Rr. Dhiasty Mahayanti, Bambang Suhardi dan Rahmaniyah Dwi Astuti Jurusan Teknik Industri, Universitas Sebelas Maret, Surakarta Keywords : tube lamp, energy efficiency, factorial experimental design, cost calculation. Performa (2004) Vol. 3, No.1: 33-48 Perumusan Masalah Observasi Awal Tujuan Penelitian A 34 Performa (2004) Vol. 3, No.1