Tankless water heater and installation cost

Looking for tankless water heater and installation cost in St. Louis, MO? Call WaterHeater Services for a contact a provider — no obligation. Licensed plumbers serve St. Louis and the surrounding area, and you'll get straight answers on timing and what affects the price.

Last updated: September 24, 2026

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What affects the price

When you are shopping for a new water heater, the final cost depends on a few moving parts. First, consider the fuel source—switching from electric to gas or vice versa involves more labor. The capacity you need, measured in gallons, also changes the price tag, as does the physical footprint of the unit in your home. If your current plumbing or venting needs updates to meet modern safety codes, that adds to the work involved. We help you sort through these variables, with exact pricing confirmed free on the call.

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This includes the unit you choose and the labor to install it. Factors that influence the final price include your current home configuration, the capacity of the tankless heater, and whether you are switching from a tank-style unit. Upgrading your venting system or gas lines are common variables that change the total investment. We provide exact pricing confirmed free on the call.

Frequently asked in St. Louis

How long do hot water heaters typically last?

In St. Louis, tank water heaters generally last between 10 to 15 years. The lifespan can be affected by water quality and usage. Tankless units often have a longer operational life. Regular maintenance is key to maximizing longevity.

What is the average cost of putting in a water heater?

What is the most efficient type of water heater?

Tankless water heaters are generally the most efficient option. They heat water on demand, so you're not constantly using energy to keep a large tank of water hot. This can lead to significant energy savings for your St. Louis household.

What are signs I need a new water heater?

Signs that indicate a need for a new water heater include leaks from the tank, rust-colored hot water, or a sudden drop in hot water pressure. If your unit is over a decade old and experiencing issues, it's probably time to consider a replacement. These are important signals.

What is the most common problem with a hot water heater?

Sediment buildup is a frequent issue that can reduce efficiency and cause noise. Other common problems include thermostat malfunctions or issues with the heating elements. Leaks from the tank or pipe connections are also a common and serious concern.

Is it worth it to repair a hot water heater?

Repairing a water heater is often a good solution for minor problems on a relatively new unit. However, if the heater is old, requires frequent repairs, or has significant internal damage, investing in a new, more efficient model is typically more cost-effective in the long run. We can help you assess this.

Also serving nearby: O Fallon · Springfield · Columbia · Champaign · Peoria

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More on this: DOE water heating — efficiency and sizing.