Call an electrician and have your wiring checked. What you are describing is not normal. Your connection from the pole to the house may be corroded and there may also be an imbalance in the two 120V legs of your 240V service. Either way, the amperage draw from the Venus is negligible so you are definitely having a service issue. My sister had a similar problem at her house with the lights always dimming when small appliances were run. I checked their line voltage and found low unbalanced voltage feeding into their house. They called the power company and it was found the connection to the house was badly corroded (not far from inland from the ocean – salt). They ran a new feeder to the house and installed new wire clamps. Fixed it right up.