Water Heater Installation in O'Fallon, MO
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What O'Fallon winters ask of a new water heater
Water heaters here work against colder incoming water from October through April, seven months of the year. On the coldest nights, when lows average 25°F, the tank has more work to do to hold its temperature.
Power loss is part of the picture too. Statewide, 19% of households went at least 24 hours without power in 2024, and O'Fallon has seen its share of winter storms and damaging wind over the past ten years. A gas water heater with a standing pilot keeps making hot water through an outage like that. One with an electronic igniter won't, until the power is back.
Whatever fuel type and size you choose, it has to meet the federal minimum efficiency set for that tank's rated volume. That minimum runs on a sliding scale, so a larger tank and a smaller one of the same type aren't held to the same number.
- 25°F
- the average winter night, and colder incoming water means longer heating
- 7 months
- October through April, the months homes here need heat
- 19%
- of Missouri households lost power for a day or more in 2024, and a heater with an electric element or electric ignition stops without it
NOAA nClimDiv, 1991–2020 normals
A heat pump water heater would save about $270 a year to run in Missouri compared with an electric water heater.
Estimates for a typical Missouri home, from EIA household energy data and Missouri fuel prices. Your home will differ.
- How do I know it's time to replace my water heater?
- Check the data plate near the top of the tank for its age, since older units are the ones most likely to fail. Watch for water pooling around the base, hot water running out faster than it used to, or water coming out rusty. Popping or rumbling sounds mean sediment has built up inside the tank, and that only gets worse over time. If the tank itself is leaking, that's not something to repair, that's the tank telling you it's done.
- Should I switch to a tankless water heater?
- It depends on what you want out of it, not on your old tank failing. A tankless unit heats water on demand instead of storing it, so you don't run out partway through back-to-back showers. The tradeoff is upfront cost and install work, since a tankless unit often needs different venting and a different gas or electric supply than what's already running to your current tank. A contractor can look at your gas line, electric panel, and where the unit would go before you decide.
- What changes when you install a tankless water heater?
- The biggest change is that hot water gets made the moment you turn on the tap, instead of sitting ready in a tank. That means no standby heat loss between uses, but it also means the unit needs enough gas flow or electric capacity to heat water fast in the moment it's needed. Venting is different too, since tankless units vent through pipe sized for the exhaust they produce, not the pipe a tank uses. Where the old tank sat may not work for the new unit, since it needs its own access to venting and to the gas or electric line.