Umthamo ngumthamo opheleleyo wombane onokugcinwa yibhetri yelanga, ulinganiswa ngeekilowatt-yure (kWh). Uninzi lweebhetri zelanga zasekhaya ziyilelwe ukuba "zibekeke," okuthetha ukuba unokubandakanya iibhetri ezininzi kunye nenkqubo yakho yokugcina amandla elanga kunye ne-solar ukuze ufumane umthamo owongezelelweyo.
Ngelixa umthamo ukuxelela ukuba inkulu kangakanani na ibhetri yakho, ayikuxeleli ukuba ungakanani umbane onokukhutshwa yibhetri ngexesha elithile. Ukufumana umfanekiso opheleleyo, kufuneka ucinge kwakhona ubungakanani bamandla ebhetri. Kwimeko yeebhetri zelanga, ukulinganiswa kwamandla ngumlinganiselo wombane onokuthi uhanjiswe yibhetri ngexesha elinye. Ilinganiswa ngeekilowathi (kW).
Ibhetri enomthamo ophezulu kunye nomlinganiselo ophantsi wamandla unokuzisa umthamo ophantsi wombane (owanele ukuqhuba izixhobo ezimbalwa ezibalulekileyo) ixesha elide. Ibhetri enesakhono esisezantsi kunye nomlinganiselo wamandla aphezulu unokuliqhuba ikhaya lakho lonke, kodwa iiyure ezimbalwa kuphela.