exhausting into my house heat ventilaion..pics

I am trying to figure out the best way to exhaust my grow room and thought about venting through my house ventilation forced heat and maybe save a couple $$$$ on the heat bill. Is this possible??any other ideas before I pull the trigger and do this.

The vent opening is 10"x4" I want to hook ducting up to that connected to a 6" vortex fan and carbon filter mounted in my flowering room.

Hydroponic stores sell vented boxes to 6" openings that do exactly what your looking for. Or you could cut a hole and double flange it. Just be sure to install past the blower out of your furnace.

I figured there has to be some sort of adapter out there but when I went to the hydro store and talked to the main dude he instructed me to build something myself..

I have been running my hot air into the house, it's so fucking cold in here all the time anything helps.

i do the same.. why not.. don't keep your house air tight, keep a little window barely cracked or whatever get some fresh air in there and keep it movin..

I live in an old house and its always a bit chilly up here in washington so anything would help

You should be able to buy a 6" hvac register from Lowes/Home Depot and hook it up in reverse to accomplish what you want to do.

Another option is to just cut out a piece of wood/metal the same size as your current register vent, cut out a 6" circle and use a 6" adhesive take off. If you have any scrap material laying around this would be the cheapest option ($6.29+tax at lowes for the takeoff).