Jim Park: The X15N, Cummins’ new natural gas engine, made a heck of a splash at ACT Expo in Anaheim this year. It’s no longer seen as a bridge engine between diesel and batteries. Judging by the ...

In some cases, geothermal electric heat pumps can save you money over the most cost-efficient natural gas boilers. They are generally more efficient than gas furnaces and use less source energy on ...