as long as the pump is at or below the pool water level, and you have a very small pool. If the pump is able to turnover all of the water in 8-10 hours, and is able to reach (but not exceed) the pool filter Design Flow Rate, the intended use of the pump (a/g or i/g) really doesn't matter.
Just like with pool pumps, the main difference in aboveground and inground pool filters is size. Unless you want to clean your filter every other day, it's important to have a filter that is properly sized to your pool (and your pump flow rate).
Inground and aboveground pool filters are available in all 3 types - cartridge, DE or sand. They operate identically; the only difference is in size and design flow rate. Speaking of size, no matter what pool type you have - it's always beneficial to have an oversized pool filter, but an undersized pool filter will barely keep up, with constant bouts of cloudy water and algae, and near constant cleaning or backwashing.
Can you use an aboveground filter on an inground pool? Sure you can, as long as the filter is matched in size to a pump that can produce enough flow rate to turnover the water in 8-10 hours. However, the largest aboveground pool filters are rated for under 15,000 gallons of pool water, so your inground pool would have to be rather small, to use an a/g filter.
In the category of pool cleaners there are more profound differences in models; aboveground cleaners are not just scaled down models of inground cleaners, but designed differently. Since aboveground pools have 90° corners where the floor meets the wall, and less curvilinear shapes, aboveground cleaners aren't asked to climb walls, or navigate complicated curves, steps and deep ends. For this reason they can be designed much more simply. They also have shorter hoses and cords, for coverage of a smaller pool.
For one thing, suction and pressure pool cleaners for aboveground pools are made to operate with less water flow, produced from smaller (a/g) pool pumps. There are many suction-side pool cleaners for aboveground pools, but only one (Polaris 65) pressure side pool cleaners. The difference between the two (in case you didn't know), is that suction cleaners attach to a suction port like the skimmer, and pressure cleaners operate on a return line, with water under pressure being pushed to the cleaner.
Robotic cleaners are available for both i/g and a/g pools, with aboveground models being much less powerful, again because they don't need to climb walls, or climb back out of a deep end.
Can you use an aboveground cleaner on an inground pool? I guess you can, if you don't mind that it won't climb the walls, and understand that it may get stuck in the deep end, without enough oomph to get back to the shallow end. Secondly, for suction and pressure cleaners, your pool should be rather small. Aboveground pool cleaners are generally slower than inground models, so they will take longer to clean the pool. And, if you have a medium to large debris load in an inground pool, it may overwhelm some aboveground pool cleaners.
For gas pool heaters and pool heat pumps, sizing a heater properly is done by considering pool size or surface area, average wind speed, average ambient temperature, and desired temperature rise.
Any heater - aboveground or inground, installed on any pool will add some heat. A heater that is too small for a pool may only add 5-10 degrees to the pool water, less during colder ambient temps or windy days, and more during the hot part of the summer, or if you use a pool cover when the pool is unused. A larger heater however can add up to 30 degrees in temperature rise, no matter what the air temperature or wind speed. A cover is always recommended, to reduce recovery time and make any pool heater more efficient.
Solar pool heaters have less distinction between aboveground and inground models - in fact, we sell the same solar heater for both pool types. For inground pools with a deep end and a larger surface area, more solar panels are needed to gain a reasonable amount of heat. But again, any amount will heat - it just depends on how much heat (temperature rise) you want.
Can you use an aboveground pool heater on an inground pool? Sure you can, if it matches up to your pool size, and will produce enough heat to satisfy your demand. Using a pool cover (solar blanket or auto cover) will reduce the amount of BTU's needed, so for a small pool under 15000 gallons, one could consider a smaller pool heater.
Salt systems, chlorinators, purifiers can also be somewhat interchangeable, again - as long as it matches up to pool size (in gallons), and also matches your expectations. Smaller equipment will do less work, and do it more slowly than larger equipment.
Inground equipment can sometimes be used on aboveground pools, but many times it is too large or too powerful, and could damage other equipment, or the pool itself.
One other consideration is pipe size. If you have 1.5" or 2" plumbing, you can't connect to something with 1.25" threaded ports - which is the pipe size for most aboveground equipment.
In addition to pipe size, all equipment has a design flow rate - and if you push too much water, too fast through it, something is going to break, and it won't perform as intended.
And speaking of the word intended - warranty claims may be denied if you are using aboveground equipment on an inground pool - contrary to its intended use.
Thanks for Reading!