We are at older sons place in northern New Mexico at 8000. The temperature dropped to 9 F with 10 of snow. We put a 60 W lamp in front bay with the LFP battery suite and it kept the space above 40 F. Son ran an extension cord to fifth wheel after I whined about needing to probably run generator in morning since I choose not to climb on top of fifth wheel to sweep off snow at age 78. Son has 10 kW of panels with 50 kW-hrs of lead acid batteries with automatic generator turn on. Reed and Elaine