The size of the filter/cover isn't really the issue...the size of the duct is what really matters. Most vents have a central duct which is where all the air is sucked into. If the duct is the same on both hoods, the only issue is going to be having the glass be in a position to stop the grease from flying up and redirecting it towards the center duct. If 36" wide will cover your pans on the range, you would be fine with it over a 36" range. Having the hood hang over the sides of the range area is just to make sure there's no escaping errant greasy vapors!

I should add that the CFMs will also play a role...but usually the higher CFM vents all use a 7 to 10 inch duct.

I'd have to disagree. Hood shape, while not the most important factor, does affect hood performance. The Euro-style hoods clearly sacrifice some performance for style.

The major issue is the lack of "sides" on the hood. A typical hood liner for example will have 6'' to 12'' sides. The resulting cavity will function as a temporary smoke trap. Thus, if searing with high heat, there will be an initial plume of smoke and fumes generated. They will travel upward, as heat rises. Particularly towards the edges of a flat Euro hood, some of the smoke will travel outwards and spill over the edges, no matter how hard your blower is pulling. Add any degree of cross ventilation and the problem is magnified. A deeper hood can temporarily trap much of the smoke until the blower air current can draw it into the ductwork. As a rule, a higher hood will outperform a flat hood with the same cfm and ducting.

The notion that a wider hood will not outperform a narrower one ("The size of the filter/cover isn't really the issue") is also incorrect. By that logic, we could just mount a naked 10'' piece of duct over our ranges and it would work just as well as a 48'' hood.

It is always true that optimal hood size should extend at least 3 to 6'' beyond the sides of the range. Remember that smoke does not rise in a perfect vertical path. There is some diffusion in all directions, and some of it inevitably will travel outwards away from the range. A hood that is no larger than the range has no chance to capture that smoke. Remember that capturing "escaping errant greasy vapors" is exactly what a hood is supposed to do.

And, it is cfm that count. Duct size is important, but only in that it determines the true cfm generated at the inlet to the hood ducting. 8'' ducting with a 1400 cfm blower will outperform 10'' ducting with a 250 cfm blower, though of course the correct configuration is 1400 cfm through 10'' duct.

Thank you, clinresga. I will rethink the Euro hood in favor a more traditional hood. Very good points!

clinresga speaks the truth!

"...capturing "escaping errant greasy vapors" is exactly what a hood is supposed to do."

Cfm considerations aren't the half of it.

Unfortunately, I speak from experience. The capture area is very important.

I think I have been misunderstood...I wanted to point out that the size of the filter cover can be deceiving. I have seen hoods that have filters that cover the entire bottom surface, but when you take them off they've got the same duct opening as other hoods of that capacity. Since the OP said that the glass hoods had a "much smaller" vent/fan I wanted to point out that it wasn't really smaller...it just had a smaller cover.

I did say that the hood should cover the burners and that capturing greasy vapors is what the overhang was for. Not that it wasn't necessary or important, just that the whole thing wasn't sucking up air, which seemed to me to be what the OP thought was happening in the non-glass hoods.

I apologize for not making my thoughts more clear.
And FWIW, I have seen hoods that are simple giant cylinders, just as you described.

evaperconti: yeah, you're right and your comments are sensible. It's definitely possible to get fooled by the "look" of the venting area into believing there is more behind there than it looks. You also make the good point that the rest of the hood is a "passive collector" of fumes, not an actively ventilated surface across its entirety. So basically we're both on the same page: make sure you know what the duct size and cfm ratings are, and then decide on how large a capture area you want. Hood shape and configuration are less critical but still important to overall performance.

No worries, clinresga! It is possible to be fooled. When I was researching hoods, I dismissed most glass canopies because the hoods with the full-coverage filters looked like they would work so much better. But I came to find out that wasn't true, for the reasons I mentioned. I know others will be viewing this thread and that is a point that might otherwise not be noticed. Hence, my clarification.

clinresga pretty much covered the topic. The hood function is capture and containment. Capture requires a large enough hood to begin with, and containment requires sufficient hood top-to-bottom depth and flow rate (cfm).

No practical hood, however, can perform capture if there are significant cross drafts. Air conditioning and make-up air diffusers need to be well away from the hood area unless very carefully designed.

kas