User Guide

180 l uponorengineering.com
1. All calculations based on cylindrical thermal resistance methodology (ASHRAE).
2. Based on uid velocity of 8 ft./sec. at 160°F/71.1°C (maximizing heat transfer from 100% water).
3. Pipe convection set to be 1.761 Btu/hr•ft²•°F (based on standard value for free convection of air).
4. This heat loss comparison uses 0.24 Btu•in/(hr•ft2•°F) as the insulation thermal conductivity.
This is a standard value for berglass pipe insulation at a 100°F/37.8°C mean temperature.
Pipe heat loss and surface temperature
1¼" Uponor PEX surface
temperature at 90°F/32.2°C ambient
Water
temp
(ºF)
Surface temperature (°F)
No insulation
½" insulation
1" insulation
1½" insulation
2" insulation
30 34.2 73.9 81.7 84.7 86.2
40 43.5 76.6 83.1 85.6 86.9
50 52.8 79.3 84.5 86.5 87.5
60 62.1 81.9 85.9 87.4 88.1
70 71.4 84.6 87.2 88.2 88.7
80 80.7 87.3 88.6 89.1 89.4
90 90.0 90.0 90.0 90.0 90.0
100 99.3 92.7 91.4 90.9 90.6
110 108.6 95.4 92.8 91.8 91.3
120 117.9 98.1 94.1 92.6 91.9
130 127.2 100.7 95.5 93.5 92.5
140 136.5 103.4 96.9 94.4 93.1
150 145.8 106.1 98.3 95.3 93.8
160 155.1 108.8 99.7 96.2 94.4
170 164.4 111.5 101.0 97.0 95.0
180 173.7 114.2 102.4 97.9 95.6
190 183.0 116.8 103.8 98.8 96.3
200 192.3 119.5 105.2 99.7 96.9
1¼" Uponor PEX heat loss
at 90°F/32.2°C ambient
Water
temp
(ºF)
Heat loss (btu/hr·ft)
No insulation
½" insulation
1" insulation
1½" insulation
2" insulation
30 -20.1 -10.0 -7.3 -6.0 -5.3
40 -16.7 -8.3 -6.1 -5.0 -4.4
50 -13.4 -6.7 -4.9 -4.0 -3.5
60 -10.0 -5.0 -3.7 -3.0 -2.6
70 -6.7 -3.3 -2.4 -2.0 -1.8
80 -3.3 -1.7 -1.2 -1.0 -0.9
90 0.0 0.0 0.0 0.0 0.0
100 3.3 1.7 1.2 1.0 0.9
110 6.7 3.3 2.4 2.0 1.8
120 10.0 5.0 3.7 3.0 2.6
130 13.4 6.7 4.9 4.0 3.5
140 16.7 8.3 6.1 5.0 4.4
150 20.1 10.0 7.3 6.0 5.3
160 23.4 11.7 8.5 7.1 6.2
170 26.8 13.3 9.8 8.1 7.1
180 30.1 15.0 11.0 9.1 7.9
190 33.5 16.7 12.2 10.1 8.8
200 36.8 18.4 13.4 11.1 9.7