There is no universally better water heater. There is one that suits your property and one that does not, and the difference is usually decided by things nobody mentions in a showroom.
How your household actually uses hot water
This is the question that matters most, and it is rarely asked.
Concentrated demand — three people showering within an hour, the dishwasher and the washing machine running in the same window — suits a tank. A tank has a reservoir of hot water ready to go, and it does not care how many things want it at once until the reservoir runs out.
Spread demand — a couple, staggered schedules, hot water wanted reliably but rarely all at once — suits tankless. It heats on demand and never runs out, but it delivers a limited flow rate at any one moment.
The failure mode people complain about with tankless is almost always this: two showers at once in a property where the unit was sized for one.
What your property will actually allow
This is what decides it in practice, especially in a condo.
Tankless units need serious capacity — a substantial electrical supply, or a gas line sized for it. In a Brickell or Sunny Isles condo, the electrical service to the unit is frequently the deciding factor, and it is worth establishing before anyone gets attached to the idea.
Space cuts the other way. If a tank is genuinely in the way — taking a closet you need, or in a unit where the original closet was sized for something smaller — that is a real argument for tankless.
Venting and condensate matter for gas units, and both are harder to retrofit than to install originally.
Hard water, which affects both
Miami-Dade water is hard, and scale is what actually kills water heaters here, regardless of type.
A tank accumulates sediment on its floor. The symptoms are rumbling or popping noises, longer recovery times, and a shortened life. An annual flush genuinely extends it.
A tankless unit scales its heat exchanger, which is where all the work happens. Descaling is not optional maintenance here; it is the difference between a long life and a disappointing one.
Neither is maintenance-free. A tankless unit sold as “fit and forget” in South Florida has been sold badly.
Cost, honestly
We do not publish prices, and anyone quoting a water heater without seeing where it goes is guessing. What we can say about the shape of it:
Tankless costs more to install, sometimes considerably, and that gap widens when the supply needs upgrading. It usually costs less to run. It typically lasts longer if maintained and less long if not.
A tank is cheaper to install, cheaper to replace, and simpler for any plumber to service.
Whether the running saving recovers the installation gap depends on your usage and how long you stay in the property. That is arithmetic somebody should do with your numbers, not a claim from a leaflet.
The part that does not show
Whichever you choose, the installation is where the money either works or does not: strapping, expansion provision, relief valve discharge, drain pan and termination, isolation valves for future servicing.
Water heater work is inspected work in Florida for good reason. That is the part nobody sees and the part that matters most the day a unit eventually fails.
The short version
Ask how your household uses hot water, check what your property’s supply will carry, and budget for maintenance either way. Then choose. Both are good answers to different questions.
What has to be true before tankless is even possible
Three things decide it, and all three are about the building rather than the heater. A quote given without checking them is a quote that will change.
Gas supply. A tankless unit fires at several times the rate of a tank, all at once. The meter and the line have to carry that, and an existing line sized for a tank plus a range often does not. Upsizing the run is frequently the largest single item on a conversion, and it is the one people are not expecting.
Venting. Condensing units produce acidic condensate and vent through stainless or polypropylene, not through the flue that served the old heater. The run has to reach an exterior wall, and in a condo that is often the sentence the whole idea ends on.
Electrical. Even a gas unit needs power for its controls and fan. An electric tankless needs considerably more than that — commonly several dedicated high-amperage circuits, which means panel capacity, which means an electrician before a plumber.
Where each one genuinely wins
Tankless is the better answer for a household that showers in sequence rather than at once, for a property that is short of floor space, and for anyone who has had a tank fail and ruin something. It cannot run out.
A tank is the better answer more often than the marketing suggests: where the gas or the venting would have to be rebuilt, where two showers run at the same time every morning, and in a rental, where the deciding factor is what a tenant can live with and what the next plumber can repair in an afternoon.
The maintenance nobody mentions at the point of sale
Both want annual attention and they want different things. A tank wants flushing to clear sediment. A tankless wants descaling — a circulating pump and a mild acid run through the heat exchanger for an hour — and in Miami’s water it wants it yearly rather than optionally.
Skip it on a tank and you lose efficiency. Skip it on a tankless and you eventually lose the heat exchanger, which is most of the value of the unit. Ask about isolation valves at installation; without them the descale is a much longer job every year for the life of the appliance.