Going tankless usually means a bigger gas line
Converting a house from a tank to tankless is real work. The unit is the easy part. The gas supply and the venting are where the job actually lives.
Here is the thing nobody mentions in the showroom. A fifty gallon tank heater sips gas slowly and stores the result. A tankless unit has no storage, so it has to produce all that heat the instant you open a tap, which means it burns gas at several times the rate the tank ever did. Your existing gas line was sized for the tank.
So a conversion is usually a gas project as much as a water heater project. The line from the meter has to be capable of delivering that volume at the right pressure while the range and the dryer are also running. Sometimes that means upsizing the run, sometimes a dedicated line, occasionally a conversation with the gas supplier about the meter itself. We do that gas work ourselves, which is why the two ends of this job do not end up as two contractors blaming each other.
Venting is the second half. Tankless units do not use the old atmospheric flue from a tank heater. They need their own sealed venting in the correct material, run the correct way, with condensate drainage on a condensing unit. Reusing an old flue is not an option, and anybody who tells you otherwise is going to leave you with a problem.
Reasons people make the switch
- The tank runs out during back to back showers on a full house
- You want the closet or garage floor space the tank is occupying
- A rental property fills up on weekends and empties midweek
- The existing tank is due for replacement anyway and it is a natural moment
- You would rather not have fifty gallons of water sitting on a finished floor
- You want the heater to stop paying to keep water hot at three in the morning
A tankless unit burns gas several times faster than the tank it replaces. The pipe has to keep up.
What a conversion actually involves here
Gas sizing comes first, and it is arithmetic rather than opinion. We total the demand of every appliance on the system, measure the length and the developed run of pipe from the meter, and work out whether the existing line can carry the new load. If it cannot, the line gets upsized. Undersized gas is why some converted homes get an underperforming unit that faults under load, and it is entirely avoidable at install time.
Venting comes second. Condensing tankless units run cool enough exhaust to use sealed plastic venting, and they produce acidic condensate that must be drained properly. Non condensing units need stainless. Either way the route, the termination clearances and the slope all matter. In tight coastal construction along 30A, finding a clean vent path is often the thing that shapes where the unit ends up hanging.
Then water. Because our supply is drawn from wells and carries dissolved mineral, scale management is part of a good tankless install rather than an afterthought. That means isolation valves installed from day one so the unit can actually be flushed, and an honest conversation about how often. Installing a tankless unit with no way to service it is setting up a failure a few years out.
Upsized gas run and sealed venting feeding a newly converted tankless unit in Santa Rosa Beach.
Get it looked at
Ask us what your gas line can actually carry before you buy a unit. That one answer decides whether a conversion makes sense for your house.
- Answered 24 hours, 7 days
- Licensed CFC1429646 and CMC1250426
- Repair first, always
Maintenance plans from $16 a month keep this kind of thing from becoming an emergency.
The conversion, start to finish
- Demand and gas load survey
We work out the flow rate you need at our incoming water temperature, then total the gas demand of the whole house so we know what the pipe has to carry.
- Gas line plan
Upsize the existing run, add a dedicated line, or confirm what is there is genuinely adequate. You hear which one before any commitment.
- Vent route and mounting
Where the unit can hang, how the vent gets out, termination clearances and condensate drainage. This often decides the final location.
- One number, both trades
Unit, gas work, venting, valves, permit and labor in a single quote from a single licensed contractor. No second bill from somebody else.
- Install and permit
Gas work, mounting, water connections with isolation valves, venting and condensate, all inspected where a permit applies.
- Commissioning
We test temperature rise at multiple flow rates and with multiple fixtures open, set the target temperature, and show you how to flush it.
Tank to tankless conversions across the Emerald Coast
We convert homes in Freeport, Santa Rosa Beach, Point Washington, Grayton Beach, Seaside, WaterColor and Inlet Beach, plus Miramar Beach and Destin. Conversions are especially popular in vacation rentals along 30A, where a house sits empty midweek and then has to serve a full occupancy Saturday. A correctly sized tankless handles that curve far better than a tank does, provided the gas line was upsized to match.
Inland we work through DeFuniak Springs, Paxton, Ponce de Leon, Vernon, Ebro and Choctaw Beach, and west into Niceville, Valparaiso and Eglin Air Force Base. Older inland homes often have small original gas runs that were only ever meant to feed a tank heater and a range, so the gas portion is a bigger share of the job there. We will tell you that up front, because finding out halfway through is nobody’s idea of a good day. Both certifications, plumbing CFC1429646 and mechanical CMC1250426, sit with the same person here.
Towns we get to most: Freeport, Santa Rosa Beach, Point Washington, Miramar Beach, Niceville, Destin, Eglin Air Force Base, Valparaiso, Ebro, Vernon, Caryville. See the full service area.
Questions we get about this
Do I definitely need a new gas line?
Not always, but frequently. It comes down to the total demand of your appliances and the length and diameter of the existing run. We measure and calculate rather than guessing, and if the existing line is genuinely adequate we will tell you and leave it alone.
Can the new unit vent through the old water heater flue?
No. A tank heater’s atmospheric flue and a tankless unit’s sealed venting are different systems in different materials. The tankless unit gets its own vent, correctly sized and terminated. This is a safety item, not a preference.
Will I really save money?
You will stop paying to keep a tank hot around the clock, which is a genuine saving, particularly in a house that sits empty part of the week. Whether that offsets the conversion cost depends on your usage and how much gas work is involved. We will lay out the actual picture for your house rather than quoting a brochure number.
Is one unit enough for a big house?
It depends on how many fixtures run at once and the temperature rise we need. Large homes sometimes need a higher capacity unit or two units in sequence. We calculate that from your fixture count and layout rather than assuming.
What maintenance does it need afterwards?
A periodic descaling flush, and on our well drawn supply that matters more than the manual assumes. We install isolation valves so it can actually be done, and we will show you how or handle it on a plan.
Are you doing the gas work, or is that somebody else?
We do it. Noah holds Florida plumbing certification CFC1429646, and gas line installation is our own work. One contractor, one quote, one accountable party if something needs revisiting.
Related plumbing work
- Water Filtration
- Gas Line Installation
- Gas Line Repair
- Repiping
- Bathroom Plumbing
- Kitchen Plumbing
- New Construction Plumbing
- Plumbing Inspection
- Hydro Jetting
Not seeing it? The full list is on the plumbing page, or just call 850-318-5777 and describe it. You can also see the work or send a note.