If you want to know which is better; natural gas heaters vs electric, there is no simple
answer.
Gas water heaters are usually more powerful than electric hot water heaters, but the gas models have specific
venting, combustion air, and gas line requirements.
There are also cost differences.
Gas water heaters are considered cheaper to operate than electric ones. The U.S. Energy Administration publishes
annual price projections for fuel to the year 2030. At one stage natural gas price projections looked the best and
were expected to decrease gadually to 2021; with electricity rates projected to rise in 2009 and in 2012 to
decrease.
But with the increased use of natural gas leading to a possibly depleting natural resource, its price is
actually increasing at a higher rate than electricity. Over the life of your tankless heater, whether gas will
still be the cheaper option is an unknown factor.
Consider rebates, low-interest loans and tax credits. The federal income tax credit is only one of many
incentives available for energy efficient water heaters. Check which are available and to what extent they offset
the higher cost of switching.
With tankless, although you won't run out of water, you are limited in the number of hot water uses taking place
at the same time.
When deciding between gas heaters vs electric, note that a two member family may not find it worth the cost
of installing either a gas or electric tankless heater.
If this two member residential dwelling has an electrical service rated at 200 amps, it need not be upgraded but
the gas service would, so it could accommodate a minimal ¾ inch gas supply line. If you use a gas tankless don't
skimp on the service because you need it for space heating, dryer and/or cooking, without all the appliances
competing for pressure.
Also when considering gas heaters vs electric, bear in mind gas water heaters are usually placed outdoors
because it's safer. If, for example, yours is in the garage, far from the master bathroom, by the time the hot
water gets to the indoor shower or sink, the water loses at least 10 degrees Fahrenheit from pushing through long
runs of cold uninsulated pipes housed in concrete slabs. To minimize this, locate your water heater as close to the
major points of hot water use as possible, especially if you live in a cold climate.
If the on-demand heater for the whole house is installed near the master bath and kitchen, you save water. Over
10,000 gallons of this precious resource is wasted every year by waiting for new hot water to reach the
fixture.
Bear in mind when reading efficiency ratings on natural gas tankless water heaters, manufacturers tend to
promote very high gallons per minute flow, but this can be deceptive. When looking at gallons per minute, the water
temperature can only be heated by 50 degrees.
This means if your source water is 55 degrees, the water coming out your shower head will be 105 degrees at its
hottest. Deduct from that about 10 degrees which will be lost along the pipes between the heater and your shower,
which means your shower water will be a lukewarm 95 degrees, possibly less during winter when your input water is
cooler. So before you buy, determine your requirements and read the specifications.
Since you lose (and pay for) 25% of the energy due to un-insulated hot water distribution pipes, insist
your hot water lines be well insulated. Your hot water will be hotter, and you'll save both water and money.
On-demand systems are healthier. Storage tanks are ideal breeding grounds for Legionella, whereas on-demand
systems are purged at each use. At shut down the water temperature in the tankless water heater increases from the
latent heat to above 120 degrees Fahrenheit, killing Legionella, despite the water being a very safe 105 degrees
Fahrenheit when delivered to you.
Make sure you don't use a tankless heater with a flow switch which heats water that is already hot. This
combination can scald users.
The biggest problem with electric water heaters is they can't put out as large a volume as gas water heaters. A
way around that is to install tandem water heaters - two electric tankless units working together.
When considering gas heaters vs electric, if your main criteria is cost right now, then perhaps the natural gas
tankless water heater is your best option.
Some things to think about:
Gas versions are said to be 82+% efficient, but this is at maximum burner efficiency. When the heater is
modulated to lower power levels required for normal water heating, the efficiency drops with the changing fuel to
air mixture.
In order to run efficiently, the burners for any gas appliance need to be properly and regularly maintained,
especially in hard water applications. Unless the heat exchanger is regularly de-scaled, the gas tankless water
heater will probably run at 65% efficiency for the first five years, and even less thereafter.
When your gas heater is installed, ask the manufacturer to provide the burner efficiency curve through the
entire range of modulation, in other words, you want the burner to be equally efficient even if you use only 25% of
its power instead of the maximum.
When trying to decide between gas heaters vs electric, these manufacturers provide both and can guide
you:
Stiebel Eltron
Rheem Manufacturing
Sets Systems
Eemax Incorporated
Noritz America Corporation
Takagi Industrial Company
Bosch USA
Bradford White Corporation
Paloma Industries
Chronomite Laboratories Incorporated
Thanks for visiting us and good luck with your purchase of natural gas tankless water heaters.
