@gson,
This functionality is not normally recommended for smart devices due to the abnormally large fluctuations in power consumption that occur and risk to the plug. However the KP125 is rate for a maximum load of 15 A, 1.8 KW for 120 V; Please ensure that any devices do not meet this threshold, as it is recommended to stay well below the maximum load of the device to ensure device longetivity. The documentation for your Washer and Dryer should list how much power is needed.
From personal experience, the load of a dryer is usually well above the maximum load of a smart device and would require a device specifically meant for the high load. Washers, on the other hand, vary greatly depending on how new and energy efficient the machine is so it is entirely dependent on the Washer's model. Also FYI, I never ended up setting a plug for my dryer as a timer on my washer would also indicate that my clothes were in long enough to dry and I have not ever missed having the functionality on my dryer