jahilliard
Senior Member
I have been asked to help with the installation of an insta-hot water heater in a customers home. The scenario is that this is about a 3000 sq ft home with a 200 Amp service. There have been a few upgrades and remodels done over the years. There is currently 2 30 Amp water heaters supplying the house and the home owner is wanting to replace atleast one, possibly both water heaters with insta-hots. The plumber explained today that just to replace one of them will take a 120 total amp insta-hot (3-40A elements). My question is if this would be a practical application with the current available service. I know these insta hots draw full name plate amperage while in use. I feel like there needs to be a service upgrade in order to practically install 1 OR 2 of these. I have seen lights in a house flicker throughout after one of these being installed under similar circumstances, just wanting some feed back from everyone possible before I go back to the customer suggesting an expensive service change to a 400 Amp service. Thanks a lot for any info!