Typically a tankless water heater can provide 2 – 5 gallons (7.6 – 15.2 liters) of hot water per minute.
For example, a heater may be capable of increasing the temperature of incoming water 60 deg. F. at 3 gallons per minute flow rate.
The temperature rise that a tankless water heater can provide and the water flow rate that it can support depend on the heater's BTU output capacity which in turn is a function of the fuel used (gas-fired or electric) and the efficiency and the size of the heater.
Also see tankless water heater Problems & Defects where we describe the Tankless Water Heater Cold Water Sandwich Effect. Readers should also
see ALTERNATIVE HOT WATER SOURCES to distinguish among these types of hot water producing systems.
The original text of this article was provided courtesy of Carson Dunlop - that text has been edited and may not entirely reflect CD's views.
Our OPINION is that readers looking for plenty of hot water heated efficiently should also consider the heater we describe
at INDIRECT FIRED WATER HEATERS
Try the search box below or CONTACT US by email if you cannot find the answer you need at InspectApedia.
Comment: decide against the tankless system
(June 30, 2011) Don Wells said:
Your findings helped me to decide against the tankless system as it seems to be high maintenance. I'll stay with the gas water heater with a good insulation rating.
My opinion is that the life and performance as well as maintenance of tankless water heaters can be good depending on the local water chemistry. Hard water can be a problem for some units.
Ask a Question or Search InspectApedia
Questions & answers out the hot water heating capacities & flow rates for tankless or demand hot water heaters.
Use the "Click to Show or Hide FAQs" link just above to see recently-posted questions, comments, replies, try the search box just below, or if you prefer, post a question or comment in the Comments box below and we will respond promptly.
 Thanks to Mark Cramer, Tampa Florida, for assistance in technical review of the "Critical Defects"
section and for the photograph of the deteriorating gray Owens Corning flex duct in a hot attic. Mr. Cramer is a Florida home inspector and
home inspection educator.
 HREF="http://www.consumerreports.org/">Consumer Reports offers an article on the efficiency versus the economy of tankless water heaters - see http://www.consumerreports.org/cro/Appliances/heating-cooling-and-air/water-heaters/tankless-water-heaters/overview/tankless-water-heaters-ov.htm
Carson, Dunlop & Associates Ltd., 120 Carlton Street Suite 407, Toronto ON M5A 4K2. Tel: (416) 964-9415 1-800-268-7070 Email: email@example.com. The firm provides professional home inspection services & home inspection education & publications. Alan Carson is a past president of ASHI, the American Society of Home Inspectors. Thanks to Alan Carson and Bob Dunlop, for permission for InspectAPedia to use text excerpts from The Home Reference Book & illustrations from The Illustrated Home. Carson Dunlop Associates' provides extensive home inspection education and report writing material.
The Illustrated Home illustrates construction details and building components, a reference for owners & inspectors. Special Offer: For a 5% discount on any number of copies of the Illustrated Home purchased as a single order Enter INSPECTAILL in the order payment page "Promo/Redemption" space.
TECHNICAL REFERENCE GUIDE to manufacturer's model and serial number information for heating and cooling equipment, useful for determining the age of heating boilers, furnaces, water heaters is provided by Carson Dunlop, Associates, Toronto - Carson Dunlop Weldon & Associates Special Offer: Carson Dunlop Associates offers InspectAPedia readers in the U.S.A. a 5% discount on any number of copies of the Technical Reference Guide purchased as a single order. Just enter INSPECTATRG in the order payment page "Promo/Redemption" space.
The Home Reference Book - the Encyclopedia of Homes, Carson Dunlop & Associates, Toronto, Ontario, 25th Ed., 2012, is a bound volume of more than 450 illustrated pages that assist home inspectors and home owners in the inspection and detection of problems on buildings. The text is intended as a reference guide to help building owners operate and maintain their home effectively. Field inspection worksheets are included at the back of the volume.
Special Offer: For a 10% discount on any number of copies of the Home Reference Book purchased as a single order. Enter INSPECTAHRB in the order payment page "Promo/Redemption" space. InspectAPedia.com editor Daniel Friedman is a contributing author.
Special Offer: Carson Dunlop Associates offers InspectAPedia readers in the U.S.A. a 5% discount on these courses: Enter INSPECTAHITP in the order payment page "Promo/Redemption" space. InspectAPedia.com editor Daniel Friedman is a contributing author.
The Horizon Software System manages business operations,scheduling, & inspection report writing using Carson Dunlop's knowledge base & color images. The Horizon system runs on always-available cloud-based software for office computers, laptops, tablets, iPad, Android, & other smartphones