Federal Energy Management Program: FEMP Designated Product: Commercial Gas Water Heaters

ENERGY STAR recently developed a performance specification for commercial water heaters. That specification is set to go into effect in February; however, manufacturers have not yet had the opportunity to have their products tested and qualified through the ENERGY STAR process.

FEMP and ENERGY STAR are monitoring the situation. As soon as a significant number of products are qualified through the ENERGY STAR process and listed in the ENERGY STAR Qualified Products List, FEMP will transition federal procurement requirements from FEMP Efficiency Requirements to ENERGY STAR-qualified products.

In the interim, federal buyers should purchase commercial gas water heaters that meet FEMP Efficiency Requirements, as documented below.

FEMP provides acquisition guidance and Federal efficiency requirements across a variety of product categories, including commercial gas water heaters. Federal laws and executive orders mandate that agencies meet these efficiency requirements in all procurement and acquisition actions that are not specifically exempted by law.

Meeting Energy Efficiency Requirements for Commercial Gas Water Heaters

Federal purchases must meet or exceed the minimum requirements listed in table 1.

^a Thermal efficiency is the ratio of heat transferred to water flowing through the water heater to the amount of energy consumed by the water heater as measured by the thermal efficiency test procedure contained in ANSI Z21.10.3-1998.

Defining the Covered Product

The efficiency requirement in Table 1 applies to commercial gas water heaters, including storage type¹, instantaneous², and hot water supply boilers³. Commercial oil, electric resistance, and heat pump water heaters are excluded. Residential water heaters are covered by a separate product overview.

Reducing Energy Costs: Save Up To $2,940 When You Buy FEMP-Designated Products

FEMP has calculated⁴ that a product meeting FEMP-designated efficiency requirements is cost effective if priced no more than $2,285 above the less efficient alternative. The most efficient level saves the average user more money: $2,940. The complete cost effectiveness example and associated assumptions are provided in table 2.

^a More efficient products may have been introduced to the market after this specification was published.

Exceptions

Products meeting FEMP-designated efficiency requirements or ENERGY STAR® performance specifications may not be life cycle cost effective in certain low-use applications, such as when a device is being purchased for backup purposes and will remain in off mode for most of its useful life. For most other average or high-use applications, purchasers will find that energy-efficient products have the lowest life cycle cost.

Complying with Contracting Requirements

Legislation and Federal Acquisition Regulations (FAR) require Federal agencies to specify and buy ENERGY STAR–qualified products or, in categories not included in the ENERGY STAR program, products that meet or exceed FEMP-designated efficiency requirements. Agencies that follow requirements to buy efficient products can realize substantial operating cost savings and help prevent pollution. As the world's largest consumer, the Federal Government can help pull the entire U.S. market toward greater energy efficiency, while saving taxpayer dollars.

These requirements apply to all forms of procurement, including construction guide specifications and project specifications; renovation, repair, maintenance, and energy service contracts; lease agreements; acquisitions made using purchase cards; and solicitations for offers. Energy efficiency requirements should be included in both the evaluation criteria of solicitations and the evaluations of solicitation responses.

FAR Part 23.206 requires Federal agencies to insert the clause at FAR section 52.223-15 in solicitations and contracts that deliver, acquire, furnish, or specify energy-consuming products. FEMP recommends that agencies incorporate efficiency requirements into both the technical specification and evaluation sections of solicitations. Agencies may claim an exception to these requirements through a written finding that no ENERGY STAR–qualified or FEMP-designated product is available to meet the functional requirements, or that no such product is life cycle cost effective for the specific application. Additional information on Federal requirements is available.

Designing a Commercial Gas Water Heater Installation

All commercial gas water heaters capable of exceeding FEMP's required thermal efficiency levels are condensing models. When installing a condensing gas water heater in an existing facility, special consideration should be given to condensate drainage, piping, and ventilation systems.

Compliant commercial gas water heaters need a drain line to dispose of condensate. Some combustion byproducts cause this condensate to be acidic, which can be corrosive to certain materials. Plastic piping typically used in new construction is not affected by this. However, acidic condensate can damage cast iron piping, which may be present in some existing facilities. In these facilities, you must either replace the drain lines with plastic or some other material immune to the effects of the acid, or install a neutralizer. A neutralizer is a device containing a base material (e.g., limestone chips) that counters the acid and eliminates the corrosive effects of the condensate. In commercial food service facilities, cleaning agents used during the dish washing process are known to neutralize acids. A neutralizer is not necessary in this situation as long the condensate line from the water heater is connected downstream from the dishwasher.

Condensing water heaters are not compatible with natural draft vent systems. When a standard efficiency gas water heater is replaced with a condensing model, the existing vent system will not work properly. Condensing water heaters are typically power-vented and include a fan that can exhaust combustion gases up to 60 feet horizontally through plastic pipes.

In new construction, condensing water heaters can be vented horizontally through an exterior wall. The end cap of this exhaust must be above the snow line or other obstructions. The vent also must be sloped toward the water heater so that any condensate formed is directed back toward the drain and does not freeze on the end cap, which could block the exhaust.

When planning the layout of a new commercial kitchen or other facility that requires a lot of hot water, locate the end uses (e.g., dishwashers, sinks) as close to the water heater as possible. Heat losses through the distribution system can be substantially reduced by minimizing pipe runs. If possible, insulate hot water pipes to further reduce heat losses.

User Tips: Using Products More Efficiently

To save additional energy, install water-efficient appliances and low-flow plumbing fittings (e.g., faucets and pre-rinse spray valves). In addition to reducing energy use, these devices reduce water consumption and its associated costs (e.g., water and sewer charges).

Buying Energy-Efficient Commercial Gas Water Heaters

When purchasing commercial gas water heaters, specify or select models that meet the efficiency requirements shown above. Information on commercial gas water heaters can be found in the Air Conditioning, Heating, and Refrigeration Institute's (AHRI) Directory of Certified Product Performance. The Federal supply source for commercial gas water heaters is the General Services Administration (GSA). GSA sells commercial gas water heaters through its Multiple Awards Schedule program and online shopping network, GSA Advantage!

Finding More Information

The following resources provide additional information surrounding the purchase of efficient products:

¹ A self-contained unit with an input rating of 75,000 British Thermal Units per hour (Btu/h) or greater that heats and stores water within the appliance at a thermostatically controlled temperature for delivery upon demand.

² A water heater with an input rating of 200,000Btu/h or greater (at least 4,000 Btu/h of stored water) that delivers heated water upon demand.

³ A packaged boiler with an input rating from 300,000 to 12,500,000 Btu/h and at least 4,000 Btu/h per gallon of water stored that has the temperature and pressure controls necessary for heating potable water for purposes other than space heating.

⁴ Based on the following assumptions: Annual energy use is based on the ANSI Z21.10.3-1998 test procedure for a 75-gallon storage-type water heater assuming a daily hot water demand of 1,000 gallons, 250 days per year of use, and a temperature rise of 80° F.

The assumed price for natural gas is $0.90 per therm, which is the average at Federal facilities in the United States. Lifetime energy cost is the sum of the discounted value of the annual energy cost based on average usage and an assumed water heater life of 10 years. Future natural gas price trends and a 3% discount rate are based on Federal guidelines (NISTIR 85-3273-26) and are from the Annual Supplement to NIST Handbook 135 and NBS Special Publication 709, "Energy Price Indices and Discount Factors for Life-Cycle Cost Analysis - 2011".

The efficiency of the base model is the minimum allowed by DOE appliance standards, the efficiency of the required model meets this specification, and the efficiency of the best available model is from the California Energy Commission (CEC) Appliance Database.

U.S. Department of Energy - Energy Efficiency and Renewable Energy

Federal Energy Management Program

FEMP Designated Product: Commercial Gas Water Heaters