What????

Money saver for the builder
 

Anything like this is a money saver for the builder. In other words a cheaper house to build.
The location of the stove is another thing, if the way to the roof is not clear then they can't go straight up and the vent has to be straight so it doesn't become a grease trap.

Most only go back into the room. That’s the way they are designed. If that’s a deal breaker for you, then that’s not the home for you. For us it’s not a big deal.. plus a neighbor of ours paid close to 2000. To have it run outside. After a year, they are having problems with squirrels and other rodents knawing at their vent, and getting into the duct. But they live near a pond so more critters I guess.

Not legal to exhaust into the attic.

I was told by previous owner that my kitchen fan vents out to the outside, but I have a suspicion it goes into the attic. Just one more of many things that will need to be changed/repaired/renovated in my old 'new' home. One thing at a time...

I have two vents coming out of the roof neat the kitchen. The straight one is the dryer as I can see. Does anyone know what the curved one is for ( per pic attached )?

The curved one is the dryer vent. The straight one is a vent from one or more of the plumbing fixtures. Every plumbing fixture has a vent, but some of them are combined in the wall before they exit through the roof.

Begs the question.
 

Assuming we all have exhaust fans in our bathrooms to get rid of moisture from bathing, why not in the kitchen as well to get rid of moisture from cooking???

Solar Tubes don't move anything except light. Codes cover exhaust fans and who can move your air and grease through your house. Apples and oranges.

We rarely turn the vent fan on but ours vents through a filter in the microwave and back into the kitchen.

Same with me. Ridiculous system!!!!

Same here, but even if you rarely use it make sure you clean or better yet repalce the filters. They can get pretty gross. We moved into a 9 year old home and it seems they always used it but never changed the flters (or if they did, they cooked a lot of greasy food).

Thanks for your post. Before we moved here, we had a countertop microwave with no vent button. As a result of your post, I examined the microwave above the stove, and saw that there is a vent fan button!! After reading online about microwaves, I guess we should start using it!