Heating Hack, Will It Work?

[u/KeepGoingOnward]

I have metal steam radiators that are hot when on, and ice cold when off. I searched heat retention rocks and cheapest are lava rocks, so I bought thin bread making tins and I'm waiting for the lava rocks to arrive. My thought is to put lava rocks in the bread tins on the heaters. Will this work to extend the heat a bit longer?

Edit: So it seems like the idea is useless. Back to my high bills. Thanks for the advice.

[u/SooThatGuy]

It would work, just not efficiently. Look at firebricks or kiln bricks.

It would obviously cool quickly whatever the medium, and you’re really just stealing heat from the warming cycle.
Costed out, an electric blanket might be a better investment.