Heat Pump, Gas, or Electric? Choosing a Pool or Spa Heater Your Sarasota Home Can Actually Power | CoHarbor Electric

A couple in Englewood called us last November with a box sitting in their garage. It was an electric pool heater they’d ordered online. There was no natural gas on their street, they didn’t love the idea of a propane tank in the yard, and electric seemed like the simple choice. Plug it in, basically.

Then they read the installation manual. The heater was rated at 27 kilowatts. At 240 volts, that’s roughly 112 amps. Their whole house ran on a 150-amp service.

We had a pretty honest conversation in that garage. The heater could be installed, technically, but only with a service upgrade, multiple dedicated circuits, and an electric bill that would’ve made them want to drain the pool by February. They ended up returning it and going with a heat pump instead, which needed a single 50-amp circuit their panel could handle.

Nobody warned them. Heater shopping tends to be all about BTUs, how fast the water warms up, and price. What the heater needs from your electrical system barely comes up, even though it’s often what decides whether the install costs a few hundred dollars or a few thousand.

So let’s go through the main options from the electrician’s side of things.

Why the Heater Is the Biggest Electrical Decision on Your Pad

On most Sarasota pools, the pump runs on a 15- to 20-amp circuit. Lights and automation are small. The heater is the wild card. Depending on what you pick, it might add almost nothing to your electrical load or more than your air conditioner.

That matters because a home’s panel and service only have so much room. Before we add any major load, we run a calculation under NEC Article 220 to see whether the existing service can carry it. With heaters, the answer swings a lot depending on the type.

Gas Heaters: Small Electrical Footprint, Other Trade-Offs

Gas pool heaters, whether they run on natural gas or propane, barely touch your electrical system. They need power for the igniter, the control board, and on some models a small blower. That’s usually a few amps at 120 or 240 volts. In many setups it’s a small dedicated circuit at the pad.

From a wiring standpoint, that’s about as easy as it gets.

Where Gas Makes Sense

Gas heats water fast. That’s why it’s so popular for spas. If you want to go from cool water to hot tub temperature in under an hour on a January evening, gas does it better than anything else. At a home in Sorrento Shores, the owners use a heat pump to keep the pool comfortable and a small gas heater just for the spillover spa. It’s a combination we see a lot around Sarasota, and it works well.

The Catch

The catch is the gas itself. Natural gas lines don’t reach a lot of Sarasota neighborhoods, especially on the barrier islands and in parts of south county. That means a propane tank, with its own placement rules, delivery schedule, and operating cost. The gas line work is handled by a licensed gas or plumbing contractor, not us. What we handle is the electrical feed and bonding. Gas heaters have metal parts that tie into the pool’s bonding system under NEC Article 680 like any other equipment on the pad.

Heat Pumps: The Sarasota Workhorse

Heat pumps are the most common pool heaters we wire in Sarasota County, and there’s a good reason for that. They work like an air conditioner in reverse, pulling heat out of the air and moving it into the water. They use far less electricity than an electric resistance heater doing the same job, often somewhere around a fifth of it under good conditions.

They also work best when the air is warm. Sarasota winters are mild enough that a heat pump does well most of the season. On the handful of genuinely cold nights, they slow down, but most people barely notice.

What a Heat Pump Needs Electrically

This is where the planning comes in. A residential pool heat pump typically needs a dedicated 240-volt circuit somewhere in the 30- to 60-amp range, with 50 amps being common. The exact breaker size comes from the unit’s nameplate, which lists the minimum circuit ampacity and maximum overcurrent protection. We follow that nameplate exactly. Undersizing it leads to nuisance tripping. Oversizing it removes protection the manufacturer is counting on.

At a home in South Venice, the previous installer had put a new heat pump on a 30-amp circuit left over from an old heater. The nameplate called for 50. It ran fine in October. The first cold week in January, when the compressor was working hardest, it started tripping the breaker every night. The owner assumed the unit was bad. It wasn’t. We ran a properly sized circuit and it’s been fine since.

Salt Air and Placement

A heat pump’s coil pulls in a huge amount of outdoor air, and near the Gulf that air carries salt. Coastal-rated or coated coils are worth it here. So is placement. We want the unit where it gets good airflow, isn’t blasted by irrigation, and has its disconnect within sight and easy reach. We’d rather talk through placement before the pad is poured than after.

Panel Capacity

A 50-amp heat pump is a real load. On a lot of Sarasota homes with 150- or 200-amp service, it fits without trouble. On older homes with 100-amp service that already run central AC, an electric water heater, and a dryer, it may not. If the numbers don’t work, the honest answer is a panel or service upgrade, which typically runs in the $1,800 to $4,500 range, and it may involve coordinating with FPL. We cover that side of things in more depth in our guide to smart electrical upgrades for Sarasota homes with pools, EVs, and outdoor living.

Electric Resistance Heaters: Simple Idea, Heavy Load

Electric resistance heaters work like a giant version of the element in your water heater. There’s no compressor and no combustion, just a heating element and a lot of current. They heat water steadily no matter the air temperature, and the units themselves are relatively inexpensive.

The trade-off is the electricity. A small 5.5-kilowatt spa heater draws about 23 amps at 240 volts, which is manageable. Full-size pool heaters are another story. Units in the 11- to 27-kilowatt range can pull anywhere from about 45 to more than 110 amps, like the one in that Englewood garage.

What the Code Adds

NEC 680.10 has specific rules for electric pool water heaters. Among other things, heaters drawing more than 48 amps have to have their heating elements split into separate circuits, each no more than 48 amps, with overcurrent protection sized accordingly. So a big resistance heater isn’t one circuit. It’s often two or three, each with its own breaker. That means more panel spaces, more wire, and a real load calculation before anybody commits.

Where Resistance Heat Makes Sense

Honestly, for whole-pool heating in Sarasota, resistance heat rarely makes sense. Heat pumps do the same job for a fraction of the operating cost. Where resistance heaters earn their place is small volumes: a self-contained hot tub, a small attached spa, or a situation where a heat pump won’t fit. Most standalone hot tubs already have a resistance heater built in, and we cover wiring those in our guide to wiring a hot tub on your Sarasota lanai or patio.

Quick Comparison From the Electrical Side

If you boil it down, gas heaters need the least from your panel, often a small circuit and a few amps, plus a gas supply you may not have. Heat pumps sit in the middle, usually one 240-volt circuit around 50 amps, with the lowest operating cost for most Sarasota pools. Electric resistance heaters need the most, from about 23 amps for a small spa heater to more than 100 amps split across multiple circuits for a full pool unit.

Solar pool heating is also worth a mention. The panels themselves need no electrical service, though the system may need a small controller or valve actuator, and your existing pump does the work. It’s a nice complement in Sarasota, but it’s weather-dependent and not usually a spa solution on its own.

Mistakes We See Before and After Heater Installs

Most heater problems we get called about start at the ordering stage. The common ones:

• Buying a heater before anyone checks what the panel can support
• Reusing an old heater circuit for a new unit with a different nameplate rating
• Ordering a large electric resistance heater without realizing it needs multiple circuits
• Placing a heat pump where it can’t breathe, or where the disconnect is hard to reach
• Forgetting to bond the new heater into the pool’s bonding system
• Skipping the permit because the heater “just replaces” the old one

That last one catches people. Heater installs in Sarasota usually need an electrical permit through Sarasota County, or the City of Sarasota inside city limits, and gas units need their own gas permit through the contractor running that line. Unpermitted heater work has a way of turning up during a home sale or an insurance inspection.

Talk to Us Before You Buy the Heater

If there’s one thing we’d ask, it’s this. Call an electrician before the heater gets ordered, not after it’s sitting in the garage. It takes us one visit to look at your panel, run the numbers, and tell you which options actually work for your house.

Get Your Sarasota Pool Heater Wired Right by Coharbor Electric

Whether you’re leaning toward a heat pump, adding a gas heater for the spa, or trying to figure out if electric is even realistic, Coharbor Electric can help you sort it out. We’re licensed and insured, and we install and upgrade pool and spa heater circuits throughout Sarasota County, from Englewood and South Venice to Sorrento Shores and the neighborhoods in between.

We’ll check your panel, tell you honestly what it can handle, and wire your heater to its nameplate and to code, with the permit and inspection handled. We can’t pick your water temperature for you. We can make sure the heater you pick has the power it needs. Give Coharbor Electric a call to schedule a pool heater electrical assessment.