When you leave a recording device, you do in a sense open up a lime of communication. With that being said, are you recording to confirm your suspicions of the home being active, or to learn possibly why it is?
How do you think you will feel since you do not want to confront any possible spirits,ghosts or what have you if you do get confirmation of activity?
I'm not asking these questions to be mean, so please don't take it as such.. but more so curious as to your intentions upon confirmation it is/isnt active. Some people are curious, but then get scared once they do get confirmation, and other people just get more curious
If you do pick up recordings are you planning on having further investigations done to try to figure out which type of activity you are having, or have someone else check it out?
Are you planning on announcing that you are recording when setting the recorder up or are you just leaving it there.. kind of blindly?
Recording, usually does not harm, but you have to be prepared for what you may or may not hear.
Honestly I would never leave a candle burn unattended, but I would love to hear any evidence you do collect, if you chose to record.