Question? Just ask us!
Free Encyclopedia of Building & Environmental Inspection, Testing, Diagnosis, Repair
InspectAPedia ® Home
AGE of WATER HEATERS
AIRBOUND HEAT SYSTEM REPAIR by WATER FEED VALVE
ALTERNATIVE HOT WATER SOURCES
ANODES & DIP TUBES on WATER HEATERS
ANTIFREEZE for BOILERS
ANTI SCALD VALVES
APPLIANCE DIAGNOSIS & REPAIR
APPLIANCE EFFICIENCY RATINGS
AQUASTAT CONTROL Functions
BACKDRAFTING HEATING EQUIPMENT
BACKFLOW PREVENTER VALVE, HEATING SYS
BACKFLOW PREVENTER, HEATER WATER FEEDER
BACKUP HEAT for HEAT PUMPS
CARBON MONOXIDE - CO
CHECK VALVES, WATER SUPPLY
CHEMICAL CONTAMINANTS in WATER
CHIMNEY INSPECTION DIAGNOSIS REPAIR
CLOGGED DRAIN DIAGNOSIS & REPAIR
CLOGGED SUPPLY PIPING
CROSS CONNECTIONS, PLUMBING
DEBRIS in WATER SUPPLY, Water Heater
DRAIN a WATER HEATER TANK
ELECTRIC WATER HEATERS
FLOODED HEATING EQUIPMENT REPAIR
FLOODED WATER HEATER REPAIR
FREEZE-PROOF A BUILDING
FROST HEAVES, FOUNDATION, SLAB
GALVANIC SCALE & METAL CORROSION
GAS BURNER Flame & Noise Defects
GAS FIRED WATER HEATERS
GAS PIPING, VALVES, CONTROLS
HEAT TAPES, Heat, Insulation prevent Freeze-Up
HEATING COST FUEL & BTU Cost Table
HEATING COST SAVINGS METHODS
HOT WATER SUPPLY
HOT WATER IMPROVEMENTS
HOT WATER DELIVERY SPEED UP
HOT WATER EFFICIENCY IMPROVEMENT
HOT WATER PRESSURE EXPANSION RATE
HOT WATER PRESSURE LOSS
HOT WATER PROBLEM DIAGNOSIS
HOT WATER QUANTITY IMPROVEMENT
HYDROGEN SULFIDE GAS
INDIRECT FIRED WATER HEATERS
MANUALS & PARTS GUIDES - HVAC
MIXING / ANTI-SCALD VALVES
NO HEAT - NO HOT WATER: HEATER DIAGNOSIS
NOISE / SOUND DIAGNOSIS & CURE
NOISE CONTROL for HEATING SYSTEMS
NOISE, PLUMBING CHECKLIST
NOISE, WATER HEATER
ODORS GASES SMELLS, DIAGNOSIS & CURE
ODORS IN WATER
PIPING IN buildings, Clogs Leaks Types
PLASTIC Plexvent / Ultravent RECALL
PLUMBING FIXTURES, KITCHEN, BATH
PLUMBING VENT DEFECTS & NOISES
PUMPS, HEAT PUMPS
PUMPS, OIL BURNER
PUMPS, PONY PUMPS
PUMPS, SEPTIC PUMPS
PUMPS, SEWAGE EJECTOR / GRINDER PUMPS
PUMPS, SUMP PUMPS
PUMPS, WATER PUMPS
PUMPS, WATER REPAIR
RELIEF VALVE LEAKS
RELIEF VALVES - TP Valves on Boilers
RELIEF VALVES - STEAM TP VALVES
RELIEF VALVES - Water Heaters
RELIEF VALVES - Water Tanks
SAFETY, HEATING INSPECTION
SCALE REMOVAL, WATER HEATERS
SEWER GAS ODORS
SOLAR HOT WATER HEATERS
SOOT on OIL FIRED HEATING EQUIPMENT
SPILL SWITCHES - Flue Gas Detection
TANKLESS WATER HEATERS
THERMOSTATS, HEATING / COOLING
THERMOSTATS, WATER HEATER
TIMERS for ELECTRIC WATER HEATERS
WATER CONSERVATION MEASURES
WATER CONTAMINANT LEVELS
WATER HAMMER NOISE DIAGNOSE & CURE
WATER HEATER ALTERNATIVES
WATER HEATER ANODES, DIP TUBES
WATER HEATER AIR INLET
WATER HEATER DEBRIS FLUSH
WATER HEATER DRAIN PROCEDURE
WATER HEATER EFFICIENCY
WATER HEATER FLUSH PROCEDURE
WATER HEATER NOISES
WATER HEATER PROBLEM DIAGNOSIS
WATER HEATER PROPERTIES
WATER HEATER SCALE - De-Liming Procedure
WATER HEATER SCALE PREVENTION
WATER HEATER SAFETY
WATER HEATERS for HOME HEATING USE?
WATER ODORS, CAUSE CURE
WATER PIPES, Clogs Leaks Types
WATER PRESSURE & FLOW MEASUREMENT
WATER PRESSURE GAUGE ACCURACY
WATER PRESSURE LOSS DIAGNOSIS & REPAIR
WATER PRESSURE REDUCER / REGULATOR
WATER PRESSURE PUMP REPAIR GUIDE
WATER PUMPS, TANKS, TESTS, WELLS, REPAIRS
WATER PUMP REPAIR GUIDE
WATER QUALITY TESTS, CONTAMINANTS, TREATMENT
WATER QUANTITY IMPROVEMENT
WATER SOFTENERS & CONDITIONERS
WINTERIZE A BUILDING
Guide to Converting to a Tankless Water Heater: this article explains the conversion from conventional hot water heaters to use of tankless water heaters, also called instant water heaters or "on demand" water heaters. We discuss how to answer the question of whether or not you should convert from a conventional tank-type water heater to a tankless or demand or POU type water heater. Our page top photo illustrates a Takagi tankless water heater. Be sure to also review Tankless Water Heater Installation & Costs where we discuss installation, operating, replacement & maintenance cost comparisons between a demand type or tankless water heater and a conventional tank type water heater.
Green links show where you are. © Copyright 2014 InspectApedia.com, All Rights Reserved.
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 Associates - that text has been adapted and edited and may not entirely reflect CD's views. Page top sketch of a point of use tankless water heater courtesy of Carson Dunlop Associates. 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. Sketch of a point of use tankless water heater shown at left was provided courtesy of Carson Dunlop Associates.
Most of us are familiar with the traditional-style water heater - that big thirty- to sixty-gallon tank taking up space in the basement near the furnace or boiler. These water heaters have served us well with few improvements for decades, but a different breed of water heater has been in use for many decades in Europe and Latin America, and has seen less widespread but growing popularity in the U.S. - the tankless water heater.
Sketch of a point of use tankless water heater (at left) courtesy of Carson Dunlop Associates.
The energy-conscious world in which we live has turned its attention to the water heaters of old and has identified two potential areas of improvement. The first is that traditional water heaters are not very efficient at converting the energy in fossil fuels into hot water. Over the last twenty years, furnace and boiler technology has improved the efficiency of home heating, but water heaters have not kept pace, even though the same technology can be applied.
The second possible improvement that can be made to water heaters has to do with the storage of hot water. Traditional water heaters use fuel to heat water inside the tank. If the water is not used, it cools to the point that it must be heated up again.
The result is that we are constantly keeping a large volume of water at a high temperature, even if we are not planning on using any of it in the next little while. This means that while we are sleeping or at work, our water heaters are burning fuel or consuming electricity keeping a whole tank of water hot.
This is not a problem in the winter, when the heat loss from the water heater helps keep the building warm. It is a challenge in the summer, when the building is already warmer than we want. Tank-type water heaters can increase air conditioning costs.
As the name suggests, tankless water heaters have no tank, and therefore no storage capacity at all. When the faucets and fixtures in the home are sitting unused, the water heater is dormant. When somebody turns on a hot water faucet, the tankless heater swings into action.
These units use more powerful burners than conventional water heaters to heat relatively small amounts of water. The result is that the water is heated much more quickly than in an older system and this hot water can be immediately delivered to the fixtures.
A significant advantage of this system is that you can't empty all of the hot water out of the tank because there is no tank - just continuous hot water.
Also, since there is no tank, the water heater itself is much smaller. In most cases, these units are wall-mounted, so we not only do we have improved efficiency, reduced fuel costs, and unlimited hot water, but more free space in our basements!
While this all sounds good so far, there is a reason that everybody isn't switching over right away.
List of Possible Costs (including hidden costs) Involved in Converting to a Tankless or Demand Water Heater
Conventional water heaters, due to their simplicity, are relatively inexpensive, while tankless water heaters are more expensive to purchase.
The complexity of taknless or demand type water heaters also means that maintenance and repairs can be more expensive as well, and while tankless units have been in use around the world for many years, the rapidly evolving technology and our cold climate means that we don't have a great idea how long the typical life expectancy will be in North American homes, though the U.S. DOE estimates 20 years.
When it comes time to change your water heater, that's a good time to consider converting from a tank type water heater and a tankless or demand system.
Watch out: as we advise at Tankless Water Heater Installation & Costs, the economic picture of going tankless may not be as rosy as portrayed, moreso depending on the typical hot water daily usage rate and the total building hot water flow rate that you expect to need in the building or home.
As we advise in that article, if saving water heating cost or return on investment is the principal reason you are considering converting from a conventional hot water tank to a tankless, demand type water heater, you should perform total cost analysis that reflects an accurate and unbiased comparison between the total costs of replacing (or installing new) a tank type water heater and a tankless or demand water heater. Be sure to include these cost factors in your analysis:
Frequently Asked Questions (FAQs)
No FAQs have been posted for this page. Try the search box below or CONTACT US by email if you cannot find the answer you need at InspectApedia.
Questions & answers or comments about benefits of installing instant or demand or point of use water heaters.
Try the search box just below or if you prefer, post a question or a comment in the Comments box below and we will respond promptly.
Search the InspectApedia website
HTML Comment Box is loading comments...
Technical Reviewers & References
Related Topics, found near the top of this page suggest articles closely related to this one.