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Frequently Asked Questions

Common plumbing questions on hot water heaters are answered here. If you still have questions about your hot water heater, call Mr. Waterheater.

Do I need a new hot water heater?

If your hot water heater is over six years old and no longer provides you with hot water, or if there is a telltale puddle on the floor, it is time to replace your hot water heater.

What factors should be considered in deciding to replace a water heater?

The age of your existing hot water heater is important, along with the climate, amount of hot water you use, and how hard your water is. The average lifespan of a residential tank-type water heater is approximately 6 to 10 years; this can be reduced through heavy use, high water pressure, thermal expansion, or a water softener, just to name a few. All hot water heaters will eventually leak, and leaking hot water heaters can make quite a mess!

Is there anything I should do before calling for service?

Be prepared to answer basic questions, like the type of hot water heater you have (gas, electric, etc), where the hot water heater is located (garage, basement, closet, etc), and the model and serial number of your existing hot water heater. We can determine the age of the hot water heater by decoding the serial number. We can also decode the model number to determine the size of your existing water heater, which allows us to suggest the proper replacement.

What has changed with water heaters since mine was installed before 2015?

The first change is the price of the water heater itself.  With the onset of the Covid pandemic, the price of water heaters (with everything else) has increased significantly. 

Also, new Department of Energy guidelines went into effect in April 2015 requiring water heaters to be more efficient.  To become more efficient, tank-type water heaters were built with more insulation.  The result is the water heaters are now wider, about two inches larger in diameter.

Effective July 1, 2003, residential gas hot water heaters had to meet a new American National Standards Institute (ANSI) standard so it will not ignite flammable vapors caused by spilled gasoline or other flammable liquid outside of the unit. The new standard does not require you to replace your existing hot water heater but all new hot water heaters must meet the standard.

In summary, over the past 20 years, the water heaters have become bigger and more expensive, but they have also become safer and more efficient.

Why is my relief valve leaking?

A relief valve is a safety device that is designed to open (or leak water) due to excessive water pressure, high water temperature or thermal expansion. The relief valve will open when the pressure reaches 150 psi or the temperature of the water exceeds 210 degrees Fahrenheit.

When the relief valve leaks, it is usually indicating a problem outside of the water heater, rather than a problem with the actual water heater. A new water heater will continue to leak if the cause, whether high water pressure or thermal expansion, is not addressed.

Why is my new water heater leaking (at the relief valve) when my old water heater did not?

The relief valve opens as a safety feature when the water pressure or temperature is too high, or there is a thermal expansion issue. Rarely it’s because the part is bad. The relief valve on your old water heater likely did not leak because it was corroded shut. Or your old water heater did not leak because it may have had a relief valve that was rated higher than that on the newly manufactured water heaters. (An old water heater could have had a relief valve that didn’t open until water pressure reached 175 psi, whereas the new water heaters open when the pressure reaches 150 psi.)

If your new water heater leaks, give us a call because additional work will be needed.

What is a self-cleaning hot water heater?
The dip tube is what takes the cold water to the bottom of the tank. In self-cleaning models, the dip tube is equipped with a fitting at the bottom that causes a spiraling effect on the incoming water. This dislodges the sediment off the bottom of the tank and lifts it up and out through the hot side. This will increase the tank’s efficiency and help the tank’s glass lining last longer.

All of the water heaters that we install are self-cleaning.
How are FHR and Therms used to compare the efficiency of hot water heaters?

The first hour rating (FHR) tells you the number of gallons per hour of hot water. Therms are related to the gas consumption of a hot water heater. When you’re shopping for a hot water heater, compare the energy factor on the Energy Guide label. FHR and Therms are not sufficient to calculate the energy factor. Also remember to compare hot water heaters of equal capacity and FHR.

What are tankless hot water heaters and are they more energy efficient?

On-demand tankless (or instantaneous) hot water heaters eliminate the storage tank by heating water directly when there is a call for hot water. These units are growing in popularity in the U.S. The energy consumption of these units is generally lower since standby losses from the storage hot water tank are eliminated. On-demand hot water heaters have three significant drawbacks:

  • Large simultaneous uses (two showers and the clothes washer, for example) may challenge their capacity, particularly in winter when the inlet water is coldest. Water will not heat unless you have a flow rate of about ½ gallon per minute at a fixture (shower head, faucets etc.).
  • Retrofit installation can be very expensive. See tankless disadvantages
  • Finally, because the efficiency tests were not developed with these designs being considered, it is not known if the energy factor or “EF” accurately estimates energy consumption.
Newer models of tankless water heaters have a small 2.5 gallon tank to keep up with demand.

See our Tankless Water Heater page for additional information.
Can I install my own hot water heater?

Water heaters should be installed by a plumber or someone with plumbing and heating experience. The Do-It-Yourself person may be able to handle many small household jobs, but the installation of a hot water heater could create a dangerous situation if performed incorrectly. There are many local codes and safety requirements that pertain to hot water heater installation and operation; without understanding these requirements, you could be breaking the law as well as endangering yourself and your family.

Do you provide financing?

Mr. Waterheater does not offer financing. We do collect payment upon completion of the job. We accept cash, checks, and major credit cards. There is a 3% fee on all credit card transactions.

Can you dispose of my old water heater?

The old water heater can be hauled away for a nominal charge or left at your curb for no additional charge. Please note that the water heater box is always left onsite with the customer to dispose of as required by the local municipality.

In severe cold weather it seems like our hot water is never hot enough. Is this a common problem?

In the winter, incoming water temperature is much colder, which causes the remaining hot water in the tank to dilute much faster (the cold water coming in is what pushes the hot out of the water heater). You may also have sediment build-up in your tank reducing the performance of your hot water heater.

Is it advisable to install an expansion tank in addition to replacing my hot water heater?

In some parts of the country the plumbing code requires expansion tanks. When the water gets heated it expands and that extra volume has to go someplace. Without an expansion tank the pressure could rise to a dangerous level in a closed system. Exploding hot water heaters are not unheard of. Be aware of any changes made to your water meter by your water company or a plumber that may have created a “closed” water system in your home.

How does an expansion tank work?

An expansion tank absorbs expanded water due to excess pressure from water heating.