Proposed Unit Heater Efficiency Standard Nears Completion
Natural Resources Canada (NRCan) reported that its recent tests to compare the efficiency of a vent damper-equipped unit heater with the efficiency of a power-vented unit heater resulted in higher efficiency ratings for the vent damper-equipped unit heater. These findings addressed NRCan’s concerns about performance regarding the reduction of off-cycle losses and cleared the way for the adoption of prescriptive efficiency requirements for unit heaters identified to those set forth by the Energy Policy Act of 2005 in the United States.
The subcommittee, however, proposed to modify the prescriptive requirements in the P.11 draft standard to include restrictions on the source of dilution air used in power venting systems. In addition, NRCan agreed to abandon the idea of requiring a minimum 80 percent thermal efficiency at both minimum and maximum input rates for large modulating unit heaters. It was agreed that unit heaters that are designed and used for make-up air applications may be adversely affected by such a requirement, and based on the small numbers sold in Canada, the requirement would place an unreasonable burden on manufacturers of such products.
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Publication date: 04/16/2007