Replaced two in my daughters house that were same brand but were about 40 years old (assuming they were original with house). Wasn't sure of old model number (no numbers visible), but was able to keep old housing (so didn't need to get in attic) and just replace fan/light components and light cover. Components were direct replacements. Good product, but they need to improve to where it can be installed without getting into attic for complete replacements. All but one of the old components still worked, so keeping those as spares, but covers had aged/yellowed and one light cover had fallen off and broke. Not bad for 40 year old fan/light/heater system.