Tankless Water Heater

The previous owners of our house did a number of “upgrades” over the years, and one of them was to install a tankless water heater. If you’re not familiar with tankless heaters, it’s basically a water heater that doesn’t keep hot water sitting around, but heats it on demand. The idea makes sense, I mean, why keep 40 gallons of water hot all the time when you don’t need it all the time?

Tankless heaters also have the advantage of not running out of hot water. In theory, you can take a shower for 6 hours and never run out of hot water! After your 6 hour shower, you can run the dishwater and do some laundry. Nice! There may be some concerns about how much hot water a tankless heater can deliver at the same time, so taking a shower while washing the dishes and doing laundry may result in warm water rather than hot water if the system can’t keep up.

Well, we managed to get eight months of usage from the tankless water heater. We moved in back in June, it was warm, and sunny, and all was good with the world. Then came winter. It was cold, and bleak, and everything sucked.

I woke up one morning, and turned on the shower so the water could warm up (oh yes, it typically takes a bit longer to get hot water from the faucet from the tankless. At least in the winter months) and it was nothing but cold cold cold water. I went to the basement to see what was up, thinking perhaps the circuit the heater was on had tripped, and I was greeted by water pouring out of every orifice of the tankless water heater. Fun! I was now standing in freezing cold water trying to solve the problem. Luckily all the water was going right down the basement drain, and not really flooding the basement. Score!

It seems that it got so cold (and yeah, this is the coldest Wisconsin winter on record for quite some time) that the water in the tiny tubes of the tankless water heater froze, and the the tiny tubes cracked, and then the water came out.

So I learned a few things:

  1. Tankless water heaters don’t work when the power is out. No power equals no hot water. None. At. All.
  2. Supposedly we could have prevented this if we had left the hot water running all night. Yes. Seriously, that was the advice of a plumber. If it’s cold, leave the hot water running.
  3. Don’t mount your tankless water heater on an uninsulated exterior wall. If the heater had been located somewhere else, or there had been more insulation between it and the concrete wall, it may not have froze.
  4. Home warranties are sometimes useless. Wasn’t covered, so we were on the hook for repair/replacement.
  5. Having more than one heating vent in the basement might be useful. I know the basement is mainly storage/laundry/workshop, but the only heating vent is on the opposite side of the basement that the water heater was on. Cold!
  6. We’re not ready for tankless.

Tankless heaters might be fine for some people. The idea is a good one, but there are a few factors that can cause problems. (Obviously!)

Tankless water heaters are also expensive. Of course you may recoup the costs over X number of years. (X may be 10 years, so you’d need to still have the same tankless heater for 10 years. It’s a gamble.)

In the end, we decided to replace the tankless water heater with an old fashioned tank water heater. It ended up being about half the price after purchasing it, and paying a plumber and electrician to install it. We also opted for an electric heater instead of gas. I’m still not 100% sure that was the best idea, but hey, the deal is done. We now use electricity to heat our water and store it in a big-ass tank for when we need it. Hooray.