INDEX

Copyrights

Getting Started
Heat Load
.....heat loss basics
Floor Output
Floor Covering
Floor Surface Temp.
Average Water Temp.
Supply Water Temp.
Tube Selection and Size
Tube Spacing
Total Tube Required
Tube Circuit Length
Number of Circuits
Actual Circuit Length
Flow Per Tube
Pressure Drop
Summarize Circuits

System Flow
System Pressure Drop

STEP (d) -
Multiply ∆T X U-Value X Area = Heat Loss (btu/hr)

example: 80˚F ∆T x U-.053 x 63 sq ft = 267 btu/hr

STEP (e) -
Repeat the same calculations for each surface in the room which is exposed to the outdoors and add the results.

example

wall: window: door: ceiling:	80˚F ∆T x U-.053 x 155 sq ft = 80˚F ∆T x U-1.06 x16 sq ft = 80˚F ∆T x U-.486 x 21 sq ft = 80˚F ∆T x U-.050 x480 sq ft = Total Heat Loss 4,750 btu/hr =	657 btu/hr 1,357 btu/hr 816 btu/hr 1,920 btu/hr 4,750 btu/hr

note: Be sure to add in ceilings that are exposed to attics and floors that are over crawl spaces. Don't add floor slabs which are poured on or below grade.

STEP (f) -
Heat Loss divided by Available Floor Area = Required Output

example: 4,750 btu/hr divided by 317 sq ft = 15 btu/hr/sq ft
(only 317 sq ft of the total floor is contributing heat)

This gives you the amount of heat each square foot of floor space will have to deliver in order to heat the room. Be sure to only include floor space which will contribute to the heating.

STEP (g) -
Repeat this procedure for each room in the house and record your findings. You will need the Required Output to determine many things in the sizing process.

Note: To calculate air infiltration losses:

multiply the room length x width x height x (inside air - outside air temp.) by the following:
0.9 BTUH (1/2 air change/hr),
0.18 BTUH (1 air change) or
0.27 BTUH (1 1/2 air changes/hr)

NEXT STEP - transfer these findings to the RadPad© Worksheet