To demand or not to demand? The tankless (and endless) hot water debate

Sep 30, 2009 by Hiromi Ogawa

Tankless water heaters have been a hot topic with our clients.  There was one instance recently when a plumber recommended a conventional water heater due to earthquake concerns (the plumber, located in California, said that the water tank also acts as a reserve for emergency water in case of a natural disaster), but most of the time, everyone agrees that tankless is the newest and most stylish way to go.

We have been explaining the pros and cons of tankless hot water units to our clients, but I came across this article that neatly summarizes what we've been talking about.

One other consideration we like to add when we talk about tankless is time of use.  In general, a conventional water heater is ideal for households where hot water is being used on and off all day, since the stored hot water in the tank gives you access to it instantly.  If the house is usually vacant for most of the day, it makes less sense to keep a 50-gallon tank of water warm while no one is using it.  So with houses (or areas of houses) with limited time of use, we usually recommend a tankless unit.

Some people have noted that tankless hot water heaters take a long time to deliver hot water to the faucet, and I have found this to be true from my own tankless unit at home.  There's a debate on whether it's worth going to tankless when you are still wasting water while you wait for the hot water to arrive (i.e., what you are saving in gas usage for heating, you are still wasting in water usage).   I believe that you just need to change the way you think about water, to adapt to a tankless system.  Here are some things I have implemented:

- keep a bin or basin near the sink so that you collect the cold water while you wait for hot water to arrive.  Use the cold water to water plants, or boil pasta.

- fill the bath tub by starting with the hot water only.  You will get cold water while you wait for hot water, then the hot water will warm the cold water that you've already saved.  Then adjust the water temperature with more cold water, if needed.

- purchase appliances that have their own hot water heater.  This is more and more common in appliances that require hot water, such as dishwashers and clothes washers.  This eliminates the need to run the tap while waiting for hot water to arrive to your appliance (which used to be true for older dishwashers).

When the contractor finished installing my tankless hot water heater, he turned to me and said "welcome to the world of endless hot water".  Which is true - the one big advantage to the tankless units is that the hot water is heated on-demand, and never ends.  My friends at eco-guides remarked that this is sometimes a blessing and a curse, since some people now want to take longer showers.  You can't win this debate.  I think it just depends on where your priorities lie, and what makes the most sense for your household.

Topics: Materials

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