How to size a colonial raditator for any given room

MaryC

Hi there,



I recently purchased colonial cast iron radiators for my house, and I'm trying to determine whether they are large enough to heat my rooms.



The BTU requirement for one of the rooms in the house is 6500BTU.



I'm just wondering, what is the procedure for sizing the radiator that will be the most efficient for this room? I don't want to oversize or under-size the radiator for the rooms in the house. I'm looking for information regarding old fashioned steam heated cast iron radiators, so if you can let me know how many sections, tubes, and what dimensions I require, I'd really appreciate it!!!! Is there a general formula for calculating this?



Thank you very much!



Best,

MaryC

JStar

Radiator

Snap a few pictures, and take measurements of the height, width, and length of the radiators. We can tell you how many BTUH each of them are.

MaryC

Steam heat radiator room size formula/calculation

Hi again,

Thank you fo your response. I'm looking for a specific formula for calculating radiator size, based on the specific room.

So, for instance, one of the rooms I have is: 15ft x 12ft x 9ft bedroom with 2 outside walls, 2 windows(32" x 64" old windows).

The radiators I have are:

5.5' wide x 21" high with 5 tubes and 22 sections

8" wide x 19" high with 5 tubes and 12 sections

8" wide x 23" high with 5 tubes and 10 sections

Basically, it'd be great to be able to calculate the size of steam radiator I'd need to supply each of the rooms with the appropriate amount of heat. All of the sites on the web seem to offer conflicting calculations and formulas, and I'm going a litle crazy trying to figure this out!!

I'd like to supply the room with an efficient amount of heat that won't require an unnecessarily large boiler to service these radiators.

Any help would be greatly appreciated.

Thank you,

MC

MaryC

Steam heat radiator room size formula/calculation

Hi again,

Thank you fo your response. I'm looking for a specific formula for calculating radiator size, based on the specific room.

So, for instance, one of the rooms I have is: 15ft x 12ft x 9ft bedroom with 2 outside walls, 2 windows(32" x 64" old windows).

The radiators I have are:

5.5' wide x 21" high with 5 tubes and 22 sections

8" wide x 19" high with 5 tubes and 12 sections

8" wide x 23" high with 5 tubes and 10 sections

Basically, it'd be great to be able to calculate the size of steam radiator I'd need to supply each of the rooms with the appropriate amount of heat. All of the sites on the web seem to offer conflicting calculations and formulas, and I'm going a litle crazy trying to figure this out!!

I'd like to supply the room with an efficient amount of heat that won't require an unnecessarily large boiler to service these radiators.

Any help would be greatly appreciated.

Thank you,

MC

Paul48

This should help

http://www.heatinghelp.com/files/posts/12408/Boiler%20Sizing%20Chart.pdf You need to do a Heat Loss for the room. A radiator section at a given height by however many columns or tubes will have a certain EDR. You multiply that times the number of section for the total EDR of the radiator, and then multiply that 240 for steam. That gives you a btu/h figure that you match to the heat loss.

MaryC

follow up question

Thank you so much!!!

I really appreciate your help. So, the total capacity of steam required to fill all of my radiators is 520 square feet. Now, in terms of buying a boiler to suit that need, do you know what the procedure is for finding out the net input and output of the steam boiler? And what is the difference between boiler input and output. My calculations have me requiring a steam boiler of a net input of 160 thousand to 180 thousand BTUs. Which, in your opinion, would be wiser to purchase - the 160 thousand BTU or the 180 thou BTU - boiler? Is there a big difference in operating cost for these? I'm thinking of just buying the larger boiler -- would buying a boiler that produces more than the required amount of steam cause any trouble?! Sorry to bug you again! I'm just trying to figure this thing out!

Any help would be greatly appreciated!!!

Thank you, again.

Best,

MaryC

MaryC

follow up question

Thank you so much!!!

I really appreciate your help. So, the total capacity of steam required to fill all of my radiators is 520 square feet. Now, in terms of buying a boiler to suit that need, do you know what the procedure is for finding out the net input and output of the steam boiler? And what is the difference between boiler input and output. My calculations have me requiring a steam boiler of a net input of 160 thousand to 180 thousand BTUs. Which, in your opinion, would be wiser to purchase - the 160 thousand BTU or the 180 thou BTU - boiler? Is there a big difference in operating cost for these? I'm thinking of just buying the larger boiler -- would buying a boiler that produces more than the required amount of steam cause any trouble?! Sorry to bug you again! I'm just trying to figure this thing out!

Any help would be greatly appreciated!!!

Thank you, again.

Best,

MaryC

Rod

Installing Radiators

Perhaps you could tell us a little more about what you are planning to accomplish. That way we will have a better idea of how to answer your questions. Do you have a steam system in your house at the moment? if so, what type of steam system is it? Is there steam piping to all the rooms in your house?

- Rod

Paul48

Math

520x240= 124,800 btus. I thought we were still determining whether we had the proper amount of radiation for a given room?

MaryC

nfo!

Hi Rod,



Thanks so much. I just bought a fixer upper house. The radiators and boiler were stolen so I'm trying to figure out the best way to heat the house. We calculated that we'll need 3btus per cubic foot, calculated radiator size, using your chart, but now we're trying to find the best boiler for our house. It's a single pipe steam system. Any thoughts would be greatly appreciated! Best, MC

JStar

Heat

How did you come up with 3btush per cubic foot? You should do a proper heat loss.

crash2009

Yes, you should

 do a proper heat loss calculation.  Likely on a per room basis.  Not sure which software to use though.



A popular method used back in 1890 was the Mills 2-20-200.  Not to accurate by todays standards, but an interesting project, and an entertaining read, just the same.



 http://www.heatinghelp.com/article/368/Dans-Stories-and-Thoughts/1588/The-Great-Experimenter



Mr Mills and his cohorts would have put 750 EDR in my place back then.  Today we are comfortable with 377EDR.  Broken down by floor that would be 170 on the main floor, 127 on the second, and 80 on the third. 

Rod

Steam System Rejuvenation

Hi - There is a bit more to this than just finding some radiators and hooking them up to a boiler. Do you already have radiators for all the room in your house?  Where are you located? We may know of a steam pro local who could help you?



In a nut shell it basically comes down to:

1. Evaluating the condition and viability of what remains of the original system and what needs to be changed /replaced.

2 Calculating the heat loss in each individual room in the house.

3  Finding a radiator in good condition that will match the heat loss and since there is   already piping, will fit properly in the original piped location. (ie: if the is only a 3ft space under a window, you don't want to put a radiator 4 foot in height at that location

To do this you will have to figure out the EDR of each radiator and convert it to btus.

(I might mention that you can work in either EDR or BTUs. It's not a bad idea to keep track of both as you are doing the calculations.)



   If you're trying to find used radiators the following book, "EDR- Ratings for Every Darn Radiator"  available in the Shop section of this website might be very useful to you.

http://www.heatinghelp.com/products/Steam-Heating-Books/25/80/E-D-R-Ratings-for-Every-Darn-Radiator-and-convector-youll-probably-ever-see

while you're there you might also want to get "The Lost Art of Steam Heating"

http://www.heatinghelp.com/products/Steam-Heating-Books/25/68/Lost-Art-Of-Steam-Heating

as that will also be a big help to you.

5. Choosing a boiler- Once you know the EDR of each radiator you can total that amount and that will tell you the capacity of the boiler you need. With the pickup factor there is already a "reserve " built in so be careful not to fall into "we'll get a larger boiler to be on the safe side". All an oversize boiler does for you is to short cyacle and burn more fuel.



The following links are to articles/videos that may be of help to you:

Video on the Importance of Boiler Piping Configuration

http://www.heatinghelp.com/article/107/Steam-Heating/118/Steam-boiler-near-boiler-piping



Replacing a Boiler Article

http://www.heatinghelp.com/article/236/For-Homeowners/1490/How-to-have-a-boiler-replaced-without-getting-steamed



Steam Heating Primer

http://www.heatinghelp.com/article/321/Steam-Heating-Basics/128/A-Steam-Heating-Primer



Boiler Ratings Explained

http://www.heatinghelp.com/article/364/Boilers/143/Boiler-Ratings-Explained



Putting together a steam system from almost scratch is doable just that you need to really do your homework! I would again recommend you consult with a good steam pro. We will also answer your questions as best we can.

- Rod