Heat Loss Calc Results - Can I use to Size air or radiant heat?

Big Ed_4

You use the total heat loss for the size boiler or furnace Then do a heat loss per room for size of radiation, duct size or radiant loop...

Heat gain total for AC system , per room for duct size ...

Your on the right track ....

jb_13

Heat Loss Calc Results - Can I use to Size air or radiant heat?

working on the design of a hydronic radiant heat system for my expanded 1920's house. as an engineer and renovation pro I am designing the system as much as I can so subs can bid on apples to apples system install.

question - i've used tlhe hvac calc program and developed heat gain and loss calcs that I feel pretty good about the data input (wall construction, insul., windows, exposure, ceilings, fireplace, people, stove, infiltration, design temp., etc.).

is there any reason that I shouldn't use the same btu's/hr in heat loss per room/level/zone to size the radiant piping heat delivery system (and thus water temps, supply pipes, and circulator selection to the rooms/zones?

i realize the radiant heat curve and net radiant temp. in the room has a bearing on comfort - but do I not need to deliver the same btu's to the room whether it's forced air or radiant- and thus can use my heat loss numbers to guide that radiant design?

is there an alternative program I can download (for heat loss calcs for a radiant system) or alternatively to help me size and distribute pex loops, supply pipes, etc. based on the house's heat loss that I've calculated?

thanks alot for any advice!

jb_13

thanks Big Ed.

so - if I've got 'x' btu's /hr. loss in a particular room - then I need to get 'x' btu's per hour in there on a design day - either by 'y' cfm of furnace hot air, or by 'z' gpm at 't' temp. through pex under the floor? in other words btu's are btu's - though the radiant delivery of the btu's should provide more comfort/less drafty feeling/more 'apparent' heat from the radiant xfer of the heat from the floor and heated objects.

does this sound right?