Gas in an unvented house ?

Where do you get makeup air from? Gas burns oxygen. Do you leave a window open a bit?

Then, where do you expect to put smoke?

If you are only cooking rice you don't need gas to do that.

There are a few more details, good to tell us, if you want a clearer understanding of the situation.

You can get a decent CFM hood and 8 to 10 inch duct for much less than what you're being quoted. There are all SORTS of price ranges. Check out the FAQ on this forum regarding ventilation to know what it is your range will require, and start shopping around.

My advice: you really do need a vent-to-roof system if you plan on cooking anything that gives off smoke/orders.

We live in Florida and can grill all year long... but recently tried recipes that required searing in a skillet. Until we had a hood vent, those recipes were off limits (especially with fish).

When our rangetop is cleared, I chop onions on a cutting board under the hood... with the hood on, no tears.

If you don't have a properly vented hood, that smoke/moisture/order has to go somewhere, and that is inside the house.

Some codes may require a vented hood with gas... I think we needed it for Orlando FL area, but I could be wrong.

Plus, hoods look cool :)

Here is a link that might be useful:

I bought a Futuro Futuro hood to go over my Bluestar range. It has 950 cfm and a 6" duct, which my contractor was able to route through the ceiling and out the back of the house. Ease of venting was one of the reasons I chose this hood. You don't necessarily have to go through the roof.

A caveat: I haven't used it yet, but I'm confident it will be adequate, especially since I got a 48" hood for a 36" range.

Yes, you need a GOOD hood,especially with a gas stove. Once you have one you will never be sorry. Do you really need a stove that is 20,000 BTU's? Maybe you could save money on the stove and use it toward buying the hood. Mine is 17,000BTU's and that is plenty even for stir frying.

Paddy- Check your math. You have to add up the BTU's of all the burners. Most good stoves are from 8,000 to 16,000 BTU's per burner, which comes to 48,000 to 96,000 BTU for a 6-burner stove.

morton5- I have the Futuro Futuro Moon Crystal for over 2+ years now and absolutely love it. You will too. My vent installer went to the side of the house instead of the roof and he was also impressed with the 950 Cfms.

drtom77- Even if your math is correct, I RARELY find myself using more than two burners at one time. Perhaps during the holidays we'll be using three burners, but that's the only time. I have a FP Cooktop with 20,000 BTU wok burner. Once I get that puppy going, I don't have time to be messing around cooking other things as that wok burner takes complete concentration or I'll end up with burned stir-fry. Even at 20K BTUs, I don't turn it all the way up. Perhaps the building inspectors use the BTU numbers to figure out the required size of the hood at Maximum capability, if that's the case, drtom77 you may be correct in adding up all of the burners. In practicality though, I don't believe most folks run more than three burners simultaneously.

We got a 36" Ameican Range which was amazing for power with 3 17,000 BTU burners and an oven you can park a car in.
You MUST have an exterior vent! Even if your doing a non code job. It's just way too unsafe and unhealthy. That said we just went right out the wall and since we were 36" from any window we never went to the roof. Passed code inspection first try.
It's a 42" 1200 CFM Presige which we never run even close to full blast for any length of time, it's great to have that power in reserve if you need it (guess how I know that). It vents into a 10" pipe, a 90 degree bend and as I said right out the wall.
We've had little underpowered vents, it's money well spent for a good one you'll only put in once.

drtom, When she said the salesman said she needed a stove rated at 20,000 BTu's I assume that was for one burner and not the total for all four.

Bacook, I have found myself using all 4 burners on my induction cooktop a few times already - and I've only had it for 2 months. With a stirfry I wouldn't want to have any more burners going, but when I am making soup on one burner, I might have some veggies roasting for it on the other and some potatoes and chicken on the other two
Or like last weekend, making pancakes on 3 burners to speed up the process. I would have used all 4, but I don't have that many pans :(