Looking for an energy star alternative to replace a tank hot water heater. I live in New England.

Asked by Daviod Blank
Stamford, CT

Need a cost effective alternative for a tank hot water heater for my home located in Stamford, CT. Home has 3.5 bathrooms. We are near empty nesters. Any Ideas?


Michael Holcomb

Answered by Michael Holcomb

Byron Center, MI

Alliance for Environmental Sustainability (Headquarters)

October 27, 2011

I can’t resist asking… do you live near empty nesters or are you about to become empty nesters? I’ll assume the latter for the purposes of this response.

Potable water heating innovation has made tremendous gains in the past few years. The old tank water heater has improved in efficiency but greater gains have been made in tankless water heaters, specifically condensing tankless water heaters.

There are options when considering a tankless system.

  • First is an on-demand, point of use tankless water heater. These units are usually installed in close proximity to the fixture.
  • Next is electric powered point of use water heaters are not suitable for most homes since they may require a significant upgrade to the electrical system if more than one is required.
  • And finally there are whole house systems. Whole house systems are sized based on flow.

My recommendation

I would recommend installing a system with a flow rate or 8.5 GPM (@ 45-degree temperature rise).

This is adequate for the average family – no sense installing a system that is adequate for two people but not suitable for 4 or 5 occupants. You wouldn’t want to have to replace your unit with a larger flow rate system if you sold the house or someone returns to the nest.

Get a whole-house condensing unit

Condensing tankless water heaters are the most efficient. I know they are fine with natural gas or propane.

I would not consider an electric whole house on-demand system because the operating cost is very high.

The Prestige Series Condensing Tankless Gas Water Heater, manufactured by Rheem, performs with an astounding 0.94 energy factor. Compare this to standard gas-fired tank water heater at 0.54 EF or a more efficient fan assisted tank water heater at 0.62 EF.

  • Costs range from $1175 - $1230 plus installation.
  • The skill level to install a tankless water heater is relatively high so I recommend hiring a professional, licensed and insured plumbing contractor.
  • You’ll need a gas line capable of providing enough gas to provide 150,000 – 200,000 Btu’s.
  • Most likely you will need to upgrade the gas line from ½-inch to ¾-inch.
  • Venting is done through PVC pipes – no chimney required. Unlike the early tankless water heaters, condensing tankless water heaters do not need to be mounted on an outside wall. PVC venting allows for a remote location up to 30-feet from the unit to the outdoors.

Tankless water heaters are becoming more common in Michigan, where I live, another cold-weather state. They are very reliable and can provide plenty of hot water for as long as you like.

Independent lab testing

I prefer Rheem because their efficiency is rated by an independent laboratory.

  • Other manufacturers choose to rate them systems in-house.
  • I prefer third-party.

GAMA ( is an independent rating organization for government energy efficiency standards.  Look for this certification on any water heater you purchase.


For more information:

Read "Get Optimal Performance from a Tankless Water Heater" for our essential tankless tips.

Tagged In: tankless water heater

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