Tankless Water Heaters Vs. Conventional Water Heaters

SpecificationsTankless Water HeaterConventional Water Heater
Max BTU.194,000 BTUAve. 75,000 BTU
Size1.6 Cubit FeetAve. 24 Cubit Feet
Dimensions23.6″(H) X 13.8″(W) X 9.4″(D)64″(H) X 26.5″(W)
Weight46 lbs.325 lbs.
Standby Heat Loss0% – No insulation required20%
Vent4″ Diameter w/ Power FanDraft Hood
Computer Modulated Gas ValvesYesNo
Computerized Safety DevicesFlame Rod, Thermal Fuse, Lighting
Protection Device, Electric Leak Prevention
Device, Overheat Prevention Device,
Freezing Prevention Device, Fan Rotation Detector
None
IgnitionSparkPilot
Electronic Flow SensorYesNo
InstallationIndoor/OutdoorIndoor Only
Minimum Flow Rate0.75 GPMNone
Size of Exhaust PipeInside: 4″ Round
Outside: Vent Cap
4″ Round
Powered CombustionYes (Fan Assisted)No (Gravity)
Gas Connection3/4″ NPT1/2″ or 3/4″ NPT
Water Connection3/4″ NPT3/4″ NPT
Characteristic
Warranty10yr. Heat Exchanger / 3 yr. Parts1 yr. Parts / 5yr. Tank
Life Expectancy10-15 Years3-8 Years
Energy CostSaves up to 50% – Unit can pay for itself
3-5 years.
Cost up to 50% More
Floor Space SavingWall mounted or outdoor installation saves
$100 per square foot of floor space.
Wastes $100 per square foot
of floor space.
Ease of InstallationSmall size allows for installation close to
point of use, eliminating need for
recirculation systems for long runs of piping
Big and Heavy. Requires mechanical closet
and/or barrier post and stand. May
need recirculation system and
additional structural requirments.
Total Installation CostTotal cost of installation roughly the
same. Less components and bulk
Cost roughly the same.
Service AbilityAll parts are replaceable – Full unit
replacement not necessary.
If tank leaks, entire unit must be
replaced.
Tank LeakageTank cannot leak – NO TANKTank leakage can cause expensive
property damage and safety concerns.
ScalingNo storage prevents most cases of
scaling. Scale can be easily cleaned and
flushed out of the unit.
When scale develops, unit must be
replaced.
Hot Water CapacityUnlimited and Instantaneous.Tank is cold when 70% of capacity
has been used. Full recovery time
can be 2 to 3 hours.
Control of Water TempatureDigital remote controller sets water
temperature.
Either preset from manufacturer
or with imprecise knob.