If you’ve ever stepped into a shower expecting warmth and instead got a blast of icy water, you know how frustrating unreliable hot water can be. For decades, traditional tank-style heaters have been the standard, but they come with a list of drawbacks: running out of hot water, wasting energy heating water you’re not using, and taking up a big chunk of space in your home. That’s why tankless water heaters have become so popular—they’re efficient, reliable, and designed for comfort.
In this guide, we’ll go over the best rated tankless water heaters on the market in 2025, how to choose the right one, and a crucial home maintenance tip most people overlook that could save you thousands in repairs. We’ll keep the language simple and the advice practical so you can make a confident choice.
Why Tankless Water Heaters Earn Top Ratings
Tankless water heaters (also called on-demand water heaters) only heat water as you need it. When you turn on a tap, cold water travels through the unit, where powerful heating elements or gas burners bring it to the perfect temperature instantly. The benefits are clear:
- Endless hot water – Never worry about who gets to shower first.
- Energy efficiency – Lower utility bills because you’re not heating water 24/7.
- Space savings – Mounted on the wall instead of taking up closet or basement space.
- Longer lifespan – Many models last 20+ years with proper care.
It’s no surprise that once homeowners make the switch, they rarely go back to tank-style heaters.
Best Rated Tankless Water Heater Overall: Rinnai RU199iN Super High Efficiency Plus
The Rinnai RU199iN consistently ranks at the top for performance, reliability, and efficiency. It’s a gas-powered unit that delivers enough hot water for even the busiest households.
- Flow rate: Up to 11 gallons per minute (GPM) – perfect for running multiple showers and appliances at the same time.
- Efficiency: High energy factor that keeps bills lower without sacrificing output.
- Design: Compact, wall-mounted, and built with durable materials.
- Warranty: Backed by a strong manufacturer guarantee.
If you have a family, entertain guests often, or just want the peace of mind that comes with a reliable system, the Rinnai RU199iN is hard to beat.
Top Alternatives and Why They’re Worth Considering
EcoSmart ECO 27 (Electric)
This electric unit is a favorite for smaller homes and warmer climates. It’s budget-friendly, energy-efficient, and compact. The main requirement? A strong electrical panel to handle its demand.
Stiebel Eltron Tempra 36 Plus (Electric)
German engineering meets quiet performance. Known for steady temperature control even when multiple taps are running, this model is stylish, reliable, and perfect for households that value quiet operation.
Rheem Performance Platinum 9.5 GPM (Gas)
One of the best rated gas units with smart features like Wi-Fi control, allowing you to monitor and adjust settings from your phone. Ideal for tech-savvy households that like convenience.
Noritz EZ Series (Gas)
Designed for easy replacement of traditional tank-style heaters, the Noritz EZ Series is durable, efficient, and a great choice for colder climates when paired with proper venting.
How to Choose the Right Tankless Water Heater for Your Home
Finding the best rated model for you comes down to understanding your household’s needs:
- Water Demand: Count how many showers, faucets, and appliances might run at the same time. This determines the GPM you need.
- Fuel Source: Gas heats faster and is better for high-demand homes, while electric can be simpler and easier to maintain.
- Climate: Colder incoming water takes more energy to heat, so choose a higher capacity model if you live in a cold region.
- Budget: Don’t forget installation costs—gas models often require venting, while electric models may need panel upgrades.
Pro Tip: Check your home’s existing gas line or electrical panel capacity before choosing a unit. This can save you from surprise installation costs.
Installation and Maintenance
Professional installation is recommended for all tankless systems, especially gas-powered models. Proper venting, connections, and safety checks are essential. Once installed, maintenance is simple:
- Flush the system annually to remove mineral buildup.
- Clean or replace filters if your model has them.
- Check for leaks or unusual noises periodically.
A well-maintained tankless heater will run efficiently for years, delivering consistent performance.
The Forgotten Side of Your Home’s Water System
While choosing the best rated tankless water heater is important, it’s only one part of your home’s water system. After all that hot water leaves your shower or sink, it heads to your drains—and if you have a septic tank, the health of that system matters just as much.
Many homeowners overlook septic maintenance until problems appear: foul odors, slow drains, water pooling in the yard, or backups inside the house. By that point, repairs can be expensive—sometimes several thousand dollars.
Why SEPTIFIX Is the Best Choice for Septic Care
SEPTIFIX is the #1 septic tank treatment in the US, trusted by thousands of homeowners to keep their systems odor-free and functioning properly. Here’s how it works:
- Easy to use: Just drop a tablet into your toilet and flush.
- Fast results: Neutralizes odors in just a few days.
- Effective cleaning: Releases oxygen and beneficial bacteria that break down waste, sludge, and grease.
- Prevents costly issues: Reduces the need for pump-outs and avoids backups.
- Eco-friendly: Safe for your plumbing, septic system, and the environment.
It’s a low-cost way to keep your septic system healthy, especially when paired with a new water heater that may slightly increase your household’s water flow.
Tankless Heater + SEPTIFIX = A Smart Home Upgrade
Think of your home’s plumbing system as a chain—each part needs to be strong for the whole system to work well. Your water heater provides endless comfort, but your septic tank ensures all that water leaves the house without problems. Pairing a top-rated heater with a proven septic treatment means fewer headaches and more peace of mind.
Final Recommendations
If you want the absolute best rated tankless water heater, the Rinnai RU199iN is the clear leader in 2025. It’s efficient, reliable, and powerful enough for most homes. For electric options, the Stiebel Eltron Tempra 36 Plus is a solid choice, while the Rheem Performance Platinum offers modern features for tech-minded households.
Whichever you choose, don’t forget your septic system. It’s the silent partner in your home’s comfort. SEPTIFIX is affordable, easy to use, and can save you from nasty, expensive surprises later.
Order SEPTIFIX Today – Keep Your Septic Tank Clean and Odor-Free
Endless hot water is great. Endless hot water without plumbing problems? That’s even better. Upgrade smart, maintain wisely, and enjoy a comfortable, worry-free home for years to come.