What Does It Really Cost to Use a Heat Pump and Swim Year-Round in Arizona?

Short answer:
less cost than most people fear, more cost if you skip a cover, and almost always less than gas for steady, everyday heat. Below, we’ll show Phoenix-specific numbers, plain-English math you can adapt to your pool, and where a heat pump shines (and where it doesn’t).

Why you’re skeptical (and why that’s fair)

If you’ve ever thought, “Of course the pool company wants me to buy a heater—translation: a new monthly bill,” you’re not alone. We hear it every week. So let’s tackle the question the way radical transparency should—by showing our work, citing independent sources, and telling you when a heater is NOT the right fit.

First, what counts as “comfortable” water?

Most families prefer 82–86°F for relaxed swimming (fitness swimmers might like 78–82°F). That’s a helpful anchor as we talk costs. usms.org

Why 85°F water can still feel cool on a nice 85°F day: your body sheds heat in water 25x faster than in air. So 80°F water can feel brisk even when the air feels perfect. Princeton University

What a pool heat pump actually does (and why AZ is ideal)

A pool heat pump works like an air conditioning unit in reverse—pulling heat from the air and moving it into the water. They’re most efficient when the air is above 45–50°F (hello, like almost every day in Phoenix winters), and they excel at maintaining heat day after day rather than “emergency” blasts. Many models also cool the water in summer when the pool gets too warm. The Department of Energy's Energy.gov+2Hayward+2

The big question: what does it cost to run in Phoenix?

The U.S. Department of Energy (DOE) publishes city-by-city estimates. For Phoenix, heating March 1–Oct 31 to:

• 82°F without a cover: $1,485 per season
  
  
• 82°F with a cover: $158 per season

In other words…USE A COVER!

Those figures assume electricity at $0.1301/kWh and a seasonal COP (efficiency) of 5.0. Arizona’s recent average residential rate runs closer to $0.1576/kWh, so scale the Department of Energy numbers up ~21% for today’s bill reality: roughly $1,800 (no cover) vs $190 (with cover) for that same season. Covers matter—a lot. The Department of Energy's Energy.gov+1

Why the massive gap? Evaporation is the #1 heat thief. A simple, low price solar cover can cut heating costs ~50–70%. The Department of Energy's Energy.gov+1

“But I want to swim in December and January…”

Phoenix nights from late fall through early spring often slide into the 40s–50s. That cools the water faster overnight, which means your heat pump works more hours to hold 82–86°F—especially if the pool is uncovered. Expect wintertime operating costs to behave like the no-cover column above unless you use a cover consistently. (Climate normally show our winter lows—and why pools lose ground overnight.) Weather Spark

Quick math you can adapt to your pool

Think of a typical heat-and-cool pump around 100k–125k BTU drawing 5 kW while running (sort of like your air conditioning unit). At $0.1576/kWh, that’s about $0.79 per hour of runtime. If you average 4–6 hours/day with a cover in shoulder months, you’re around $95–$140/month. Double the runtime or lose the cover and, well…you can see where the bill goes. (Rule of thumb based on manufacturer specs and our field data.) Prod 15.3.8521+1

Want a faster way to estimate runtimes? Department of Energy’s sizing formula assumes 1–1.25°F (one to one point two-five) per hour of heat gain under mild wind. If you’re trying to climb 6°F, you’re looking at roughly 5–6 hours of runtime that day. Holding temperature day-to-day typically takes less. The Department of Energy's Energy.gov

Installation cost in AZ (typical ranges)

• Heat pump unit + install: $3,500–$7,000+ depending on pool size, equipment pad location in relation to your main house-panel, and electrical work. This range matches Phoenix-area pricing and national guides.

Heat pumps usually cost more upfront than gas but way less to run long-term thanks to higher efficiency (COP often 3–7). With good maintenance, they also tend to last longer. The Department of Energy's Energy.gov

What actually drives your monthly cost (and how to bend the curve)

1) A cover (or not)

This is the single most powerful lever—on par with switching from gas to electric in terms of savings. Expect 50–70% less heating cost with consistent cover use. The Department of Energy's Energy.gov

2) Target temperature

Every extra degree takes energy. If the family is happy at 82–84°F instead of 86–88°F, you’ll notice it on the bill. (World Health Organization suggests 78–86°F is generally comfortable and safe for recreational swimming.) usms.org

3) Nighttime lows and wind

Phoenix’s big day-night swing means overnight is when you lose ground; add wind and evaporation accelerates. Typically, the water temperature ends up matching the overnight low.

4) Circulation method

If heated water returns from floor pop-ups (in-floor cleaning), heat rises and mixes more evenly—think heating a pot of water from the bottom instead of blasting a torch across the top. Standard wall returns, on a pool vacuum pool, send warm water out mid-wall, so stratification can lengthen heat-up time. (This is one of those “design details” that quietly helps the bill.) Who would have thought that the cleaning system can influence your pool heating bill so much!

5) Pool surface area

Heaters are sized to surface area and temperature rise, not just gallons; bigger surface = more evaporation to fight. The Department of Energy's Energy.gov

Heat pump vs. gas vs. solar in Arizona (cost picture)

• Heat pump — Best for steady, everyday heating Oct–May; highly efficient in our climate; slower to “boost” temp on a chilly morning. Operating cost is usually lower than gas for ongoing use. Many models cool in summer. The Department of Energy's Energy.gov+1
  
  
• Gas — Great for speed (spa nights, last-minute pool parties). For daily use, the bill climbs fast; typical gas heating can be $300–$500/month for weekend use...don't ask about the potential bill if you're heating a pool daily with a gas heater.
  
  
• Solar — Free sunshine after the install, but output depends on sun + roof space; often paired with a cover. (Solar + heat pump is a strong combo for near year-round use but you do lose specific temperature control being so dependant on sun + lack of cloud cover…and Arizona gets some clouds during the Fall and Winter)
  

Phoenix-specific cost reality (putting DOE + AZ rates together)

• With a cover: Department of Energy’s Phoenix estimate to maintain 82°F Mar–Oct is $158/season at $0.1301/kWh. Using Arizona’s recent $0.1576/kWh average, that’s ≈$190 for the same period. That’s less than $25/month over 8 months—why we harp on covers. The Department of Energy's Energy.gov+1
  
  
• Without a cover: Same period jumps from $1,485 to ≈$1,800, or ~$225/month for Mar–Oct. Year-round without a cover? Budget more; winter nights drag temps down, increasing runtime. The Department of Energy's Energy.gov
  

“Will a heat pump truly make my pool year-round?”

Yes—with the right expectations. Think of it like your air conditioning unit during the summer…can your A/C get your home into the 60’s inside when its 120 degrees outside? Yes, it sure can. It's just going to take longer, some good planning on your part and the right expectations :

• For Oct–May, a heat pump + cover maintains 82–86°F reliably for most pools.
  
  
• Dec–Feb is very doable, but expect more runtime (and costs) on cold snaps; some families layer in a hybrid approach: heat pump for everyday, gas for fast weekend boosts or spa nights. Many heat pumps work at roughly a 50% efficiency when the daily high temperature is below 50 degrees…thankfully for Arizonans, that isn’t a frequent occurance. The Department of Energy's Energy.gov
  

   

  
  

Let’s compare the value side, not just the bill side. Most AZ families tell us their unheated pool is truly comfortable for 5 to 5.5 months a year. Why? Water tends to trend toward the overnight lows absent heating or a cover. In Phoenix, those lows are pleasant in summer but dip in colder seasons—so your pool feels cold even when afternoons are lovely. Add a heat pump + cover and you’re swimming 9–12 months by design, not by luck. (Climate normals and DOE’s Phoenix data back up why covers + steady heat change the math.) Weather Spark+1

If you paid, say, $5,500 installed and used the heater 8–10 months each year for the next decade, the cost per extra swim-month is often far lower than families expect—especially compared to gas fuel costs for the same usage profile. And unlike gas, a heat-and-cool unit keeps your water from getting too warm during peak summer, which many families end up loving. Crosswind V – Raypak

The subjective question that should be asked, “what is it worth to me to double my swim season per year?” 

Who should (and shouldn’t) choose a heat pump

Great fit if you:

• Swim several days a week outside of summer
• Want predictable, efficient warmth vs. on-demand blasts
• Will use a cover (even a simple solar blanket)

Think twice if you:

• Only want the pool warm on only a handful of days during Fall and Winter (a gas heater may be more efficient to own/run for only a few days of use during a pool “off-season”)
  
  
• Won’t use a cover and insist on 88–90°F water in January (possible, but your bill will reflect it; a gas heater is most effective in hitting those spa-temps of 90 to 104 degrees but expect to see that in your gas bill)

Real-world tips to cut the bill (without cutting swim time)

1. Cover it nightly. This is 50–70% of your savings. Set it and forget it. The Department of Energy's Energy.gov
2. Pick a “set-and-hold” temp. Holding 84°F all week is cheaper than constantly reheating from 78°F.
3. Get an automation panel that makes heat control and scheduling easy; it will actually help you reduce ownership cost Poolside Tech
4. Let in-floor pop-ups do their thing. If your pool isn’t already built, choose bottom-up circulation so it mixes heat faster and more evenly than mid-wall returns.
5. Block the breeze. Even a low fence or windbreak near the water line reduces evaporation.
6. Size it right. Heaters are sized to surface area and desired temperature rise; under-sizing makes it slow and inefficient. The Department of Energy's Energy.gov

Straight talk, then a few options

If you’re only planning to swim June–September and don’t mind chilly, colder seasons and don’t see yourself swimming during the Fall or Winter, you don’t need a heater. Honest. If, however, you want year-round or near-year-round swimming, a heat pump + cover is usually the lowest-cost way to do it in Arizona—and far gentler on monthly bills than running gas every day. (DOE’s Phoenix table and Arizona’s kWh rates are the receipts.) The Department of Energy's Energy.gov+1

Ready to see your exact numbers?

• Ask Shasta for a quick sizing + run-cost projection. We’ll look at your pool’s surface area, wind exposure, returns vs. in-floor cleaning, and your preferred temperature—then model expected runtime with/without a cover.
  
  
• Prefer to browse? Our e-commerce division, Shasta Pool Supply carries heat-and-cool models from Raypak, Pentair and Hayward; we can pair you with a unit that fits your pad, your electric, and your goals. We even can sell pool covers. Shasta Pool Supply
  
  

FAQs (for searchers who landed here with specific questions)

How fast will a heat pump warm my pool?

Plan on 1–1.25°F per hour in mild wind with a correctly sized unit. It’s terrific at maintaining temperature day-to-day. The Department of Energy's Energy.gov

Can heat pumps run in Phoenix winters?

Yes. They operate efficiently above 45–50°F, which covers the vast majority of Phoenix winter days. The Department of Energy's Energy.gov

What’s the difference on my bill if I use a cover?

In Phoenix, DOE’s model shows season cost dropping from $1,485 → $158 (82°F target) when adding a cover—before adjusting for today’s kWh rate. Scaling for Arizona’s recent average takes that to roughly $1,800 → $190. The Department of Energy's Energy.gov+1

Your Pool, Your Season — Let’s Make It Work for You

Whether you’re dreaming of a new pool built around year-round comfort, giving your backyard a remodel that finally fits your lifestyle, fine-tuning your system through service and repair, or simply looking to buy direct and handle it yourself—Shasta is here to help you make confident, informed choices. No pressure. No guesswork. Just clear answers, real numbers, and a team that helps you decide what’s best for you.

Start where it fits:

•  New Pools – Design your perfect pool with comfort and efficiency in mind.
•  Service & Repair – Keep your pool running like new all season long.
•  Pool Remodeling – Transform your existing pool into something better than ever.
•  Shop Shasta Pool Supply – Order trusted products and equipment directly, anytime.
  
  

Your next season of swimming starts with one simple step—ask Shasta for clear answers and honest guidance.