How Much Does Tankless Installation Cost?
Tankless water heater installation costs $1,400 to $5,600 for most homes, and typical installed jobs land between $2,600 and $2,800. On gas installs, the step between the two common Rinnai sizes, 160,000 and 199,000 BTU, runs about $350.
| System | Installed Range |
|---|---|
| Electric whole-house tankless | $800–$3,000 |
| Gas non-condensing tankless | $1,400–$3,800 |
| Gas condensing tankless | About 25% above a non-condensing tankless install; the unit itself adds $200–$500 |
This table shows installed tankless water heater totals by system, with condensing models priced as a premium over standard gas units. Local quotes generally fall within these same price ranges. Tampa Bay electric tankless installs run $1,278 to $2,264, gas installs run $2,854 to $4,574, and a like-for-like gas tankless swap runs $2,400 to $3,000.
Three line items push a tankless installation above a standard tank swap, and each one is a requirement covered further down this page. Venting adds $100 to $1,000, upsizing the gas line adds $300 to $2,000, and a whole-house electric tankless unit may require a dedicated electrical circuit. FL Water Heater Pros does not perform electrical upgrades or interior wiring for additional circuits. When electrical work is needed, we can coordinate with our electrical partner, or you can use a licensed electrician of your choice. Any required electrical work would be handled separately from our tankless installation. A first-time conversion from a tank to a tankless water heater adds $1,000 to $1,500 over a like-for-like swap because the gas, venting, and piping are being built rather than reused.
What Does the Installation Process Look Like?
A professional tankless water heater installation in St. Petersburg follows five steps, and at FL Water Heater Pros, the owner performs the installation.
Every tankless install includes the permit, a pressure test, the inspection, and haul-away of the old unit.
Remove the old water heater.
We drain and disconnect the existing tank or tankless unit and haul it away as part of the installation price.
Mount the tankless unit.
The wall location is set for service access, vent routing, and drainage, and then the tankless water heater is anchored to the structure.
Connect the water lines with isolation valves.
Isolation valves on the hot and cold connections let the tankless unit be flushed and serviced later without shutting down the house; repiping to the new connection points is the longest part of the job.
Run the gas line and venting, or confirm the wiring.
Gas tankless models get the gas connection and dedicated vent run; on an electric tankless install, we coordinate with your electrician, who has the dedicated circuit in place before mounting day.
Commission the system and register the warranty.
We pressure test the tankless installation, fire the unit, set the output temperature, and register the manufacturer warranty, which our labor warranty matches.
This diagram shows a wall-mounted tankless water heater with the isolation valves, vent termination, and condensate drain labeled.
What Does a Tankless Install Require in Florida?
A tankless water heater install in Florida may require a dedicated gas line, dedicated venting or an outdoor-mounted unit, adequate electrical service, a condensate drain on condensing models, and a permit. Five requirements decide most tankless quotes:
Dedicated gas line. A gas tankless water heater burns fuel faster than a tank, and the supply line in an older St. Petersburg home often needs upsizing to feed it.
Dedicated venting or an outdoor mount. An indoor gas tankless unit needs its own sealed vent run; Florida's climate allows outdoor-mounted tankless models, which skip long vent runs entirely and lower the install cost.
Electrical service. A gas tankless unit needs standard 120V power for its ignition and controls, while a whole-house electric tankless system draws enough amperage to require a 150 amp or larger panel plus the dedicated circuit your electrician installs.
Condensate drain. A condensing tankless water heater produces acidic condensate that must route to an approved drain.
Pinellas County permit. A permit is filed on every tankless water heater we install, and the inspection that follows is part of our standard process, never an extra.
Gas or Electric Tankless: Which Should You Install?
Gas tankless water heaters are preferred for most St. Petersburg homes with gas service: they carry the lowest operating cost of any water heater type and keep up with high-demand households. On gas installs we quote both common Rinnai sizes, and the step from the 160,000 BTU unit to the 199,000 BTU unit is modest, so most households take the larger burner; the 199,000 BTU gas tankless is the unit we expect to install most in St. Petersburg.
Electric tankless water heaters install for less, skip venting entirely, and fit homes without gas service. The scoping condition is your electrical panel: a whole-house electric tankless unit works when the electrical panel has the spare amperage for it, and when it does not, the cost of a panel upgrade changes the math in favor of gas. Want the full picture of how on-demand systems perform before choosing a fuel? Tankless Water Heaters: Pros, Cons & Whether They're Worth It in Florida covers both sides in depth.
Can You Install a Tankless Water Heater Yourself?
No. A gas tankless water heater should only be installed by a licensed plumber. Mistakes involving gas piping, venting, or combustion can cause carbon monoxide poisoning, fire, and a failed inspection.
A plug-in, point-of-use electric tankless water heater serving a single sink may be within the skill set of an experienced DIYer. Always follow the manufacturer’s instructions and applicable permit, electrical, and plumbing requirements.
Where exactly does Florida draw the legal line for homeowner water heater work? DIY vs. Professional Water Heater Installation: Florida Rules & Risks draws it clearly.
What Size Tankless Unit Does Your Home Need?
Your home needs a tankless water heater sized by flow rate: count the fixtures that run hot water at the same time and match the GPM band.
1 to 2 simultaneous fixtures: a 3.5 to 5 GPM tankless water heater
2 to 3 simultaneous fixtures: a 5 to 7 GPM tankless water heater
3 to 4 simultaneous fixtures: a 7 to 9+ GPM tankless water heater
A typical two-shower St. Petersburg home sits in the 5 to 7 GPM band, and Florida works in your favor here: warm incoming groundwater means a tankless unit delivers more flow at temperature than the same unit would up north. Sizing by bathrooms and occupants instead of guesswork keeps you from paying for capacity you never draw. Does your fixture count put you at the top the range What Size Water Heater Do I Need works the numbers room by room.
Is Tankless the Right Choice for Your Home?
Choose a tankless water heater when gas service is available, space is limited, and you expect to remain in the home long enough for its potential long-term benefits to offset the higher installation cost.
A tankless system provides continuous hot water and may last longer than a standard tank when properly installed and maintained. A traditional tank replacement, however, typically costs less upfront and may restore hot water during the same appointment.
The bottom line is that tankless may provide greater value over years of ownership, while a standard tank is usually the more affordable immediate option. Still deciding which system is right for your home?
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Choose a tankless water heater when gas service is available, space is limited, and you expect to remain in the home long enough for its potential long-term benefits to offset the higher installation cost.
A tankless system provides continuous hot water and may last longer than a standard tank when properly installed and maintained. A traditional tank replacement, however, typically costs less upfront and may restore hot water during the same appointment.
The bottom line is that tankless may provide greater value over years of ownership, while a standard tank is usually the more affordable immediate option. Still deciding which system is right for your home?
Tank vs. Tankless Water Heaters: Which Is Right for Your Florida Home? compares purchase price, operating cost, and fit.
We install Rinnai, Navien, and Rheem tankless water heaters, complete most tankless installations with Rinnai and Navien units, recommend Rinnai first for St. Petersburg homes, and list every line we work on under Water Heater Brands We Install & Service.