What does this mean to you?

I asked the same question about my Outback that has a label right on the side of the camper, "Polar Package." What exactly does that mean? Well, after 4 winters, all it means is, the underbelly is enclosed and the head ducts are not insulated under the floor, thus allowing radiant heat under the floor to prevent pipes from freezing.

Um... I've never trusted it. I winterize with the "pink stuff" all my waterlines and if using the camper in consistent below 32 degrees (F) weather, we dry camp, use a port-a-potty, and never let any water go down the drains or toilet. My tanks are NOT heated. Also, there is a considerable heat loss under the floor which is really noticeable in cold weather. Considering I winterize with the "pink stuff", I unhook one furnace vent from the furnace and let blow directly into the the main living area. It's unbelievable how much difference in heat fills the living area this way opposed to keeping the duct hooked up under the floor and to the vents. (Of course, the floor is a bit colder, but it's got carpet, so no biggie.

"Winter package", "Polar package" can mean just about anything. And like you said above, you can still get frozen pipes under the cabinets and such.

Remember.... the more space that you want heated, the more propane you'll use. In zero degree weather, a 30 pound propane tank will last me 2 days, even bypassing the floor duct and supplimenting with electric space heaters.

Electric space heaters will not heat UNDER the trailer either. Only your on-board furnace will, unless you completely skirt your camper and install a separate furnace under there.

In marginal weather, (below 32 one day, above the next, and so on, the "Polar package" does OK, but only if day time temps get above 32 for a while. Once everything stays below 32, day and night, I don't take chances, I winterize.

My FW is a 4-season unit, and is actually insulated quite well. It is by far the most quiet of 4 owned, and heats/cools easily. It does have it's weak areas, such as low point drains, fresh water tank drain exposed, and outside shower, that is not in heated basement. I've also used foam pipe wrap on the low pts, and fresh tank drain hose, when night time temps dropped to around 20F. Where I live, Winter temps often hit -20F, and can get -30 or lower. I think mine is a 3-season in my area. I do like that mine has heat vent routing running through kitchen cupboards, near basement plumbing, and even along side of water pump. Of course there is also the added vent from furnace to warm entire tank area.

A true 4-season??? NO, but by design, an obvious attempt was made to get as close as possible.

Jerry

I think one has to be skeptical of such claims. I doubt there are any laws about having to meet any criteria. If legitimate, to me it would mean well insulated walls, thermal payne windows, strong furnace, heated tanks, etc. probably the weight will be a little heavier. But if it's like "ultra lite" doesn't really mean much.

It seems your current TT already has some sort of arctic package from your description. This site offers a decent description of an arctic package. Even owning one of these cold weather TT's is NO guarantee you won't have freeze ups. I live in a cold area and winterize and store my camper for 5-6 months. Even being further south than I you've seen what cold weather can do to your TT.
If your considering a new TT I'd get the best winter package available but you may still have an occasional freeze up like you encountered. Fortunately in your location you can get more months of use than I. This year has been a cold winter for much of the east coast.


https://kirklandrvsales.com/rv-arctic-packages-outlast-cold/

Depending on the brand I'd say not uncommon. 4 season rated can be as simple a a vent blowing in the tank areas. Most all nicer TT's have enclosed under bellies anyway. Most RV MFG's lie about R values. Looking at how they're constructed is the only way to know if what you're buying will withstand harsh elements.
My tank valves are fully enclosed in insulation. I've never had them in temps below 29* so I have no idea if my 4 season 5th wheel is really 4 season. I can tell you one thing it's not as good in the heat. No one really talks about 4 season and heat. Try staying in 100+ degree heat for days on end.
I recently watched a video of an Airstream Globetrotter. The guy doing the walk through even mentioned that the model he was talking about really wasn't rated for very cold temps even though it was well insulated.