“Most people think electrical upgrades are needed if they add electric appliances, but this can be avoided with thoughtful selection of efficient products or by using load sharing devices.  Choosing power efficient appliances can help you avoid upgrading the utility service wire and your circuit breaker panel. The Watt Diet Calculator takes information about a home and estimates the size of the electrical panel needed for that home. It can help homeowners, building owners and contractors determine if a panel must be upsized in order to electrify the home.”

 

 

“This spreadsheet is from a multifamily-dwelling project where we applied the watt diet approach too at RedWood Energy. It is not robust, but it clearly demonstrates how this approach can help avoid costly electric service upgrades. By changing the power rating (blue text) or opting for different appliances to shift to load to the general load (like the dryer load in cell D34), you can quickly see how the feeder loads for the dwelling units and buildings (orange cells), and the entire property are affected (yellow cells). The original designed load was estimated to be 89-amps for the 591 sq ft studio apt (in-suite laundry). We reduced this to 63-amps per unit without sacrificing any appliances or comforts.

 

The dryer-load shift was due to replacing the 5,000W electric resistance dryer with a combo washer/dryer that will use the 20-amp, 1,500W laundry-circuit load that is already included in the calculations.”