Feasibility Check- Using Arduino to control temp/humidity

Hello all and thanks to you who read this.

I am simply looking to get a feasibility check for my project. The goal of the project is to use Ardunio to maintain a certain temp and humidity in a refrigerator.
My solution is to use the Ardunio to turn off and on the power supply to the humidifier and the refrigerator to control the temp/humidity.

I know that these tools already exist:

Temperature Control
http://www.amazon.com/Johnson-Controls-A19AAT-2C-Temperature-Controller/dp/B0002EAL58,

Hydrostat
http://www.control3.com/4190p.htm

My question is, does anyone know of any power control units that interface well with Ardunio?

The reason I will be using Arduino is for automation and data logging.

Thank you,

sds7c4

A relay shield or relay module.