October through May
Heater season is the longest season we have.
Central Texas gives you a swimmable pool about four months a year without a heater, and about ten with one. The catch is that our water is hard on heat exchangers, and most heaters here die of chemistry, not age.
Before the first cold night
Nobody thinks about the heater until the day they want it, which is the worst possible day to find out it doesn't work.
- Fire it up in early October, not in December. Finding a problem when you don't need it yet is the whole point.
- Look for scale on the heat exchanger — that's the number one killer in our water
- Check for rodent damage and wasp nests inside the cabinet. Extremely common here after a summer of not running.
- Confirm the pressure switch and flow are right. Most 'heater won't fire' calls are actually flow problems.
- Read the error code, if there is one, before anyone touches anything
- Check the gas line and the vent path are clear on gas heaters
- Verify filter pressure is normal — a dirty filter starves a heater and it will refuse to run
- Confirm the bypass valves at the pad are actually set to send water through the heater
Why heaters fail early around here
It's almost always water chemistry, and it's almost always preventable.
Central Texas fill water is hard and alkaline. Left alone, calcium comes out of solution and deposits on the hottest surface in the system — which is the inside of your heat exchanger. Scale insulates it, so the heater burns more fuel for less heat, runs hotter, and eventually fails.
Push the other direction and it's worse in a different way. Water that's aggressive on the LSI scale pulls metal out of a copper heat exchanger and you get pinhole leaks. Either extreme kills the most expensive item on the pad.
This is the practical reason LSI balancing matters and why a chemistry report with real numbers on it is worth having. A heater is a multi-thousand-dollar piece of equipment whose lifespan is decided almost entirely by the water you run through it.
What it costs to run
Rough expectations, so nobody gets a surprise bill.
Gas heater
Fast — it will heat a pool in hours. Expensive to run continuously, which is why most people here use one for weekend heating rather than holding temperature all season.
Heat pump
Much cheaper per degree, but slow, and it loses efficiency as the air gets colder. Great for holding a temperature October through November and again in March, less useful in a January cold snap.
Cover
The unglamorous answer. Most of a heated pool's heat leaves through the surface overnight. A cover cuts heating costs more than any equipment decision you'll make.
A practical tip that saves real money: heat to swimmable, not to warm. Most people find 86–88°F comfortable. Every degree above that costs noticeably more, and going from 88 to 92 roughly doubles what a lot of owners expect to pay.
Cold water changes everything else too
Even without a heater, your pool behaves differently below about 65 degrees.
Salt cells slow down. Most stop producing entirely below roughly 60°F. That's normal, not a fault — but it means your chlorine has to come from somewhere else for a couple of months.
LSI targets shift. Cold water is naturally more aggressive, so the balance that was right in July is not right in January.
Run time comes down. Cooler water needs less circulation, and this is the one time of year when a free-nights energy plan genuinely works in your favor.
Freeze protection matters more than the heater. A heater doesn't protect anything from a hard freeze. Moving water and a tested freeze setting do.
What we can and can't do with a heater
Straight boundaries, same as everything else.
In house: chemistry that protects the heat exchanger, filter and flow work that lets the heater run, checking valve configuration and bypasses, reading error codes, spotting scale and corrosion early, and wet-side plumbing around the unit.
Referred out: gas line work, high-voltage and panel-side electrical, and heater installation or replacement. Those need the right license and you deserve someone who has it.
Get the heater checked before you need it
A seasonal tune-up covers the heater, the pad, the flow, and the chemistry that keeps all of it alive. Best booked in early fall.