Can I install insulation on the ceiling of an old unfinished basement? I have a bungalow home with hardwood floors.
Actually adding insulation is both beneficial for sound reduction and heat retention. When you insulate your floors you prevent heat loss from your basement, especially if you live in Northern States where it gets cold like me. This also helps keep rooms at even temperatures which makes your HVAC system operate more efficiently. Also, if you're outside walls in your basement are not insulated then I wouldn't install it in the floor. As it would be more beneficial to get those outside walls done first then insulate the floor. You'd be well on your way to a finished basement as well. Python is right about doing it completely or not at all. Hope this helps!
Yes. If you're using bats with a vapor barrier put the vapor barrier side against the wood floor.
Even if the basement is conditioned another benefit of insulation is to reduce noise transmission from any appliances (like air handlers) that may be running down there.
When I started working chief engineer on one site told me something that describes this situation the best: "When you are cold do you eat your coat or do you wear it?” To put it differently every type of insulation, thermal included should be placed on the outer side of the building. From how you described I realized that you are planning to do it from the inside. Or did I have it wrong? Anyway, you can isolate basement, best to use Styrofoam or something like that, but it is highly recommended that you do it from the outside, which in a case of basement, sadly can be a problem, since most of it is under ground.
EDIT: Plus I forgot to mention that partial installing insolation partially (just ceiling or one wall etc.) doesn’t make much sense, and could cause even more problems. If you want to do it you should do it completely.