BlueHeat Cable and Part Calculation BlueHeat Product Details ESTIMATING MATERIALS Gutter Heating Cables - Determining the necessary materials for gutter ice melting requires a few simple measurements. First calculate the total length of gutters to be heated, including downspouts. The length of gutters is then doubled to obtain the amount of cable required. DS-2 clips are used every few inches, including in downspouts, to assure the cables don't cross. Downspout hanger kits are used at the top of the downspout. The cables are controlled by gutter mounted snow switches, which are activated when moisture and low temperatures are present. Gutter Ice Melting Calculator Enter lineal feet of rain gutters & down spouts: Enter number of down spouts:  ft. Roof Heating Cables - Calculating the amount of cable needed for roof de-icing can easily be done after taking a few simple measurents. Measurent A, shown in Figure 1 to the right, will always be a constant 2 feet. Measurement B will either be 1-5 feet, which is the distance from the roof edge to about 6 inches above the roof eave, where the wall and the overhang meet. The final needed measurement is the length of the roof edge. Warmzone highly recommends heating the gutters as well to prevent refreezing in the gutters. Roof & Gutter Ice Melting Calculator Enter lineal feet of rain gutters and down spouts: Enter number of down spouts: Length of Roof Eaves: Measurement B:    1 2 3 4 5   feet  ft.  ft.