 Harder on your truck's engine than highway driving. In addition to operating costs, many governments impose no idling laws and regulations with fines as high as $25,000. Instead, there are many alternatives. An extra blanket for cold temperatures. Window screens for when the weather is warm. Bunk heaters and various auxiliary power unit options abound in this day and age, too. Many powered just by batteries. Otherwise, diesel and gas gensets burn far less fuel than your truck's engine. Research options to find your fit.