To convert energy consumption from units (kWh or kilowatt-hours) to joules, you can use the following conversion:

1 kilowatt-hour (kWh) = 3.6 × 10⁶ joules

Given that the household has consumed 250 units of energy:

Energy in joules = Energy in units (kWh) × Conversion factor

First, convert the units to kilowatt-hours:

250 units * 1 kWh/1 unit = 250 kWh

Now, convert kWh to joules using the conversion factor:

250 kWh * 3.6 × 10⁶ joules/kWh = 9 × 10⁸ joules

Therefore, the energy consumption of 250 units for the household in joules is 9 × 10⁸ joules.