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Gas Tankless Water Heater

Done correctly, gas tankless water heater upgrades can save significant utility expenses while providing unlimited hot water, longer life, and added safety by eliminating the potential for back-drafting of combustion gases.

Water heating is the second largest energy expense in a home – typically 18% of the total utility bill. High-efficiency gas tankless water heaters eliminate heat loss from stored hot water in tank systems and use more efficient burners for significant energy savings. The combustion process is decoupled from the indoors with ducting for outside combustion air and exhaust air. This mitigates potential back-drafting of combustion gases that can occur with less efficient atmospherically vented gas tank water heaters. These systems also provide added durability compared to tank systems, which are to leaks.

Checklist

This U.S. Department of Energy checklist includes important specifications that can contribute to a complete and quality installation. All work shall comply with these specifications, all relevant codes and standards, and all manufacturer installation instructions. The contractor shall check each box on the checklist below and sign and date at the bottom to certify the work is completed.

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Preparation


The existing hot and cold water pipes around the water heater shall be inspected for water leaks before installation, and if any leaks are found they shall be reported to the homeowner for repairs before continuing the work.

The existing gas service line shall be inspected to determine if the size is adequate for the tankless gas water heater. If not, the gas line shall be replaced with one of adequate size.

The contractor shall determine whether the water heater model to be installed requires an outlet or a hard-wired power supply, confirm the availability of an electrical outlet or supply near the location for the water heater, and install an outlet if necessary.

The water hardness shall be tested and recommendations shall be made to the homeowner about installation of a water softener if the tested level exceeds manufacturer-specified limits.

The water heater shall be sized based on the maximum demand anticipated and the temperature rise needed (which depends on climate).

Installation


The water heater installed shall be ENERGY STAR certified.

Collection and disposal of combustion condensate shall be provided if necessary. For a closed water supply system (i.e., with a back-flow preventer in the cold water supply), provisions shall be made to control thermal expansion (i.e., install an expansion tank if needed).

Where required by local codes, a mixing valve shall be installed to reduce the point-of-use temperature of the hot water to prevent scalding.

Where water leakage from the water heater could cause damage to the home, a building code-compliant emergency drain pan shall be installed with a ¾" drain line or larger running to a drain or pumping to daylight.

All accessible pipes connected to the water heater shall be insulated with a minimum of R-3 pipe insulation.

The water heater shall be installed in compliance with manufacturer’s specifications and relevant industry standards.

If installation of a new sealed-combustion, direct-vented water heater results in a vacated entry point in the chimney, the hole in the chimney wall shall be sealed.

Commissioning


The water heater shall be commissioned in compliance with the manufacturer’s specifications and relevant industry standards.

All operation and maintenance procedures shall be reviewed with the homeowner.

The gas line shall be tested for leaks after installation is complete.
Gas Tankless Water Heater

Tips to Sell Quality Installed Home Improvements

Home Improvement Expert is a valuable tool for organizations committed to quality installed work. The following tips help optimize the value of this tool when selling home improvements:

Trust Matters: Inform homeowners how your work conforms to this world-class expert guidance. Recommend they visit the DOE website as evidence these are indeed official best practices.

Knowledge Matters: Take advantage of the Building America Solution Center as a resource for becoming an expert on these projects.

Clarity Matters: Tell prospective clients to contrast your expert-recommended best practices with other contractors.

Value Matters: Advise prospective clients to insist other bids also include these checklists to ensure equivalent quality work.

Message Matters: Showcase on your website and marketing materials that your company uses the highest quality best practices specified on HIE Checklists.

Experiences Matter: Provide visual evidence contrasting the difference between poor and high quality work such as infrared images; pre- and post-energy bills; short and long warranties; and simple charts and graphics depicting performance advantages.

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Disclaimer

This content is a work created with funding provided by the United States Department of Energy under Contract no DE-AC05-076RL01830 for the operation of Pacific Northwest National Laboratory. The information and guidance provided by Pacific Northwest National Laboratory (PNNL) in the content are intended solely for educational purposes only and do not constitute formal training or certification. It is provided with the explicit understanding that neither the United States Government nor the United States Department of Energy, nor the Contractor, nor any or their employees, nor any jurisdiction or organization that has cooperated in the development of these materials, makes any warranty, express or implied, or assumes any legal liability or responsibility for the accuracy, completeness, or usefulness or any information, apparatus, product, software, or process disclosed, or represents that its use would not infringe privately owned rights. Reference herein to any specific commercial product, process, or service by trade name, trademark, manufacturer, or otherwise does not constitute or imply its endorsement, recommendation, or favoring by the United States Government or any agency thereof, or Battelle Memorial Institute. The views and opinions of authors expressed herein do not necessarily state or reflect those of the United States Government or any agency thereof. Viewers assumes full responsibility for all actions that they may take from information provided in this content including ensuring the safety, code compliance, and proper functionality of any products they choose to install. Installation and use of such products should be performed in accordance with local regulations and manufacturer instructions.