Hot water heaterYup, this is GReg again, with the house renovation project. Todays energy woe’s revolves around a Tankless water heater. For those of you who are not familiar with these, these things replace a normal hot water heater and heat the water as needed, so your system is not sitting there all day heating water that is not used. No matter how good a blanked is on your hot water heater, you’ll never do as well as a tankless/on-demand system.

The economics: up to 16% of your power/fuel bill (realistically more like 11%-13%) is spent on heating hot water.

Tankless systems can save up to 60% over a traditional system (45% seems more typical from what I’ve been reading) Depending on your current system this can translate into savings over a traditional hot water heater of about $12.50/month or $150/year. More if you hot water heater is more than about 12 years old and is filled with the build up that forms in those things. (Your tank is filled with crud, and your spending your money heating crud not water). The on-demand systems do not build up crud and have a lifespan of about 20 years. Tankless systems cost between $800 and $1500 depending on how much you want to run a the same time (even the small ones claim to support two showers at the same time). Add to that $200 to get it put in and you see a $3000 savings for a cost of $1000. Green profit in my pocket.

What’s more, since these things are tiny and can be mounted on the outside of your house, you can put them closer to where you water is used, instead of in your garage or basement. This means less time to wait to get the hot H20 to you, and less water wasted.

This is what I was talking about when I said Return On Investment items.

And it gets better. If you rush, you can get a $300 tax credit on putting one in, dropping the base cost to about $500 plus instillation. The credit ends on December 31.

Perfect huh?

Now for the problems…

There are two competing brands in the USA that make these things. The classic firm has been Rinnai and the new upstart is Bosh. A few friends have the Bosh system and love it. It has a great wall mounting system that makes it easy to put in, but we found a problem. It has a minimum heating energy output of 30,000 BTU. This means that the water going into the system needs to be no more than 70 degrees F or the system shuts itself off heating nothing. I’m in Florida, the ground water in the winter is 72 degrees. It goes back. The bummer part is it’s going back with a 10% restocking fee :(

The Rinnai’s minimum heating output is 15,000 BTU. Much better, it can handle up to about 90 degree input I figure. Once you get over 80 degrees the minimum flow per minute you need to run to keep it from turning off goes up, but that’s ok.

Since I’m about to mod this thing (I’ll explain this later) for comfort and to improve it’s cost savings even more, i need this lower energy out put level.

By the way, I’m installing this directly below the master bath. No more waiting for hot water to run across the house.