In　practice,　a　system　may　consume　more　and　more　energy　when　it　ages.　In　addition,　the　practical　system　usually　has　an　increasing　failure　rate.　Considering　both　system　energy　consumption　and　system　failure,　this　paper　proposes　a　maintenance　policy　that　replaces　the　system　if　the　system　age　reaches　a　certain　value　or　the　energy　consumption　cost　per　unit　time　reaches　a　threshold.　Numerical　examples　are　proposed　to　illustrate　the　solving　of　the　optimal　maintenance　policy　to　minimize　the　expected　per　time　cost.　©　2020　IEEE.