The best propane tankless water heaters can potentially save you up to hundreds of dollars per year on your hot water heating costs.
Sounds like a pretty good deal, right?
Well, there is a pesky word in that first sentence.
You may or may not save money.
Getting a propane on demand water heater if you’re looking to replace a tank is probably going to save you some money.
You just need to buy the right one.
There is no one size fits all scenario, so I will try to highlight all the information you need to make an informed choice.
Before I get into the in-depth article, check out this handy comparison table to see how the propane tankless water heaters reviews stack up against each other.
In this article:
- Tankless Propane Water Heater Prices
- Calculate How Much Propane You Need
- How Much Propane Does a Tankless Water Heater Use?
- Installation Costs
- Propane Tankless Water Heater Savings
- Best Outdoor Propane Tankless Water Heater | Rheem RTG-95XLP 9.5 GPM Review
- Takagi T-KJr2-IN-LP Indoor Propane Endless Water Heater Review
- Bosch 830 ES LP Therm Review
- Rinnai RL94IP Propane Review | The Best Whole House Propane Tankless Water Heater
- Marey Power 10L 3.1 Review | Best Cheap Propane Tankless Water Heater
Tankless Propane Water Heater Prices
This is the million dollar question that everybody thinking about a tankless water heater has.
How much does a propane tankless water heater cost?
There are a couple of variables at play here.
How much the actual inline water heater costs to purchase and how much it costs to operate a tankless propane water heater.
In this article, I review the top five propane tankless water heaters that vary in price, so to get a ballpark idea of how much it costs to buy one, you can simply look at the comparison table above.
Expect to pay anywhere between a few hundred dollars to over one thousand depending on the size you need.
For operating costs, this is a very difficult question to answer. Not least of which because of the varying price of a gallon of propane. Depending on where you live and the time of year, the prices can change dramatically.
Calculate How Much Propane You Need
As an average, a gallon of propane costs $2.40 at the time of this writing.
But, what does that really mean? That’s how much it costs per gallon but how much hot water will that gallon of propane produce?
To break this down into bite sized chunks, let’s start with BTU.
There are 91,502 BTU in a gallon of propane. It takes 1 BTU to heat up 1 pound of water 1 degree F.
To understand how much propane you will use over the course of the day with your tankless propane water heater, we need to calculate the BTU you will use.
How Much Propane Does a Tankless Water Heater Use?
We can only deal in generalities and analogies since I can’t actually know how much water you will use, what your temperature rise is, etc.
Here are the metrics you need to start with.
1 gallon of water weighs 8.35 pounds
1 BTU will heat 1 pound of water 1 degree
To heat a gallon of water up by 1 degree, it takes 8.35 BTU
That is the starting point. That part does not vary at all. What does vary is how much you need to heat your water and how many gallons per minute you use, then how many gallons per day you need to heat.
Hypothetical example time!
Here is how much it may cost to take showers
2 Person Household
1 shower each per person per day
1.5 GPM low flow shower head
15 minute shower per person per day
1.5 gallons per minute x 30 minutes = 45 total gallons
45 gallons of water x 8.35lbs = 375.75 pounds
Hypothetical temperature rise = 35°
375.75 x 35 = 13,221.25 total BTU for this scenario
At a cost of $2.41, that means those two showers will cost $.35 per day.
Obviously, you also will be doing laundry, washing dishes, running a faucet, etc. This is just a good starting point to see how you calculate how much propane you will need per day to run a tankless water heater.
Again, there are too many variables to put a firm number on how much it costs to install a propane tankless water heater.
Let’s assume you already have a propane tank and are looking to install an indoor tankless propane water heater.
You’ll need to have gas lines of ½ inch or ¾ inch depending on the make and model of the on demand water heater.
If you already have the right size gas lines then all you will need is for a plumber to run water lines to where you need the unit. Then a venting system will need to be installed to run the exhaust out of the house.
A professional can usually have this done in 2 to 3 hours depending on how you’re already set up.
Find out how much it costs for labor per hour in your area for a good plumber and that is your labor cost.
For venting, pipes and other accessories, plan to spend an additional few hundred dollars.
There is no doubt that a propane tankless water heater is going to cost more than an electric, so if budget is a concern you may want to consider an electric unit. Of course, there are some huge differences between the two so make sure you read my article that compares gas and electric tankless water heaters so you can see which one is right for you.
To find out what size tankless water heater you need, check out this article with a handy sizing calculator to zero in on the right one for you!
Propane Tankless Water Heater Savings
Now for the good part!
How much will you save by using a tankless propane water heater?
Generally, you can expect 20-30% savings on your propane usage per month on average.
Propane is not exactly cheap, but it is efficient with BTU usage and using a tankless on demand water heater vs a tank system make it even more efficient.
Generally, people report saving $200 or so per year on their propane by switching to tankless.
Another factor in the savings department is the longevity of a propane tankless water heater. They last much longer than tanks. Not needing to replace the inline water heater as often will also save money. Where a tank water heater lasts an average of 7 years, a tankless can last 15 or more.
It will eventually end up paying for itself with those kinds of savings.
Best Outdoor Propane Tankless Water Heater | Rheem RTG-95XLP 9.5 GPM Review
- 9.5 GPM Water Flow
- Outdoor with Remote Control
- Low NOx Emissions
- Hot Start Programming – No Cold Water Sandwiches
- Self-diagnostic system
- Very expensive
When you spend over a thousand dollars for a tankless water heater you have high expectations that should be met.
What a nice surprise then when you purchase the Rheem RTG-95XLP propane tankless water heater.
It gives you the high water flow you would expect for the money with 9.5 GPM which can supply a medium sized house with endless hot water. In addition, it has some nice features that put it above the competition.
Hot Start Programming
Namely the Hot Start Programming that does away with cold water sandwiches.
A cold water sandwich is a slightly annoying feature of most tankless water heaters. It happens when the hot water is turned off and the tankless stops heating the water. Obviously, the water is now cold since it is not stored hot in a tank. If you turn the water on right away, the water comes out cold until the heated water can reach your fixture. The dreaded cold water sandwich is no more with the Rheem RTG-95XLP!
The Rheem RTG-95XLP stays in a ready fire state so that back to back uses don’t end up getting cold.
After 500 uses, the Rheem RTG-95XLP will send an alert to the homeowner that it should be checked out. This is especially true if you live in an area with hard water to check on any scaling. If so you may need to do a flush to clean the heating elements and keep them in good working order.
Any problems with the tankless water heater will be detected by the inner circuitry and will also be sent in an alert.
Water Savings Setting
If you decide to set this feature up, then you can have it so that the water flow is lowered while you wait for the hot water to arrive at the fixture.
This can save up to 1,100 gallons of water per year.
It is totally optional, though, so if you want full flow and less time to get hot water to the faucet, then you can keep this feature off.
Good news for the homeowner is that this is an outdoor unit so there is no venting necessary.
This saves quite a bit of money since installation can be done by anybody with any kind of basic DIY ability. It’s just a matter of finding a spot outside and hooking it up to the gas and water lines.
The only part that is slightly intrusive is drilling a hole through the wall to run the remote control to the inside of the house. You’ll need this to be done to avoid having to go outside to adjust the tankless water heater when you want to change the temperature.
Cold and Altitude Resistant
Don’t worry if you live somewhere that has some cold winters or if you live at high altitude.
You can live anywhere up to 8,400 feet of elevation without any chip necessary to reprogram the propane on demand water heater. It will work the same as at sea level.
And even exposed outside, it will work efficiently in temperatures that go as low as -30°F.
Got a cabin out in this mountains? You’re still covered even if you can’t find a professional to come out and install this for you!
What to Watch Out For
I wouldn’t classify the following features as negatives, but something that you should be aware of.
Namely, it is activated at 0.26 GPM of water flow but won’t start heating until it detects 0.4 GPM. If you’re using a low flow faucet that gives up less than that, then you will end up with cold water.
The other thing to consider is that this is under Rheem’s class of “medium efficiency” tankless water heaters. It has an 82% efficiency rating.
You’ll still see some savings even at that efficiency rating. Something in the 20% range of what you are spending now if you have a tank hot water heating system.
The high price tag might put some people off, but saving on the cost of installation should offset that. Together with the fact that you get very good GPM water flow, an intelligent operation and a very sturdy and durable propane tankless water heater, the Rheem RTG-95XLP is definitely worth the money.
- All copper heat exchanger
- 3″/5″ concentric vent system with an integrated condensate collector
- Requires 120V power supply
- Activation flow rate of .40 GPM
- Weighs 54 pounds
- Size = 14 x 10 x 26 inches
Takagi T-K4-IN-LP Indoor Propane Endless Water Heater Review
- Great price
- 6.6 GPM max flow rate
- Includes remote control
- Ideal for small homes
- Low NOx emissions
- Many safety features
- Vent fan can be noisy
If you live in a small to medium sized household, then the Takagi T-K4-IN-LP is tailor-made for your needs.
It can be very tempting to go well over what you think your water demand is, but using a tankless water heater that is made for your type of usage is the smart play.
One of the points of having a propane tankless water heater is for it to pay for itself over time with the savings you get from reducing your propane usage.
Takagi makes an excellent tankless water heater and leads the industry in catering to its medium sized household customers.
Here are some ways that the Takagi makes sense for you.
Since this is the first thing most people are concerned about, we should start with how cost-effective the Takagi T-K4-IN-LP is.
Many propane tankless water heaters in the same category are easily hundreds of dollars more and in some cases are even twice the cost.
This does not mean it is cheap. It means you are getting a good deal on something that can have a big effect on your propane bill.
Takagi T-K4-IN-LP Installation
Installation is pretty straightforward in most cases. The venting is 4inch stainless steel which is fairly common in most houses. This is where the cost of installation can vary, of course. If you need to do custom venting, then the cost certainly rises here.
If you are at all handy then the installation can be done yourself.
The instructions that come with the Takagi T-K4-IN-LP manual are easy to follow and very detailed. A DIY installation shouldn’t be too difficult for most people.
The downside is that the venting kit does not come included and must be bought separately.
At a 30°F temperature rise, you can get a water flow rate of 6.6GPM. What this means is that you can have two showers and a washing machine running without any issues like the water getting cold.
That temperature rise is not going to be in effect for many parts of the country outside of the warm Southern and Southwestern states.
However, even at a temperature rise of 50°F and the output temperature set to 105°F, you can still get 4.2 GPM which is pretty good for a small or medium sized household.
Here is the temperature rise chart to see how it fares with different incoming and outgoing temperature settings.
With water inlet and outlet thermistors, the Takagi T-KJr2-IN-LP can give a highly accurate reading so you can get the exact temperature that you want and maximize the GPM water flow rate.
What to watch out for
As is the case with any tankless water heater, the warranty is void if you do the installation yourself. If you are unsure of how to do the installation without making an error that could jeopardize the functionality of the propane tankless water heater, then you may want to consider a professional.
That said, however, the cost of the Takagi T-K4-IN-LP is lower than what you would pay for the installation, so even if you void the warranty by doing it yourself, you’re probably going to save money anyway.
With a bunch of safety features which include freeze protection in case you lose heat in your home, the thermistors to keep the temperature of the water from getting too hot and automatic shut off give a lot of peace of mind.
The low purchase price and the savings over time make it a very good value. It is not going to be ideal for everybody especially for those with high water demand, but that is the nature of propane inline water heaters in general.
If your needs line up with the features of the Takagi T-K4-IN-LP, then you’re going to be happy!
- 140,000 BTU
- 38 lbs. weight
- Direct Vent Stainless Steel
- All Copper Heat Exchanger
- Safety Devices: Flame Sensor, Overheat Prevention Device, Freeze Protection
- 3/4″ Water Connection
- 6.7 x 13.8 x 20.3 inches
Bosch 830 ES LP Therm Review
- 8.3 gallons per minute capacity
- Patented burner design
- Energy Star rated certified
- Built in freeze protection
- Electronic ignition
- Very expensive
We might be seeing the end of the days of the cold water sandwich that is a common problem with tankless water heaters.
This is the second propane on demand water heater on the list that has solved that problem. This time it is the Bosch 830 ES LP Therm.
With a unique design to the heat exchanger, there is a modulating temperature sensor that supplies a constant flow of hot water while still keeping propane consumption low.
Bosch being a German company means some good engineering and attention to detail.
8.3 GPM flow rate at a 35°F temperature rise makes this a very good choice for medium to large sized households.
If you live in a warm part of the country then you can enjoy that high GPM pretty much year round.
In colder climates, obviously, the GPM will be lower so make sure you understand how much water demand you have at your peak point of the day.
As I mentioned, you can expect some good engineering from this propane tankless water heater. The Bosch 830 ES LP Therm is confident that it will last a while and back up that thought with a 15-year heat exchanger warranty.
Tankless water heaters are known for how they can last much longer than a tank, but this warranty shows that Bosch goes above and beyond when it comes to longevity.
Though it is only rated at 83% efficient, this is definitely good when it comes to propane. Since propane is energy dense it is naturally more efficient than natural gas or electric so even 83% will give you savings of up to 30% from your propane usage.
It is Energy Star rated and can qualify for some healthy rebates from the government.
There is no pilot light that wastes propane as it has an electric ignition.
The Bosch 830 ES LP Therm is quite flexible when it comes to installation. It can be vented vertically or even horizontally. The vents need to be stainless steel but can either be 3 inches or 4, adding to the versatility.
This can give you some savings on installation since you may not be constricted by where and how you install it. Often, the installation costs get higher when there are limiting factors and your plumber has to do a custom fitting for it to work.
This also means that you may be able to install this yourself if you have any type of handy abilities.
What to watch out for
There really isn’t much of a downside to this tankless propane water heater. The only thing that really comes up is the price.
What makes this more expensive than other tankless water heaters that can provide the same BTU and GPM?
Two things come to mind immediately. Longevity first and foremost. This unit will pay for itself many times over during the course of its long lifetime.
Then there is the elimination of the cold water sandwich through the unique patented heat exchanger.
I love Bosch products and the Bosch 830 ES LP Therm is no exception to the rule that they make some very good appliances.
A 15 year warranty for the heat exchanger says a lot about how confident that Bosch is that your unit will be dependable. This should give you some good peace of mind that you’re getting good value for the money.
- 83%+ thermal efficiency
- Vertical or horizontal venting
- 175,000 max input (BTU)
- 0.5 minimum flow activation trigger
- Weighs 74 pounds
- Size is 11.2 x 17.9 x 30.5 inches
- Gas and water ¾” NPT inlet
Rinnai RL94IP Propane Review | The Best Whole House Propane Tankless Water Heater
- Great for large households
- 9.4 GPM water flow
- 1/2″ Gas Line Compatible
- Wifi ready (sold as an add on)
- Recirculation system for instant hot water
- Low NOx emissions
- More expensive than others in class
When it comes to the best whole house propane tankless water heater, then you can’t do much better than the Rinnai RL94iP.
With 9.4 GPM, a recirculation ready system to keep water hot and wifi ready to monitor your usage, it is the best way to say money and enjoy endless hot water.
Here are the features that set Rinnai apart from other inline water heaters.
At a 30°F temperature rise, the Rinnai RL94iP can give you 9.4 gallons per minute water flow rate. That is enough to keep hot water flowing at multiples fixtures at the same time.
A family of four with teens will have no problem running two showers, a faucet and a washing machine at the same time. And with hot water to spare.
The minimum flow to trigger the heater is 0.4 GPM, which is pretty much standard among the better brands.
Installing a Rinnai RL94iP is no harder or easier than any other indoor tankless water heater, but what is better are the instructions. They make it very easy for somebody who is even only moderately handy complete the installation.
Of course this all depends on your home and where it will be located. And it needs to be done carefully to avoid any gas leaks or malfunctions.
Adding to the versatility is the fact that it is compatible with ½ inch gas lines so it can be used in older homes without an expensive upgrade of gas lines.
And as is the case with every other brand, the warranty is void if you install it yourself, or use somebody who is not certified to install Rinnai specific tankless water heaters.
The money saved by installing it yourself is more than the cost of the unit, generally, anyway.
This is a mid efficiency tankless water heater that gets an 83% thermal efficiency rating. This is still enough to return up to $400 per year in propane savings at the current $2.41 cost per gallon of propane at the time of this writing.
What can end up neutralizing the propane savings, however is using the recirculation pump to make sure there is no delay in hot water arriving to the fixture.
As I just mentioned there is the optional recirculation pump that continuously circulates heated water throughout the water lines to make sure that you get instant hot water in addition to endless.
This is optional and doesn’t impact the operation of the Rinnai RL94iP if you choose not to have it.
Another nice feature is the Wifi ready system. This is an add on and is not already set up, but is a very nice way to monitor your usage.
Called Control-R, it is an app that connects your smartphone to your Rinnai RL94iP. Through the app you can change the temperature settings and if you have the recirculation pump set up, turn that on. This avoids the water being heated and circulated when it isn’t needed.
It can also send you maintenance alerts by programming the alerts to happen after a set number of operating hours.
Rinnai is known to be one of the leaders in tankless water heater technology. With the extras that make owning the Rinnai RL94iP as easy as can be, it doesn’t come much more convenient as this.
Easy to install, easy to use and providing whole house endless hot water, it is very easy to recommend this.
It is quite high in price, but with the extras that set this apart, and the fact that it can pay for itself in just a few years it really is suddenly doesn’t seem so expensive.
- 10,300 – 199,000 BTU/h
- Direct electronic ignition
- Minimum activation flow rate: 0.4 GPM
- Includes isolation valves for easy maintenance
- Weighs 50 pounds
- 9.3 x 14 x 23 inches in size
Marey Power 10L 3.1 Review | Best Cheap Propane Tankless Water Heater
- Great low price
- 3.1 GPM for small home or cabin
- No electrical connection needed
- Easy to install
- Supports cascading multiple units
- 1.0 GPM minimum flow activation
Let me start by saying that the Marey Power 10L 3.1 is not a perfect solution for everybody. The reason for the review is to show that you can get a good propane tankless water heater even at a very cheap price.
You’ll need to carefully evaluate if this inline water heater is going to serve your needs before you purchase.
With a maximum 3.1 gallons per minute flow rate, this really should not be advertised as a whole house on demand water heater.
With low flow fixtures, you may get two showers running simultaneously, but that is only if you have a 30°F temperature rise.
Realistically, you may get a shower and a dishwasher running at the same time. If you have a bigger house with high water demand, then there is the benefit that you can install multiple units and use the cascade feature so they sync up with each other. The low price makes this a very attractive option when you need higher GPM.
The downside is that the minimum activation GPM is 1.0. If you have a fixture that runs less than that, then you won’t activate the heat exchanger and you will not have hot water.
This is one of the best propane tankless water heaters for the DIY installer. There is no electrical connection necessary, so that adds to how easy it is to install.
Both the gas and water lines are compatible with ½ inch pipes so it can be used in older homes or RVs and makes the installation much less complicated.
The only thing to really make sure of are the local codes for venting.
The installation instructions are very clear and will give the multiple options available for the venting materials.
Who is this best for?
This propane tankless water heater is ideal for small households. If your water demand is low then you can enjoy endless hot water.
People that live off grid will also see some nice benefits. It uses two D batteries so it does not need to be hooked up to an electrical connection. For off grid living, this is a nice bonus.
RVs and cabins are also an ideal application for the Marey Power 10L 3.1.
This is not the best propane tankless water heater out there. It does have some inconvenient features like the high minimum activation flow rate and the inability to set the water temperature in small increments.
That said, if you are on a tight budget and have low water demand, then it makes sense to purchase the Marey Power 10L 3.1.
- Weighs 21 pounds
- The size is 6.9 x 13.6 x 23.6 inches
- Two D batteries required (not included)
- 79,228 Max BTU
- Energy efficiency up to 87%
LP gas tankless water heaters are not a one size fits all scenario.
Everybody’s needs are different, so what works for me may not work for you.
I hope that after reading these propane tankless water heater reviews you are closer to making a purchase. A purchase that will surely change the way you approach heating your water.
I am here to help so if you have a question about any of these tankless propane water heaters on this list, or any that didn’t make the list, then drop a comment in the box below and I will get back to you ASAP!