Load caulc variation

Big Will

After running the numbers I realized I needed the cooling load also. With slant finn I cam up with 37K btu. With a standard manual J work sheet I came up with 28k btu. I assume that the slant finn is putting in a pick up factor. I could not see this indicated in the help manual for the program though.

Derheatmeister

I have not used slat fin's programm in Years but have found that the heat loss was allways unjustified higher compaired to Siggys,Watts or wrigth softs Programms...may have something to do with sales on equipment??

What is a "Pick up factor"?

Big Will

Reference to recovery from a cold start. If you size to load to a load on a design day cold start it takes too long to get warm. I was taught to find my actual load on a design day and add 10% for "pick up". Since the equipment rarely falls exactly at the load it usually does not matter due to the gap between what you need and whats available in the equipment line to be used.

scrook_3

I=B=R net ratings

include 15% pickup factor to hot water boiler output (33% for steam) to gives a little extra to ramp up boiler, piping & radiation from cold.

[Deleted User]

Don't forget the lights...

Internal lighting can add up to be a BIG load, and if ignored, will cause human discomfort during warmer OSA conditions.

Remember, each watt is worth 3.41 btuH, so a 60 watt bulb equals 204 btuH. It adds up quick... And then theres the TV, PC, refrigerator, stove, and on and on.

ME

Big Will

That is a good point. The electronics in custom homes in general is just really getting extreme. We are doing one in San Fransisco now that has a mirror/TV in his master bathroom. Never seen that before costs Over five Gs and it is only 36". But hey its a mirror also so what do I know. We bought a flat screen after Christmas and it puts out tons of heat.