When you are looking at pool heaters, there are four main options – gas, electric, solar and heat pump. All of these different ways to heat a pool bring in cool water from the pool, heat it and then send the warmed water back into the pool. How they differ is in how they generate the heat. Gas pool pumps burn natural gas or propane in a combustion chamber to generate the heat. Electric pool heaters use the same principles as small electric heaters in your living room, running electricity through resistive wiring to generate heat, except that water circulates around the heating element via pipes. Solar hot water heaters use glass, dark plastic and/or rubber to capture and concentrate the sun’s heat and warm water pumped into them. This is in contrast to solar pool covers that act like an insulating blanket to prevent heat loss at night, though some of these pool covers have solar concentrating bubbles on the surface to provide a portion of the warming effect solar concentrators in solar pool heaters.
What are the Strengths and Weaknesses for Each of These Different Ways to Heat a Pool?
Gas Pool Heaters
Advantages of Gas Pool Heaters
Gas pool heaters generate the most heat in a short period of time, so they are the best choice for heating up a pool from near freezing to comfortable temperatures quickly.
Gas pool heaters can maintain the same water temperature as long as they run, and they are independent of air temperatures and the amount of sunlight available. Gas pool heaters can be cheaper to operate than heat pumps in cooler climates.
Only a gas pool heater will heat up a small pool quickly to spa like temperatures. They are perfect for heating up the sauna, hot tub or other small body of water on impulse, whereas other pool heaters require you to plan ahead to benefit from it.
Disadvantages of Gas Pool Heaters
You have to have either a gas connection to the house to run a gas pool heater or a large supply of propane. And having a gas connection to the house isn’t enough – you have to run a gas pipe to the gas pool heater, as well. A few run on fuel oil, but unless you’re in the Northeastern United States, that’s very rare.
You may pay less for the gas pool heater upfront but will pay more for its operations over the life of the unit.
Conversely, it costs about as much to run regardless of weather conditions or air temperatures since its efficiency won’t change unless the water temperature is changing a lot, too.
Gas pool heaters break down more often than comparable pool heating options. They are more sensitive to corrosion when the pool pH is unbalanced.
Pool Heat Pumps
Advantages of Pool Heat Pumps
Pool heat pumps are more energy efficient than electric heat pumps. They cost less to operate than a comparable electric pool heater.
They don’t release exhaust into the pool area.
They can run for years without needing repair; gas pool heaters need repairs more often.
You can improve the efficiency of the pool heat pump by cleaning the coils periodically and giving it adequate air flow, and it needs only a fraction of the space of a solar pool heater.
Disadvantages of Pool Heat Pumps
They don’t run when air temperatures are around 45º to 50ºF, and their efficiency goes down along with the air temperatures.
Heat pumps cost the most to operate when you need them the most – in short, the colder the weather, the higher the electric bill to run it to try to make the water warm.
Not all pool service companies have the refrigerant on hand to recharge the pool heat pump if the coil starts leaking refrigerant, and it is very rare to find an HVAC company willing to service a leaking pool heat pump. This means that unless pool heat pumps are common in your area, getting it repaired will be challenging.
Electric Pool Heaters
Advantages of Electric Pool Heaters
You can use electric pool heaters in homes without a gas connection. And there is no ongoing maintenance cost (gas bill) after you install it.
There are no emissions in and around the pool.
These are among the cheapest pool heaters to install and have a relatively low ongoing operating cost.
Disadvantages of Electric Pool Heaters
The electric pool heater will take longer to heat up the pool than a natural gas pool heater. Their most common result is warm water in the afternoon with tepid water in the morning.
They typically last about ten years, half as long as the average solar pool heater. Their operating life is about as long as a comparable gas pool heater.
Solar Pool Heaters
Advantages of Solar Pool Heaters
This is the most eco-friendly pool heating solution available. And if you can use the existing pool water pump to circulate the water, you don’t add to your electric bill at all.
They have almost no maintenance unless the glass of the glazed solar collector breaks or the pump that circulates the water needs to be repaired.
Solar pool heaters can be used to cool off the pool water in very hot climates.
Disadvantages of Solar Pool Heaters
Solar pool heaters just aren’t an option if you don’t have enough sunlight to benefit from it. You may not have the ideal southern exposure to make use of a solar pool heater, and even when you do, you’re looking at a solar collector covering at least half the surface are of the pool. Not everyone can cover that much roof surface or take up part of the yard with collector panels.
Solar pool heaters, assuming it isn’t something built into the pool cover, are expensive given the BTUs they produce.
They take the most time to warm up your pool of any pool heating option.
Solar pool heaters are unreliable; you can’t be sure that it won’t be overcast or cloudy for several days, rendering the solar pool heater useless.