Tankless Water Heaters: Worth It, With Eyes Open
Endless hot water and a wall instead of a cylinder. The unit is the easy part, the gas line, the vent and the annual descale are where the honesty is required.
A tankless retrofit is planned work. Quote it before the old tank fails, not after.
The principle
No storage, no standby loss, no running out
A tank keeps forty or fifty gallons hot around the clock in case you want some. A tankless unit heats water only while it is flowing: you open a tap, a flow sensor fires a modulating burner or element, and water passes through a heat exchanger on its way to the fixture. Close the tap and it stops.
The consequences follow from that. There is no standby loss, so efficiency is higher. There is no finite reservoir, so a long bath does not exhaust the supply and the fourth shower is as hot as the first. And there is no forty-gallon cylinder of water in your house waiting to fail, which, if you have ever replaced a ceiling, is a real benefit.
The trade-offs also follow. Output is limited by flow rate rather than volume, so demand at the same instant is what constrains it. There is a short delay while the burner fires and the exchanger comes up to temperature. And a very low flow, a barely-open tap. May not trigger the unit at all.
Georgia's incoming water temperature helps here. Groundwater arriving at a mild temperature rather than a near-freezing one means a given unit delivers more usable flow than it would in a northern state. Sizing still has to be done properly, but the climate is on your side.
Sizing
Gallons per minute, and temperature rise
Two numbers again, and neither of them is capacity. Flow rate in gallons per minute is how much water the unit can deliver at once. Temperature rise is how much it can raise the incoming water's temperature at that flow, and the two trade against each other. Any unit delivers less flow at a higher rise.
Rough fixture demands: a modern shower 1.5 to 2.5 gpm, a kitchen tap 1.5 to 2.2, a bathroom basin 1 to 1.5, a bath filling 4 or more. A household wanting two simultaneous showers plus a kitchen tap needs roughly 5 to 6 gpm at a Georgia winter rise, which is a large residential gas unit, not a small one.
Winter is what sizes the unit. Incoming water is coldest in January and February, so the required temperature rise is highest exactly when demand is highest. A unit sized on summer performance disappoints in winter, and that disappointment is the single most common complaint about tankless systems, almost always a sizing failure rather than a technology failure.
Electric tankless deserves a specific warning. Whole-house electric tankless units draw enormous current, frequently well beyond what a typical Georgia residential panel and service can supply without an upgrade. They work well for a single fixture or a remote outbuilding. For a whole house, gas is usually the realistic option.
Undersizing is the mistake that gets made
Ask what flow rate the proposed unit delivers at a 70°F rise, not at its headline maximum. The headline number is measured at a small rise nobody experiences in a Georgia February.
The real cost
What a retrofit actually involves
The unit price is what gets advertised. The install is what the bill is made of, and on a tank-to-tankless conversion the install is substantial. None of this is a reason not to do it. It is a reason to know before you commit.
Usually a bigger line
A tank heater might draw 40,000 BTU. A whole-house tankless unit can draw 180,000 or more, on demand. The existing half-inch branch is frequently inadequate, so the work often means a larger line back towards the meter, and sometimes a meter upgrade from the gas utility. This is the biggest single variable in the quote.
New, and not the old flue
Condensing tankless units vent through sealed stainless or approved plastic pipe, usually horizontally through a wall, with specific clearances from windows, doors and soffits. The old atmospheric flue cannot be reused. Where the unit sits determines how hard this is.
Acidic water needs a drain
Condensing units produce condensate that is mildly acidic and must be drained, often through a neutraliser. That means a drain within reach or a condensate pump, and it is a detail commonly skipped on cheap installs.
Isolation valves and, often, a filter
Service valves either side are essential. They are how the unit gets descaled, and without them annual maintenance becomes a plumbing job every time. Where water is hard, a sediment filter or softening is worth considering to protect the heat exchanger.
Even gas units need power
Modulating burners, fans and controls need a receptacle at the unit. It also means a gas tankless unit does not produce hot water in a power cut, unlike an old standing-pilot tank, worth knowing if outages are common where you live.
Gas, vent and plumbing all inspected
A conversion touches gas piping, venting and water piping, and it is permitted and inspected work throughout Georgia. That is a feature: gas sizing and vent termination are exactly the things you want a second set of eyes on.
Ask for the gas line and venting scope in writing. That is where quotes genuinely differ.
Get a Tankless QuoteStraight answers
Good candidates, and poor ones
Worth it when:
- You run out of hot water regularly and the household schedule is not going to change.
- Space matters, reclaiming a closet, or freeing a garage corner.
- The heater sits above finished space and you would rather not store forty gallons up there.
- You are already opening walls, running gas, or building an extension. Marginal cost is far lower with access.
- You are staying in the house long enough for the efficiency to matter, and you will actually descale it.
Think harder when:
- The existing tank has just failed and you need hot water today. A conversion is not an emergency job; replace like-for-like now and convert on your own schedule if you still want to.
- Gas supply would need major work back to the meter and demand is modest.
- You are considering whole-house electric tankless without a service capable of supporting it.
- Hot water demand is low. Two people in a small house with one bathroom may never recover the install premium.
- You will not maintain it. An undescaled unit in hard water underperforms and fails early, and that is a self-inflicted outcome.
A middle option worth knowing about: a hybrid heat pump tank. Much of the efficiency benefit, ordinary venting, no gas work, and it keeps the storage buffer. In a Georgia garage or basement it is frequently the better value upgrade. See water heater installation.
Ownership
Descaling is not optional
A tankless unit passes all your water through a narrow heat exchanger at high temperature. Minerals precipitate there. Scale reduces flow and heat transfer, makes the unit work harder, and eventually causes it to throw error codes and shut down. The fix is an annual descale, circulating a mild acid solution through the exchanger via the isolation valves, which takes about an hour.
- Annually where water is moderately hard; more often where it is harder. Much of Georgia is moderate, but well water varies enormously. See water filtration and treatment.
- Clean the inlet filter at the same time. A blocked screen looks exactly like a failing unit.
- Keep the vent terminal clear of nests, leaves and shrubbery, and check it after storms.
- Note the error codes. Modern units self-diagnose accurately, and the code on the display saves the plumber diagnostic time. Write it down before you reset.
- Winter care. Most units have built-in freeze protection that requires power. If a hard freeze coincides with an outage and the unit is on an exterior wall, the exchanger is at risk. See freeze protection.
Maintained properly, a tankless unit commonly runs twenty years, roughly double a tank's life, with parts that are individually replaceable rather than a single cylinder that either holds water or does not.
Annual descale keeps the warranty valid and the flow where it should be.
Book Tankless ServiceQuestions we get on the phone
Answered plainly
It will not run out, but it is limited by how much it can deliver at once. Sized correctly for your simultaneous demand it feels endless. Sized too small it delivers hot water indefinitely at a lower flow, which is why undersizing produces disappointment in a Georgia February when the required temperature rise is highest.
A tank-to-tankless conversion usually needs a larger gas line back towards the meter, brand-new sealed venting through a wall, a condensate drain with a neutraliser, isolation valves and a receptacle at the unit, plus permits and inspection for gas, vent and water. The gas line is the biggest variable, and it is the item to get specified in writing.
For a single fixture or an outbuilding, yes. For a whole house, whole-house electric tankless units draw very high current, often beyond what a typical Georgia residential service and panel can supply without an upgrade. Gas is usually the realistic whole-house option.
Yes, and it matters. An annual descale through the isolation valves clears mineral scale from the heat exchanger, and the inlet filter should be cleaned at the same time. Skipped descaling reduces flow, causes error codes and shortens the unit’s life. It is the main reason a tankless install disappoints its owner.
Commonly around twenty years with annual descaling, roughly double a conventional tank. Individual components (the fan, the igniter, the flow sensor, even the heat exchanger) are replaceable, so the unit does not reach a single point where it either holds water or does not.
Usually not in an emergency. A conversion involves gas, venting and permits, so it is planned work, and doing it under pressure with no hot water in the house is how corners get cut. Replace like-for-like now if you need hot water today, then price a conversion properly on your own schedule.
Thinking about going tankless?
We will size it for a Georgia winter and put the gas and vent scope in writing before you commit.
(866) 559-0826