Why Choose Blend Door USA?

Made in AmericaBlend Door USA manufactures solid aluminum replacement HVAC doors to replace the failing plastic doors in your vehicle.  We are located in Applegate, Michigan and do all of our production there. We do not import any part of our products from foreign sources. We entered the Blend Door market in 2006 when we started producing aluminum replacement doors for some of the big name automobile manufactures.  Due to non-disclosure agreements, we are not allowed to tell you which one or for what vehicles. We have produced in excess of 100,000 doors under these contracts and are still producing them to this day. We are the only manufacturer to mass produce aluminum replacement HVAC doors for any major corporation.

Seeing the quality (or lack thereof) that was available to the general public, Blend Door USA decided to enter the consumer market in 2014 to start selling our doors directly to the public.  We began with single doors for the 3rd generation Dodge Ram and have been continuously expanding our product lines since then. We are the experts in this industry and have the absolute highest quality replacement HVAC doors available anywhere.

Our Doors

CNC Milling MachineWe manufacture all of our products from solid pieces of aluminum. There are no welds or rivets in any of our products.  Everything is CNC machined to maintain the highest quality possible and to ensure a perfect fit every time.

Driver with CamOur drivers are key-cut so they will solidly engage the doors and will never fail. In the few instances where a key-cut driver won't work, the drivers are drilled with an off-set bore and are held in place with a cap screw.  This allows the drivers to stay engaged with the door when there is not an actuator holding it in place, like the 3rd gen Ram dual zone blend door drivers. All splines are broach cut into the drivers to ensure perfect engagement with the electronic actuators. 

Door Key Aluminum SolidSo why do we use aluminum instead of steel? Aluminum is much lighter than steel, and it will never rust. Since the aluminum is lighter, we are able to make the doors significantly thicker and still maintain the same weight.  This allows our doors to be much stronger than any steel replacement ever could be. Aluminum can be machined in a solid piece, which is why our doors do not have any welds or rivets holding them together.  Steel doors are tack welded together, which creates a weak spot and potential failure. For an HVAC system, aluminum is superior in every way. Our doors are the strongest in the market, period.

Our Foam Seal

We use open cell foam to seal our doors.  Most factory open cell foam is a polyester based foam that is biodegradable, which is why it comes apart and blows out of the vents.  Our foam is a synthetic polyether based foam that is not biodegradable and therefore will not deteriorate like the original foam. A common question that we get here is “Why don’t you use closed cell foam like the other guys?” The simple answer is, we’d love to, but we have yet to find closed cell foam that will perform satisfactorily in an HVAC box. There are a few requirements that foam must meet in order to be acceptable for use on our replacement doors:

  • The durometer or “squishiness” of the foam must be soft enough to sufficiently seal the box. The plastic housings have a very loose tolerance for what can be considered “flat.” We’ve had boxes here that have had as much as 1/4 inch gap on the sealing surface when the door was closed.  The foam must be able to compress completely on the high side in order fully seal on the low side. Most closed cell foams are too hard to seal properly.
  • The foam must be durable enough to withstand the extreme heat and extreme cold that an automobile will experience. The air conditioner evaporator will produce air temperature around 40 degrees F and the heater will produce around 200 degrees F. Don’t forget the interior temp when the car sits outside in the summer sun all day in Arizona or all night in a North Dakota winter. Very few types of foam can withstand this kind of abuse.
  • The foam must be American made.  We pride ourselves with an American made product produced by American workers.  We will not lower our standards by using a cheaper foreign made foam to increase our profit.  

      We are continuously testing new types of foam in order to provide you with the highest quality products available.  If we ever find closed cell foam that meets all of these requirements, we will start using it to seal our doors.  So far, every type of closed cell foam we have tested has failed on one or more of the requirements. The open cell foam we currently use passes all of these tests and will not deteriorate like the OEM foam does.  You will not be disappointed in the performance of our products.


      We are the experts in the blend door industry and we manufacture the highest quality products right here in America. We are so confident in our products that everything we produce is guaranteed for life.  Compare us to any other manufacturer of automotive HVAC doors and you will see why Blend Door USA is the clear choice. 

      Now you can fix your heater for those cold winter mornings and fix your air conditioner for those hot summer days.  No matter what you drive, if we don't have it in stock we can build a set of custom doors just for you.  Fix it once; fix it right; with Blend Door USA.