Kitchen exhaust - Is a Recirculating hood effective?

those ae not worth having. That's a major defect of the house and to properly *fix* it would require $$$ as you already know.

vegetation said:   It will help prevent grease build up on your kitchen surfaces, but wont do much for venting smoke and odors.

Agreed. We made this mistake in a recent kitchen upgrade, too late to reconnect to the outside world, we regret it.

Works for us but maybe you cook more than we do...

ZenNUTS said:   those ae not worth having. That's a major defect of the house and to properly *fix* it would require $$$ as you already know.

Yes...the price difference between non venting and a venting one is huge (in the range of 3x-4x of non venting). One option that was discussed was to have the ducts not be inside the ceiling but be visible. Wifey shoot that down very quickly. The other option of going parallel to the rafts has an unknown in that it might hit the metal support beams (almost certain that it will) and there is the master bedroom over the kitche n ceiling.

frugalpete said:   i have no idea, but just curious if its possible to use the flexible aluminum ducting for dryer exhaust to route through the ceiling and roof?

I can ask but the problem is the wrought iron beams and the rafts going in the wrong direction in this instance.

Seal said:   aga1000 said:   Here is the setup - The cooking range in my house is on an island. It does not have any exhaust right now. I have looked at exhaust that vent down, and at chimney exhausts. The problem is that I cannot vent outside if I use a chimney hood becuase of the way the rafts in the ceiling are laid out among other major structural issues. So the only feasible option seems to be a chimney hood that re circulates the air. I have had some people tell me the recirculating with carbon filter should be sufficient. So, my question to all of you is - is a charcoal filter effective in cleaning the grease etc from the air? And if it is then is there some places which sell the activated charcoal cheap.

I should also add that my wife loves to cook.

Thanks for all your help.

We had a similar setup and suffered for a number of years until we replaced the exhaust to vent outside the house.
Recirculation is OK if you do not cook much more than reheating take outs or occa. cup of soups.

So a charcoal filter was not much help either?

bondo123 said:   is your kitchen situated near the perimeter of the house ? ie. not in the center of the house, if yes, maybe you can relocate the range next to an outside wall so you can vent directly through the wall, our house didn't come with a hood and outside vent, we looked into a recirculating hood, after some research shot down the idea because it was just not effective

Only one wall of the kitchen is on the outside and that side has the dishwasher and the sink. Let me run this by my wife but i think that she loves the cook top on the island as it allows for conversation with guests and watching tv when alone. Thanks.

What's above the kitchen?

comprx said:   What's above the kitchen?

The master bedroom.

ganda said:   I have a externally venting downdraft island extractor and it's crap. I can't imagine how awful a non-venting one would be. I *used* to have an externally venting above the range hood that was awesome and I miss it

Is the kitchen for cooking in, or watching TV/entertaining?

It is for boyh as the kitchen, entertainment room and breakgast area are one area.

ganda said:   I have a externally venting downdraft island extractor and it's crap. I can't imagine how awful a non-venting one would be. I *used* to have an externally venting above the range hood that was awesome and I miss it

Is the kitchen for cooking in, or watching TV/entertaining?

I also have a external venting downdraft and it doesn't do much. Probelm is that heat rises along with the steam and aromas and the top of the pot is out of range of what the fan can pull. Don't like how it affects the burners while cooking either.

Jon

donnytong said:   I've been through all this and the only option is to vent outside. I've used both recirculating and down draft vents and they are no good for any real cooking. My alarms would go off whenever i cook steak or fried fish. Not to mention all of the odor and smoke travels to the second floor bedrooms. You must get an external vent. You can actually get a chimney vent and run the piping along the ceiling. All you need to do is build a cover to make it look better. I don't have any recommendations for down drafts or recirculating vents but if you can get an external vent, then look into the brands vent a hood or Kobe. These are pricey but you won't be disappointed.

You were not kidding about vent a hood being pricey,,,

VERY IMPORTANT - Vent outside. And buy a bigger, more powerful fan than you think you'll need. I put in a 850CFM Broan Stainless hood, vented outside, and it is wonderful, but I still wish I'd bought a bigger/higher CFM fan. You'll be glad you spend this mooney, don't skimp here.

-Unless, that is, you are only building an ornamental showplace kitchen that you don't intend to really cook in.

One thing is don't get caught up on the whole cfm rating. Most manufacturers will list an insanely high CFM, but it won't work to its full potentials without the following:

1) Shape/design of the hood and how well it captures the effluents. If it's pitched upwards, then it'll capture more smoke and effluents.
2) Size of the duct tubing. Most minimum requirements will be 6 inch ducting, but if you can install an 8 inch ducting, then your options for high performance hood vents will be in a differnent level. NEVER restrict your duct work. e.g. don't connect 8" to 6" ducts. Minimize the number of bends to maximize airflow out of the house.
3) Fans. Should have 2 fans for maximum 'sucking' power and be able to push the byproducts out of your ducts.

Basically a 600-700 cfm vent system that have all three items above will outperform a 900 cfm vent hood.

Of course this is all yap on my part unless your wifey agrees to let you install an external vent hood system. I really don't want you to make my previous mistakes. I ended up spending a lot more money than I had too! If you need more info, let me know.

Also, I forgot to mention about the recirculation vents. The air gets recirculated through the top of the vent, so if you have cabinets above or close to the vents, then it'll get sticky.

donnytong said:   One thing is don't get caught up on the whole cfm rating. Most manufacturers will list an insanely high CFM, but it won't work to its full potentials without the following:

1) Shape/design of the hood and how well it captures the effluents. If it's pitched upwards, then it'll capture more smoke and effluents.
2) Size of the duct tubing. Most minimum requirements will be 6 inch ducting, but if you can install an 8 inch ducting, then your options for high performance hood vents will be in a differnent level. NEVER restrict your duct work. e.g. don't connect 8" to 6" ducts. Minimize the number of bends to maximize airflow out of the house.
3) Fans. Should have 2 fans for maximum 'sucking' power and be able to push the byproducts out of your ducts.

Basically a 600-700 cfm vent system that have all three items above will outperform a 900 cfm vent hood.

Of course this is all yap on my part unless your wifey agrees to let you install an external vent hood system. I really don't want you to make my previous mistakes. I ended up spending a lot more money than I had too! If you need more info, let me know.

Also, I forgot to mention about the recirculation vents. The air gets recirculated through the top of the vent, so if you have cabinets above or close to the vents, then it'll get sticky.

On 2 - Hopefully there is enough space in the ceiling to put 8" ducts. There will have to be at least 2 turns.
So do you not have any issues with negative airflow? Too much air flowing out and pulling in the exhaust from the water heater or the gas central heating unit?

aga1000 said:   secstate said:   aga1000 said:   Correct WhyMingWhy... Most of the research that i did pointed to it being not very effective. I will take a second look at the down draft option. Thank you.

I have a pop-up down draft in my kitchen rennovation and it is a pretty high-end and powerful one and it is only marginally effective. It does a good job for the pots at the back unless they are very tall stock pots. It is not very effective for the front row, particularly the taller the pot. I have had a recirc one in a previous location and a decent down draft is better than recirc but cannot compare to an overhead that is vented.

This is very similar to reviews that I have found online. So, maybe it is not an option.

Yeah my wife did not want a hood over the island so we stuck with downdraft. Our rises about 8" inches but there were some that rose to 11" as I recall but they were a lot more $$$. Any additional height would help but in the end it just is not going to work as well as a hood that vents outside.

aga1000 said:   On 2 - Hopefully there is enough space in the ceiling to put 8" ducts. There will have to be at least 2 turns.
So do you not have any issues with negative airflow? Too much air flowing out and pulling in the exhaust from the water heater or the gas central heating unit?

Where is your water heater or gas central heating unit located? On the same level as your kitchen? My heating system is in the basement thus I don't have an issue of pulling airflow away from the heating unit. I have ductless minisplit air conditioners instead of central air, thus I don't have an issue with that either.

There is one little trick I learned from my contractor. Open the window a little and it will provide the airflow to minimize negative airflow or backdraft. I usually have two windows slightly opened at all times (on the floor with the kitchen) when we are home.

Or you can look into this product called "make up air unit"... http://www.ccbinnovations.com/index.php?option=com_content&view=... This unit is connected to your vent hood, so it turns on automatically when your vent hood is turned on.

Thank you all for your suggestion. I am going to have to go with an exhaust that vents out. On with trying to get quotes for this work and I can already hear my wallet crying.