What Does “Energy Efficient” Really Mean? A Homeowner’s Guide to Water Heater Ratings

The Big Picture: Why Efficiency Matters

Before diving into the details, it’s important to understand why an energy efficient water heater is a pretty big deal.

According to the U.S. Department of Energy, your water heater is typically the second-largest consumer of energy in your home, accounting for nearly 20% of your total utility costs. A more energy efficient water heater ensures that nearly every penny you spend on gas or electricity is actually going into heating the water, rather than losing heat in the way of “standby loss” (heat escaping through the tank walls) or “flue loss” (heat escaping through the vent).

Decoding the Metrics: UEF, Thermal Efficiency, and More

When you look at the specs of a water heater, you’ll see several different efficiency ratings. Here’s what they actually mean for you:

1. Uniform Energy Factor (UEF)

Introduced by the Department of Energy to replace the older “Energy Factor” (EF), the Uniform Energy Factor, or UEF, is the industry-standard rating of overall efficiency.

• How to read it: The higher the UEF number, the more efficient the unit.
• What it means for you: A unit with a UEF of 0.90 is significantly more efficient than one with a 0.60. For example, high-efficiency heat pump water heaters can have UEF ratings well above 3.0 because they move existing heat from the surrounding air rather than just creating heat from scratch. The AeroTherm^® Series G2 Hybrid Electric Heat Pump Water from Bradford White has a remarkable 4.20 UEF.
• It’s important to note different fuel types have different operating costs and the UEF rating is not always a direct correlation.
  • For example: electric water heaters in general are more expensive to operate than natural gas units.

2. Thermal Efficiency

Thermal efficiency measures how much of the energy from the fuel source is actually transferred to the water. If a heater has a 95% thermal efficiency rating, it means 95% of the heat generated by the burner stays in the water, while only 5% is lost.

• What it means for you: The higher the number, the more efficient the water heater (and the more you’ll save on your utility bills).
• Bradford White Tip: If you see a unit labeled as “High Efficiency” or “Condensing,” it likely has a Thermal Efficiency of 90% or higher.

3. First Hour Rating (FHR)

While UEF tells you how efficiently the unit works, the First Hour Rating (FHR) tells you how effectively it meets your needs.

The FHR is an estimated number of gallons of hot water the heater can supply in its first hour of operation (starting with a full tank of hot water). The FHR is derived from a standardized test called the Simulated Use Test. Products are separated into categories and tested with other similar units.

The Goal: You want a balance of a high UEF for energy savings and a sufficient FHR for comfort. Your plumbing professional can help guide you through the process of choosing the best water heater for you. Don’t have a plumbing professional? Click here to find a Bradford White plumber near you.

The “Yellow Label”: Understanding the EnergyGuide

Every new residential water heater is required by law to have a bright yellow EnergyGuide label. This is your “cheat sheet” for energy efficiency. It provides two vital pieces of information:

• Estimated Yearly Operating Cost: This gives you a dollar amount based on average national energy prices. It allows you to see how much you might save over the life of the unit compared to a cheaper, less efficient model.
• The Range of Efficiency: A horizontal scale that shows how that specific model compares to other models of similar capacity.

Efficiency Beyond the Numbers

A high UEF rating is a great start, but true efficiency also depends on the quality of the build. Bradford White water heaters are Built to be the Best^® for exceptional quality, so they are designed to be efficient over the long-term. Here are a few innovations that contribute to a Bradford White water heater’s reliability, performance, and efficiency:

• The Vitraglas^® Tank Lining: Our exclusive glass lining protects the tank from the corrosive effects of hot water, extending the life of the unit.
• Exclusive Microban^® Antimicrobial Technology: Microban^® provides additional product protection by helping to prevent the growth of bacteria, mold and mildew on the surface of the tank lining.
• Hydrojet^® Total Performance System: Over time, sediment (minerals in your water) can settle at the bottom of the tank. This sediment acts as a barrier between the heat source and the water, forcing the heater to work harder. This reduces both the efficiency and performance of the water heater. This is especially a big deal for you if you have mineral rich, “hard” water. Our exclusive Hydrojet^® system creates turbulence to reduce sediment buildup, maintaining high efficiency and performance for years to come.