How to Choose a New Electric Water Heater
Earlier this week we wrote about how to install a new water heater. To accomplish that job, the first thing you’ll need to do is pick out a new heater. All electric water heaters are not created equal. Here’s some things to consider the next time you’re in the market:
Tankless vs. Traditional Water Heaters
A traditional tank-based water heater stores pre-heated water in a resevoir. When you turn on a hot water spigot, hot water flows out of the tank and cold water flows in. The tank slowly heats water up the new water to the desired temperature. The downside to tank-based systems is that there is a cost to keeping an inventory of hot water on hand. Even if you don’t use any hot water in a month, you’ll still be paying for the electricity to keep the water in the tank hot. Tankless water heaters heat water on demand… they don’t keep any reserve, and so you don’t pay for them while they aren’t in use… sounds great, but as usual, there are potential drawbacks:
- All tankless heaters have flow rate limits, which directly correlate to the power supplied to the heater… This means that you must make sure that you have sufficient amperage coming into the tankless heater, which is usually higher than the standard service to a tank-based model.
- When over flow-rate limits, some tankless heaters osscilate between hot and cold… this means that instead of getting warm water in your shower, it could be worse: you could have scalding water for 5 seconds, and freezing water for 5… back and forth…
- Tankless systems can be installed in parallel to achieve better results, but this requires purchasing two systems, and paying for additional electrical installation.
Large vs. Small Tank Systems
In our household, bigger is better in the water heater department. The larger the tank, the more hot water you’ll have available. That said, the bigger the heater, the more expensive to buy, and to run. Consider how much hot water you’ll actually need to meed your water demands. For a family of four, a 50 gallon tank is sufficient for most. If you’ve got a big family, consider an 80 gallon. Either way, make sure the tank will fit in the space you have available.
Materials – Heating Elements and Tank Walls
More expensive heaters will be constructed with stainless steel elements (instead of copper), which won’t corrode over time, and thus will last longer. Expensive heaters are also built of thicker-grade steel, which reduces the liklihood of rust.
Green Energy Features
Some water heaters will have more sophisticated electronics that can help make your heater more efficient. For instance, if you’re installing a tank-based model in a vacation home, you may be able to set the heater to a “vacation” setting, which will detect when the water isn’t used for a long time and will lower the average tank temperature until flow is detected again.
Energy Consumption – Check the Label!
Whether you choose traditional or tankless, do your research. In the U.S., all tankless and tank-based systems will have energy guide stickers to help you estimate the total power consumption of the water heater over a year’s period.
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5 Responses to How to Choose a New Electric Water Heater
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July 31st, 2009 11:38 am
Another option for homeowners that have hot water heating (rads or in floor radiant) is the option of an indirect hot water tank. A smaller indirect tank (40 gal or so usually) is used that is heavily insulated and contains a heat transfer coil that is linked to the boiler. The boiler heats water which is circulated through the coil. During the winter, the cost for heating the hot water is negligible (in cold climates) as the boiler is heating the rest of the house. During the summer, the main heating circuit is disabled, and provided the boiler is a modulating/condensing system with a high efficiency rating the cost to heat the water is similar to a very efficient tank system. Recovery rates are fast, in the 5-7 gallons/minute range, so even if you use up the water in the tank, you still get hot water in a fashion similar to a tankless system.
This isn’t an option for everyone, but for those who have boiler systems, it’s something to consider.
July 31st, 2009 12:02 pm
We’ll be adding a propane water heater to the Stone House project and are also considering a tankless for the upstairs.
July 31st, 2009 4:39 pm
On-Demand water heaters are also really cool. These heaters can make an unlimited amount of hot water on demand. This technology has gotten so good that we build homes with these that heat all the domestic and heating water on demand. Good stuff!
July 31st, 2009 10:09 pm
On-Demand water heaters are also really cool. These heaters can make an unlimited amount of hot water on demand. This technology has gotten so good that we build homes with these that heat all the domestic and heating water on demand. Good stuff!
Sorry, should have mentioned great post! Waiting on your next post!
July 31st, 2009 11:10 pm
LOL. Thanks for the encouragement, Todd!
NP – very good information about the boiler…