Cold outside - Fires inside

It's very cold in whole Europe at the moment. During the weekend it was around -15C in the mornings and now during the week around -10C. But during the days the temperature have raised to a little bit under 0C most of the days. Lucky enough we have a good heating system in the house with a heat pump that uses thermal energy from the ground. But the best thing is our fireplaces. One wood stove in the kitchen and a large fireplace in the living room. And we have our own forest, so we can keep the fires burning as much as we want!