Indoor/Outdoor 24 Feet String Light, 12 Vintage ST19 bulbs, 2200K

Watts measure the amount of electrical energy a fixture consumes, while lumens measure the actual brightness (the amount of visible light produced). In the LED era, wattage is no longer a reliable indicator of brightness. When replacing old fixtures or comparing new ones, always look at the lumen output to determine how bright the light will be.

CRI is a scale from 0 to 100 that measures how accurately a light source reveals the true colors of objects compared to natural sunlight. A higher CRI (90+) ensures colors look vibrant and accurate, which is critical for retail displays, kitchen countertops, and bathroom vanities. A lower CRI (under 80) can make colors look washed out or dull, regardless of the color temperature.

For traditional incandescent fixtures, dimmability depended purely on the bulb. For modern LED lighting, dimmability depends on the internal LED driver or the specific LED bulb used. A fixture is only dimmable if its driver is explicitly rated for it. Furthermore, the fixture must be paired with a compatible dimmer switch (such as a standard TRIAC/Phase-cut dimmer or a 0-10V commercial dimmer) to prevent flickering and buzzing.

An integrated LED fixture has the LED diodes and driver built directly into the housing, meaning there are no traditional bulbs to screw in or replace. This allows for sleeker, lower-profile designs and better heat dissipation. However, if an integrated fixture fails after its warranty period, you typically have to replace the entire unit or the internal driver, rather than just swapping out a bulb.

Unlike traditional bulbs that simply burn out and go dark, LEDs gradually lose their brightness over time (lumen depreciation). The L70 rating indicates the number of operating hours it takes for the LED fixture to degrade to 70% of its original brightness. For example, a fixture rated for "50,000 hours L70" will still work after 50,000 hours, but it will be noticeably dimmer than when it was first installed.