I don't have a 5er, but some things are basic and common to all types of RV that makes warm up time different for each one.
First is outside temperature. If your camper is not warmed up at all and you are heating it from scratch, it will take much longer to warm to 70 degrees if the outside temperature is 10 degrees (F) opposed to 60 degrees (F). The colder it is outside, the longer it takes.
Second is the amount of space it takes to heat, even with the same square footage of inside space between campers. For example, is your basement in the 5er heated? If so, it will take longer to heat the living quarters. Is the underbelly heated? You'd be surprised how MUCH heat goes down there, robbing the heat from the inside living area.
Next is the interior height of the ceiling. Face it, more space takes longer to heat and more energy. If your 5er is very tall, there's a lot of space up high that needs to warm up first before the heat moves to a comfortable temperature at the floor.
Third, is also a space factor, how many slide outs do you have? Face it, with slide outs in the extended position, you have more space to heat. The same furnace will heat the same camper with the slides in much faster, then open one slide at a time to keep the heat up. If you have only 1 slide, it will warm up much faster than if you have 5.
Fourth is the construction of the camper itself. Some campers are just sealed up better and will hold heat (and air conditioning) better than others. Breaks in seals around slides and windows will let heat escape and cold in. And how well insulated are the heat ducts in floor, AND how much length of run are the heat ducts in the floor. Longer campers have longer distances to run heat, and then pumping heat up into a second level floor is VASTLY different between 5er and 5er also. All of these design elements are factors factor that drastically differentiate between camper to camper.
So, the exact same furnace in different camper can take longer or shorter to warm the inside of the unite to the same temperature, depending on the camper itself. All these factors are unique for each camper. Outside temperature, amount of space, and construction of camper.
We loose a lot of heat to the underbelly, so I found out by playing around with the furnace duct work in our TT. When I disconnected the ducts from the furnace at the furnace and let it blow air from there, the camper warmed up much, much faster than when all the ducts were connected. I then realized how much is blowing or warming under the floor. My camper is suppose to have the "polar package" so now I know what they mean by "polar package." The underbelly heats up before the living area.... really!
One trick you can do to warm your camper faster is to fire up the furnace with all the slides in. This will warm up a smaller space first. Then expand the slides and it will seem to warm the rest up pretty fast. When temperatures are between zero (F) and 32 (F), and the camper has not been heated, this is how I always start the heat up, with all slides in. Less space, faster heat!
