Long Island's swim season typically runs from late May through mid-September, roughly 16 weeks. With the right pool heater, you can stretch that to 24 weeks or more — swimming comfortably from April through October. Here is everything you need to know about pool heating options, costs, and what works best on Long Island.
Why Heat Your Pool on Long Island?
Long Island sits in USDA hardiness zone 7a, which means spring nights regularly dip into the 40s and fall temperatures drop quickly after Labor Day. Without a heater, your pool water temperature will hover around 60 to 65 degrees in May and drop below comfortable levels by late September. A heated pool maintains 80 to 84 degrees regardless of air temperature, turning your backyard into a usable space for half the year instead of just a few summer months.
Beyond personal enjoyment, a heated pool increases your property's appeal and gives your family significantly more return on the investment you made in building the pool. Many Long Island homeowners find that a heater pays for itself in additional use within the first two seasons.
Option 1: Natural Gas Pool Heaters
Gas heaters are the most popular choice on Long Island, and for good reason. Most homes in Nassau and Suffolk County already have natural gas service from National Grid or PSEG, making installation straightforward. A gas heater works by burning natural gas to heat water as it passes through the unit before returning to the pool.
How Gas Heaters Perform on Long Island
Gas heaters are the fastest at raising water temperature. A 400,000 BTU gas heater can raise the temperature of a 20,000-gallon pool by about 1 to 1.5 degrees per hour. That means you can go from a cold 60-degree pool to a comfortable 82 degrees in roughly 15 to 20 hours of continuous running. This makes gas heaters ideal for Long Island homeowners who do not use their pool daily but want it warm on weekends or for gatherings.
Installation and Equipment Costs
A quality gas pool heater from brands like Hayward, Pentair, or Raypak costs between $3,000 and $5,500 for the unit itself. Professional installation on Long Island, including gas line connection, plumbing, electrical, and permitting, typically adds $1,500 to $3,000. Total installed cost runs $4,500 to $8,500 depending on your setup and the heater size you need.
Monthly Operating Costs
This is where gas heaters get expensive. On Long Island, natural gas prices average around $1.50 to $2.00 per therm. Running a 400,000 BTU heater to maintain temperature on a 20,000-gallon pool costs approximately $800 to $1,400 per month during the shoulder seasons when the heater runs frequently. During July and August when ambient temperatures help, monthly costs drop to $300 to $600. Over a full extended season from April through October, expect total gas costs of $3,000 to $5,500.
Best For
- Homeowners who want heat on demand rather than constant warmth
- Weekend swimmers who heat the pool Friday and turn it off Monday
- Pools that already have gas lines running nearby
- Spas and hot tubs that need rapid heating
Option 2: Electric Heat Pumps
Heat pumps have become increasingly popular across Long Island in recent years. Unlike gas heaters that generate heat by burning fuel, heat pumps extract warmth from the surrounding air and transfer it to your pool water. Think of them as an air conditioner running in reverse. They do not create heat — they move it, which makes them dramatically more efficient.
How Heat Pumps Perform on Long Island
Heat pumps work best when outside air temperatures are above 50 degrees Fahrenheit. On Long Island, that means they perform well from mid-April through late October. They heat water more slowly than gas — typically raising temperature by 1 to 2 degrees over a full day of operation — but they are designed to maintain a constant temperature rather than heat on demand. Once your pool reaches the target temperature, the heat pump cycles on and off to keep it there at minimal cost.
The catch is that heat pumps struggle in cold weather. When air temperatures drop below 50 degrees, efficiency drops sharply. During Long Island's cooler spring and fall mornings, the unit may run longer to compensate. Below 45 degrees, most heat pumps shut off entirely.
Installation and Equipment Costs
Heat pumps carry a higher upfront cost than gas heaters. A quality unit sized for a typical Long Island pool (100,000 to 140,000 BTU) runs $3,500 to $7,000 for the equipment. Installation costs on Long Island run $1,000 to $2,500, bringing total installed cost to $4,500 to $9,500. Some premium inverter-driven models from brands like Hayward and AquaCal can exceed $10,000 installed but offer superior efficiency and quieter operation.
Monthly Operating Costs
Here is where heat pumps shine. Because they move heat rather than create it, they operate at a coefficient of performance (COP) of 5.0 to 6.0, meaning they produce 5 to 6 units of heat for every unit of electricity consumed. On Long Island, where PSEG electricity costs average $0.22 to $0.28 per kWh, monthly operating costs for a heat pump run $150 to $350 during peak use. Over a full April-through-October season, expect total electricity costs of $800 to $1,800 — roughly one-third the cost of running a gas heater.
Best For
- Homeowners who swim regularly and want constant pool temperature
- Budget-conscious owners who prioritize low monthly costs
- Environmentally conscious homeowners looking to reduce carbon footprint
- Pools that will be heated from April through October each year
Option 3: Solar Pool Heating
Solar heating uses your existing pool pump to circulate water through solar collector panels, typically mounted on your roof. The sun heats the water as it flows through the collectors before it returns to your pool. On Long Island, we get an average of 4.5 to 5.5 peak sun hours per day from May through September, making solar a viable option for extending the season modestly.
How Solar Heating Performs on Long Island
Solar pool heaters can raise water temperature 8 to 12 degrees above what an unheated pool would be. In practical terms, that means instead of a 68-degree pool in June, you might have a 78-degree pool. Instead of your pool dropping to 65 degrees in late September, solar collectors can keep it around 74 to 76 degrees. Solar heating effectively adds 4 to 6 weeks to your swim season — typically letting you swim from mid-May through early October.
The limitation is obvious: solar heating depends entirely on the sun. Overcast days, rainy stretches, and short fall days reduce output significantly. Solar also cannot heat a pool on demand. You cannot decide Saturday morning that you want a warm pool by Saturday afternoon.
Installation and Equipment Costs
A solar pool heating system for a typical Long Island pool requires 200 to 400 square feet of collector panels. Total installed cost runs $3,000 to $7,000, depending on roof accessibility, panel type (glazed vs. unglazed), and system size. Unglazed rubber or polypropylene panels are less expensive ($3,000 to $4,500 installed) but less efficient in cooler weather. Glazed panels cost more ($5,000 to $7,000 installed) but retain heat better and work in temperatures down to 40 degrees.
Monthly Operating Costs
Solar heating has essentially zero operating cost beyond the electricity your pool pump already uses to circulate water. If you need to run the pump an extra hour or two per day to push water through the collectors, you might add $15 to $30 per month in electricity. Over an entire season, operating costs are typically under $100 total. This makes solar the cheapest option to run by a wide margin.
Best For
- Homeowners with south-facing roof space free of shade
- Budget-conscious owners who want modest season extension with minimal ongoing cost
- Eco-friendly homeowners who want a zero-emission heating solution
- Pools that primarily need a boost during the existing swim season rather than major off-season extension
Head-to-Head Comparison for Long Island Pools
Here is how the three options stack up for a typical 18x36 inground pool (approximately 20,000 gallons) on Long Island:
- Gas heater: $4,500-$8,500 installed, $3,000-$5,500 per season to run, adds 8-10 weeks to swim season, heats on demand
- Heat pump: $4,500-$9,500 installed, $800-$1,800 per season to run, adds 8-10 weeks to swim season, maintains constant temperature
- Solar: $3,000-$7,000 installed, under $100 per season to run, adds 4-6 weeks to swim season, dependent on sunshine
Which Size Heater Do You Need?
Sizing a pool heater correctly is critical. An undersized heater will run constantly without reaching your target temperature, wasting energy and money. Here are general guidelines for Long Island pools:
- Small pools (up to 15,000 gallons): 200,000-300,000 BTU gas heater or 80,000-100,000 BTU heat pump
- Medium pools (15,000-25,000 gallons): 300,000-400,000 BTU gas heater or 100,000-125,000 BTU heat pump
- Large pools (25,000+ gallons): 400,000+ BTU gas heater or 125,000-140,000 BTU heat pump
For solar, the general rule is that your collector area should be 50 to 100 percent of your pool's surface area. A 16x32 pool (512 square feet of surface) needs 256 to 512 square feet of collector panels.
The Hybrid Approach: Best of Both Worlds
Many Long Island pool owners are choosing a combination system: a heat pump for daily temperature maintenance paired with a gas heater for quick boosts. The heat pump keeps the pool at 80 degrees all week at low cost, and the gas heater can bump it up to 84 or 86 degrees before a weekend party. This hybrid setup costs more upfront ($8,000 to $15,000 total installed) but gives you maximum flexibility with reasonable operating costs.
Another popular combination is solar panels paired with a heat pump. The solar does the heavy lifting during sunny days, and the heat pump fills in the gaps during overcast weather and cooler mornings. This combination keeps seasonal operating costs under $1,000 while still delivering a reliable 80-plus degree pool from April through October.
Long Island-Specific Considerations
Before choosing a heating system, keep these Long Island factors in mind:
- Wind exposure: Coastal areas of the South Shore, the Hamptons, and the North Fork experience more wind, which cools pool water faster. Wind-exposed pools benefit from gas heaters or heat pumps over solar, and a quality pool cover becomes essential
- Natural gas availability: Most of western Suffolk and Nassau County have natural gas service. Eastern Suffolk towns may rely on propane, which costs 30 to 50 percent more to run than natural gas
- HOA restrictions: Some Long Island communities restrict rooftop solar panels. Check your HOA rules before committing to solar heating
- Pool covers matter: Regardless of which heater you choose, a solar or thermal pool cover reduces heat loss by 50 to 70 percent. A $200 cover can save you $1,000 or more per season in heating costs on Long Island
- PSEG rebates: PSEG Long Island occasionally offers rebates on energy-efficient heat pumps. Check their current programs before purchasing
Our Recommendation for Most Long Island Homeowners
For the typical Long Island pool owner who swims regularly from late spring through early fall, an electric heat pump offers the best balance of performance, cost, and season extension. The higher upfront cost pays for itself within two to three seasons compared to a gas heater, and you get the same 8 to 10 extra weeks of swimming.
If you swim infrequently or only want warm water for occasional gatherings, a gas heater's on-demand heating makes more sense despite higher running costs. And if your primary goal is modest season extension with minimal investment, solar is hard to beat.
Ready to Extend Your Swim Season?
The best pool heating system depends on your swimming habits, budget, and property setup. Request a free consultation and we will evaluate your pool, discuss your goals, and recommend the right heating solution for your Long Island home.