Cooler nights don’t have to end your swim season. With the right heater, sensible temperature settings and a pool cover you actually use, many pools stay comfortable well into fall. Here’s how the options compare and how to keep heating costs under control.
Heat pump or gas heater: which suits fall?
For steady fall swimming, a heat pump is usually the cheaper heater to run, as long as the outside air stays above about 45°F to 50°F (7°C to 10°C). A gas heater warms the water faster and holds temperature in any weather, which suits pools that are only used now and then.
| Heat pump | Gas heater | |
|---|---|---|
| How it heats | Moves heat from the outdoor air into the water | Burns natural gas or propane |
| Weather | Efficient while the air stays above about 45°F to 50°F | Holds any temperature regardless of the weather |
| Heating speed | Steady, even heat once it reaches your temperature | Heats the pool quickly |
| Running cost | Much lower annual operating costs | Higher energy bills |
| Upfront cost | Costs more to buy, and typically lasts longer with proper maintenance | Lower purchase price |
| Best for | Pools used regularly through the fall | Pools used occasionally, or warmed up for a weekend |
A heat pump works a little like an air conditioner in reverse. A fan draws outside air over a coil, the refrigerant inside absorbs its heat, a compressor raises that heat and a condenser passes it into the pool water as it circulates through the unit. The colder the air it draws in, the harder it has to work, which is why heat pumps lose efficiency as fall nights get colder. With proper installation and maintenance, a heat pump pool heater can last 10 or more years.
What temperature should you set?
Most pools are kept between 78°F and 82°F (about 26°C to 28°C). Every degree you add costs more to maintain, so set the lowest temperature your family is comfortable with.
- The American Red Cross recommends 78°F (about 26°C) for competitive swimming. Young children and older swimmers may prefer 80°F (about 27°C) or higher.
- Each degree higher can add 10% to 30% to your heating energy costs, depending on where you live.
- Turn the heater down or off whenever the pool won’t be used for several days. Reheating does not use more energy than you save by turning it down; that’s a myth.
Why a pool cover is the best fall upgrade
Evaporation is by far the largest source of heat loss from a pool. Covering the pool whenever nobody is swimming is the single most effective way to cut heating costs, with savings of 50% to 70% possible.
A cover helps in other ways too:
- It cuts the top-up water the pool needs by 30% to 50%.
- It reduces chemical use by 35% to 60%.
- It keeps leaves, dirt and other debris out of the water, which cuts cleaning time.
The catch: a cover only saves energy when it’s on the pool. Make it part of the routine every evening. If you also want a cover that adds safety over the off season, read our guide to pool safety covers.
Fall leaves: keep them out of the water
Falling leaves are the other fall job. Leaves that sink and sit on the floor break down in the water, which can stain surfaces and makes the water harder to keep balanced.
- Skim the surface often while trees are dropping, before leaves have a chance to sink.
- Empty the skimmer and pump baskets more often than in summer. Full baskets restrict circulation, which the heater and filter rely on.
- Keep the cover on overnight and on windy days.
- Trim branches that hang over the pool.
When it’s time to close instead
If nights regularly drop below the range where your heat pump works efficiently, or the pool simply isn’t being used, heating it makes less sense. That’s the time to plan your pool closing, and our article on when to close your swimming pool walks through the timing. In warmer areas where pools stay open all year, regular service through the fall keeps the water ready whenever you want it.
How Puddle can help this fall
Weekly pool service keeps the water balanced and the baskets clear while you keep swimming. Every visit ends with an E-Report showing what was done, your chemical readings and before and after photos. Our technicians are CPO certified, and you’ll get a quote within 24 hours. Request a quote from your local Puddle team.
Frequently asked questions
Is it worth heating a pool in the fall?
For many pools, yes. A heat pump keeps running costs down while the air stays above about 45°F to 50°F, and a cover can cut heating costs by 50% to 70%. If you only swim now and then, a gas heater can warm the pool quickly when you need it.
How cold is too cold for a pool heat pump?
Heat pump pool heaters work efficiently while the outside temperature stays above about 45°F to 50°F (7°C to 10°C). Below that, they lose efficiency and energy bills rise. Gas heaters can hold temperature in any weather.
Should I turn my pool heater off when I’m not using the pool?
Turn it down or off whenever the pool won’t be used for several days. It’s a myth that reheating uses more energy than you save. Day to day, the bigger saving comes from keeping the pool covered when nobody is swimming.
What temperature should my pool be in the fall?
Most pools sit between 78°F and 82°F (about 26°C to 28°C). Choose the lowest temperature your family finds comfortable, since each extra degree can add 10% to 30% to heating energy costs.
Sources: US Department of Energy, Energy Saver guides to heat pump pool heaters, gas pool heaters, pool covers and managing pool temperature.
