Electric Water Heaters – The Pros and Cons

In the last couple of posts, I’ve discussed efficiency regulations that will affect new water heater installations beginning April 16, 2015. In this post, I’ll look at electric water heaters and how they might fit into your future hot water plans.

An electric water tank uses electricity to generate heat. Electric tanks have two heating elements – one in the upper portion of the tank and one in the lower portion of the tank. The upper element does most of the heavy lifting, while the lower element is used to heat the water at the bottom of the tank and maintain the overall water temperature.

Since they don’t produce exhaust, electric water heaters are incredibly efficient – 95% or better in most cases – but they draw an enormous amount of power. The larger the tank is, the more power it will need to heat and recover from heavy use. Because electric water heaters are already so efficient, the new efficiency regulations won’t impact them, but don’t assume that “efficiency” translates to low operating costs. It doesn’t. Electric water heaters are truly expensive to operate, even with their exceptionally high efficiency ratings.

Electric water tanks tend to have low standby losses, which means that only the lower heating element is used to maintain water temperature once the water has been heated. The design and insulation of the tank are often sufficient to maintain the desired water temperature.

Recovery times on electric water heaters are long. Once the tank has been used, it will take an electric water heater much longer to recover than a gas-fired one. Electric water heaters also have a noticeably higher operating cost, largely because electricity is more expensive than other fuel alternatives.

Electric water tanks are generally less expensive to purchase than their gas-fired cousins, but the capacity and life expectancy of electric water heaters are similar to those of tanks that use other heat sources. Installing a replacement electric tank can be inexpensive, but installing an electric water heater as a replacement for another fuel type can come with a high price tag!

Electric water heaters usually require a household electrical service of 200-300 amps, and your service must also supply 240 volts. Electric water heaters require dedicated, large circuit breakers and special large diameter wiring, so you may need to give your electrical service a major overhaul if you want to (or have to) install an electric water heater as a replacement for a non-electric model.

If you’re considering a replacement water heater, and you want to move to a different water heating technology, please contact us at Boston Standard Plumbing & Heating at (617) 288-2911 anytime. We can explain all of your options and let you know what modifications may be needed to install a new water heater in your home.