Like others have said, I have used mine for the past 10 years, I only use it just before we go to bed mostly to heat up the bathroom area so wife can take a shower in warmth. I actually like the portable one that you can put it where you want heat. Never used it at night. Only use the MH heater in the morning to take the chill off from the night temps. It really saves on battery power. It has low O2 shut off and if it is tipped over will shut off. I have only used it down to 32 F and it heats the MH fine. Worked fine at YNP ft never had it higher.