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Water Heater Installation Tankless

  • Alma 

Do you need on-demand hot water? Welcome the the world of water heaters tankless style. There are some pros and cons to choosing a tankless water heater. Some advantages include improved energy efficiency and a continuous supply of hot water. The biggest con being the price tag.


  • On-demand hot water
  • Energy efficiency
  • Reduced energy bill in the long run
  • Increased home value
  • maximizing space
  • Longer lifespan


  • Upfront cost
  • Limited flow rate
  • Complex installation
  • Incoming water temperatures affect performance
  • More prone to problems from hard water


Plumber working on a tankless water heater

Installing a whole home tankless water heaters

After weighing the pros and cons, if you decide a tankless water heater is the best for your household, you should consider temperature rise, size, fuel type, and ventilation. Temperature rise is how much the water needs to be heated based on the temperatures of the water flowing into the home. When looking at size, you’ll want to consider the flow rate or gallons per minute (GPM) and the unit’s dimensions. Tankless water heaters come in three fuel types: gas, electric, and propane. Gas and propane water heaters require ventilation, whereas electric ones do not.

Temperature Rise

Homes in areas prone to harsh winters will need a higher flow rate than homes in warmer climates. This is due to a temperature rise, which looks at the base temperatures of water entering the home. In Florida, for example, the winter water temperatures entering the home might be in the mid-60s, maybe into the 70s. On the other hand, in Utah, temperatures entering the home in winter might be in the 40s. The Utah tankless water heater has to heat the water a lot more than the tankless in Florida. The Utah home will want to size up in flow rate to ensure the hot water demand is met both in summer and winter.   

Flow rate Gallons Per Minute (GPM)

Tankless water heaters are sized by their flow rate, which is how much hot water passes through the unit or how many gallons of water can be heated per minute (GPM). However, the GPM is affected by outside water entering the home. This means the actual flow rate will be lower during winter than in summer. Tankless water heaters’s GPM is tested under ideal conditions, therefore, you might want to get a higher GPM tankless if you live in an area prone to harsh winters. below are the general recommendations:

  • Family of 2: 6-8 gallons 
  • Family of 3: 7-9 gallons
  • Family of 4: 8-10 gallons
  • Family of 5: 9-11 gallons
  • Family of 6: 11+ gallons

Tankless water heater dimensions

If you’re replacing a tank-style water heater with a tankless one, you’ll have plenty of room for installation. A tankless is much smaller, sometimes half the size. However, with that being said, it’s still a good idea to know the dimensions of your tankless so you can preplan where to mount it, and if it’s a gas-fueled model, plan out the ventilation system. Usually, the dimensions are around 2-2.5 feet wide and 3-4 feet tall; every unit will come in different shapes and sizes. It’s best to double-check with the manufacturer for the exact measurements. 

Fuel type: Tankless gas water heater vs electric

A tankless tank needs a fuel source to heat the water. This can be gas, electric, or even propane. However, propane tankless systems are not recommended for household or commercial uses; they’re more for RVs or cabins. Propane is a more dangerous fuel source than gas or electricity.

Electric tankless systems have heating coils. When the water moves through the unit, the heating component turns on. The coils heat up, which heats the water to the desired temperature. The water then leaves the tankless to where it’s needed in the home or business.

Gas tankless systems have a burner assembly fueled by natural gas. When the water flow is initiated, the burner ignites and heats a heat exchanger; once the water reaches the desired temperature, it exits the unit. The combustion gas produced by the burner has to be vented safely outside the home.

Water Heater Ventilation 

Tanks don’t require venting; however, gas tankless systems do. This is where replacing a traditional tank unit with a tankless can get complicated. However, replacing it with an electric unit solves the issue as it does not require ventilation. 

Power vents use indoor air for combustion, and the exhaust is vented outside. This is the most popular vent type. A direct vent pulls air from the outside for combustion and then has a second vent for the exhaust.

Install a tankless hot water heater

This is an oversimplified instruction on how to install a tankless water heater. It’s always best to read the manufacturer’s instructions. 

  1. Turn off the water supply to the old water heater.
  2. Drain the old water heater if it’s tank-style.
  3. Remove the old water heater.
  4. Assess pipes as they might need to be adjusted to accommodate the tankless.
  5. A gas water heater will need ventilation put in.
  6. Install the new tankless water heater.
  7. Connect the new water heater to the water supply.
  8. Connect the gas or electric line.
  9. Connect the gas tankless to ventilation.
  10. Turn on the water supply to the new water heater.

Price to install a tankless water heater

There are a few things to consider: the unit’s cost and the labor required to install it. DIYs can save money by installing a tankless water heater themselves. However, to install it, you will be working with electrical and possibly gas lines, so caution is advised. Sometimes, having a skilled professional plumber install it is worth the additional piece of mind, knowing it was done correctly. At Sunset Plumbing, we work with Navien tankless water heaters.    

We like to be upfront with our pricing, many because we know we offer some of the best prices in town, and we pride ourselves on a clean, professional installation. Our starting price is $3,200. This is for a tankless water heater replacement from another tankless unit. If you are replacing a tank-style water heater the installation is a little more tricky and requires more labor. 

  • Navien Tankless Water Heater Replacement:  $3,200
  • Tankless Water Heater Replacement From a 50 Gallon:  $5,600
  • Tankless Water Heater Replacement From a 40 Gallon:  $5,600


Tankless water heaters are gaining popularity. Having on-demand water is very convenient. However, tankless water heaters do have cons, the biggest one being the price. Hopefully, you now better understand how to choose the size (flow rate) that best suits your household or business.

Looking for a Tankless water heater installer near me

We’d be happy to install your water heater for those who live in Utah, particularly the Utah County or Salt Lake City area. Just get in touch here. We proudly serve Utahans, families, and businesses. We offer 20 years of plumbing experience and promise you upfront, affordable pricing and professionalism, and we’ll get the job done right. 

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Alma Bradshaw

About The Author

Hello, My name is Alma Bradshaw. I'm a licensed plumber with over 20 years of experience in the industry. It's important to stay informed and up-to-date on the latest plumbing techniques, innovations, codes, and regulations. Learn more about plumbing here and feel free to comment below with any questions.

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Sunset Plumbing Utah

1562 Evans St, Lehi, UT 84043

Sunset Plumbing

776 N 470 E Genola, UT 84655

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Sunset Plumbing Utah

1562 Evans St, Lehi, UT 84043

Sunset Plumbing

776 N 470 E Genola, UT 84655

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