Change is coming — and homes across Massachusetts will be safer because of it.

Regulations taking effect Thursday require that homes built before 1975 and that are being sold must be equipped with smoke detectors with a 10-year life span.

“What we’ve seen in the past eight to 10 months across the state is that our fatal fires involve homes that have smoke alarms in them, but they are inoperative,’’ Fire Marshal Peter J. Ostroskeysaid recently.

Ostroskey said that as investigators have searched charred wreckage of fatal fires, they have discovered that batteries have been removed, or the alarms have not been replaced even though they are no longer functioning properly because they are too old.

He said smoke detectors must be replaced at least every 10 years because they lose the life-saving sensitivity in their sensors.

“We believe that having a 10-year sealed battery . . . will improve the operating status of smoke alarms in residences,’’ he said, adding that detector packaging makes clear the life cycle of the batteries included in the equipment.

Ostroskey said the 1975 cutoff date for single-, double-, and triple-family homes was chosen because homes built after that were already required by the state building code to have hard-wired power supplies for smoke detectors.

But even those hard-wired detectors need to have backup batteries replaced, and the detectors should be replaced every 10 years, too, he said.

As part of the fire prevention effort by his office, Ostroskey stressed that the arrival of the heating season is the right time of year to have professionals examine furnaces and chimneys to ensure that they are safely operating and are not potential fire sources.

John R. Ellement can be reached at ellement@globe.com. Follow him on Twitter @JREbosglobe.