Quick take
Variable-speed boosters can reduce unnecessary full-speed operation when household demand is low. Estimate annual cost from actual input power × runtime, not horsepower alone.
Use electrical input, not only horsepower
Motor horsepower describes mechanical output, while household electricity billing depends on electrical input in kilowatts over time.
Runtime dominates annual cost
A large pump that runs only during demand may use less annual energy than a smaller poorly controlled pump that cycles frequently.
Variable-speed systems
Integrated boosters such as DAB Esybox adjust speed to demand, improving pressure control and potentially reducing unnecessary energy use.
Do the calculation
Annual kWh is approximately input kW multiplied by total operating hours. Multiply by local electricity price for a rough annual cost estimate.