How to Choose A Tankless Propane Water Heater?

how to choose propane tankless water heater

A tankless water heater is designed to be a more energy-efficient way to get a steady supply of hot water. They are engineered to avoid the weaknesses of the standard heaters. They utilize either electrical elements or powerful gas burners. They heat water rapidly at the time needed. In this case, we will focus on propane tankless water heaters.

Propane features clean-burning and proper energy production and has therefore become popular for hooking up home appliances. Using propane to fuel your water heater is a great idea as it emits up to 60% less greenhouse gas than the regular gas. It saves energy and money in the long run. In this article, you will get to know how to choose the ideal tankless propane water heater, the amount of propane used, as well as how long they last. Read on.

Quick Pick on Best Propane Tankless Water Heaters

How to Choose A Proper Tankless Propane Water Heater For Home Use

Tankless water heaters are becoming more popular since recent years. Another thing is propane tankless water heaters produce more a larger temperature rise compared to the electrical models. They are also more powerful. But how can you know which one is ideal for you?

how to choose propane tankless water heater

Hot Water Needed

Before purchasing a tankless water heater, you need to make a few considerations—for instance, the hot water needs for your entire household. The rating of the tankless water heaters is by the possible maximum temperature rise at a particular flow rate. You need to determine the amount of water needed at peak demand and how much heating the incoming cold water needs.

To do this, you are required to list all the fixtures in your house that require hot water and sum up their flow rates. You can check online or refer to their documentation if you are not sure of the flow rates. This helps you to know the desired flow rate required by the water heater. You can reduce flow rates by installing water fixtures with low-flow.

Temperature Rise

Also, you need to ascertain the incoming water temperature and then calculate the temperature rise. You can get this by subtracting the temperature of the incoming water from the output temperature that is desired. Depending on the geographical temperature, the temperature rises will vary.

A greater flow rate translates to a lower temperature rise. This will help you know the tankless water heater that will meet all your household needs. If you are running two appliances at the same time, you need to get one that produces enough hot water needed. It is, therefore, crucial that you do not need undersize your tankless water heater to save on money.

Existing Plumbing

Another factor that you may need to consider is the limitations that are imposed by your house and the existing plumbing. Homes that have an undersized gas supply need pipes with larger diameters for the delivery of more fuel. Alternatively, the provider will be required to increase supply pressure to your home. The cost may be substantial; updating the gas service will mean a new regulator and meter, and gas repiping needs a lot of labor.

Electronic Ignition System

Also, ensure that the model you intend to buy uses electronic ignition devices. These prevent the continuous fuel consumption of a pilot light that is always on. Most of the newly manufactured propane tankless heaters on the market employ this technology. In this case, you do not have much to worry about.

Recommended Propane Water Heater with Electronic Ignition

  • Endless Hot Water: Our tankless hot water heaters let you enjoy unlimited hot water flow throughout the house with a compact and durable design that fits your home and lifestyle
  • Energy and Space Efficient Tankless Gas Water Heater: This small hot water heater conserves energy, only heating when necessary; Enhanced scale detection lessens possibility of serious, long-term damage to unit
  • Optimal Water Pressure: This tankless water heater offers a high-performance hot water flow rate up to 5.3 GPM for a powerful, constant stream that serves up to 4 appliances at once
  • Professional Installation Recommended: Visit the Find a Rinnai PRO page on our website to locate a qualified technician in your area to install your tankless water heater; We do not recommend installing a water heater without a technician
  • Guaranteed to Last: 10-, 5-, and 1-year residential factory warranty for heat exchanger, labor, and parts, respectively

Vent Pipes

The vent pipes that are recommended for the tankless water heaters are the large stainless steel. These can sustain very high temperatures. Do not think of trying to reuse those from your old water heater. You may, therefore, need to add in a cost of new venting to your budget of a tankless water heater. Also, propane tankless water heaters have two methods of venting. The code requirements and other specifics of venting may be difficult- professional installation is highly recommended.


The available space for the tankless water heater is also a factor. Depending on the venting method, you need to choose accordingly. The venting methods are power vent and direct vent. The direct vent units require two separate vents- the exhaust and intake. They save on time and space. They are ideal for cramped locations. The power vents require only a single ventilation pipe that is the exhaust.

They need large spaces, unlike the direct vent, for sufficient air into the unit. The location preferred for the power vent units should provide sufficient fresh air that is necessary for the unit. Whichever method you decide to use, there are governing strict codes on where and how venting will be installed. For installation of the tankless water heater, ensure that you hire an experienced local and fully licensed professional.

How Much Propane Does A Tankless Hot Water Heater Use?

It is essential to calculate the amount of propane used to fuel your tankless water heater. You will learn your total spending and thus proper budgeting. To calculate the usage of your water heater, you need to first understand its functions. Also, you need to know that the burning depends highly on geographical temperature. The water quality is also a determining factor.

For hard water, more propane will be burned. For you to determine the amount of propane a tankless water heater uses, there are many other considerations you need to make. Calculating the propane burned per gallon of water will make the task easier. Here we will calculate propane as gallons.

Generally, if the family consists of two people, about 15 gallons of propane will be sufficient. 3 or 4 people will use 25 gallons monthly. For any family with more than five people, 35-40 gallons will do for all household chores.

How Long Does A Tankless Water Heater Last?

Tankless water heaters have a life expectancy of up to 20 years. Proper maintenance, usage, and water quality impact its actual life. Compared to a tank water heater, the tankless water heaters last twice as long. This ultimately makes them a better value.

Final Word

If you’re tired of running out of hot water, then tankless water tanks may just be a worthwhile solution. They are designed to heat water effectively at the time you need it, unlike the standard tank heaters. Propane tankless water heaters are known to save on energy and water. They are efficient, lasts longer, and are a better value in the long run. They are becoming more and more popular; you sure do not miss out. Get one for a better hot water experience in your household.

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David: Penn State-educated Mechanical Engineer and Business-savvy Fluid Dynamics Specialist. Balances family plumbing business support with a thriving engineering career at a top, undisclosed company. (they want it that way) I help Will with plumbing and HVAC needs on his Real Estate.

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