The leaves look to be fleshy, so I believe this is Crassula ovata, common name Jade or Money plant. You say you water when the soil is completely dry; if you mean you wait for all of the soil in the pot to be completely dried out, that's too long for the plant. Whilst these plants should not be overwatered, going into drought in between waterings will mean leaf loss.
If the soil is currently completely dry, give it a good water now - leave it sitting in water in the bottom tray for 30 minutes, then empty that out. Water again when the surface of the soil feels dry to the touch, but not so dry the soil in the pot is shrunken from the sides. Water well, and empty out the tray after 30 minutes, and again 30 minutes after that if it refills, so that the plant is not left sitting in water. Continue in this way ongoing.
These plants do very well in bright daylight or sun, so you don't need to find a sunny spot for it. If regrowth of leaves does not occur along the bare branches, you will need to cut back each one to where healthy growth does occur so that you can create a bushy plant. Further care info https://www.houseplantsexpert.com/jade-plant.html