Are ED28 and BT28 bulbs interchangible?

ED28 and BT28 bulbs are not interchangeable due to differences in their shape and design. ED28 bulbs have a larger, elliptical shape, while BT28 bulbs are more bulbous and tapered. Additionally, they may have different base types and wattage specifications, which can affect compatibility with fixtures. Always check the specific requirements of your fixture before substituting one bulb type for another.