The single most important number on any bill is monthly kilowatt-hours consumed. Twelve months of it, capturing summer cooling and winter heating, is the foundation of every honest system design. Dollars mislead; usage in kilowatt-hours is what your roof actually has to produce.

Connection fees, meter charges, and delivery minimums are billed regardless of usage — solar cannot erase them. Knowing your fixed floor keeps expectations honest: a system that offsets one hundred percent of usage still leaves a small monthly bill, and that is normal, not a failure.

Tiered plans punish heavy usage, which solar erases from the top tier first — excellent economics. Time-of-use plans price evenings high, which favors batteries and daytime load shifting. Identify your schedule on the bill before anyone models your savings, because the strategy differs for each.

Seasonal swings hide in annual averages: a home averaging nine hundred kilowatt-hours may peak at fourteen hundred in July. Pull a full year of statements from your utility portal before the site visit — designs built on real baselines are the ones that hit their projections.