How many times per day, (on average) will a gas water heater, (domestic) cycle on if nobody's home?

Insufficient information to even guess.. far too many variables.

It all depends on the ambient temp around the heater (some are in unheated spaces others) , how well the heater is insulated, and what water temperature the thermostate is set to.

Yep.

Hmmm...

Actually, water heaters are so highly insulated over the last two decades or so that a water heater shouldn't really cycle at all after it recovers from the morning's normal use. If it does cycle on, it should only do it once even if it is in a "cool " basement. Here, the only real heat loss from a water heater is from the T&P valve (very small loss here and nowadays we insulate these believe it or not) and from the first 10 feet of hot water piping (why hot water pipe should be insulated out of a water heater for the first 10 feet (after 10 feet heat loss is considered "negligible)....notice that when you touch a water heater it is cold, so no real heat loss through the tank itself. Further, with the heat trap nipples they have been installing for decades now, there is even less heat loss with these systems.

Anyway, why are you asking Ideaguy?

mark

Bottom line! It all depends on the size of the heater. It will take more energy,
Gas or electricity ) to keep a 80 gallon heater up to temperature then a 40 gallon one. Good luck, Tom

Just like said above - there is way too many variables to even guess... Can you tell us why are you asking ? Maybe we can approach it from the other end

Back to you / Milo

Hi Nazia.

We appreciate you posting but you didn't read the question from Ideaguy properly.

Ideaguy asked, "How many times per day, (on average) will a gas water heater, (domestic) cycle on if nobody's home?"

Answers are as above.

Have a good day!