How can I stop cold air coming thru range hood in mobile home?

These are supposed to have a damper in the pipe that closes to keep the air from coming back down. Occasionally even the best one will allow a little air to sneak back down. If there is more than that the system needs to be checked out to find why it does not work. May be clogged with grease if it is an older home.

I have felt the cold on those -10 degree days and would do almost anything to stop the cold just for today. You could try removing the filter and wrapping it in a plastic grocery bag and reinstalling. Just for today because it is not a fix.

A quick solution can be to simply cover the hood with some cardboard when the vent is not in use.

Maybe an outside dryer vent that only opens when air passes through.

I taped cardboard over my vent. Then did not use the vent until the spring. It did not seem to be a problem when cooking. If I needed to, I opened a window for a bit.

I would consult HVAC people. You don’t want to create a toxic fix or a fix that creates bad air in your home.

You can have a more advanced exit pipe installed. It is a flap type that opens when the fan is on. I just used a dryer vent hood that is typically on the outside of a brick and mortar home. I attached over the existing exit pipe. The hood really helped block the wind, but was still open.

Check.the.size.of.exteior.exit.and.go.to.materials.store.and.buy.

a.lenght.of.4ft.conduct.,,install.it.fromexit.hole...down.and.the.conduct.beeing.

downwards.will.not.let.cold.air.in.because.only.hot.air.wants.to.go.upwards

some.are.3x8...orx12...or.round.4.to.6.in.type.some.dryer.tube.could.do.it..

check.it.out.and.putting.the..end.of.conduct.in.a.box.

with.a.furnace.filtes.would.help

you.can.also.ask.a.ventilation.tradesman.to.look.into.it.

This is an exhaust fan so you are pulling warm air from inside the house to the outside. Go to Home Depot or Lowes or a hardware store and ask them how to resolve your issue.