Attic Humidity Levels

Proper ventilation will help maintaining a constant temperature in your attic.

Attic humidity levels.

According to the environmental protection agency epa indoor humidity levels should be kept below 60 percent relative humidity and ideally between 30 and 50 percent. The recommended humidity level for all rooms including the attic and crawl space in the winter is 30 to 40 percent in cold climates. If you ve got a spray foamed attic and you ve got high humidity here s how to fix it for good. During the winter months the recommended relative humidity inside a house is anywhere between 30 50 percent.

Winter air is by nature not humid so the problem must be condensation related. If water is running down the window or objects seem wet to the touch then the humidity is far too high. During the spring summer and fall relative humidity rh in a spray foamed attic often exceeds the comfort threshold of 60. The moisture was rising with the warm air of the home as it escaped past the insulation and it was trapped in the attic because there was no roof ventilation.

Humidity settings are another issue that can make or break the performance of your heating and cooling systems and your attic ventilation. The humidity in the basement measured 40 the first floor was 45 50 but the attic was 62. A hygrometer is a small gadget that measures the relative humidity level and temperature quickly and easily. When it exceeds that threshold by too much and for too long you could experience problems like mold growth.

When it comes to humidity you would be best to have the levels below 50 to avoid mold growth and structural rot. If there is excessive moisture accumulation in your attic it will condense on cold areas mainly on the underside of your roof deck. The normal indoor humidity range in winter should be 15 to. You can check the humidity level by observing the windows and the objects in the attic.