Tankless Water Heaters Vs. Conventional Water Heaters

Tank vs Tankless?

Specifications	Tankless Water Heater	Conventional Water Heater
Max BTU.	194,000 BTU	Ave. 75,000 BTU
Size	1.6 Cubit Feet	Ave. 24 Cubit Feet
Dimensions	23.6″(H) X 13.8″(W) X 9.4″(D)	64″(H) X 26.5″(W)
Weight	46 lbs.	325 lbs.
Standby Heat Loss	0% – No insulation required	20%
Vent	4″ Diameter w/ Power Fan	Draft Hood
Computer Modulated Gas Valves	Yes	No
Computerized Safety Devices	Flame Rod, Thermal Fuse, Lighting Protection Device, Electric Leak Prevention Device, Overheat Prevention Device, Freezing Prevention Device, Fan Rotation Detector	None
Ignition	Spark	Pilot
Electronic Flow Sensor	Yes	No
Installation	Indoor/Outdoor	Indoor Only
Minimum Flow Rate	0.75 GPM	None
Size of Exhaust Pipe	Inside: 4″ Round Outside: Vent Cap	4″ Round
Powered Combustion	Yes (Fan Assisted)	No (Gravity)
Gas Connection	3/4″ NPT	1/2″ or 3/4″ NPT
Water Connection	3/4″ NPT	3/4″ NPT
Characteristic
Warranty	10yr. Heat Exchanger / 3 yr. Parts	1 yr. Parts / 5yr. Tank
Life Expectancy	10-15 Years	3-8 Years
Energy Cost	Saves up to 50% – Unit can pay for itself 3-5 years.	Cost up to 50% More
Floor Space Saving	Wall mounted or outdoor installation saves $100 per square foot of floor space.	Wastes $100 per square foot of floor space.
Ease of Installation	Small 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 Cost	Total cost of installation roughly the same. Less components and bulk	Cost roughly the same.
Service Ability	All parts are replaceable – Full unit replacement not necessary.	If tank leaks, entire unit must be replaced.
Tank Leakage	Tank cannot leak – NO TANK	Tank leakage can cause expensive property damage and safety concerns.
Scaling	No 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 Capacity	Unlimited and Instantaneous.	Tank is cold when 70% of capacity has been used. Full recovery time can be 2 to 3 hours.
Control of Water Tempature	Digital remote controller sets water temperature.	Either preset from manufacturer or with imprecise knob.