steam radiation

Big Ed_4

You can add a TRV valve to the vent on the radiator to throttle it down....
Make sure you boiler is big enough to supply the extra radiation.

World Plumber

Radiation size

Thinking about adding heat to back rooms. Looking at the heat loss the radiators are slightly over double the heat loss rating in the rest of the house. Would it be wise to continue this sizing method. If I match the load will I have cold rooms with the others oversized?

Jamie Hall

the real trick

and it isn't all that easy is to make sure that the radiation available in each space being heated is in the same ratio to the heat loss from that space in each room in the house -- that is, if the radiator in, say, the living room appears to be twice as big as it needs to be, but the radiators in all the other rooms are also twice as big as they need to be, all will be well (steam does an amazing job of self-balancing). However... if you have twice as much radiation in one room as you need, and the rest of the house is just as much as necessary, then that one room will be too hot (conversely, if it's half as much it will be too cold, etc.).
The calculations for heat loss from each room aren't that hard -- just tedious.
Have fun!