what is the difference between a commercial water heater and residential water heater?Those who are looking on manufacturer websites for a water heater for their home may end up a bit confused. Many manufacturers offer residential and commercial water heaters that look fairly similar. The residential tanks are intended to be used in single-family homes, while commercial tanks are intended for large residential complexes, office buildings, and other applications which require large amounts of hot water. Considering they can seem so similar, is there a good reason to choose one over the other? We will explain the difference between residential and commercial water heaters below and give you some tips about which you should choose.

Tank Size and Pressure

One of the major differences between residential and commercial water heaters is the size of the tank. Residential water heaters are typically around 30-gallons to 60-gallons in size but may range up to 100. Commercial tanks are much larger, typically starting at 100 gallons and ranging up to 500 or more. As they can deliver more hot water, these heaters are ideal for high-demand situations such as hotels and apartment buildings.

Water heaters may also produce water at different pressures, but this isn’t necessarily the case that residential heaters are lower pressure than commercial ones. Heaters at different pressures may or may not be suitable for use as part of a radiant heating system.


Residential heaters are typically capable of producing water at up to 140 degrees Fahrenheit. Commercial heaters may generate water at much higher temperatures. They may need to run the water further, which means it will lose more heat during transit and needs to be warmer. In addition, commercial plumbing systems have additional safeguards and designs to properly mix that warmer water with cold water before it reaches someone’s faucet.

Water Output

All tank-based water heaters have a tank full of water and heat it up. When you have used all of that water, the heater needs to work to fill up the next tank-full of water. Commercial water heaters may be able to do this faster, meaning they have a more consistent water output. Smaller residential water heaters will take longer to recover after you have used all of the water.

ASME Standards

Water heaters that are over 100gallons or that are intended for commercial use need to meet ASME standards for construction and operation. These standards include a thicker shell and other improvements which may give the commercial water heater a longer life.

When Should You Choose a Commercial Water Heater?

Of course, if you need a water heater for a large residential building or commercial application, you need a commercial water heater. These will create enough hot water for you and typically work much more efficiently than a series of smaller water heaters would.

But, what if you live in a single-family dwelling? Most homeowners will be best served with residential options, but there are some situations where you could consider a commercial option, including:

  • You have a hot tub or other spa features which need more hot water
  • You have an oversize tub that cannot be efficiently filled by a residential water heater
  • You have unusually large hot water needs because your home is unusually large or inhabited by many people
  • You’re using a radiant heat system that needs a lot of hot water

You should seek a professional’s advice about which one is best for you. Having years of experience with any type of water heaters in Discovery Bay, our team can help you out.