We've lived in this house for 20 years and the hot water heater (tank style) was 2 years old, as was the rest of the house, when we moved in. In the last year or two we've started to have occasions when we run out of hot water. At first we put it down to volume - we have an 18 yo and a 22 yo, so they have showers, and they have friends over, and some mornings we're trying to accomodate 4 or 5 showers. But now it's two showers,or one shower and a load of laundry, and suddenly there's no hot water for dishes. Having read that hot water heaters usually last 10 years, I guess we need to replace this one. We're considering tankless, but:

  • We're on a well. The water is hard (the kettle scales a lot) and cold
  • We have electric heat
  • Our service is 200 A
  • In the winter, we set the heat back overnight so the house is cool, and warm it up in the morning (right around when showers would be happening)
  • Here in Ontario, electricity is charged at time-sensitive rates
  • We don't have natural gas available (we live in the middle of nowhere)
  • We don't have a propane tank already and don't want one

Is tankless still a sensible option for us? Roughly how much more do they cost - given that we're not taking out a working tank and replacing it just for energy savings, but instead have to buy a new heater, is it not too bad?

And finally, would it be worth it to get someone to clean/flush/repair in some way our 20 year old heater, that we have never done anything to, in order to save the cost of replacing it?

4 Answers 4


Without natural gas or propane, your only source of heat is electricity. Electric tankless water heaters would probably require a new circuit to be run. Here's a table of typical power and wire requirements:


The smallest unit they recommend for a shower is the RTE13 which takes 13 KW or 54A@240V. This requires #6 wire. If your incoming temp is 40F and desired out temp is 110F, you need 70F of temp rise and the RTE13 will provide 1.27 GPM.

Many people think they want tankless because the mfg tell them tankless is more efficient. There is some truth to this for gas fired water heaters but in the case of electric water heaters, the difference in efficiency is very small.

  • The last time I looked into tankless for a 50 gallon replacement, they wanted a separate 110A circuit. If you have natural gas already installed, you're in like Flynn. Commented May 13, 2014 at 22:55

I would check the operation of the heating elements. On my heater, when the lower element burned out, we had a reduced quantity of hot water (basically the top half of the tank). Replacing an element is much cheaper than a whole tank.

Response to comment: I wouldn't recommend doing it yourself unless you are knowledgeable and comfortable with electrical work. That said, I checked mine with an ohmmeter. This page has more details:


  • And how do I check that? It sounds like a great idea. Commented May 7, 2012 at 21:56

With the water heater that old its probably not worth the money to flush it. Especially since it hasn't been maintained over the years.


You might want to investigate an oil fired water heater. I have owned one mfg'd by Bosch; it works well: very quick recovery, long life (15 yrs so far), has replaceable anode elements for rust control. They are expensive initally, however the quality is high.

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