In this thesis a church named Hamrånge, located North of the town Gävle in Sweden, has been studied. In this church thermal comfort is a problem that need to be considered. There is poor insulation and air leakage in the building envelope. And appearance doesn't allow to add any additional insulation, becauce people want to keep its original appearance. In cold weather the church is heated by bench heaters and radiators through direct electicity.