When a water heater needs replacing, most homeowners ask the same question: stick with a tank, or switch to tankless? Neither is right for every house. Here's how to think it through, with the things that are different along the Front Range.
How each one works
A tank water heater keeps a set amount of water hot at all times, usually 40 to 75 gallons in a house. When you use hot water, cold water refills the tank and gets heated. Use more than the tank holds, and you wait for it to recover.
A tankless water heater heats water as it flows through. Open a hot tap and the burner fires; close it and the burner stops. It won't empty, but it can only heat so many gallons per minute at once.
What's different in Colorado
- Cold incoming water. In winter, water enters the house much colder than in summer. A tankless unit has to raise it more degrees, which lowers how many gallons per minute it can deliver. Size for January.
- Altitude. Gas appliances lose some output at elevation. Both tank and tankless gas heaters have to be set up for altitude according to the manufacturer.
- Minerals. Tanks collect sediment. Tankless heat exchangers collect scale. Either way, periodic flushing matters.
- Gas supply. A tankless unit draws a lot of gas when it fires. Some homes need a larger gas line to the unit.
Side by side
| Tank | Tankless | |
|---|---|---|
| Up-front cost | Lower | Higher, especially if gas or venting needs upgrading |
| Hot water supply | Limited by tank size and recovery | Continuous, within its flow rate |
| Typical life | 10 to 15 years (U.S. DOE) | More than 20 years for most units (U.S. DOE) |
| Space | Floor space for the tank | Mounts on a wall |
| Maintenance | Occasional flushing | Periodic descaling and filter cleaning |
| Power outage | Many standard gas tanks keep working | Most need electricity to run |
| Install | Usually a like-for-like swap | More involved: gas, venting, condensate, power |
When a tank makes sense
- Your current tank kept up fine and you want a simple replacement
- You may move in the next few years
- Your gas line or venting would need significant work for tankless
- You want hot water during a power outage
When tankless makes sense
- You run out of hot water with back-to-back showers or a big tub
- You'd like the floor space back in a utility room or closet
- You plan to stay long enough for a longer-lasting unit to pay off
- You're comfortable keeping up with maintenance
Whichever you pick, size it for the coldest morning of the year. Nobody should skip second breakfast over a cold shower.
Questions to ask before you choose
- How many showers, tubs and appliances run at the same time in your house?
- Is your current gas line big enough for a tankless unit?
- Where would a tankless unit vent, and where would condensate drain?
- How long do you plan to stay?
If you're weighing it up, we're happy to look at your setup and talk through both. See tankless water heater installation or water heater repair and replacement.