6 Most Important Tankless Water Heater Features to Consider When Making a Purchase

If you are in the market for a tankless water heater, you will want to know what features deserve your attention. What should you look for when buying a tankless water heater? We at Tankless Guide think these  are the 6 most important tankless water heater features to consider.

Tankless Hot Water Heater Fuel Source

You’ve got your choice of high-efficiency gas tankless heaters or electric tankless heaters that are also energy misers. What’s the right choice for you? You’ll have to evaluate the relative costs of gas and electricity in your area, as well as the availability of gas. On average, heating with natural gas is less expensive than heating with electricity. Also gas units are available with Energy Star Ratings. Natural gas offers a greater cost advantage than propane, and propane is still slightly more cost-effective than electricity. The lower operating cost of a gas furnace can be offset by higher installation costs because a gas line and an exhaust vent must be installed. Electric models just need a power supply. You will also want to look at the original investment in the tankless heater

Single Use or Whole House Tankless Water Heaters?

Do you want to supply on-demand hot water to your entire home or just part of it? For supplying water to the entire house, large-capacity gas models are a better choice than electric models because electric tankless heaters can’t match their output. For a single rooms or single points of application, small electric tankless heaters are a very popular choice. They are efficient, easy to install and eliminate standby heat loss – wasted energy – from heated water cooling in the pipes between the tankless heater and faucets throughout the house. If you choose to go electric, you’ll need 3-4 to supply the hot water needs for a 2-3 bedroom home with a laundry and dishwasher. By the way, it is common for homes to feature a combination of gas and electric tankless water heaters to precisely match the equipment to the hot water needs. That’s part of the beauty of tankless heaters – the ability to customize your approach.

Tankless Hot Water Heater Capacity

Gas tankless water heaters supply between 2.5 and 11.0 gallons per minute (GPM) of hot water, depending on the model you choose. In electric tankless water heater models, your capacity choices range from about 1.0 GPM to about 5.0 GPM. Take inventory of your home. How many water sources are you likely to be using at once? Do people take showers while laundry or the dishwasher is running? Add up the number of gallons per minute of hot water you need at peak times from these various sources. If you aren’t sure how many GPM your shower or sink faucet is, or anything else, use 1.5-2.5 GPM per application as a guideline. If you know you’ve got low-flow fixtures, use 1.0 GPM when factoring in those faucets. Also, consider your climate. A cooler climate reduces the number of GPM of any model. If you live in the south, don’t reduce the GPM. If you live in a moderate climate, reduce GPM by 10-15%. If you live in a cool climate, reduce it by 20-30% when factoring. For example, a gas-fired tankless water heater that can produce 10.0 GMP in Florida will produce about 8.5 GPM in Virginia and 7.0 in Minnesota. This is true year-round because ground water stays consistent in temperature all the time. Ground water is just colder in the north than in the south.

Top Tankless Heater Brands

The brand tankless hot water heater you choose does matter. The top manufacturers of gas heaters are Rinnai, Bosch, Rheem, Takagi, Navien and a few others. The top electric tankless water heaters are made by Stieble Eltron, Titan and a few others. Read well-researched tankless water heater reviews and guides to learn about the brands to determine their quality and learn about their features.

Tankless Heater Price

With tankless water heaters, you generally get what you pay for. The best are not cheap. However, they pay you back by being very efficient, reducing standby heat loss and lasting for up to 20 years with good maintenance. They have a much longer lifespan than tanked water heaters. If you buy a cheap gas or electric tankless heater, you’ll get cheap performance that simply won’t last as long. If you plan to move in a 1-4 years, investing in tankless models might not be cost-effective, though they will help you sell your home. If you plan to live in your home for 5+ years, tankless heaters will pay for themselves in that time, if not before, and then save you money from that point forward. Generally the upfront cost is worth it in the long run

Consider an Outdoor Tankless Water Heater

If you plan to install a gas tankless water heater, using an outdoor model might be a good idea. First, it doesn’t have to be vented, saving you money on installation. If you plan to use it to supply water to a hot tub/spa or to help heat a pool, an outdoor model is ideal too. Operating costs will be higher in cooler climates because they have a freeze-prevention system that uses energy. For many applications in warmer climates, they are a very good choice.


This tankless water heater guide will help you choose the model or model that are right for your home. Evaluate your needs, read tankless guides and reviews, compare models to one another and your budget, and you’ll be able to customize a plan to deliver continuous hot water wherever it is needed. You made it this far you might also want to look at another article on which tankless heater is best for you


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2 Responses to “6 Most Important Tankless Water Heater Features to Consider When Making a Purchase”
  1. Jim says:

    I’m seriously considering changing over to tankless but am unsure of what is best for my house. I have a 4 bedroom home with 2 full and 2 half baths. 3500 square ft above ground and 2000 below. Our house is set up so that on the east side of the home we have 2 sinks in the basement, the kitchen, laundry room and a half bath on the main floor and a full bath on the second floor. On the west side of the house we have a half bath & extra sink and dish washer in the basement, and the master bath with shower, jacuzzi tub and 2 sinks on the main floor. The current water tank is on the east side of the house so it takes a long time to get hot water to the master bath and the 75 gallon tank still can’t fill up the tub before going cold. How many tankless units do I need, what size and what location?

    Thanks for your help!

    • DaveT says:

      Jim: Thank you for your note. I am going ahead and posting your question in hopes others will jump into this conversation. you have a large project. I will do some homework and try and respond as soon as I can.

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