Top 3 Best Propane Tankless Water Heaters (2025 Review)

Do you want to find the best propane tankless water heater?

Propane tankless water heaters can be an efficient and space saving way to heat water.

In this product review, I go over...

  • My #1 top pick for the best propane tankless heater
  • Choosing the correct flow rate
  • Why you should install flush valves

Let's get started with this guide!

top best rated propane tankless water heater reviews

ImageProduct
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1. Rinnai V53DeP
  • Propane Fired
  • 5.3-GPM Flow Rate
  • WiFi
  • Propane Fired
  • 5.3-GPM Flow Rate
  • WiFi
View on Amazon
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2. Rinnai V65iP
  • Propane Fired
  • 6.5-GPM Flow Rate
  • WiFi
  • Propane Fired
  • 6.5-GPM Flow Rate
  • WiFi
View on Amazon
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3. HappyBuy 18L
  • Propane Fired
  • 4.8-GPM Flow Rate
  • 0.80 Energy Factor
  • Propane Fired
  • 4.8-GPM Flow Rate
  • 0.80 Energy Factor
View on Amazon

Our Overall #1 Rated Pick

My overall top pick for the best propane tankless water hater goes to the Rinnai V53DeP because it has an energy factor rating of 0.81 and a max flow rate of 5.3-GPM. 


The nice thing about this heater is that it can be WiFi-connected so that you can control the schedule through your phone or even put it into vacation mode. It is also very compact with a small footprint.


This Rinnai unit is the best propane tankless water heater currently for sale! Rinnai quality can't be beat and it frequently goes out of stock so order it on Amazon for quick shipping.

What Are Propane Tankless Water Heaters?

Propane tankless water heaters can be a very efficient and space-saving way to heat your home's water. Propane itself is a clean-burning alternative fuel that has been used for a long time to power heavy duty propane vehicles.

These tankless heaters work basically the same as natural gas tankless units, and that you connect your cold and hot water lines to the heater, and a propane gas line. You will have isolation valves (shutoff valves) for the hot and cold as well as a shutoff valve for the propane line.

I also recommend that a flush valve kit is installed with propane tankless water heaters.

Read Also: How To Flush A Tankless Water Heater? 

Why Install Flush Valves For Propane Tankless Heaters?

Flush valves are inlet and outlet valves where you can connect flexible water lines to them. These water lines (such as washing machine hoses) will allow you to drain the tankless water heater and circulate vinegar through the unit.

This is required annual maintenance in order to remove scale (lime buildup) on the inside of the heat exchanger, and to reduce the risk of corrosion. The flush valves will also allow you to quickly drain the tankless heater if cold temperatures threaten to damage the unit.

Read Also: What Are The Best Condensing Tankless Water Heaters?

top best rated propane tankless water heater reviews

How To Choose The Flow Rate For Propane Tankless Water Heaters?

For any propane tankless water heater, it is important to choose the right capacity or flow rate of the unit. Most propane tankless water heaters will have maximum flow rates between 3-GPM (gallons per minute) and 8-GPM.

Peak Demand

To calculate the correct flow rate, you will need to add up the GPM rating of all your household fixtures/appliances that use how water so you can know the 'peak demand'. Peak demand is how much how water these fixtures will use if all were turned on at the same time.

Read Also: How To Adjust Temperature On Rinnai Tankless Water Heaters?

Temperature Rise

In addition to peak demand, you want to know your temperature rise. Temperature rise is that the amount that the propane heater will have to raise the incoming cold water to the target hot water temperature.

If you live in a cold climate, you will have to factor in a greater temperature rise during winter, and this requires more energy or a propane tankless heater with higher GPM (and subsequent higher BTU). Unfortunately, when homeowners make the mistake of undersizing propane tankless water heaters, the hot water supply will be limited.

If you have any doubts about calculating flow rate, consulting a qualified plumber is recommended.

Read Also: What Are The Best Tankless Water Heaters For Cold Climates?

What Is The Best Propane Tankless Water Heater?

Here are my complete reviews of the top propane tankless water heaters, check it out below...

The Rinnai V53DeP is a propane-fired tankless water heater that is designed to be installed outside. This Rinnai heater is a medium efficiency tankless heater with an energy factor rating of 0.81.

It has a max flow rate of 5.3 gallons per minute, and is suitable for small to medium sized households. One nice feature about this Rinnai propane tankless heater is that it is compact, smaller than comparable heaters, and can save a lot of space.

The V53DeP can also be WiFi connected and you can control it through your phone, setting timer schedules and other adjustments.

Pros

  • Outdoor installed
  • Energy factor 0.81
  • 5.3 max flow rate
  • WiFi connected

Cons

  • Complaints of shipping damage
  • Will need more than one for larger house

The Rinnai V65iP is a high quality propane tankless water heater that is to be installed indoors.

This propane tankless unit has a max flow rate of 6.5-GPM and is suitable for homes with up to 2.5 bathrooms.

Similar to other Rinnai models, the V65iP can be connected to WiFi, and you can set schedules through your phone and even put it in vacation mode.

This tankless unit has a medium efficiency rating with an energy factor score of 0.80.

Pros

  • Max 6.5-GPM flow rate
  • Control schedules through phone app
  • Up to 2.5 baths
  • Propane fuel

Cons

  • Additional items (venting & fittings) can be costly

The HappyBuy is a premium propane tankless water heater that is great for a small home, cabin, or RV use.

It has a stainless steel outer case that is built tough for outdoor installations with freeze protection as well as a low flow shutoff feature.

The HappyBuy propane tankless heater has a maximum flow rate of 4.8-GPM and it has 81% efficiency or energy factor.

It is easy to make temperature or gas adjustments with this propane heater by simply turning the knobs on the front.

Pros

  • Stainless steel case
  • 4.8-GPM max flow rate
  • Includes portable shower shower head kit for RV/cabin
  • 81% efficiency

Cons

  • Only front panel is stainless

My #1 Top Pick: Rinnai V53DeP

My overall top rated pick for the best propane tankless water heater goes to the Rinnai V53DeP. Here's why...

#1. Propane Fired

You can hook up propane to this tankless unit which is great for homes with propane tanks, RV use, or even a small cabin. This unit also comes with a shower head kit for outdoor showers.

#2. WiFi Connected

This Rinnai propane heater can be connected to a phone app so that you can control timer schedules and even put it into vacation mode.

#3. Compact

This propane tankless water heater is very compact and lightweight so it is easier to install and takes up less bulk.

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