Significant changes to the 2018 International Residential Code

The 2018 Significant Changes guides are available for the International Building, Residential, Fire, Plumbing, Mechanical and Fuel Gas Codes. This valuable series can help any code user save time by zeroing in on the most critical changes in the 2018 International Codes. The Code Council’s technical experts provide summaries, analysis and graphics for these changes making them clear and easy to understand.

2018 International Residential Code

A modification to Section N1104.1 (Lighting) of the 2018 International Residential Code (IRC) states that: the required percentage of permanent lighting fixtures having high-efficacy lamps has increased from 75 percent to 90 percent.

This change is significant because the definition for high-efficacy lamps and the requirement for a certain percentage of high-efficacy lamps in permanent lighting fixtures first appeared in the 2009 IRC. Lamps have traditionally been referred to as light bulbs. By definition, high-efficacy is determined by the lumens (light emitted) per watts (W) of power to produce the light. The acceptable ratio of lumens to watts depends on the wattage of the lamps. For example, a 60-watt or greater lamp must produce at least 60 lumens/W to be considered high efficacy. Examples of high-efficacy lamps are compact fluorescent lamps (CFLs), T-8 linear fluorescent lamps and LED lamps.

Since the 2009 code, the lighting market has been rapidly moving toward high-efficacy lighting and phasing out incandescent lamps, which are not high efficacy. The 2009 IRC required at least 50 percent of the lamps in permanently installed lighting fixtures to be high-efficacy lamps. In the 2012 edition, that number was raised to 75 percent. In the 2018 code, the percentage of permanent lighting fixtures containing only high-efficacy lamps has increased to 90 percent to align with market trends and improve energy savings. Switching to an LED lamp, for example, can reduce electricity consumption by more than 80 percent when compared to an incandescent bulb. The new requirement still allows 10 percent of fixtures to have lamps that are not high efficacy to accommodate decorative incandescent lighting.

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