Tankless Water Heater Buying Guide: What to Look Out For When Buying a Tankless Water Heater

Last updated on April 26th, 2024 at 01:10 pm

Image from Amazon

As part of my interest in green products, I thought it will be beneficial to the visitors to my site for me to write and provide information in a review about what to look for when you purchase a tankless water heater.They are also called on-demand or tankless water heaters.

So what are tankless water heaters? On-demand or tankless water heaters basically start producing hot water only when you turn on your tap or faucet.

The main difference between a tankless water heater and a conventional tank water heater is the absence of a storage tank. A tankless water heater basically works by heating up your water as it runs through its heating coil when you turn on your faucet or tap. So there is only hot water only when you turn on your faucet.

During my research for this buying guide, besides in store units I have also considered units that are sold online from sites like eBay, Lowes, Home Depot and Amazon.

One good thing about shopping online is that you can get it at a much cheaper price than local shops due to the removal of charges like rental and overheads. These sites have readily available stock with free shipping for most areas, saving you the hassle of transportation.

During the process of researching I have also discovered that, among the online sites, Amazon has the widest range of products available and with the lowest price tags for most products. So here is the link for the tankless heater models and their prices carried by Amazon: Tankless Water Heater Best Deals.

So without any further a due…

What to Look Out For When Buying a Tankless Water Heater?

Image from Amazon

Tankless water heaters are available in different sizes, production capacities, source of fuel and of course different brands. An obvious thing to look out for is the Size and Weight of the tankless water heater that you are interested.

This is important especially since some models will be mounted on the wall. However not to worry most models especially those produced by household names like Rinnai and Rheem are actually very small, compact and lightweight.

Next up is the Capacity of the water heater that you will be requiring in your household. It is measured in gallons per minute (GPM)There are many capacitites of tankless water heaters readily available online or on the market.

Your heater’s capacity is very important especially if your household is a big one or your usage is very big.  For such situations, you will require a tankless water heater with a larger capacity like the Rinnai RL94iN, or a Rheem RTG-95DVN.

However if your usage is going to just to provide heated water for a bidet, a model with a smaller capacity like the Rheem RTE 9 will be suitable for you and less of a burden on your budget! At the end of the day… Not One Size Fits All!

Summary of Specifications for Eccotemp L10

Dimensions Height = 28.0 in.
Height + Raincap = 35.0 in.
Width = 13.5 in.
Depth = 6.5 in.
Weight = 18 pounds
Installation ModeIndoors and Outdoor (Temporary setup)
Production Capacity Maximum of 2.65 GPM
Temperature Range 80-165 Degrees Fahrenheit
Power SourceLiquid propane and 2"D" Battery operated ignition
Ideal Operating Pressure 25-80 PSI
Heating power74,500 BTU
Energy Efficiency 85%


The Energy Factor of your heater should be taken into account as well. This is a measure of the overall energy efficiency of your tankless water heater and to be Energy-Star certified1. Installation of a Energy-Star certified product will allow you to apply for tax rebates of up to 300 USD. So using a tankless water heater lowers your carbon footprint in the long run!

(Download the List of Energy-Star certified Gas Tankless Water Heater here) 


A better energy factor means that your unit has a higher overall efficiency in the utilisation of energy source to fulfil its primary purpose that is to heat up your water. Remember a higher energy factor doesn’t mean you will save in your utilities! But it will ensure that you utilise more energy for heating your water instead of going to useless heat production!

Photo credit Wikipedia.org

Another criteria is the Energy Source powering your heater. There are many types of tankless water heaters available on the market that are powered by different fuel sources like the popular electric-powered Rheem RTE series, the Rinnai tankless water heater series powered by natural gas and propane and the versatile Eccotemp tankless water heater series like the Eccotemp L5 and L10 that are powered by batteries that allows you access to hot water at off-the-grid locations like your log-cabin or campsites.

The energy source will also determine the cost of your utility bills or installation costs that you are going to pay for tankless water heater.  

The Temperature Range of your tankless water heater, and your inherent water supply should also be considered. You will not want to get a unit that do not provide enough heat or need to work overtime to heat up your water supply.

While I am at this issue of Climate, if your region has very cold winters it will not be suitable to install an outdoor tankless water heater for your usage for fear of damage especially to the piping due to froze damage.

Mode of Installation of your heater is another factor to be considered. Tankless water heaters, especially those powered by natural gas, is a relatively new technology but now you can get licensed installers that are readily available to help you install your unit for a cost. However there are also enough successful cases of DIY installation of tankless water heater to show that it can also be a project for those DIY enthusiasts!

Other units like those powered by electricity are essentially just plug-and-play models, with no need for other accessories, but a dedicated 120V power outlet for it to prevent overloading of your power points.

The Accessories that come with the tankless water heater that you bought can also be considered especially if it helps you to save on your costs. Most companies will provide a whole lot of accessories from these essential ones like gas regulators, hose fittings to those even minute ones like Teflon tape.

Another feature that I feel that people can overlook is your access and ease of Adjusting the Temperature of your tankless water heater. However most models like the Bosch tankless water series has digital panels and dials that allow for easy adjustment and display of your selected temperature settings easily and clearly.

The Length and Coverage of Warranty that covers your tankless water model should also be considered. Here is the link1 to Energystar.gov that shows the length and type of warranty that you will be getting for your Energy-Star certified tankless water heater models.  A related subject to this will be the Customer Support for your tankless water heater model.

While I am sure that all companies strive to provide quality after sales services, some companies especially Eccotemp has been mentioned by customers to provide exceptional support and sometimes going the extra mile like ensuring the delivery of a replacement spare part to a customer the next day plus showing patience on the phone lines.

I have also provided a list of references and links to useful websites that provide a more in-depth explanation of some bits of information like energy factor that I have explained in passing in the buying guide above. Hopefully this Tankless Water Heater Buying Guide is useful for you!

List of References

1) http://www.energystar.gov/index.cfm?c=water_heat.pr_crit_water_heaters (accessed 29th April 2012)


(Last Updated 29th April 2012)



  • Wilson Yeo

    I am the admin of Green Energy Helps and I possess a keen interest in how green energy and leading a green lifestyle can help to reduce our individual carbon footprints. I will be providing information about green energy and lifestyle tips with unbiased reviews on green products for your consideration. Note: This website uses affiliate links which may earn a commission for purchases made at no additional cost to you.

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