I want to know if there is an approximate or exact way to know the consumption in watts of household appliances in a house from the monthly consumption that reaches the bill.
Taking into account that it arrives in kWh and I want to convert any value, which would be the best option.
305 kWh to W
Best Answer
If something uses N kWh in a 30-day month, has an average consumption of
$$N \frac{1000\text{ W/kW}}{720\text{ h/month}}\text{ watts}$$
In other words, to convert "energy" to "power", divide by "time".
Just as an example, suppose you use a 1500 W toaster for 3 minutes to make toast for breakfast. That would be a total of
$$1500\text{ W}\frac{3\text{ min}}{60\text{ min/hr}} = 75\text{ Wh} = 0.075\text{ kWh}$$
of energy. If you do that every day for a month, the total energy would be
$$0.075 \cdot 30 = 2.25\text{ kWh}$$
The average power of the toaster over the entire month would be just
$$2.25\text{ kWh} \frac{1000\text{ W/kW}}{720\text{ h/month}} = 3.125\text{ watts}$$
as compared to its peak power of 1500 watts.
In other words, a 3-watt alarm clock, which runs continuously, costs you the same amount in electricity as the toaster.