10 Best Filters for Tankless Water Heaters — Rated by Our Team

Water quality keeps getting worse as industrialization spreads, which makes purification equipment more important than ever. But why stop at just filtering when you can heat and filter at the same time?

Tankless water heaters are a smart upgrade over traditional tanks. They’re energy efficient, compact, and give you hot water on demand without the waste of keeping a huge tank heated around the clock.

Here are 10 of the best tankless water heater systems available. I’ve evaluated each one for heating performance, energy efficiency, and how well they protect against contaminants.

Quick Comparison Chart

1. Takagi Natural Gas — Best Overall

The Takagi T-H3-DV-N tankless water heater is best suited for larger households thanks to its very effective and fast heating system. It operates on natural gas and is extremely energy efficient, providing an on-demand hot water supply without ever running out.

The water heater can continuously heat more water due to its sophisticated heating system and tankless design. It produces up to 10 gallons of hot water per minute. For a dedicated pre-filter, consider adding a hot water filter upstream.

It’s perfect for multiple use points, and users never have to worry about running out of warm water as it makes sure instant cold water heating.

This water heater has a longer life compared to other models because natural gas operation leaves little to no point of failure. It also has integrated computerized safety features that make sure it never overheats or runs dry and damages itself.

It comes in a compact package and is very good for space-saving, making it easy to set up indoors.

2. Rheem RTEX-18 — Best Electric

The Rheem RTEX-18 is the best fit for small and medium households with two to three water usage points. It provides a water supply of 4.4 gallons per minute, making it a solid option for around-the-clock hot water.

This tankless water heater features a digital adjustable thermal controller and an on-face digital temperature reader for convenience. It makes setting the temperature according to your needs extremely easy.

The highly durable copper heating elements allow for a long-lasting and dependable lifespan while maintaining high energy efficiency. Pairing it with an inline water filter protects the heating elements from calcium and scale damage. Its functional and space-effective design makes installation extremely simple.

3. Rinnai V65IN — Best Smart Home

Rinnai has a hundred-year history of providing customers with the best quality products and is a highly trusted brand among the masses. The V65IN is an indoor water heater system that operates on natural gas and is very efficient and sustainable compared to older tank heating systems.

It supplies up to 6.5 gallons of hot water per minute, so you never have to worry about running out. The advanced technology and smart heating system circulates water through all your water pipes to supply instant hot water whenever needed.

It comes in a small package that’s extremely space-effective and can easily be installed in any place. The high-quality heating elements make it extremely energy-efficient and minimize CO2 emissions.

This heater can be controlled via the Control-R 2.0 mobile app, which is WiFi ready. It enables users to remotely set timers, create schedules, and put the heater into vacation mode whenever needed from a far-off location.

Rinnai provides a 10-year heat exchanger warranty and a 5-year parts warranty, making it one of the most unique options available. For hard water areas, pairing with a water softener or filter protects the heat exchanger.

4. Ecosmart POU 3.5 — Best Compact

The Ecosmart POU 35 is a super-compact tankless water heater system that’s perfect for apartments and single sink usage. The integrated high-quality copper and stainless steel components make it highly durable and energy-efficient.

As it’s recommended for a single-use point, its energy efficiency is unmatched. Its ability to supply consistent and instant hot water makes it a great option for apartment-style living spaces.

It also features face thermal reading for ease of use. Ecosmart is available in larger sizes for multiple use points, so you can choose the model that best fits your requirements.

5. Titan N-120 — Best Energy Saver

The Titan N-120 is the best tankless water heater filter for most average-sized homes due to its ability to provide an endless supply of hot water. It heats water only when needed, creating savings of up to 60% on your bills.

This water heater features thermal control with four different temperature levels ranging from low, low medium, high medium, and high. You can choose the setting that best fits your needs at any given time.

With its compact and industrial design, installation is straightforward. You never have to worry about running out of hot water thanks to its efficient tankless design and smart heating capabilities.

6. Marey GA10LP — Best Propane

The Marey GA10 comes in two variants: one that operates on liquid propane and another on natural gas. It’s best suited for a family home with its tankless heating system capable of providing a steady flow of hot water to multiple points of use.

The water heater provides a steady flow of hot water on demand instantly whenever needed, heating up to 3.1 gallons of hot water per minute. The best-in-class temperature controls give users the ability to control both the input water flow and gas for top temperature management.

The compact design makes it super easy to install, and a step-by-step guide is included so you can handle installation yourself without any third-party charges. Since it operates on gas, it can save considerably on electricity bills and is an amazing choice for areas that experience frequent power outages.

Its rustproof design helps with no water is lost due to leakage.

7. Eemax EEM24013 — Best Self-Modulating

The Eemax EEM24013 is best suited for small residential or commercial heating needs, good for up to two use points. Its highlighting feature is the most advanced self-modulating technology available.

In simple terms, the unit adjusts how much energy it needs to consume based on how much water needs to be heated. This makes it extremely power efficient, heating only the water you need when you need it.

It features a dial for precise temperature adjustment along with a digital temperature reader on the face. The stainless steel components and advanced manufacturing process guarantee rustproof and contamination-free water supply.

8. Camplux TE11 — Best Modern Design

The Camplux TE11 is a sleek and modern tankless water heater that has been developed by years of experience to fit into modern homes with style. Its state-of-the-art manufacturing and high-quality stainless steel components guarantee long-lasting durability.

The remote controller is handy for setting temperatures and saves your favorite settings for easy recall with a single press. The heater is compact and offers multiple mounting angles so you can place it wherever suits you best.

It also comes packed with safety features and on-face touch controls for temperature adjustments. The digital display provides real-time temperature information at a glance.

9. Eccotemp L10 — Best Outdoor

If you’ve ever been camping or staying at a cabin with no hot water, the Eccotemp L10 is for you. Pair it with a hose water filter for cleaner input water at the campsite. It’s designed for outdoor use and operates on liquid propane that can easily be carried to a camping site or cabin.

With Eccotemp’s weatherproof rain cap design, it’s perfect for outdoor conditions. It comes with all necessary parts for easy outdoor use, including a chrome showerhead and a stainless steel hose.

All you need is a gas cylinder and a garden hose for water input, and you’ll have instant heated water wherever you need it. The automatic safety shutoff timer provides added peace of mind during use.

10. Stiebel Eltron DHC-E12 — Best Multi-Point

Stiebel Eltron makes many models of different sizes, but the DHC-E12 is their best tankless water heater for multi-point usage. It’s feature-packed with the latest technology and highest quality components for a long and reliable experience.

Its sleek and compact design makes it easy to place anywhere. It features highly advanced self-modulating technology that makes it extremely energy efficient while maintaining consistent temperatures.

The temperature adjustment dial on the front cover is capable of making micro-adjustments to the heating output. The copper components make sure a long lifespan, and the advanced microprocessor maintains constant temperature even if the water flow rate varies.

Do Hot Water Heaters Have Filters?

Filters are necessary for tankless heaters. When hard water is heated, many heavy minerals and other contaminants lead to scale buildup in the pipes of the tankless heaters.

Dust and other grime may enter the exhaust system, leading to lesser airflow within the heater. Using a proper filter cartridge can prevent this buildup. This can reduce the capacity of the heater over time.

To prevent scale buildup, it’s advisable to have a whole house water filter installed. This will help remove contaminants from the water entering your tankless heater and extend its lifespan significantly. A sediment water filter upstream of your heater is especially important for well water homes.