how many light bulb are on at any given time in the USA

I am not 100% about this, curious to hear feedback:

[Pop US] * [1/people per household ] * [# rooms per household] * [light bulbs per household] = # light bulbs in the US. Let's assume another 25-50% for businesses.

Once we have the # of light bulbs, we need to give out how many are on in any given time. Let's assume a standard distribution across the day and say that 6 hours out of 24 hours the bulbs are on.

We have [# of lightbulbs US] * [6/24] = # lightbulbs that are on per hour.

@ Others: would this work?

I agree with the previous answer. We might take additionally into account that not all bulbs are switched on at the same time - by a factor or so.

Hi,

That's one of the most common market sizing questions and I've seen the solution in multiple casebooks. You can find it easily if you google.

Best!