Tankless Water Heaters

I recently had a few people ask about tankless water heaters, so I decided to do some research.  The first place I went to was Consumer Reports.  I didn’t bother going any further.

The process of heating water in your house accounts for approximately 30% of your home’s energy costs (on average).  Some makers of gas-fired tankless water heaters claim their products can cut your energy costs up to half over regular storage heaters.  Don’t run out to buy one.

A gas tankless water heater uses high-powered burners to quickly heat water as it is running through a heat exchanger.  The average savings was 22% over the gas-fired storage tank models that were tested. 

This translates into an average savings of about $75 per year, based on 2008 national energy costs.  However, the tankless models cost so much more than the traditional version, and it can take up to 22 years to break even – longer than the 20-year life of many models. 

Furthermore, Consumer Reports conducted an online poll of 1,200 readers which revealed wide variations in installation costs, energy savings, and satisfaction.  Many of the electric models can’t deliver hot water fast enough to replace a conventional water heater.  Most homeowners with electric service only don’t have the option of gas models, and would have to upgrade their electrical service in order to power a whole-house tankless model. 

There are a few other issues that manufacturers have yet to resolve.  They often claim that their products are able to provide an endless amount of hot water.  But inconsistent water temperatures were a common complaint among the respondents polled by CR. 

When you turn the faucet on, tankless models feed in some cold water to gauge how big a temperature rise is needed.  If there’s cool water lingering in the pipes, you’ll receive a momentary “cold water sandwich”.  And a tankless water heater’s burner might not ignite when you try to get just a trickle of hot water for, say, shaving.

Tankless hot water heaters don’t delivery hot water instantaneously either.  It takes time to heat the water to the target temperature, and just like storage water heaters, any cold water in the pipes needs to be pushed out.  Tankless models electric controls mean you’ll also lose hot water during a power outage.

Tankless water heaters cost $800 to $1150, compared to $300 to $480 for storage tank models.  Tankless models need electrical outlets for their fan and electronics, upgraded gas pipes, and a new ventilation system.  This all brings the average installation costs to $1200, compared with $300 for storage tank models. 

During CR’s long-term testing, an indicator on the tankless model warned of scale buildup.  They paid $334 to replace valves and have a plumber flush out the lines with vinegar. 

Many industry experts recommend that tankless models be serviced once a year by a technician.  Calcium buildup can decrease efficiency, restrict water flow, and damage tankless models.  Experts suggest installing a water softener if your water hardness is above 11 grains per gallon.  Ignoring this advice can shorten your warranty. 

This research proved to be an eye-opener for me.  I hope it helped you as well.