I just ordered 2 x Honeywell C7089U1006 outdoor temp sensors for my trane 803 (visionpro 8321). I always know what the outdoor temperature is as I have plenty of outdoor sensors (in the attic and around the outside of the house). What got me going about these was the ability to lock out the heat strips above a given outdoor temp - arkansas winters being usually mild - (albeit the given cold day). I saw this as a potential energy saver as I could prevent the heat strips from kicking on unless really necessary. How low can I expect the heat pumps (XR13's) to function properly without hurting anything? what setpoints would you recommend for this?