If I heat my main level with a gas fireplace and run my heat pump in fan-on mode, do you think this will heat my basement also? trying to save some money, power bills are crazy this year.
It would certainly help heat the rest of the home with the fireplace and the fan on continuous but the basement will be somewhat cooler. If the fireplace were in the basement you would have a more even temperature doing this. Most gas fireplaces are not that efficient, usually about 60%. i would think the heat pump would be more efficient than the fireplace unless it's depending on the electric elements too much because of some problem with the heat pump. Have you had it serviced lately?
Don't forget. Unless you have a direct outside air supply to the fireplace, you are sending a lot of house air right up the chimney and sucking cold air into the house from any small cracks around windows and doors. Fireplaces need go be designed very carefully to provide a true net positive addition to your home's heating. They need an outside combustion air supply, tight glass doors on the front and a good heat exchanger built in with fan to be efficient. Only if you have air registers or an open air return in the basement will you get any benefit from the circulating fan.
