using System;

using System.Linq;

public class Program

{

    public static void Main()

    {

        // will be some Brivo made up value like "US/Eastern"

        var tzStr = "US/Central";

        // split to US and Eastern so we can find both in the windows TZ string...

        string[] tzParts = tzStr.Split(new char[] { '/' });

​

        var sysTzs = TimeZoneInfo.GetSystemTimeZones();

        var sysTz = sysTzs

            .Where(t =>

                   t.DisplayName.Contains(tzParts[0]) &&

                   t.DisplayName.Contains(tzParts[1]))

            .FirstOrDefault();

​

        Console.WriteLine("timezone: " + sysTz.DisplayName);

        Console.WriteLine("offset: " + sysTz.GetUtcOffset(DateTime.Now).TotalMinutes);

    }

}