Water Heater Guide: Tank or Tankless

You use hot water every day without thinking about it, until a cold shower reminds you. Water heaters fail more often than most appliances, and our hard water makes the job tougher. This guide compares tank and tankless models, explains the warning signs of a failing heater, and covers the upkeep that helps one last.

How a tank water heater works

A standard tank water heater stores hot water and keeps it ready. Cold water enters through a dip tube that carries it to the bottom of the tank. A gas burner or electric elements heat it, and hot water leaves from the top when you open a tap.

• The anode rod is a metal rod inside the tank. It corrodes on purpose so the tank lining does not.
• The thermostat sets how hot the stored water gets.
• The temperature and pressure relief valve opens if heat or pressure gets too high. It is a key safety part.
• The flue on a gas unit carries burner exhaust out of the house.

Tank heaters are simple and familiar. Their downside is that they keep a full tank hot all day and all night, and when the tank runs out, you wait for it to refill and reheat.

How a tankless water heater works

A tankless unit heats water only when you need it. Open a tap, and water flows through a heat exchanger where a powerful burner or element warms it on the spot.

Endless hot water, within limits

A tankless heater does not run out the way a tank does. It does have a flow limit. If you run two showers, the dishwasher and the washing machine at once, a unit that is too small may not keep up. Sizing it to your household matters.

Less space

Tankless units hang on the wall. They open up floor space in a utility room or basement.

Different install needs

Gas tankless heaters often need a larger gas line and different venting than a tank. That can add to the first-time install. We check your gas supply and venting before recommending one.

Tank or tankless: which fits your home?

Both are solid choices. The right one depends on how you use hot water and what your home is set up for.

A tank may fit if

• You want the simplest replacement for the tank you already have.
• Your hot water use is steady and your current tank keeps up.
• You would rather not change gas lines or venting.

A tankless unit may fit if

• Your family runs out of hot water often.
• You want more room in a tight utility area.
• You are willing to keep up with yearly descaling, which matters a lot with our hard water.

Our tankless water heater page goes deeper on sizing and install, and our water heater installation page covers both types.

Signs your water heater is failing

Rusty or cloudy hot water

Rust-colored hot water can mean the inside of the tank is corroding. If only the hot side is discolored, the water heater is the likely source.

Popping or rumbling sounds

Sediment and mineral scale settle at the bottom of a tank. Water trapped under that layer boils and pops. It makes the heater work harder and can shorten its life.

Hot water runs out fast

A thick layer of sediment takes up space in the tank. A broken dip tube or a failing element can also cut your supply short.

Water around the base

A small puddle may come from a loose fitting or the relief valve. Water seeping from the tank itself usually means the tank is failing and needs to be replaced before it lets go.

Pilot or ignition trouble

A gas heater whose pilot keeps going out, or that will not light, may need a new thermocouple, igniter or control. Our water heater repair service handles these.

Hard water and your water heater

Northern Utah water carries a lot of calcium and magnesium. When water heats up, those minerals drop out and form scale. In a tank, the scale settles on the bottom. In a tankless unit, it coats the heat exchanger and can trigger error codes and lower flow.

Two steps help:

• Regular flushing or descaling. Draining some water from a tank once a year clears sediment. Tankless units need a descaling flush, usually once a year in our area.
• A water softener. Softened water leaves far less scale behind. A water softener protects your water heater, your fixtures and your appliances.

Checking the anode rod every few years is also smart. Once it has worn away, the tank itself starts to corrode.

What size water heater do you need?

A water heater that is too small leaves the last person in line with a cold shower. One that is too big wastes energy keeping extra water hot. Sizing works differently for each type.

Sizing a tank

For a tank, the key number is how much hot water it can deliver in the first hour of heavy use. Think about your busiest morning: how many showers run back to back, and whether the dishwasher or washing machine runs at the same time. A household that has grown since the old tank went in may need a step up.

Sizing a tankless unit

For a tankless heater, the key is flow rate, measured in gallons per minute. We add up the fixtures you are likely to use at the same time. Then we account for how cold the incoming water is. In a Northern Utah winter, water comes into the house much colder than in summer, so the heater has to work harder to raise it to shower temperature.

Thinking about the future

If you plan to finish a basement, add a bathroom or grow your family, tell us. Sizing for the next several years avoids replacing a heater that is still working but no longer keeps up.

Small habits that help

• Spread out heavy hot water use, such as laundry and dishes, so they do not overlap with showers.
• Insulate exposed hot water pipes in a basement or crawl space to keep heat in and protect against freezing.
• Look at the area around the heater once a month for drips, rust or scorch marks.
• Write the install date on the tank with a marker so you always know its age.

Safety basics for any water heater

• Keep stored items, paint and gas cans away from a gas water heater.
• Do not cap or plug the relief valve. If it drips, have it checked.
• Make sure the vent pipe on a gas unit is secure and sloped correctly.
• Set the temperature high enough for your needs but low enough to avoid scalding, especially with small children in the home.
• Know where the cold water shutoff is, so you can stop a leak quickly.

Replacing a water heater

When a tank is leaking or repairs keep adding up, replacement is the safer move. We help you choose a size and type, remove the old unit, update connections, venting and the relief valve line as needed, and test the new heater before we leave. We offer free estimates on new system installations, and financing is available through our lending partners.

Call about hot water

No hot water, odd noises or a leak at the base? Call (435) 730-2536. Our office is open Monday to Friday, 8 AM to 6 PM, and we offer 24/7 emergency plumbing service. You can also schedule online.