Formula to calculate BTUs from old radiators?

Wet_behind_the_ears

Probably my dumb, but searching this great site for what I assume is a simple calculation is proving challenging.  Lots of help on the net to tell me how to calulate my BTU requirement, but not the actual output of my old radiators.



I suspect the rads are circa 1930 - very heavy!



We have just replaced the empty air behind the walls with 3.5" of sprayed in foam, and the old windows with low e thermopane - so we know we have way too much heat overall  and also lots of different sized radiators, so loooking to match old rads with new rooms' heating requirements in some cases, and replace with new rads in others.



As a result, want to calculate the output in BTUs of various size rads, and can't seem to find a calculator for that.



For example: I have one radiator that is

49" long, 9.5" wide, and the fins 17" high.

Fins are 20 wide by 6 deep, approx 1.25 inches in diameter, on 2.5" centres.



All feeds are at the bottom - some same end and others opposite end feeds.

All are painted wit metal paint, some - some white enamel and other silver



Any suggestions welcome.



Thanks very much.

CMadatMe

Hot Water Rads

There is 150 btu's per sqft of edr for cast rads. You must calculate the sqft of edr for the rads. How many column, height and length are needed to calculate edr as well as type of rad. Try this to assist you in sizing them.

http://www.usboiler.burnham.com/contractors/tool-box-sizing

Wet_behind_the_ears

Thanks!

Thanks, Chris

Wet_behind_the_ears

Thanks!

Thanks, Chris

CMadatMe

Welcome

But do me one favor. The out put of those rads is useless without doing a heat loss of the home. Do one...Then take each room and compare the rads to the loss and find yourself a heating curve. Take advantage of the cast and save yourself fuel dollars while providing ultimate comfort.