Certain example embodiments of this invention relate to vacuum insulating glass (VIG) units including infrared meltable glass frits, and/or methods of making the same. More particularly, certain example embodiments relate to increasing the amount of ferrous oxide in glass frits (e.g., lead-free glass frits) used to form edge seals such that the glass frits absorb an increased amount of IR energy. The techniques of certain example embodiments make it possible to expose some or all of the VIG intermediate assembly to infrared source(s), since the glass frit will heat up faster than the substrates thereby reducing the likelihood of the first and/or second substrate melting and losing heat treatment strength. In certain example embodiments, the frit's glass redox (FeO/Fe2O3) preferably is at least about 0.02 higher than either (or the higher) of the substrates' glass redox (FeO/Fe2O3), more preferably at least about 0.04 higher, and most preferably at least about 0.06 higher.