Replacing Smoke Alarms

The smoke alarms used in our condos is by USI Electric, Model # 1204. If you look inside the unit, it states that units should be replaced every ten years. This is because the isotope sensor in these ionization detectors is consumed in about ten years.

These detectors aren't stocked at either Lowe's or Home Depot, so it may be necessary to find an online vendor (USI doesn't sell direct). The Model 1204 sells for around $15 each.

The USI website lists the following other brands as compatible or identical, but they may not be stocked locally, either:

Firex: #4518
BRK: 9120B or 4120SB
Kidde: 1275Eh or i12040

Newer smoke alarms include the USI Electric Model MDS107, an upgraded "IOPHIC" version that is designed to respond to fast flaming fires as well as slow smoldering fires. This model, which includes battery backup, has a new-style connector that must be wired into your home circuit in place of the older models' connector. It carries a 10-year warranty. It is recommended that all of your wired smoke alarms on the same circuit be of the same model to avoid false alarms.