Thread: re; tankless water heaters

What the consenus about tankless water heaters, are they worth the added cost to buy and Install, are they really that energy effificent to warrant the extra cost to install. thanks for any input.

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Originally Posted by daniel nantell

What the consensus about tankless water heaters, are they worth the added cost to buy and Install, are they really that energy efficient to warrant the extra cost to install. thanks for any input.

I have heard both ends of the tale but I use to put them in remodels I did it the past. They were electric and kinda sort not that much savings. The newest answer I have heard personally was a friend of mine with a gas tankless and her and especially her daughter takes endless showers and they also have gas heat. This past winter their gas bill was maybe 40 a month. In the long run I think they pay out. If you think f it once you spend that considerable amount more it is gone and done with and all you are left with is that lower bill per month . So yes I think they are worth it.

I have a gas tankless water heater that uses a direct vent. It uses less gas than a fireplace pilot light! Do not go with an electric tankless water heater. We just had a long thread on this issue last week.

I can highly recommend gas tankless based on personal use and use by tenants.

They are subject to poor installation, not your average water heater installation; i.e. only licensed plumber who is familiar with on-demand systems

Tankless Warranty Limits (check during your inspection)

From Rinnai install manual

*Period of coverage is reduced to 3 years from date of purchase when used as a circulating water heater within a hot water circulation loop, where the water heater is in series with a circulation system and all circulating water flows through the water heater, and where an on-demand recirculation system is not incorporated.

On-demand recirculation is defined as a hot water re-circulating loop or system that utilizes existing hot and cold lines or a dedicated return line, and only activates when hot water is used. It can be activated by a push button, motion sensor, or voice activation but not by a temperature sensor. A timer added to a standard re-circulating pump is not considered as on-demand.

Use of an MCC-91 controller in a residential dwelling will reduce the warranty coverage to that of a commercial warranty application.

Pump should be controlled by an Aquastat, Timer or Combination Aquastat and Timer. Pump to be sized to maintain circulation loop temperature. A minimum of 3 GPM flow is recommended for the circulation system. The pump should be sized to overcome the pressure loss through the Rinnai water heater, supply and return plumbing. Reference the Rinnai Hot Water System Design Manual, Pump Sizing for Circulation. Pump to be of bronze or stainless construction

**There are restrictions on use for hydronic space heating (radiators, in-floor)

*** Water quality (poor) may require conditioning

**** Service valves should be installed for flushing (vinegar or citric acid) maintenance due to mineral deposit build up. If not installed; may void warranty on heat exchanger!


Takagi - This warranty will not cover the followings:
1. Any Takagi unit that is not installed by a licensed plumber, gas installer, or contractor.
2. Defects or malfunctions due to improper installation, abnormal application, and lack of maintenance.
3. Damage due to abuse, accident, fire, flood, freezing, or any act of GOD.
4. Failure of Takagi unit due to the water heater being operated in a corrosive, chemically contaminated, lint, fiber glass, or any similar environment.
5. Failure of Takagi unit due to abnormal hardness water quality (scale build up), incorrect water pressure, untreated well water, incorrect supply voltage, incorrect and/or high (excessive) supplied gas pressure from Uniform Plumbing Code specifications.
6. Failure due to excessive temperature that is higher than the factory calibrated temperature limits.
7. Failure or damage due to unauthorized alterations, attachments, repair and/or improperly converted gas type, or using a different supply gas type as specified on the rating plate.
8. Damage due to freezing environment without proper preventive measure as instructed in the installation manual.
9. Damage from condensation due to extensive vent length without condensation drip and/or not following the installation manual.
10. Damage from not installed in accordance with applicable local, state codes, ordinances and good trade practices.
11. Unit is installed outside the United States of America and Canada excluding U.S. territories.

For commercial, industrial, and/or recirculation* applications (heating or domestic) and/or more than a single family residential dwelling, the heat-exchanger is covered within three (3) years of usage excluding labor and shipping.
*This does not include on-demand recirculation systems. An on-demand recirculation system is a system that utilizes either a push button or other type of manual activation (rather than a temperature sensor or timer) to activate the circulation pump. An on-demand recirculation system can use either the existing cold water line as the return line or have its own dedicated return line.

I have gas fired tankless water heaters at my home, my office and at 3 of our rentals. They can work well, but we encountered a number of issues when installing them.

I’ve put up this page describing some of the installation issues we encountered, and how to resolve them:

Tankless Water Heater Installation FAQ - Paragon Home Inspections Evanston / Chicago / Skokie / Wilmette / Morton Grove / Glenview / Northbrook / Illinois