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Conservation: Be Smart & Build Smart

Built Smart Users Manual: Alerts
Electrical Contractor Alert

Built Smart Users Manual | Specifications | Alerts | Water

This is a Seattle City Light BUILT SMART project and the following requirements must be met when constructing a BUILT SMART building in the Seattle City Light service area.

For a detailed explanation of program requirements, please refer to the BUILT SMART Technical Specifications provided to the General Contractor.

Intermittently Operated Whole House Ventilation Requirements

  • Whole-house ventilation fan must have a sone rating of 1.5 or less.
  • Whole-house fans must meet the following Washington Ventilation and Indoor Air Quality code prescriptive sizing requirements:
Unit Square footage Number of Bedrooms Minimum /Maximum Fan Flow
at 0.25 in W.G.
Less than 500 2 or less 50-75 cfm
501-1000 2 or less 55-83 cfm
1001-1500 2 or less 60-90 cfm
501-1000 3 bedrooms 70-105 cfm
1001-1500 3 bedrooms 75-113 cfm
  • All exhaust fans must vent to the building exterior.
  • All bathroom spot ventilation fans must have a minimum listed rating of 50 cfm @ 0.25 WG.
  • All kitchen spot ventilation fans must have a minimum listed rating of 100 cfm @ 0.25 WG.
  • Intermittently operated fans (or other non-heat-recovery systems) exhausting from the building shall be ducted to the outside and have a back draft or automatic damper in the exhaust duct.
  • Intermittently operating, whole-house exhaust fans shall have both automatic and manual controls. Automatic controls shall include a time clock or cycle timer with a minimum of three on-off periods per day and be set to provide at least 8 hours of mechanical ventilation per day. The control apparatus pins, etc., for automatic control shall not be removable.
Continuously Operated Whole House Ventilation Requirements
The BUILT SMART program now recommends a continuously operated ventilation system be installed as the preferred method of meeting the requirements for whole house ventilation in all BUILT SMART residences. Surface-mounted exhaust fans shall meet the following:
  • Airflow capacity must be rated at 0.25 wg external pressure by HVI.
  • Fan noise level shall not exceed 1.0 sones.
  • Fan motor power draw shall not exceed 35 watts.
  • Fan motor shall be rated for continuous use.
  • Continuous fans shall be sized to meet the WSA V1AQ Code requirements.

Heat Lamp/Fan Combinations
All heat lamp/fan combinations located in bathrooms must be wired and switched to operate separately. NOTE: If the bathroom fan is not a whole house fan, a one-hour crank timer in place of a switch is recommended.

In-Wall Heaters
In-wall heaters are to be mounted on interior walls or insulated from the exterior to full value of wall insulation.

Exterior Wall Cover Gaskets
Exterior-wall electrical cover plates must have foam gaskets or be caulked and sealed to limit air leakage.

Recessed Light Fixtures
All recessed light fixtures must be of low air leakage type (interior use, between floors).

Thermostats - Zone Heating
Each separate heating system in the unit shall have at least one thermostat per zone mounted on an interior wall, at the manufacturer's recommended height, to regulate temperature. Each thermostat shall have numerical degree settings. Thermostat accuracy shall be +/-2 degrees F or less. Electronic or Vapor Diaphragm thermostat types are allowed. Bi-metal thermostats are not allowed.

For more information, call Peter Held, BUILT SMART Program Coordinator, at 206.684.3605.


Interested in BUILT SMART incentives?
Contact an Energy Advisor at
or call (206) 684-3800.


The Seattle City Light Web Team:

Seattle City Light -- 700 5th Avenue, Suite 3200, Seattle, WA 98104-5031 -- 206.684.3000
Mailing address: 700 5th Avenue, Suite 3200, P.O. Box 34023 Seattle, WA 98124-4023