When It’s Time to Upgrade

If the hot water runs out before everyone has showered, your bills have crept up for no obvious reason, or repairs on the old tank are adding up, tankless is worth pricing. A unit mounts on the wall, frees up the closet or the corner of the garage, and heats water as it passes through rather than keeping fifty gallons hot around the clock.

Navien and Rinnai are the two we install most. Both are solid, both are serviceable, and parts are easy to get, which matters more than it sounds when something fails on a Friday.

What a Conversion Actually Involves

Going from a tank to tankless is not a like-for-like swap, and this is the part people are not expecting. A gas tankless unit burns at a far higher rate than a tank, so it usually needs a larger gas line run back toward the meter. It needs its own sealed venting rather than the old flue, which means a new penetration through a wall or roof. It needs a condensate drain. And it needs mounting somewhere that makes sense for both the gas and the vent.

None of that is difficult work, but it is most of the gap between the price of the unit and the price of the job. We look at your gas line and where the heater would go before quoting, rather than giving you a number over the phone and revising it in your hallway.

Descaling and Maintenance

This is the single thing that decides how long a tankless unit lasts around here. Nashville water is hard, and scale builds up inside the heat exchanger where you cannot see it happening. Left alone it restricts flow, makes the unit work harder for the same hot water, and eventually takes the exchanger with it. We have replaced tankless heaters that failed for no other reason.

Flushing once a year is usually enough for a house. If you are on well water, or there is no treatment on the incoming line at all, it wants doing more often. If you would rather deal with the cause than the symptom, water softening or a salt-free conditioner stops the scale forming in the first place. That is exactly what we fitted alongside a new Navien in West Nashville, after hard water had already killed the tankless unit that was there.

Repair or Replace a Tankless Unit

Tankless heaters are repairable in a way that tanks often are not. Flame rods, igniters, sensors, gaskets and control boards are all serviceable parts, and a unit throwing an error code is usually telling you which one. We brought a Rinnai back in Nashville recently by replacing the flame rods on the unit that had stopped firing.

The exception is the heat exchanger. If that is cracked, or scaled past recovery, the economics change fast, because the exchanger is most of what you paid for the unit. On a heater already ten years old or more, replacing it is usually the better call. A cracked exchanger on a unit still in warranty is a different conversation, so it is worth knowing what yours is covered for before anyone quotes you a new one.