Peak Demand Charges: Why Your Bill Spikes on the Same Day Every Month

Unlike a residential bill, many commercial and industrial tariffs charge separately for the highest demand (kW) recorded during a short window in the billing period, on top of total energy consumed (kWh). This means one brief spike — several large machines or AC units starting at once — can raise the bill for the entire month, even if overall consumption that day was otherwise normal.

Without demand monitoring, a facility has no visibility into when that peak actually happened or what caused it — the bill just arrives higher, with no obvious explanation. In most cases, the cause is a predictable, recurring pattern: several large loads starting simultaneously at shift change, for example, that nobody had connected to the bill before it was actually measured.

Demand monitoring with real-time alerts lets a facility catch an approaching peak and stagger equipment start times, or shed non-critical load briefly, before the peak is recorded. This is typically the single highest-leverage fix in an energy optimisation plan for sites on demand-based tariffs, because it directly targets the specific mechanism driving cost, not just overall usage.