Tankless Water Heater Repair & Installation in Alpharetta, GA

The most common complaint about a tankless water heater often has nothing to do with a broken part. The heater works, yet it cannot keep up when two showers and the dishwasher run together. In Alpharetta homes with several bathrooms, that usually comes down to sizing: how many gallons per minute the unit can heat, and by how many degrees. Our Georgia water heater overview describes the other heater types. With a tankless unit, the real question is how well it is matched to the household, and what to do when the match is off.

Flow rate and temperature rise, in plain terms

A tankless unit's capacity is a trade-off between two numbers. Flow rate is how much hot water leaves the heater each minute. Temperature rise is the gap between the water coming in and the temperature you set. Because the heater has a fixed maximum output, the more degrees it must add, the fewer gallons per minute it can deliver at that temperature.

That explains why the same heater can feel generous in August and stingy in January. Incoming water is colder in winter, the required rise climbs, and the flow the unit can fully heat shrinks. A rating at one temperature rise says little about performance at another; the manufacturer's full performance chart does.

Adding up what the house actually uses

Sizing starts with the fixtures likely to run at the same moment, not the total count in the house. A realistic peak might be two showers and a kitchen faucet on a weekday morning, or a tub filling while the washer runs. Each fixture's flow rate is printed on it or listed by its maker, and older showerheads often use noticeably more than newer ones. Total the peak fixtures, compare that figure with the heater's capacity at your winter temperature rise, and whether one unit is enough usually becomes clear.

Signs your current unit is undersized

• Water turns lukewarm as soon as a second hot fixture opens, then recovers when it closes.
• The heater trims the flow to protect temperature, so a shower that started strong weakens.
• A large tub cannot be filled hot unless other use stops.
• The shortfall is worse in winter and nearly vanishes in summer.

The same symptoms can come from scale in the heat exchanger, a clogged inlet screen, a gas supply that cannot feed the burner at full fire, or a shower valve that mixes poorly. Those get checked first, because correcting them costs less than a second heater. Low incoming pressure can also cap the flow; if pressure is the suspect, our water pressure and PRV service covers the testing.

Options when one unit cannot keep up

Once the heater is confirmed healthy and simply too small, there are a few paths:

1. Replace it with a larger unit, provided the gas supply, venting and electrical can support the higher input.
2. Add a second unit linked to the first, so both fire at high demand and take turns at other times; manufacturers sell linking kits and manifolds for this.
3. Trim peak demand with lower-flow showerheads, or by moving a habitual long tub fill to a quieter hour.
4. Return to stored hot water, where a tank's reserve suits the household better; that route is covered by our gas water heater repair and installation service.

Permits and inspections in Alpharetta

Upsizing a tankless heater can touch plumbing, gas piping and sometimes electrical work. In the city, Construction and Inspections staff in Community Development issue plumbing and electrical permits. That office can confirm what a larger unit at your address needs, and the permit is generally in hand before the new heater goes in.

Questions about tankless sizing in Alpharetta

How many gallons per minute does a family need?

It depends on which fixtures run together, not on the number of people alone. Showerheads sold in the U.S. are capped at 2.5 gallons per minute and many use less, while kitchen faucets run a little lower, so two showers and a sink can call for roughly five to seven gallons per minute. Compare that peak with the heater's chart at your winter temperature rise.

How do I find my heater's capacity at winter temperatures?

Look up the performance chart for your model in the installation manual or on the manufacturer's website; it lists the flow the unit can heat at several temperature rises. To estimate your winter rise, run a cold tap for a minute on a January morning, measure the water with a kitchen thermometer and subtract that reading from your set temperature.

Will a bigger tankless heater fix lukewarm water at one far bathroom?

Not necessarily. Lukewarm water at a single distant fixture is often a delivery problem: hot water cooling in a long pipe run, or a fixture flowing below the heater's minimum activation rate. A recirculation setup or a small point-of-use heater may solve it where a larger main unit would not.

Planning a sizing visit

List the bathrooms, any large soaking tub and the times of day hot water runs short. Note the heater's model from its label and whether the shortage changes with the season. With that in hand, we can tell whether repair, a second unit or a different heater is the sensible step.

Wondering whether your Alpharetta heater is the right size? Reach Alpha Plumbing and Sewer at (404) 409-4448 and we will work through the numbers with you.