One way of finding out about your fireplaces is to hire a chimney sweep who also does more than just sweep, in other words has expertise on installations, repairs, etc. When he or she comes to clean, which you should do before you do anything, especially if you're new to the house and don't know what was done before, you can ask questions about what you want to do.

Since you're not interested in heating, but want a gas fire for atmosphere, you don't want to spend money on a gas insert. They're expensive and the best way to heat. As you probably know, gas logs come either vented or nonvented. In my opinion, and I'm not alone in this, nonvented should be outlawed. Many municipalities have building codes that disallow them in sleeping rooms because they take oxygen out of the air and cause fumes to build up because they cannot get vented out. If you are at all concerned about indoor air quality, you won't get unvented. Consumer Reports has a good article on that issue, which you can get from their website without paying.

The one problem with the vented logs is that you have this vent that's locked in the open position. You may not want that especially when it's very hot in the summer or when it gets cold in winter. One way of managing that problem is to get good glass doors that close off your firebox when you're not using it.

Another thing you can do: If you're on speaking terms with the party who sold you your house, or if the broker is still in contact with them, find out from them about the fireplaces. Or ask a neighbor -- maybe they know what they did.

Another idea that I have seen is to put candles inside the fireplaces; maybe a theme for each or color theme? I have seen where people do this in their homes when they don't use the fireplace and also for the off-heating months.

It can look very pretty.