Dear Mr. Energy: Replacement water heaters

Dear Mr. Energy,

I need to replace my old, inefficient hot water heater. What should I get to save the most energy (and therefore the most money)?

–Morrisville Mama

Dear Mama

You’ve said that your goal is twofold: to save the most energy over the long haul, as well as to save the most money. In a perfect world the answer to this question would be the same. But alas (Mr. Energy has always wanted to say alas!), we are not living in a perfect world.

First, the type of hot water heater that is most energy efficient to run is a solar hot water heater.

This is also the most expensive type of hot water heater to install. According to American Council for an Energy-Efficient Economy, the overall cost of this type of heater over a 13-year period (which is the average lifetime of all hot water heaters) is about $7000.

The type of hot water heater that’s least expensive to install is the conventional electric storage model, but this is the most expensive to run, even if it’s an energy efficient model. Its 13-year lifetime costs are about $6500.

An on-demand hot water heater, which is what Mr. Energy has in his home, is on the lower end in terms of energy costs per year, but not the lowest. It’s about half-way between solar and conventional storage models. But at a lower cost to install it is a pretty good option for many people, with its 13-year cost at $5000, and if you curb your hot water usage by using cold water in your wash, for example, you can come in well under the yearly costs that the ‘average’ family generates.

Finally, the overall cheapest system to install and run is an electric heat pump water heater. This is a relatively new type of hot water heater and it works much the same as the electric heat pumps people use for their homes. It costs about double to install one of these over a conventional gas or electric storage model, but uses only a touch more energy a year than a solar hot water heater (an estimated $190/year). According to industry models, this type of heater will cost a homeowner only a little over $4000 in the 13 years it will last.

With the possibility of HomeStar/Cash for Caulkers looming on the horizon, which will extend and increase rebates on replacement of hot water heaters if it passes, plus any rebates your electric or gas companies may be offering, the installation costs of many of these items may be cut significantly, which is nothing to sneeze at.