are hybrid trailers cold in winter?

All campers are cold in winter. Each type need aftermarket tricks to not freeze to death in or damage plumbing.

"Are hybrid trailers cold in winter?"

Are you planning on winter camping? Like in January/February?

We've camped as cold as the upper 20's with our old hybrid. The furnace pretty much runs non-stop. Some folks augment it with an electric heater. Yes, the bunk is colder. But we've never felt the need for pugs, and we use an open sleeping bag on top the mattresses. Of late my wife has been using a heating blanket. But we tented long ago and had a pup for a long time. We've slept in some pretty cold weather, so the hybrid is nice and toasty warm in comparison.

Agree, what do you consider "cold"? We loved our ROO HTT and it came with heated mattresses standard. Don't know about other brands. We used PUGs and wore warmer PJs. The company that makes PUGs has come out with a surround that fits inside the tentends for more insulation. Somehow, I was always the one who ended up sleeping on the outside and yes, I could feel the colder air. It was not bad enough to say I was actually uncomfortably cold, but there is a difference between the inside and the outside. If you love the HTT, I would suggest you check these surrounds on the Pop Up Gizmo site. They are reasonably priced and may be the answer to your question.

Our hybrid came with electric mattresses. Between them and the furnace nice and warm.

What do you mean by "cold"? I have camped in sub freezing nights and kept warm. As Bikendan says, PUGs and Reflectix help a lot.

We've had our hybrid for nearly 8 years.
We've even camped in snow and stayed warm.
By using PUGs and Reflectix, we've stayed warm.
Of course, the few times we had hookups, the heated mattresses help too.

Yup...

Yes they get cold, unless you can afford to run the heater enough to heat a tent. Even with "pop up gizmos", and foam pads under the matresses, we'd get cold at about 30 or so. Had to fight to see who the dog would sleep with!