"Heatilator" has become a generic word like "kleenex" to mean a metal fireplace with air heating channels built into or surrounded by masonry and vented through a masonry chimney.

"Heatilators" were popular in the 1950's through the 1980's becasue any mason could build brick around them without having to know much about fireplaces.

The question here is how long do they last and are they safe after they have rusted out?

Above is a picture of an older Heatilator built in 1952. Not only is it clearly rusted out, the owner reported numerous mouse nests in the cavities that might have caught fire had the fireplace been used. Since the heatilator was only surrounded by one wythe of 4" thick masonry, we think a substantial fire outside of the metal heatform could have spread to the siding or the roof and the situation was dangerous. Moreover it was insidious since the homeowner didn't see or know about the deterioration until he decided to replace the heatilator.

So how long will they last and when should you replace or at least check for corrosion? This particular heatilator was removed in 2008 so you could say it lasted over fifty years but it wasn't used for the most recent twenty years and look how bad it is. Maybe fifteen years? Maybe at least in twenty years it would be worth removing some brick behind the fireplace to see if it is still intact.

Here's another rusted out heatilator
Heatilator replaced by Rumford and here
and another that was "Rumfordized"
But is the Rumford as efficient as the Heatilator was?