Tankless Water Heater in Illinois | 911 Plumbing IL
from $1,899
Plumbing Tankless Water Heater in Illinois
Installation and service of tankless water heaters — Navien, Rinnai, and Rheem. Endless on-demand hot water with correct gas-line sizing, venting, and condensate handling, plus descaling and error-code service for units already installed.
Tankless Water Heater is one part of our water heater services coverage in Illinois. For the full picture — symptoms, costs, and when to repair vs. replace — start with the complete Water Heater Repair guide, or browse every water heater services service we offer.
A tankless water heater heats water on demand as it flows through the unit, so it never runs out and never keeps 50 gallons hot around the clock waiting to be used — which is why families that constantly ran out of hot water and homeowners tired of an energy bill for standby heat both end up here. A tankless unit delivers endless hot water, lasts closer to 20 years versus a tank's 10-to-15, and hangs on a wall to reclaim the floor space a tank ate. Installed correctly, it's the last water heater upgrade most Illinois homes need for a long time.
The correctness is where tankless installs go right or wrong. On-demand heating draws a large burst of gas, so most conversions need a larger gas line and sometimes a meter upgrade; the high-efficiency condensing units need proper venting and a condensate drain with neutralizer; and the unit has to be sized to your climate's incoming water temperature and your peak simultaneous demand, or it delivers a disappointing lukewarm flow. We size by real demand and inlet temperature, run the gas, venting, and condensate to code, and commission the unit so it delivers its rated flow across Illinois — not the underwhelming trickle of an undersized install.
Tankless units also need service that a tank doesn't, and we do both sides. Hard water scales the heat exchanger over time, dropping output and eventually throwing an error code, so an annual descaling flush is what keeps a Navien or Rinnai performing — and when a unit does flash a code for ignition, flow, or scale, we read it, descale or replace the sensor, and clear it. Whether it's a new install, a conversion from tank, or service on a unit you already own, we handle the whole tankless picture across Illinois and Illinois.
Different job? Start on the right page:
Water Heater Repair — if your existing tank unit needs a fix, not a conversion.
A tank that can't cover back-to-back showers is undersized, and a tankless unit ends the problem with endless on-demand hot water. It's the most common reason Illinois homeowners make the switch.
You want the floor space back
A tank takes a sizable footprint in a closet, utility room, or basement, while a tankless unit hangs on the wall. The reclaimed space is a real win in a tight Illinois home.
Your energy bill carries standby heat
A tank reheats its stored water around the clock whether you use it or not. A tankless unit only fires when you draw hot water, cutting the standby waste for the Illinois home.
Your old tank is failing
When a tank reaches end of life, replacement is the natural moment to go tankless. We size and price both so the Illinois decision is informed, not rushed.
Your tankless is throwing error codes
A Navien or Rinnai flashing an ignition, flow, or scale code needs service, not replacement. We read the code and descale or repair it on the Illinois visit.
What's behind it — and how we fix it
Undersized existing tank
A tank spec'd too small for the household runs cold under simultaneous use, and no tank swap fixes back-to-back demand like on-demand heating does. It's the core reason for a Illinois tankless conversion.
Scale in the heat exchanger
Hard water deposits scale inside the heat exchanger, dropping output and eventually triggering error codes. An annual descaling flush is what keeps a Illinois tankless at full performance.
Undersized gas supply
Tankless units draw a large gas burst that an old undersized line can't feed, causing ignition faults and low output. Upsizing the gas line is often the fix behind a struggling Illinois install.
Ignition and flow-sensor faults
Igniters, flame sensors, and flow sensors wear and foul over years of cycling, throwing codes and dropping the unit out. We carry the common sensors for the Illinois service call.
Venting or condensate problems
A blocked vent or a clogged condensate drain shuts a condensing unit down on a safety fault. Clearing and correcting them restores the Illinois unit to service.
From call to fix — our process
1
Book by phone or online. Choose a 2-hour arrival window online or by phone for tankless water heater in Illinois; confirmation lands in under five minutes with the tech's name and photo attached.
2
Diagnosis at your door. The tech diagnoses your tankless water heater at the house — free on most repairs, $39 for minor service calls and waived if you proceed — and walks you through the issue and the fix before starting.
3
Flat-rate quote. You get a flat-rate tankless water heater quote in writing, good for 30 days — no hourly creep and no add-ons after the fact.
4
Fixed in one visit. The truck arrives stocked with the common valves, fittings, cartridges, and fixtures, so tankless water heater usually finishes in a single visit.
Tankless water heater cost in Illinois: what to expect
Tankless Water Heater in Illinois starts at from $1,899, every tankless water heater quote is flat-rate and presented in writing before work begins — no surprise add-ons, no hourly creep. Seniors (65+) and military save 10% on labor, and financing covers projects over $1,500 at 0% APR for 12 months, with no prepayment penalty.
What makes our tankless water heater different in Illinois
We've been a trusted choice since 1974 — over 50 years of family-owned plumbing service across Illinois. Our techs are CSLB-licensed (#1098234), background-checked, and complete an internal 12-week training program before rolling on calls alone.
Our tankless water heater carries a 10-year workmanship guarantee — separate from any manufacturer warranty on the parts themselves. If the tankless water heater we performed fails because of how we did it, we come back and fix it free for a full decade. Appliances and fixtures we install are backed by their full manufacturer warranty, and the parts and accessories we fit carry standard 1–5 year warranties by item.
We quote tankless water heater on honest scope: no unnecessary up-sell, salaried (never commissioned) technicians, and a transparent diagnostic so you see exactly what we see — including the parts still in good shape. If a repair is the right call we say so; if replacement is the better long-term economics, we say that. The flat-rate tankless water heater quote is written and good for 30 days.
Tankless water heater coverage, city by city
We provide tankless water heater throughout Illinois, with fast coverage in every major Illinois metro.
Reach times for tankless water heater vary by traffic and time of day, so we quote an accurate ETA when you call — and the dispatch line routes straight to an on-call technician, no voicemail in between.
Your tankless water heater questions, answered
Top questions homeowners searching for Tankless Water Heater near me ask us:
How long does a tankless install take?
A tankless conversion typically runs 4–8 hours because of the gas-line, venting, and mounting work — longer than a tank swap. A like-for-like tankless replacement is faster. We scope your Illinois install and give a firm timeline.
Does a tankless heater need maintenance?
Yes — an annual descaling flush clears the scale that hard water builds in the heat exchanger, which protects output and prevents error codes. We offer scheduled descaling for Illinois tankless units to keep them at full performance.
What does a tankless conversion require?
Usually a larger gas line, new venting, and a condensate drain for condensing units, plus a wall-mount location and correct sizing for your inlet water temperature. We handle all of it to code so the Illinois unit delivers its rated flow.
Why is my tankless heater showing an error code?
Codes usually point to ignition, flow, or scale faults. We read the specific Navien, Rinnai, or Rheem code, then descale the exchanger or replace the sensor causing it and clear the fault on the Illinois visit. We serve ZIPs .
Is a tankless water heater worth it?
For a household that runs out of hot water or wants to reclaim space and cut standby energy, yes. It delivers endless hot water and lasts closer to 20 years, though it costs more up front and needs a larger gas line and venting. We price it against a tank for your Illinois home.