Roof Assembly U Values

The u values in the model should accurately reflect the window product used.

Roof assembly u values.

Effective u value 0 75 x 0 08 0 25 x 0 16 0 1 the effective r value for the wall assembly is 1 0 1 10 lower than the nominal r value of the. 0 26 2 fiberglass insulation. 0 21 2 fiberglass insulation. Flat metal roof.

0 90 1 fiberglass insulation. 0 071 6 fiberglass insulation. The center of glass u value is usually about 0 28 or so. The effective u value of this wall assembly would be calculated as.

In the us market the most common commercial windows are metal framed with a thermal break a very small one and double pane low e glazing. U value requirement opaque doors 1 0 w m k. If we look at the two values mathematically u value is the reciprocal of r value. A u value is typically a low number because it is a rating of how much heat energy is lost or gained.

Building thermal envelope opaque assemblies intended to comply on an assembly u c or f factor basis shall have a u c or f factor not greater than that specified in table c402 1 4. It is a way of measuring the insulating properties of the building element. Values of the rso are given by the architects pocketbook as. 0 039 12 fiberglass insulation.

Commercial buildings or portions of commercial buildings enclosing group r occupancies shall use the u c or f factor from the group r column of table c402 1 4. These figures are given in the units of m2k w. 0 05 8 fiberglass insulation. The up out values apply mostly to winter conditions and the down in values apply mostly to summer conditions.

It is measured in units of w m 2 k watts per metre squared kelvin. That is u 1 r and r 1 u. 0 027 wood roof. For each different material multiply the thickness by the standard r value per inch for that material.

The u value assesses the rate of heat loss gain through all the thicknesses of the combined elements that make up a building component such as a wall floor or roof. 0 48 1 fiberglass insulation. U value requirement semi glazed doors 1 2 w m k. Roof ceiling 0 04.

U value requirement windows whole window u value 1 4 w m k. To calculate the total r value of a roof assembly find the total thickness in inches of each type of insulating material within the system. The whole assembly u value is typically between 0. Remember the values calculated here should be taken as a rough guide as certain materials i e.

There are a few good u value calculators online that if you are short on time are worth checking out. 0 16 3 fiberglass insulation. Roof ceiling 0 1. Rso is the surface resistance of the external face again this could be a roof wall floor etc.

U value is generally used to rate door or window units. Reflective or foil insulation the total r value effect cannot be calculated by straight addition of all the component r values. The lower the u value the more energy efficient the system in question will be.