Effectiveness of de-icers will vary depending on several factors, many of which are out of control of the manufacturer and applicator.

The most important factor for ice melter performance is the ability for the de-icer to form a brine at the temperature used.  During the melting process, the brine concentration dilutes, subjecting the melting area to refreezing.  Therefore, for an ice melter to continue to be effective, supplemental applications may be needed to restore the effective more concentrated brine solution.  Other factors that might influence melting include humidity, wind, sunshine and color of the treated surfaces.

Timing of the application also affects ice melter performance.  Early treatments of snow and ice melters help prevent ice from forming a solid bond with the concrete surfaces.  Later applications are required to bore through the ice to reach the pavement, becoming more dilute as they work through these ice layers.

Another important consideration is the amount (and type) of precipitation received.  Ice is denser than snow and will usually require more de-icer to get the job done.  Best results are observed when applied to surfaces with less than one half inch of snow or ice.  Performance of nearly all de-icers drops off considerably when snow depth exceeds two inches.