Why is it important?
To operate a radiant cooling system without producing condensation water on the surfaces, the system operating temperature at the radiant surface (or of any uninsulated piping) should be at least 1 °F above the dew point. The charts below show the dew point at various indoor conditions of RH and temperature. For customers in dry or moderate climates, the loops can be quite cold (generally under 60° F) which can deliver up to 14 BTU per ft^2 (floor) or up 27 BTU per ft^2 (ceiling) according to the type of radiant design, panels, coverings, etc. The CXRC radiant cooling controller makes sure that the loop temperature does not drop below the user-defined delta to the dew point. In some climates, a dehumidifier may need to come on a few days each year to deal with excess humidity for added comfort and to suppress the dew point to allow colder water in the loop. ASHRAE guidelines suggest indoor humidity to be </=60% RH.
See the dew point calculator on tab 5 here.
At 80°F
| T | RH | DP | Days to Mold | EMC |
|---|---|---|---|---|
| 80°F | 55% | 62°F | No Risk | 9.90% |
| 80°F | 54% | 62°F | No Risk | 9.70% |
| 80°F | 55% | 62°F | No Risk | 9.90% |
| 80°F | 53% | 61°F | No Risk | 9.50% |
| 80°F | 52% | 61°F | No Risk | 9.40% |
| 80°F | 51% | 60°F | No Risk | 9.20% |
| 80°F | 50% | 60°F | No Risk | 9.10% |
| 80°F | 49% | 59°F | No Risk | 8.90% |
| 80°F | 48% | 58°F | No Risk | 8.80% |
| 80°F | 47% | 58°F | No Risk | 8.60% |
| 80°F | 46% | 57°F | No Risk | 8.50% |
| 80°F | 45% | 57°F | No Risk | 8.30% |
| 80°F | 44% | 56°F | No Risk | 8.20% |
| 80°F | 43% | 55°F | No Risk | 8% |
| 80°F | 42% | 55°F | No Risk | 7.90% |
| 80°F | 41% | 54°F | No Risk | 7.70% |
| 80°F | 40% | 53°F | No Risk | 7.60% |
| 80°F | 39% | 53°F | No Risk | 7.40% |
| 80°F | 38% | 52°F | No Risk | 7.30% |
| 80°F | 37% | 51°F | No Risk | 7.10% |
| 80°F | 36% | 50°F | No Risk | 7% |
| T = Temperature in Fahrenheit, RH = Relative Humidity percentage, DP – Dew Point | ||||
At 78°F
| T | RH | DP | Days to Mold | EMC |
|---|---|---|---|---|
| 78°F | 55% | 61°F | No Risk | 9.90% |
| 78°F | 55% | 61°F | No Risk | 9.90% |
| 78°F | 54% | 60°F | No Risk | 9.70% |
| 78°F | 53% | 60°F | No Risk | 9.60% |
| 78°F | 52% | 59°F | No Risk | 9.40% |
| 78°F | 51% | 58°F | No Risk | 9.30% |
| 78°F | 50% | 58°F | No Risk | 9.10% |
| 78°F | 49% | 57°F | No Risk | 8.90% |
| 78°F | 48% | 57°F | No Risk | 8.80% |
| 78°F | 47% | 56°F | No Risk | 8.60% |
| 78°F | 46% | 56°F | No Risk | 8.50% |
| 78°F | 45% | 55°F | No Risk | 8.30% |
| 78°F | 44% | 54°F | No Risk | 8.20% |
| 78°F | 43% | 54°F | No Risk | 8% |
| 78°F | 42% | 53°F | No Risk | 7.90% |
| 78°F | 41% | 52°F | No Risk | 7.70% |
| 78°F | 40% | 52°F | No Risk | 7.60% |
| 78°F | 39% | 51°F | No Risk | 7.40% |
| 78°F | 38% | 50°F | No Risk | 7.30% |
| 78°F | 37% | 50°F | No Risk | 7.10% |
| 78°F | 36% | 49°F | No Risk | 7% |
| T = Temperature in Fahrenheit, RH = Relative Humidity percentage, DP – Dew Point | ||||
At 76°F
| T | RH | DP | Days to Mold | EMC |
|---|---|---|---|---|
| 76°F | 55% | 59°F | No Risk | 9.90% |
| 76°F | 55% | 59°F | No Risk | 9.90% |
| 76°F | 54% | 58°F | No Risk | 9.80% |
| 76°F | 53% | 58°F | No Risk | 9.60% |
| 76°F | 52% | 57°F | No Risk | 9.50% |
| 76°F | 51% | 57°F | No Risk | 9.30% |
| 76°F | 50% | 56°F | No Risk | 9.10% |
| 76°F | 49% | 56°F | No Risk | 9% |
| 76°F | 48% | 55°F | No Risk | 8.80% |
| 76°F | 47% | 55°F | No Risk | 8.70% |
| 76°F | 46% | 54°F | No Risk | 8.50% |
| 76°F | 45% | 53°F | No Risk | 8.40% |
| 76°F | 44% | 53°F | No Risk | 8.20% |
| 76°F | 43% | 52°F | No Risk | 8.10% |
| 76°F | 42% | 51°F | No Risk | 7.90% |
| 76°F | 41% | 51°F | No Risk | 7.80% |
| 76°F | 40% | 50°F | No Risk | 7.60% |
| 76°F | 39% | 49°F | No Risk | 7.50% |
| 76°F | 38% | 49°F | No Risk | 7.30% |
| 76°F | 37% | 48°F | No Risk | 7.20% |
| 76°F | 36% | 47°F | No Risk | 7% |
| 76°F | 35% | 47°F | No Risk | 6.90% |
| T = Temperature in Fahrenheit, RH = Relative Humidity percentage, DP – Dew Point | ||||
At 74°F
| T | RH | DP | Days to Mold | EMC |
|---|---|---|---|---|
| 74°F | 55% | 57°F | No Risk | 10% |
| 74°F | 55% | 57°F | No Risk | 10% |
| 74°F | 54% | 56°F | No Risk | 9.80% |
| 74°F | 53% | 56°F | No Risk | 9.70% |
| 74°F | 52% | 55°F | No Risk | 9.50% |
| 74°F | 51% | 55°F | No Risk | 9.40% |
| 74°F | 50% | 54°F | No Risk | 9.20% |
| 74°F | 49% | 54°F | No Risk | 9% |
| 74°F | 48% | 53°F | No Risk | 8.90% |
| 74°F | 47% | 52°F | No Risk | 8.70% |
| 74°F | 46% | 52°F | No Risk | 8.60% |
| 74°F | 45% | 51°F | No Risk | 8.40% |
| 74°F | 44% | 51°F | No Risk | 8.30% |
| 74°F | 43% | 50°F | No Risk | 8.10% |
| 74°F | 42% | 49°F | No Risk | 8% |
| 74°F | 41% | 49°F | No Risk | 7.80% |
| 74°F | 40% | 48°F | No Risk | 7.70% |
| 74°F | 39% | 47°F | No Risk | 7.50% |
| 74°F | 38% | 47°F | No Risk | 7.40% |
| 74°F | 37% | 46°F | No Risk | 7.20% |
| 74°F | 36% | 45°F | No Risk | 7.10% |
| 74°F | 35% | 45°F | No Risk | 6.90% |
| T = Temperature in Fahrenheit, RH = Relative Humidity percentage, DP – Dew Point | ||||
At 72°F
| T | RH | DP | Days to Mold | EMC |
|---|---|---|---|---|
| 72°F | 55% | 55°F | No Risk | 10% |
| 72°F | 55% | 55°F | No Risk | 10% |
| 72°F | 54% | 55°F | No Risk | 9.90% |
| 72°F | 53% | 54°F | No Risk | 9.70% |
| 72°F | 52% | 54°F | No Risk | 9.50% |
| 72°F | 51% | 53°F | No Risk | 9.40% |
| 72°F | 50% | 52°F | No Risk | 9.20% |
| 72°F | 49% | 52°F | No Risk | 9.10% |
| 72°F | 48% | 51°F | No Risk | 8.90% |
| 72°F | 47% | 51°F | No Risk | 8.70% |
| 72°F | 46% | 50°F | No Risk | 8.60% |
| 72°F | 45% | 50°F | No Risk | 8.40% |
| 72°F | 44% | 49°F | No Risk | 8.30% |
| 72°F | 43% | 48°F | No Risk | 8.10% |
| 72°F | 42% | 48°F | No Risk | 8% |
| 72°F | 41% | 47°F | No Risk | 7.80% |
| 72°F | 40% | 46°F | No Risk | 7.70% |
| 72°F | 39% | 46°F | No Risk | 7.50% |
| 72°F | 38% | 45°F | No Risk | 7.40% |
| 72°F | 37% | 44°F | No Risk | 7.20% |
| 72°F | 36% | 44°F | No Risk | 7.10% |
| 72°F | 35% | 43°F | No Risk | 6.90% |
| T = Temperature in Fahrenheit, RH = Relative Humidity percentage, DP – Dew Point | ||||
At 70°F
| T | RH | DP | Days to Mold | EMC |
|---|---|---|---|---|
| 70°F | 55% | 53°F | No Risk | 10.10% |
| 70°F | 55% | 53°F | No Risk | 10.10% |
| 70°F | 54% | 52°F | No Risk | 9.90% |
| 70°F | 53% | 52°F | No Risk | 9.70% |
| 70°F | 52% | 51°F | No Risk | 9.60% |
| 70°F | 51% | 51°F | No Risk | 9.40% |
| 70°F | 50% | 50°F | No Risk | 9.20% |
| 70°F | 49% | 50°F | No Risk | 9.10% |
| 70°F | 48% | 49°F | No Risk | 8.90% |
| 70°F | 47% | 49°F | No Risk | 8.80% |
| 70°F | 46% | 48°F | No Risk | 8.60% |
| 70°F | 45% | 47°F | No Risk | 8.50% |
| 70°F | 44% | 47°F | No Risk | 8.30% |
| 70°F | 43% | 46°F | No Risk | 8.20% |
| 70°F | 42% | 46°F | No Risk | 8% |
| 70°F | 41% | 45°F | No Risk | 7.90% |
| 70°F | 40% | 44°F | No Risk | 7.70% |
| 70°F | 39% | 44°F | No Risk | 7.60% |
| 70°F | 38% | 43°F | No Risk | 7.40% |
| 70°F | 37% | 42°F | No Risk | 7.20% |
| 70°F | 36% | 42°F | No Risk | 7.10% |
| 70°F | 35% | 41°F | No Risk | 6.90% |
| T = Temperature in Fahrenheit, RH = Relative Humidity percentage, DP – Dew Point | ||||
