Are you wondering, “how long does it takes for a water heater to heat up?” Search no longer — our complete guide answer this question and much more. Read on to learn all you need to know.

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Now that you’ve seen that water heaters can take anywhere from about half an hour up to more than 2 hours to heat up, let’s look at the factors that affect how long it takes.

First-Hour Delivery Rate

All water heaters have a first-hour delivery (FHD) rating. The FHD indicates how many gallons of hot water the heater can provide in an hour when it is full. FHD rates are given in gallons per hour (GPH).

A high FHD rate means you’ll get more hot water sooner than you would from a unit with a lower FHD rate. For a 50-gallon unit, a FHD rate of about 60 to 80 GPH is good.

Recovery Rate

A water heater’s recovery rate is how many gallons of hot water the unit can provide per hour as it is being used. It tells you how quickly the water heater can recover (aka refill) with cold water and heat it up.

A unit with a high recovery rate will provide hot water faster because it takes less time to heat it up. So even if you’re using a lot of hot water at once, a water heater with a high recovery rate will be able to heat the incoming cold water quickly.

Power Source

A water heater’s power source (gas or electricity) has a lot to do with how long it takes to heat water up. Electric water heaters are known to take longer to heat water. This is because it’s less efficient to use electrical heating elements than gas burners.

Your average 50-gallon gas water heater might have a FHD rate of 80 to 90 GPH, but a 50-gallon electric water heater will have a FHD rate of about 58 to 66 GPH.

While you might have to wait about 30 minutes for an average gas water heater to heat all the water in the tank, you’ll have to wait twice that long for an electric model.

Water Heater Type

Storage water heaters are those with tanks that hold and heat water. Tankless water heaters don’t have storage tanks and heat the water right before it comes out of the tap.

There’s a huge difference in how long it takes these two types to heat water.A storage water heater takes anywhere from 30 minutes up to about an hour and a half to heat up.

A tankless water heater generally makes hot water available instantly. If too much hot water is being used at once, the flow rate (in gallons per minute) will drop, but the water that does come out will still be hot.

Read Next: Best Tankless Water Heaters

Water Heater Size

A storage water heater’s size, or gallon capacity, has a lot to do with how quickly it can heat water. Typically, storage water heaters can hold anywhere from about 30 to 80 gallons of water.

Smaller tanks heat water faster (and run out of hot water faster) because there are fewer gallons to heat. This is just like heating water in a small 2-qt. saucepan on the stove versus a full 12-qt. stock pot.

The water in the saucepan will boil faster.But larger tanks don’t take as long to heat up as you might think. Bigger electric models have two heating elements to help the process along.

Large capacity gas water heaters have a bigger gas burner to help them heat up quicker.Still, if you have a 30-gallon capacity water heater, you won’t wait as long for it to heat up as if you had a 50 or 80-gallon unit.

Read Next: Best Small Water Heaters

Original Water Temperature

The original water temperature has a lot to do with how long it takes for a unit to heat it up. If the inlet water temperature is low, the water heater must work harder to raise the water to the temperature you’ve chosen.

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In colder climates, the inlet water temperature is usually about 40 degrees Fahrenheit. In warmer climates, it’s about 50 degrees. The water heater takes time to heat water from 40-50 degrees up to 140 degrees.