Do you want to find the best tankless water heater for cold climates?
Even though most tankless heaters have internal heaters to protect against freezing, they all have outdoor temp ratings which they can't go below.
In this product review, I will go over...
- My #1 top pick for the best tankless water heater for cold climates
- How to protect your pipes from freezing
- Choosing the flow rate
- Indoor vs Outdoor Tankless Heaters
- And why electric heaters can't handle very cold water
Let's get started with this guide!
| Image | Product | |||
|---|---|---|---|---|
Top Pick  | Top Pick | Rheem
|
| View on Amazon |
 | Rinnai V65IN
|
| View on Amazon | |
Best Outdoors  | Best Outdoors | Rinnai V53DeP
|
| View on Amazon |
 | Takagi
|
| View on Amazon | |
 | Noritz
|
| View on Amazon |
My Overall #1 Rated Pick
- Freeze protection
- Includes electric blower
- 8.4-GPM Max
- Energy Star Certified
- Natural Gas
- High efficiency Condensing
- Lower Cost PVC Venting
My overall top pick for the best tankless water for cold climates goes to the Rheem Prestige heater. This tankless unit has the power to give you on demand hot water even when the supply water gets very cold. It is a high efficiency condensing unit and can provide up to 8.4 gallons per minute of water. It is energy star certified, runs on natural gas, and it uses lower cost PVC for the vent piping.
Top 5 Cold Climate Tankless Water Heaters
Short on time? Check out our top 5 tankless water heaters for cold climates below! Keep reading for more details on each pick and to see our buyer's guide.
How To Pick The Best Tankless Water Heater For Cold Climates?
Tankless water heaters can be great alternatives to tanked water heaters because they never run out of water.
The water is heated on demand as it passes through the tankless heater, consistently providing hot water for your household.
But what about areas with cold climates? Tankless heaters can work great in cold areas as well under certain conditions...
Read Also: What Are The Best Outdoor Tankless Water Heaters?
What Fuel Type Is Best For Tankless Water Heaters in Cold Weather?
If your area experiences numerous days below 32F, then I recommend that you opt for a natural gas (or propane) tankless heater rather than electric.
The problem with electric water heaters is that they simply can't handle the colder water temperatures of areas with cold climates, and will heat up the water very slowly—negating the entire point of going tankless. The only exception I can think of is if you have well water just because the water is warmer deeper in the earth.
But if you have an electric water heater during a cold season, you may only get warm water at the tap—not hot water.
Choosing The Flow Rate
One of the most important considerations for a tankless heater to handle cold climates is the flow rate.
The flow rate is a rating of how much hot water the unit can provide on a gallons per minute basis. The higher the flow rate means that the heater will have a higher capability of handling the colder incoming temperature in cold areas. When the cold water supply drops in temperature as the outdoor temp drops, this will automatically reduce the flow rate because more energy is required to raise the temperature.
So if you start with a high flow rate (larger GMP capacity tankless unit), then the drop in flow rate (due to the colder water supply) won't be as significant. But if you start with a lower flow rate, then this may end up with just lukewarm water or hot water supply will be limited.
I recommend that you consult with a qualified plumber to determine the best flow rate for your area of the country. It will depend on how cold your supply water gets during winter, as well as the water needs of your household.
Read Also: What Is The Best Point Of Use Tankless Water Heater?
Indoor Tankless Unit Better Withstand The Cold
For one, if you get several days or more of weather below 32F, then you may want to opt for an indoor unit. With an indoor unit, since the space is conditioned, you won't have to worry about the tankless heater freezing unless it is installed in an unconditioned garage.
Since tankless heaters are so compact, they can be installed in a basement, a closet, or other small area. If the indoor heater is installed in an unconditioned area, then some of the same rules as outdoor heaters will need to apply.
Buying Tips For Outdoor Tankless Heaters
If your only option is to install a tankless heater outdoors, then there are a few considerations. For one, you better make sure you know what outdoor temperatures the heater can withstand.
Temperature Ratings
For the Rinnai V53DeP for example, will not freeze even if the outdoor temperature goes as low as -4F if it maintains electrical power.
This -4F temperature rating also only applies if the tankless heater has wind protection.
If there are high winds, the wind chill factor can make the outdoor temperature much colder.
Read Also: What Are The Best Outdoor Tankless Water Heaters?
Heat Tape To Internal Piping Prevents Freezing
In cases where the outdoor temperature will go far below the temperature rating of your unit, you may need to apply some heating tape to the internal piping of the tankless heater.
This video by a builder named Matt Risinger shows how to do it:
Protect The Exterior Piping
This buying tip can apply for indoor units but mainly for outdoor units. Even though most outdoor tankless heater have internal heaters that offer some freeze protection, they will not protect the exterior piping.
And if the exterior piping to the heater freezes, it will cause the tankless heater to freeze and malfunction—possibly damaging the unit. In addition to the external plumbing, you will also need to protect any condensate lines as well.
If the condensate line freezes, this will also cause the unit to stop working and possibly harm it. You can protect your tankless water heater by ensuring that all pipes are covered in insulation (including the condensate line) or wrap them with heat tape. However, the heat tape will only keep providing protection as long as you have power.
Read Also: What Is The Best Point Of Use Tankless Water Heater?
What Is The Best Tankless Water Heater For Cold Climates?
Here are my full reviews for the best tankless water heaters for areas with cold climates. Check it out below...
The Rheem Prestige Series tankless condensing water heater (RTGH-84DVLN) is a premium high efficiency indoor heater with 157,000 BTUs. This Rheem heater has an electric heater for freeze protection in cold climates and can handle outdoor temps as low as 30F.
This ultra efficient tankless unit is powered by natural gas and can handle the water temperatures associated with cold climates. This tankless water heater has a low NOX burner which is great for the environment, it is also energy certified.
It also has a high capacity at 8.4 gallons per minute (max rate). This Rheem tankless water heater is energy star certified and has a very high Energy Factor score of 0.94.
Link to manual.
Pros
Cons
The V65IN is a high quality indoor tankless water heater that is great for cold climates. This unit requires a condensate collector for cold climates, and it can handle temperatures up to -22F for this indoor model and not freeze if power is maintained.
This indoor tankless unit uses natural gas to heat the water, and it has an Energy Factor (efficiency rating) of 0.82. The nice thing about this tankless water heater is that you can control it remotely through a phone app.
The maximum output of the V65IN is 6.5 gallons per minute (maximum) which is good for small to medium sized houses, and it is rated at 150,000 BTUs. Another great feature about this Rinnai heater is that it has leak detection technology which monitors leaking and can even turn on the unit.
Link to the manual.
Pros
Cons
The Rinnai V53DeP is a great outdoor tankless water heaters that can be used in cold climates. This tankless heater can handle outdoor temperatures up to -4F if it maintains power and is protected from the wind.
It can produce a maximum of 5.3-GPM and it has a max 120,000 BTU. A nice feature of this Rinnai heater is that you can control it using a phone app, and even put it in vacation mode.
This unit has a medium efficiency with an Energy Factor rating of 0.82.
Link to the manual.
Pros
Cons
The Takagi TH3DV is a powerful indoor tankless water heater that can handle the water in cold climates, and uses natural gas. This 199,000 BTU heater has a maximum output of 10-GPM.
It is also highly efficient since it is a condensing heater with an Energy Factor of 0.95. This Takagi heater is also sophisticated, it doesn't use a pilot light and has computerized safety features.
The heat exchanger uses a commercial level copper alloy for durability and a long life.
Link to manual.
Pros
Cons
The Noritz NRC661-DV is a compact indoor tankless water heater that can handle the colder water temps of cold climates. It has a max BTU output of 110,000 and a max 6.6-GPM.
This tankless heater has automatic freeze protection from temperatures down to 30F if the combustion air intake is from outdoors. If below 30F, it will need additional freeze protection measures.
Since it is a high efficiency condensing heater, lower cost PVC piping can be used for the venting. It also comes with a remote thermostat.
Link to manual.
Pros
Cons
My #1 Top Pick: Rheem
My top rated pick for the best tankless water heater for cold climates goes to this Rheem indoor heater. Here's why...
#1. High BTU
This tankless heater has a max of 157,000 BTUs which means if your groundwater or cold supply is very cold, this tankless heater can still give you on demand hot water.
#2. Indoor
This compact tankless unit can be installed anywhere indoors even a closet which is great if you want to save space.
#3. PVC Piping
Since it is a high efficient unit, this Rheem heater uses PVC piping which is less expensive that installing double walled venting.
2 thoughts on “Top 5 Best Tankless Water Heaters For Cold Climates (2025 Review)”
Looking for a small Electric tankless for small cabin in Montana. Would not be there in winter, would be indoor. Would I need to drain(winterize) ? Any additional information would be appreciated
Thank You
Hi Linda,
I recommend buying a tankless water heater that has some freeze protection built-in, but it is always recommended to winterize the unit if you will be away for long periods.
Cheers,
Arie