Are there fans for radiators to improve performance?

Question

I lived all my life with forced air heating and cooling, but my house now has steam radiators. They perform ok, I suppose, but I know from trying that just letting the convection cause the airflow leaves them very inefficient.

With a small 6 inch fan blowing at low speed on a radiator, the room temperature will go up 5-10 degrees F.

I would prefer not to have to run power and fans to every rad in the house. I was wondering what the options were for fans to improve the radiators performance.

Standard round fans are the wrong shape, and only target a small portion of the radiator surface.

I would love something that could draw power from the heat difference, since all it needs is low speed fans to move air better than convection does.

Answer 1

An alternative that might work in some rooms is a ceiling fan that has a low speed (we have some 6-speed models in our home where the lowest speed just circulates the air slightly). This would help move air around in the room (and thereby helping to move some heat away from the radiators) and has the added plus that you can use it on higher speeds for summer cooling.

We have forced hot air heat, and our master and living room have high ceilings, so we run the fans year-round.

Answer 2

I saw some small heat-powered fans for wood stoves in a Lehman's catalog a few years ago. I'm not sure if a radiator would put out enough heat to spin one.

Answer 3

you could make a sterling engine that powers a little crossflow fan and a shroud that guides the airflow

but sterling engines don't start easily, powering the fan (or starting the sterling) from the flow in the pipe might be more reliable