Posted: July 20, 2026
What’s Your Water Heater’s Efficiency Rating?
How household water heater efficiency is measured
With prices on just about everything rising in recent years, it makes sense to look for energy savings wherever you can find them. One bright spot for propane-powered homeowners is that U.S.-produced propane remains more affordable and price-stable than most other energy options. And you can stretch those savings even further by investing in high-efficiency equipment. Your water heater is one of the best places to start because it accounts for roughly one-fifth of your home’s total energy consumption.
In this article, we’ll walk you through how water heater efficiency is measured so that you can make a confident, informed decision.
The Key Efficiency Metric: UEF
When shopping for a new water heater, the most important number to understand is the Uniform Energy Factor, or UEF. This rating measures how effectively a unit converts energy into hot water. The higher the UEF, the more efficient the water heater.
One important detail: water heaters are grouped into usage categories called BINs, and UEF scores should only be compared among models within the same BIN. The yellow Energy Guide label on each unit makes this easy. It displays the UEF rating alongside an estimated annual operating cost, so you can weigh models side by side and calculate the real long-term value of investing in a more efficient unit.
Two More Numbers Worth Knowing
Beyond UEF, a couple of additional metrics can help you choose a water heater that fits your household’s actual hot water demands:
- First hour rating: For traditional tank-style water heaters, this measures how many gallons the unit can deliver in its first hour of operation, a good indicator of whether a tank can keep up with a busy morning in your home.
- Gallons per minute: For tankless water heaters, this measures how quickly the unit can deliver hot water on demand. The higher the GPM, the better it can handle simultaneous uses like a shower running while the dishwasher is going.
Which Type of Water Heater Is Right for You?
Koppy’s Propane installs two types of propane water heaters, and both offer excellent efficiency and performance for homes throughout Lancaster and across Central and Southeastern Pennsylvania:
- Traditional propane water heaters: Today’s storage tank models are significantly more efficient and longer-lasting than older units. If your household has consistent, predictable hot water needs, a modern propane tank water heater delivers reliable performance at a great value.
- Propane tankless water heaters: These on-demand systems heat water only when you need it, eliminating the standby energy losses that come with keeping a full tank hot around the clock. They can be up to 34% more efficient than conventional units and provide a virtually endless supply of hot water, all while taking up a fraction of the space.
If your current water heater is more than 10 years old, now is a great time to start exploring your options. An aging unit works harder, costs more to run, and is more likely to leave you with cold water at the worst possible moment.
Contact Koppy’s Propane today to learn more or to get started on a water heater upgrade.