Easy to install. I worked according to the instructions. I had to purchase it for an on demand water heater I bought here at Revain. He coped with the task without any problems. Currently running for 7 months. It is highly recommended that you know what you are doing before playing around with the switch box. It's 90% common sense and 10% fear. Common sense simplifies setup, and fear keeps you from being careless and shocked to death.