Electric water heater rating by brand

[GaryS]

One of my water heaters has developed a leak after 7 years, so it's time to replace. The 60 gal FHR Bradford White heater I'm going to replace has a very low energy efficiency rating and I want to replace it with the best practical choice. I want something that will last for much more than 7 years and I want the highest energy efficiency rating. I much prefer to spend the money once and not have to worry, or regret a purchase for the rest of the product life.

Does anyone know if there is a website where electric water heaters are quality and efficiency rated by brand and model? A search hasn't turned up much.

[LazyPup]

Electric water heaters use direct immersion type resistance heating elements, therefore there is no associated flue losses. That means that electric water heaters are 100% fuel efficient. (100% of the input energy is transferred to the water.)

One BTU will raise one pound of water one degree Farenheit.

One gallon of water equals 8.43 lbs.

Assuming the cold water to be entering the tank at 50degF and the tank set at the code standard of 120degF the heating differential is 120-50 = 70 DegF.

multiplying the differential (70degF) times the weight of water (8.43lbs/gal) equals the BTU requirement per gallon. 70x 8.43 = 590.1 BTU/gal.

First hour rating is based upon a cold startup, therefore a 60 gallon water heater from cold start at 50degF to the demand temp of 120degF would require 60gal x 590.1BTU/gal = 35,406 BTU

1 BTU requires .2930 watts thus for 35,406 BTU it would require 10,373watts.

60 gallon tanks typically have three 4500 watt heating elements.

Given that the water heater elements are immersed in the water and there is a 100% transfer efficiency to the water it then stands that the size, shape or type of material used to construct the vessel will have no bearing upon efficiency.

Almost all electric water heaters use basically the same Robert-shaw type thermostates and heating elements therefore in the final analysis there is precious little difference in the heating system.

For electric water heaters the true measure of quality then is determined by the quality of materials to construct the vessel. I.E. Steel, glass lined steel or stainless steel. Obviously the glass lined tank would offer a greater corrosion resistance that would a steel tank, while the stainless steel would offer top of the line corrosion resistance.

Efficiency is determined by comparing standby heat loss (the amount of radiational energy loss per hour).

The Plumbing codes now require all water heaters to have a minimum R-12 insulation. Any additional insulation value above R-12 would equate to increased energy efficiency.

Therefore when comparing electric water heaters you will find that if they are constructed with the same type of water vessel and the same insulation value, they will all provide about the same overall performance.

This is one instance when price and warranty would probably be a very good indicator of overall economy.

Im my humble opinion i would stay with the old standard trade names such as Rheem or A.O.Smith with total confidence.