We own a portable catalytic heater, a great heater for silently producing a lot of heat. We sometimes carry it with us if we're expecting a particularly cold location while boondocking
or when going to really out of the way places.
Our general rule is to not run any heater when asleep other than the electric blanket. We simply do not like the trailer 'jet engine like', start and stop nature of the typical trailer propane
heater and never use it. Secondarily even with all the backup systems including our CO detector and an Oxygen
depletion shutoff control we would not feel comfortable running a catalytic heater while sleeping.
Sometimes we'll run an electric heater if it's extremely cold but usually turning it on just an hour or so before we get out of bed. Saying that, if we know the temps are going to be really low we seek a powered situation if possible.
If connected to power the twin sized electric blanket is more than adequate down to any temperature we're likely to be camping in... outside temps in the teens F. While boondocking
on occasion we'll run the electric blanket off an Inverter, at least initially to make things toasty warm before getting into bed.
All in all it's interesting how little heat it takes to make the small volume of the trailer comfortable at most outside temperatures. Ginny jokes that making a cup of tea in the morning heats the place up, certainly making breakfast does.