Tankless Water Heater Installation in O'Fallon, MO
Hot Water That Keeps Up, Sized for a Missouri Winter
At On Time Experts Heating, Air & Plumbing, tankless water heater installation swaps your storage tank for a wall-mounted gas unit that heats water as you use it. We size it for your household and winter water temperatures, handle the gas line and venting, and price it upfront.
What Tankless Water Heater Installation Services Do We Provide?
On Time Experts Heating, Air & Plumbing provides tankless water heater installation that replaces a storage tank with a wall-mounted unit that heats water only when a tap opens. The job includes sizing the unit, resizing the gas line where needed, new venting, and connecting the water lines, drain and power.
It makes sense when your tank heater is near the end of its life and you want hot water that doesn't run out, more basement room and no energy spent keeping a full tank hot. It suits households with back-to-back morning showers that plan to stay long enough for the savings to cover the higher up-front cost.
If the gas or venting route at your house would be hard, a new tank may be the better value, and we'll tell you so.
What Is Included in Our Tankless Water Heater Installation Services?
A tankless install covers:
- Sizing: Match the unit to your peak flow rate and the winter temperature of your incoming water.
- Removal: Take out the old tank heater.
- Mounting: Mount the new unit, usually on a basement wall near the old heater's spot.
- Gas line resizing: Resize the gas line so the unit gets enough gas at full output.
- Venting: Run new sealed venting through a side wall or the roof.
- Condensate drain: Route a drain for condensate, the slightly acidic water a high-efficiency unit gives off.
- Startup and testing: Check gas pressure, then run several faucets at once.
If you'd rather stay with a tank, our water heater repair and replacement page covers that option, and our gas line repair and installation page explains the gas side of the job. We install tankless units across O'Fallon, St. Peters, St. Charles and nearby communities.
Where the job requires a permit, it's permitted.
Why Is Professional Tankless Water Heater Installation Important?
A tankless water heater only performs as well as its sizing and gas supply.
Size the Unit for January, Not a Mild Day
A tankless water heater is sized by two numbers: how many gallons per minute your home uses at once, and how many degrees the unit has to raise the incoming water. Two showers and a dishwasher running together can take around 5 to 6 gallons per minute.
Incoming water in a St. Louis-area winter can drop into the 40s, so reaching 120 degrees takes a rise of 70 degrees or more. A unit sized on a mild day can fall short in January. Manufacturer lineups such as Navien's residential tankless water heaters show how wide the range of sizes runs, which is why the choice should follow your peak use.
Give the Unit Enough Gas
A whole-house gas tankless unit can draw up to about 199,000 BTU per hour, compared with about 40,000 for a typical gas tank. The half-inch line that fed the old tank often can't carry that, so gas line sizing is part of every install. Now and then the meter is undersized too, which is Spire's to upgrade.
What Happens During a Tankless Water Heater Installation Visit?
Most installs follow this order:
- Talk through your hot water use. We ask how your household uses hot water and look over the heater, gas meter and venting route.
- Get the plan and the price. We size the unit, explain the gas and venting work and give you upfront pricing.
- Prep on install day. We protect the floors and stairs, shut off water and gas, and remove the old tank.
- Install the system. We mount the unit, run the resized gas line, install the venting and condensate drain, and connect the water lines.
- Start it up and test it. We restore gas and water, start the unit, check gas pressure and run several faucets at once.
- Walk through the controls. We show you the settings and the maintenance schedule, then clean up.
You'll know the full price before install day.
Frequently asked questions
Most homes need at least part of the gas line resized for tankless water heater installation. A whole-house gas tankless unit can use several times the gas of a tank heater, and the smaller line that fed the old heater often can't supply it.
The fix is usually a larger line from the meter or a main branch, sized from the unit's rating and the length of the run. It's gas work for a plumber, not a weekend project.
Most tankless water heater installation jobs take one full day when the unit replaces a tank heater in a basement. The time goes into removing the old tank, mounting the unit, running gas, vent and drain lines, and testing.
Longer gas or vent runs, a finished basement or a permit sign-off can add time.
After tankless water heater installation, most units need descaling about once a year, and homes with harder water may need it more often. Descaling circulates a cleaning solution through the heat exchanger, the coil where the water is heated, to remove the mineral scale that builds up over time.
Cleaning the inlet filter screen usually happens at the same time, and following the manufacturer's schedule helps the unit keep its flow and efficiency.
Tankless water heater installation is worth it when you want hot water that doesn't run out, plan to stay for years and have a practical route for the gas line and venting. It costs more up front than a tank heater, mostly because of that gas, venting and condensate work.
It uses less energy because it doesn't keep a tank of water hot all day, and it often outlasts a tank when it's descaled on schedule.
Yes, as long as the hot water you use at one time stays within the unit's flow rate. It never runs out the way a tank does, but open more taps than it's sized for and the water gets cooler.
That's why sizing for your busiest morning and coldest incoming water matters most in tankless water heater installation.
How Much Does Tankless Water Heater Installation Cost?
A tankless unit costs more to install than a tank heater, mostly because of the gas, venting and drain work that comes with it.
Factors that can affect the cost include:
- Unit size and model: Based on your peak hot water use.
- Gas line work: How much line has to be resized between the meter and the unit.
- Venting: Distance and route, side wall or roof.
- Condensate drain: How far the drain line has to run.
- Power: Whether there's an outlet near the mounting spot.
- Permits: Requirements for your municipality.
You'll get upfront pricing before any work begins, with the gas, venting and drain work included in the quote.
Why Choose On Time Experts Heating, Air & Plumbing for Tankless Water Heater Installation?
We'll tell you whether tankless fits your house before we talk about models.
Straight advice: If a tank heater is the better value for your house, that's what we'll recommend.
One plan: The gas line, venting and drain are sized and priced with the unit.
Upfront pricing: You see the full price before install day.
Schedule Tankless Water Heater Installation
If your tank heater is getting old and tankless has crossed your mind, call On Time Experts Heating, Air & Plumbing.
We'll walk through sizing, gas and venting for your house and give you an upfront price.