For bulbs labeled A19, A15, and A21, what does the "A" mean, and how do those numbers relate to the bulb?

The "A" refers to the traditional, pear-shaped bulb, a common style for homes. The number indicates the bulb's diameter at its widest point, in eighths of an inch, so an <a href="https://www.homedepot.com/b/Lighting-Light-Bulbs/A19/N-5yc1vZbmbuZ1z0vvrd?emt=plpfaq_2504_lightbulbs" style="text-decoration: underline;">A19 bulb</a> is 19/8 inches wide, an <a href="https://www.homedepot.com/b/Lighting-Light-Bulbs/A21/N-5yc1vZbmbuZ1z0vvpm?emt=plpfaq_2504_lightbulbs" style="text-decoration: underline;">A21</a> is slightly larger at 21/8 inches, and an <a href="https://www.homedepot.com/b/Lighting-Light-Bulbs/A15/N-5yc1vZbmbuZ1z0vvqn?emt=plpfaq_2504_lightbulbs" style="text-decoration: underline;">A15</a> is smaller at 15/8. Knowing this helps when choosing the right size for your fixtures and the light needed.

Which features should I look for when purchasing light bulbs?

There are many different features that will elevate your lighting, including <a href="https://www.homedepot.com/b/Lighting-Light-Bulbs/White/G9/Enclosed-Fixture-Rated/N-5yc1vZbmbuZ1z17hnfZ1z17hpeZ1z1bkiy?emt=plpfaq_2504_lightbulbs" style="text-decoration: underline;">enclosed fixture rated</a>, <a href="https://www.homedepot.com/b/Lighting-Light-Bulbs/White/G9/Energy-Saving/N-5yc1vZbmbuZ1z0u085Z1z17hpeZ1z1bkiy?emt=plpfaq_2504_lightbulbs" style="text-decoration: underline;">energy saving</a>, and more.

Which white light bulbs are the top rated?

The <a href="https://www.homedepot.com/p/YANSUN-40-Watt-Equivalent-G9-Base-Non-Dimmable-LED-Light-Bulb-in-Warm-White-3000K-5-Pack-H-110VGD00102G9-5/312297710?emt=plpfaq_2504_lightbulbs" style="text-decoration: underline;">40-Watt Equivalent G9 Base Non-Dimmable LED Light Bulb in Warm White 3000K (5-Pack)</a> is one of our top-rated white light bulbs.

I'm looking for an outdoor security light for my garage. What should I consider?

Check out <a href="https://www.homedepot.com/b/Lighting-Light-Bulbs/HID/N-5yc1vZbmbuZ1z0vxiq?emt=plpfaq_2504_lightbulbs" style="text-decoration: underline;">HID bulbs</a> for high-intensity, far-reaching light or a good <a href="https://www.homedepot.com/b/Lighting-Light-Bulbs/LED/N-5yc1vZbmbuZ1z0vxij?emt=plpfaq_2504_lightbulbs" style="text-decoration: underline;">LED</a> option for outdoor security lighting. Both can come in a variety of wattages and color temperatures. Consider using an accessory like a motion sensor for added security and energy savings.