Whichever fireplace you have, you always need to take into consideration the size of your room and the size of the flame / heat emitted. Be prepared to open a window for 5 minutes after the fire has been on for an hour in case it gets too hot. People often refer to ethanol fireplaces as decorative (which they mainly are!), and they are surprised by the amount of heat produced. An average bio fire will produce approx. 3 kW of heat - an equivalent (or more) of an electric heater, and it will increase the temperature in your room (depending on the size of the room) on average by 2-3 degrees Celcius.