Now that its been a couple of years of living with an on demand hot water heater (also called a tankless hot water heater), I wanted to put in my two cents. When we renovated the house I really didn’t want anything to do with a regular hot water heater. A: they take up a ton of room and B: They run out! Seriously, it just seemed to me that common sense would say that heating the water ONLY when you need it would be a lot more economic then paying to keep a huge amount of water hot all of the time. So, how’s that been working out for us? Well, there’s a lot that goes into that answer!
First, I want to say that I have no regrets. I was the one that installed our on demand hot water heater and it wasn’t at all hard to do. If, for instance, your big old tank hot water heater dies suddenly and you decide to replace it with an on demand instead, you could literally get it done (by yourself) in a weekend with a little bit of basic electrical and plumbing knowledge. This is not a tutorial on how to install one of these bad boys but I will say that they take a TON of electrical power. You will wonder, as you’re installing it if you are, in fact, installing a bomb in your basement. Nothing else electrical in your home will come close to the ampage these things need to run. I spent over $600 on the enormous electrical wires alone and the huge breakers to run this thing and, during all of that and because of it, I did wonder if it was going to cost a fortune every time we wanted hot water.
Our electrical bill is half of the national average right now and rarely gets much above $100 per month so, all in, I believe it was the right choice from a cost perspective. I would say we run hot water every day here, whether it is just washing our hands, taking a shower or bath, or using our dishwasher. I do have to mention though our on demand hot water heater cost us $800 brand new from Menards. So, all in, do I think I’m saving money compared to a tank hot water heater? A little, but I DO NOT believe it would be worth replacing a perfectly functioning tank hot water heater. (In other words: Don’t replace your tank with one of these until you need to.)
So, how does it work?
At our kitchen sink, our shower and sink on the main floor and our sinks/bathroom down in the basement, we have no problems and get hot water there without delay and without incident. (Our water heater is directly beneath our kitchen in the basement.) However, if we mix the hot water (at any time at any of these locations) with more then a little cold water we run the risk of the hot water heater cutting off completely. Here’s the thing with these on demand water heaters: If you don’t run enough water through them they’ll either cut off or not kick on at ALL. We have a well here and a pressure tank so our water pressure isn’t even comparable to say the water pressure most people get in town on city water.
When we first took a shower in our master bathroom the water NEVER got hot. We tried the sink up there (on the second floor) and the water NEVER got hot. If we ran them both at the same time – then we would get hot water! In the end, every time we wanted hot water at our sink or in our shower, we had to run our tub faucet at a trickle to keep enough water running through the on demand hot water heater so it would keep heating the water. We lived with this for quite awhile until I couldn’t stand it anymore and unscrewed the filter from the sink faucet and: problem solved. Now we just have to be careful because every time we turn on our sink we get a torrential flood. The shower we took care of by replacing the shower head (I happened to have an extra one) and that immediately fixed our problem of hot water in our master bathroom. However, we have hard water (and no water softener) so, over time, the shower head will slowly get gummed up with calcium and needs to be taken off and thoroughly cleaned or it won’t let enough water through it to give us hot water to shower with and then we’re back to running the tub faucet when we shower. *sighs*
In the end, we can live with all of that because seriously, shower heads really should be cleaned every couple of months anyway. The big problem was that we couldn’t mix cold water EVER (not even a little bit!) or the on demand hot water heater would stop heating water in our master bathroom. So, after much adjusting, we had to find the perfect temperature that we both could live with to shower in because we couldn’t add cold water to it at all. Joe liked the water hotter then I did so it was a bit of a give and take until we were both happy with the temperature. (Note here: by the time the water gets up to our second floor it is cooler then say, at our kitchen sink, so the water is still hot enough there that I feel comfortable washing dishes by hand.)
None of this would be a problem if A: you live in town and have great water pressure and/or B: You have a water softener. Our special little mix of low pressure well water and no water softener is causing us these annoying issues that most folks just wouldn’t have. Do I regret our on demand hot water heater now that we’re living with these issues? No, because in the end, it is not that big of a deal. However, I did get a real laugh when I did a google search for on demand hot water heater problems and the first one that came up was, “Shower not getting hot water.” So, we’re not the only folks that ran into this situation and I have to believe that any “low flow” shower heads or faucets would literally never get hot water – so that’s something you have to keep in mind if you consider going on demand.
Now we purchased the biggest on demand hot water heater that they make so it would take care of our whole house and if I could go back I think I would have installed a small on demand hot water heater on every floor instead. It would have cost more (so much more electrical wire to run…) but smaller on demand water heaters require less water run through them to kick on. So then we wouldn’t have ANY of these issues at all and if you look at the manufacturer websites for these things, that really is what they recommend. So, if you’re considering going on demand I would recommend you purchase a small one for every floor or one for each kitchen and bath.
Hope that helps if you’re considering making the switch!