Posted: May 18, 2026

What to Know About Water Heater Efficiency Ratings

Let Tevis help you get robust, efficient hot water for your home.

Let’s be honest — when your home’s water heater isn’t performing at its best, it can cause some considerable friction in your household. Suddenly, everyone is monitoring each other’s shower times. You need to plan laundry and dishwashing for times when folks aren’t bathing.

And don’t forget that heating water can comprise roughly one-fifth of your home’s energy consumption. At Tevis, we can help you upgrade to a more efficient and high-performance system — one that gives you quicker and more plentiful hot water while lowering your energy usage.

In this post, we’ll talk about how water heater efficiency is measured and what the most efficient options are for your home.

How is water heater efficiency measured?

When you’re researching new water heaters, the Uniform Energy Factor (UEF) is the key efficiency metric to understand. The UEF measures how effectively a water heater converts energy into hot water — the higher the rating, the more efficient the unit and the less it costs to operate.

Water heaters are assigned UEF ratings within specific usage categories called BINs, and it’s important to compare UEF scores only among models within the same BIN. The yellow Energy Guide label on each unit displays its UEF rating alongside estimated annual operating costs, making it easy to compare models side by side and calculate the long-term savings of investing in a higher-efficiency unit.

What other metrics can help in choosing a water heater?

Two other water heater metrics that can be helpful have to do with how quickly a given unit can deliver hot water. These are:

• First Hour Rating (FHR): How much hot water a tank-style unit can generate in its first hour of operation.
• Gallons Per Minute (GPM): The rate at which a tankless system can deliver hot water on demand.

What kind of water heater should you consider?

If you’re looking for a high-efficiency water heater that delivers reliable hot water for showers, faucets and appliances while meaningfully reducing your home’s energy costs, Tevis’s service division, Modern Comfort, is ready to help. We handle more water heater installations than virtually any other company in our service area, and we offer a range of top-quality options to suit every home and budget:

• Traditional water heaters — Today’s conventional storage tank models are more efficient and longer-lasting than ever before.
• Indirect-fired water heaters — Pair one of these units with a high-efficiency oil boiler or furnace, and you’ll enjoy some of the lowest hot water costs available to homeowners.
• Tankless water heaters — These gas-powered tankless units deliver a virtually endless supply of hot water exactly when you need it, while taking up a fraction of the space of a traditional tank. They can be up to 34% more efficient than traditional units.

If your current hot water system is more than 10 years old, then it’s a good idea to start exploring your replacement options. With the Tevis team helping you, we can find the ideal water heater upgrade and get it in place with minimal disruption to your daily life — so you can start enjoying longer showers and lower energy spending!

Get in touch with the Tevis team today for a free estimate on a new water heater. We proudly serve households in Baltimore County and throughout Central Maryland and Southern Pennsylvania.