.png){kind=logo}
Should You Close Your Pool—or Hold Off? How to Capture Those Last, Golden Swims
- Peter J. Sroczynski
- Sep 10
- 4 min read
Picture this: It’s a quiet Saturday. The calendar says fall, the backpacks are lined up by the door, and the neighborhood feels calmer. Yet the sun still lingers late in the afternoon and the air turns warm enough that a dip sounds perfect. Many years, we get a stretch of gentle warmth—often called Indian Summer (also known as Second Summer)—that can run well into October, sometimes even November, especially after the first frost.
A quick note on the name: Some folks prefer “Second Summer” or “St. Martin’s Summer”—both refer to the same autumn warm spell after an early frost.
So, do you close your pool the minute school starts? Or do you give yourself permission to enjoy a few more sun‑splashed weekends?
Why Holding Off Can Be the Best Choice
1) Those bonus warm weeks are real. Meteorologists describe Second Summer as a short run of abnormally warm, calm days after the first frost—exactly the kind that make for serene, crowd‑free swims.
2) You’ve already invested. You’ve maintained water balance, kept up with cleaning, and created a space your family loves. Stretching the season a few more weeks maximizes your return—especially if you can keep the water feeling welcoming.
3) Closing strictly by the calendar can backfire. Many pros suggest closing when water temps stay below ~65°F, because algae growth slows and most people stop swimming then—not just because it’s September. If you’re enjoying the pool and can keep it warm, you don’t have to rush.
The Real Challenge Isn’t Air—It’s Water
Even on sunny days, cool nights pull heat from your pool. The main culprit is evaporation, which can account for up to 70% of total heat loss (every pound of 80°F water that evaporates carries away ~1,048 BTU of heat). That’s why water can feel chilly even when the afternoon air is comfortable.
Good news: A simple solar/safety cover can dramatically cut this heat loss, shrink energy bills, and keep the warmth you’ve already paid for—often saving 50–70% in heating costs.
Make Fall Swims Feel Like Summer: Add a Jandy JXI Pool Heater
If fall’s your favorite time to swim—quiet, golden, and relaxed—temperature control is the unlock. The Jandy JXI is a compact, efficient gas heater that warms quickly and keeps water right where you like it.
Why pool owners love the JXI for fall:
Fast, dependable warmth. Gas heaters excel at quick heat‑up and maintaining a set temperature regardless of weather swings—ideal for shoulder season use.
High thermal efficiency. JXI models are rated up to 84% thermal efficiency (model‑dependent), helping you get more heat from every fuel dollar.
Ultra‑compact, install‑friendly. A small 2’×2’ footprint and smart design make JXI a strong retrofit for many equipment pads.
Automation‑ready. Pair with AquaLink® / iAquaLink® for “set‑and‑swim” convenience from your phone.
Bonus: VersaFlo™ Integrated Bypass = Extra Savings
Choose a JXI with VersaFlo™ Integrated Bypass and the heater automatically bypasses the heat exchanger when you’re not actively heating, reducing pump head loss so you can run your variable‑speed pump at lower RPMs—and save up to 20% more energy (Jandy’s field data even shows up to ~$350/yr in electricity savings in certain scenarios).
“What Will It Cost Me to Heat in the Fall?”
Let’s make it tangible. A typical 21,000‑gallon pool needs roughly 175,100 BTU to raise the water 1°F. A 400k BTU gas heater (running at ~80–84% efficiency) can increase that about ~1.8°F per hour, using roughly 4 gallons of propane per hour. Your local fuel price determines the exact hourly cost.
How to lower that cost:
Cover the pool when not in use (biggest saver—cuts evaporation/heat loss). Here at JPS, we don't recommend this option as this tends to Bake the pool and cause Algae Growth.
Use VersaFlo™ on the JXI to reduce pump energy when not actively heating.
Aim for 78–82°F. Each 1°F increase can add ~10–30% to heating energy use. Find your family’s comfort point and stick to it.
When Is the Right Time to Close?
If you’re still getting warm spells and your family’s swimming, enjoy it. But plan to close when:
Water temps hold below ~65°F for days in a row.
Leaf drop overwhelms your maintenance routine.
A Polaris Skim Bot can help you with the daily chore of skimming Leaves.
Your schedule or budget says it’s time.
When you do close, follow a thorough winterization checklist (balance water, clean, lower water level per cover type, protect plumbing) to make spring opening a breeze.
Quick Sizing Guidance (So Your Heater Actually Delivers)
Proper sizing considers surface area, desired temperature rise, wind exposure, humidity, and cool nights. The U.S. Department of Energy recommends using Pool Area × Temperature Rise × 12 to estimate the BTU/hr requirement (for ~1–1.25°F rise per hour at ~3.5 mph wind) and notes that gas heaters are ideal for quick heat and on‑demand use. Our pool Technicians can finalize the right size for your pad and plumbing.
Take a moment to...
Think about your family’s favorite pool memory from this year—the cannonballs, the laughter, the late‑day float when everything else was finally quiet. Now imagine two or three more weekends like that. That’s the gift of waiting a bit longer—and of keeping the water comfortably warm so everyone says “yes” to a swim.
Ready to Keep Swimming? We Can Help.
At JPS Pool & Spa Services, we make extending your season easy:
Jandy JXI heater installation (with VersaFlo options)
Fall tune‑ups to keep equipment efficient
Covers and energy‑saving tips for lower operating costs
Contact us today to get started:
Phone: (609) 709-5858
Don’t close your pool too soon—let’s capture a few more golden swims.
FAQs
Q1: Is it wasteful to heat a pool in the fall? Not if you use a cover (cuts 50–70% of heating loss from evaporation) and a right‑sized, efficient heater. Gas heaters are ideal for quick, occasional fall use, pair with a cover for the best ROI.
Q2: How warm should I keep the water? Most families enjoy 78–82°F. Each extra degree can raise energy use ~10–30%, so pick a “happy temperature” and maintain it.
Q3: What makes the JXI stand out? High thermal efficiency (up to 84%), ultra‑compact footprint, fast heating, and VersaFlo™ to reduce pump energy when you’re not actively heating. It’s also automation‑ready with AquaLink® / iAquaLink®.
Q4: When should I definitely close? When water temps consistently sit below ~65°F, or if leaf drop and maintenance become unmanageable.
Comments