Do you need a heated pool in AZ?

No, a heated pool is not required in Arizona, and many Phoenix-area pools are used without heating for much of the year. Summer water temperatures often exceed 85°F, and spring and fall are usually comfortable without a heater. A heater mainly extends the season into winter, which is short and mild in the Valley. Whether to heat depends on how you plan to use the pool. Most owners in the Phoenix metro find that a heater is useful only for a few cool months, which is why many choose a solar cover or no heating at all.

Does putting a tarp over a pool make it warmer?

Yes, a tarp or cover placed over the pool surface traps heat and reduces evaporation, which can noticeably raise water temperature. Solar-specific bubble covers work best; ordinary tarps help less because they may not block evaporation or let heat escape easily. Cover types compared: | Cover Type | Heat Retention | Typical Cost | Notes | |------------|----------------|--------------|-------| | Solar bubble cover | High | $150-$400 | Absorbs sun, traps heat, reduces evaporation | | Standard vinyl safety cover | Low to moderate | $1,000-$3,000+ | Safety focus, minimal heating | | Mesh safety cover | Low | $800-$2,500 | Keeps debris out, little heat gain | | Plain tarp | Low to moderate | $20-$60 | Can trap some heat but may trap moisture and be unsafe | For most Phoenix pools, a solar bubble cover is the best choice for warmth.

How much does it cost to upkeep a pool in Arizona?

In the Phoenix area, routine pool service typically runs about $120 to $200 per month for weekly cleaning and chemical balancing. Total annual upkeep often reaches $2,000 to $4,000 once you add chemicals, equipment electricity, and occasional repairs. Costs rise with pool size, heavy debris from desert dust or monsoon storms, and hard water scaling.

How to reset pool heater?

To reset a pool heater, first turn off power or the gas supply and wait about 5 minutes. Then restore power or gas and press the reset or ignition button, following the model's instructions on the rating plate or manual. If the heater will not restart or shows an error code, stop and call a licensed technician, since repeated reset attempts can mask a real fault.

How to warm an inground pool without a heater?

The most effective heater-free methods are solar covers, solar rings, and simply running the pump during the warmest part of the day. In Phoenix, the sun does much of the work, so pool owners often need only minor adjustments to keep water comfortable through spring and fall. The most common options include: - **Solar cover (solar blanket)** — Bubble-style covers that float on the surface and trap heat ($50-$300 depending on size) - **Solar ring or solar dome** — Floating devices that heat a small section of water ($30-$150) - **Run the pump midday** — Circulating water through the filter and exposing it to sun can raise temperature slightly, using existing equipment at little extra cost - **Dark pool surfaces** — Darker tile or plaster absorb more solar energy than lighter finishes In Arizona, a solar cover used nightly can add several degrees over a few days, which is often enough for comfortable swimming outside summer.

Is it cheaper to heat a pool with gas or electricity?

In Arizona, heat pumps (electric) are usually the cheapest to run, while gas heaters have lower upfront cost but higher operating expense because natural gas and propane prices have risen. The best choice depends on local utility rates and how often you heat the pool.

Is it okay to run a pool heater all night?

Running a pool heater overnight is generally fine and is often the most efficient approach in Arizona, since nighttime is when pools lose the most heat. Keeping a cover on the pool and setting a moderate temperature usually costs less than reheating the water after it cools.

What is the cheapest way to resurface a pool?

The cheapest way to resurface a pool is a basic white plaster replaster, which typically costs $4,000 to $8,000 for an average Phoenix-area pool. Choosing standard plaster over pebble or quartz, keeping the existing shell and tile in good condition, and avoiding unnecessary extras like new coping or equipment upgrades will keep the cost down. - **Standard white plaster** — lowest material cost ($4,000-$8,000) - **Drain and clean plus acid wash only** — minimal cost if the surface is sound - **Crack and leak repair first** — prevents paying to resurface over a problem - **Skip extras** — tile, coping, and equipment can be done later if not urgent

Pool Heater Not Heating: Common Causes and What to Check

Low water flow, a wrong mode or setpoint, a closed gas supply or tripped breaker, and a lockout code are the most common reasons a pool heater is not heating. Work through the checks below in order, from look-only to hands-on, and stop at the red flags.

Symptom	Likely area	Homeowner check	Stop and call a pro?
No power or blank display	Power supply or controls	Look at the breaker and the display	Yes, if the breaker trips again
Heater fires then shuts off	Low water flow	Baskets, filter, valves, bypass	Yes, if flow is good and it still shuts off
Lit but water stays cool	Settings or heat loss	Mode, setpoint, cover use	Not at first
Heats slowly	Size, weather, run time	Cover, run schedule, airflow	No, often normal
Error code showing	Model-specific fault	Record the code, read the manual	Yes, if it returns after a reset
Gas smell or water leak	Gas line or heat exchanger	Nothing, leave it alone	Yes, immediately

Three cases: no power, cool water, or slow heating

These are different problems. Sort yours into one of three cases: no power or display, the heater fires but the water stays cool, or it heats slowly and never reaches the set temperature.

Pool heater next to pump and filter on an equipment pad — A pool heater installed beside the pump and filter equipment

The type of heater matters too. A gas heater relies on an ignition sequence. A heat pump relies on a compressor and fan, and it will not run at all when an error condition such as a water-flow-switch fault is active.^[6]

Before you check anything, write down the brand, model and serial number from the data plate, plus any code on the display. Some controls will even scroll back through the last five codes.^[4]

Low water flow stops most heaters from firing

Low flow is the most common reason a heater stops firing. Heaters use a pressure or flow switch that keeps the burner or compressor from running without enough water, which is why the display can be lit while nothing heats.^[6]

How the parts connect

Where water must flow to reach the heater

Skimmer and pump baskets
Keep clear
Pump
Running and primed
Filter
Check the pressure gauge
Valves
Open in the right positions
Heater bypass
A partly open bypass sends water around the heater
Heater
Return line to pool

Run these no-tools checks in order:

Confirm the pump is running and primed, and that water is visibly returning to the pool.
Clear the skimmer and pump baskets.
Check the filter pressure gauge. A reading well above normal suggests a clogged filter.
Confirm the valves are open in the right positions.
Check any heater bypass, since one left partly open sends water around the heater.

A running pump does not guarantee adequate flow. A variable-speed pump on a low filtration schedule may not push enough water through the heater.

If the pump itself is struggling, see pool pump not working for priming, seal and capacitor checks.

Clean a dirty filter by the manufacturer's instructions, and never open a pressurized filter until the pump is off and pressure is fully relieved. If pressure stays high after cleaning, a pool filter repair may be the real fix.

Pro tip

Note the filter pressure reading when the filter is clean. A reading well above that number later is an early sign that flow is dropping and the heater may stop firing.

602 Pool Pros

Settings and error lights to check

Confirm the heater is switched to pool mode rather than spa. Make sure the thermostat is set well above the current water temperature, and that no timer or schedule is blocking heat.

Then read the code or lights. Do not guess. Hayward's service guide, for example, ties its high-sense condition to specific sensor readings, which shows why codes must be read against the manual for your exact model.^[5]

How it works

How to handle an error code

Step 1: Record the code
Write it down from the display
Step 2: Read it against your model's manual
Step 3: Reset only as the manual describes
Step 4: If it locks out again, call a technician

Read the code, reset once as directed, then call if it returns

Reset the unit only as the manual describes. If it locks out again, stop and call.

Gas or power supply checks

Keep this tier to looking only. Check that the breaker has not tripped, the gas shutoff handle is open, and a propane tank is not empty if you use one.

Stop here: do not open the cabinet or touch gas lines, pilot tubing, orifices or wiring. Arizona's R-6 pool license excludes gas lines and electrical work beyond the first disconnect, so these jobs may belong to another licensed trade.

If you smell rotten eggs or hear hissing, leave the area, avoid switches and flames, and call 911 and your gas utility from a safe distance.^[1]^[2]

The Arizona Corporation Commission likewise advises contacting your gas company first and calling 911 in an emergency.^[3]

Return water runs warm, not hot

Expect mildly warm, not hot. A heater adds only a limited amount of heat on each pass, so the return line should feel gently warmer than the pool. Your manual lists the rated rise for your model.

Slow heating on a cool desert night can also be normal. Evaporation and radiative loss at night can erase much of the day's progress, especially with no cover and short run times. Heat pumps in particular lose output as the air cools, so judge them during the warmest part of the day.

If you want warmth without a working heater, a solar cover is the simplest step, since it cuts evaporation and overnight loss.

When to stop and call a licensed technician

Stop here for any of these:

A gas smell, burning smell or scorch marks
Water leaking from the heater
Repeated lockouts
Clicking with no ignition
Breakers that trip
Soot or odd flames

Phoenix-area companies' own websites, checked October 2026, most often list diagnostic fees of $85 to $95, with a full spread of $75 to $165. Ask for an itemized written quote for the repair itself.

Key takeaways

Check flow, settings and codes before calling anyone
Never open the cabinet or touch gas lines or wiring
Diagnostic fees most often run $85 to $95
Ask for an itemized written quote for the repair

Before you hire, look up the company on the Arizona Registrar of Contractors search at roc.az.gov/before-hire. Confirm the license is active, that the class (R-6, CR-6, B-5 or KA-5) covers the work, and check bond and Recovery Fund status.

Ask directly: "Does your license cover the gas or electrical part of this repair, or will someone else handle it?" Our guide to Arizona pool license classes explains the differences.

Checklist

Before you hire a pool technician

0 of 6 ticked

Look up the company on the ROC search
Confirm the license is active
Confirm the class covers the work
Check bond and Recovery Fund status
Ask for a written contract with the license number if the job is over $1,000
Ask for proof of workers' compensation

Tick them off as you go. Nothing is saved or sent.

Jobs over $1,000 need a written contract showing the license number and the ROC complaint notice. "Licensed, bonded and insured" in an ad proves nothing, so ask for proof of workers' compensation.

For diagnosis in Phoenix, Mesa, Scottsdale, Tempe, Chandler and Gilbert, see pool heater repair.

Pool heater not heating FAQ

How to make a pool warmer without a heater?

Use a solar cover, add solar heating, and reduce evaporation. Keeping the pool covered when idle, especially overnight, holds in the heat you already have.

Why does my pool heater not ignite?

Check flow first, then the gas supply (handle open, propane level) and any error code. Ignition parts sit inside the cabinet, so repeated failures or clicking without a flame mean a licensed technician.

Why is my heat not getting up to set temperature?

Confirm the setpoint, mode and run schedule, then check flow and the cover. Undersized equipment, cool nights and heat pump limits can also keep the pool short of the target.

How warm should water be coming out of a pool heater?

Only mildly warm. Each pass adds a limited rise, and your manual lists the rated figure for your model.

Why is my pool heater on but the water is cold?

The display can be lit while the burner or compressor is locked out for low flow, a code or a closed gas supply. Check the pump, filter, valves, bypass and fault code.

Can a dirty pool filter stop a heater from working?

Yes. A clogged filter restricts circulation enough that the flow or pressure switch can keep the heater from firing. Clean it safely, then retest.