Articles

Submitted By: Bart Carr (bart_carr@yahoo.com)

Challenge
Last November, our old water heater died.   A dead water heater is something that can’t wait to be fixed or replaced.  We (my wife Surinder and I) moved quickly and decided to explore “tankless” gas water heating systems.  We knew that a growing number of people were turning to tankless heaters as an energy efficient method to heat water.  We referred to two excellent success stories offered on the Sustainable Lafayette website to give us information on others experience, performance, and cost.  Although more expensive then traditional tank heaters, we quickly came to the conclusion that tankless was the way to go due to increased efficiency and our concern about the environment.

However, we had a second challenge that a tankless heater would not address.  During our home remodel in 2001, we repositioned our old water heater in our newly remodeled home (to save replacement cost … it still worked fine at the time!) at one end of the house.  This meant that hot water users in the middle of the house (the kitchen) and far end (my daughter’s bathroom) had to wait long periods of time (3-5 minutes) for the hot water.  This was not only aggravating but also wasteful.  So we decided to use the installation of a new tankless heater as an opportunity to install a new system that would solve our water waste predicament.

Solution Details
After conducting our own market research, telephone interviews, and checking references, we contracted with Phillips Plumbing to install a Noritz Model N-0751M tankless gas water heater.  This model is a mid-size heater, sized for the needs of our four-bathroom home.  Since tankless heaters are more expensive, our first inclination was to “go small” and install a smaller heater rated for a two-bath home (we normally don’t use more then two bathrooms at a time).  However, our plumber/installer convinced me that getting an appropriately sized heater was the best way to go, so we opted for a larger unit.  The Noritz is the top selling brand of tankless heaters (according to my own research) so I was satisfied we were going with the best size, make, and model!

When considering and selecting a tankless system, an important consideration (and potential cost issue) will be access to gas and exhaust venting. Although most everyone uses tank heaters that burn natural gas, the gas needs for a tankless system are considerably greater. This is because tankless systems use the large amounts of gas for very short periods (“bursts” as described by our installer) to heat water quickly. In order to serve the increased gas needs of the tankless system, larger diameter pipes are required from the gas meter or central supply pipe in your home. Luckily this wasn’t a big issue for us, since our storage closet is next to the gas meter! Regarding exhaust venting, tankless systems give off hot exhaust gas that requires special venting and/or chimneys. This is not necessarily a big or expensive modification but you need to understand that you won’t be able to re-use of the existing vent from your old tank system.

Regarding cutting our water waste from having to run hot water the length of the house, our plumber/installer from Phillips offered an ingenious solution!  He installed a Metlund Demand Pump Systemdesigned to recirculate hot water, on demand, from our new tankless system.  Our Metlund pump was positioned at the farthest water fixture requiring hot water (in this case, our daughter’s bathroom).  A simple and inexpensive modification to our existing water piping created a close loop system that would recirculate hot water.  Finally, the Phillips plumber/installer installed wireless switches in our other bathrooms and kitchen in between the new water heater and far bathroom with recirculating pump. The results of this set up allow us to press the wireless button at any location and within 30 seconds we have hot water with virtually no water waste!  The pump quickly pulls hot water from the new heater to all fixtures in our home and recirculates the cold water already in the pipes back through the water heater.  A simple, ingenious, and relatively inexpensive system that really works!  By the way, the recirculating pump system also works with traditional tank water heaters too!

Benefits & Payback
Tankless systems are not cheap although current rebates can really soften the cost. Our Noritz tankless system cost, including gas line modifications and sales tax was $3,600.00.  We paid an additional $400 for the Metlund Demand Systems Pump making our total investment about $4,000.00.

I compared use of the tankless water heater over five-month periods in 2009 (with new tankless heater) and 2008 (with the old tank heater).  Average natural gas cost for the 2008 period averaged $65 per month (this includes gas needs for cooking).  The average for the same period during the prior year (with old tank heater) was $116 month, a $51 difference! Now if I could just get my two daughters and wife to take shorter showers, the money savings would be even greater!

Regarding water savings, I cannot offer a similar comparison. However, I can tell you that the water savings are significant when you consider that a 3-5 minute wait in the far bathroom used by my daughters now takes, on average, 20 seconds!

Informational Links

Installer – Phillips Plumbing

Products Installed:
Noritz Tankless Water Heater, Model N-0751M

Metlund Demand Systems Pump, Model S-50T/S-70T