For light, you might look into pseudo-fluorescent bulbs that have the standard tube shape but are constructed with LEDs.

If you take your hood to a sheet metal shop, they should be able to advise on matching stainless steel types. Also, they should be able to build an extension -- perhaps for a lower cost.

Good idea about LED tubes. I just did a quick search and don't see a 17 inch replacement, but some fabrication wouldn't be too hard to make something work. It's a DAH 18 with a curved front so fabrication from scratch would be impossible by a good shop but I don't think it would be easy or cheap. Can't hurt to ask around though. With the work and cost involved though, would I just be better off buying another?

Do you mean buying another VaH, or buying another brand of hood, perhaps one that incorporates the characteristics that commercial hoods have embraced for maximizing performance and efficiency. This ties into your baffle question.

My motivation to trample this ground yet again is weak at the moment, but en brief: Both VaH fans and baffles capture grease by centrifugal extraction -- the baffles by two direction reversals in the air flow; the VaH by throwing the air against an impingement surface. I don't have a VaH, but my impression from others' comments here is that baffles are easier to clean.

Closer to my own interests is the question of actual air flow performance. VaH claim certain air flows, but these at best apply to the hood hanging freely in the air. With ducting and a roof or wall cap, and the very likely restrictions of the make-up air path, the actual flow rate will be less -- just as it is for the flow rates specified for conventional blowers. The question then is which technology (stretching the meaning of the word to its limits) produces sufficient restricted flow in the setting where it is installed.

Data published by VaH shows that their fans have shallower fan curves, so they are less suitable where flow restrictions are present than conventional blowers. (VaH designs avoid the flow restriction that is presented by baffles, for example, so they start off with an advantage, but this advantage becomes a disadvantage when a complete system including the inevitable, intended or accidental, make-up air path is accounted for.)

For many, noise is a performance factor. The lowest noise solution will be based on an exterior roof or wall blower, or an inline blower, supported by a silencer located in the ducting between hood and blower. This applies wherever there is sufficient space and the ducting is long enough to accommodate a silencer. One can easily talk next to my hood connected to a 1500 CFM (nominal) roof blower at full power with an inline silencer in my attic. VaH Magic Lungs, on the other hand, are at one's ear level, and in my view only compete for noise with hood interior mounted conventional blowers.

Independent of the above considerations, one should first determine the flow rate needed, then apply loss factors for the blower sizing. This can only be done when one has determined how well the hood canopy is expected to capture the rising and expanding cooking plumes, and at what height one intends to place the hood for free cooking access and sightlines. There are important differences in performance and convenience between shallow low hoods, larger pro-style higher hoods, and large commercial hoods mounted four or more feet above the counter.

We can go over these aspects to the degree you wish, but first I recommend you search for and read the many related topics on this forum that I and others have contributed to that address these principles. This will take some time.

Alternatively, reading the first 20 pages in the Greenheck kitchen ventilation system design guide will provide a commercial perspective overview explaining the principles that also apply to residential cooking plume capture and containment. Then we will have a common ground to take some short cuts to scale general requirements to specifications for a residential hood acceptable to you.

http://www.greenheck.com/media/pdf/otherinfo/KVSApplDesign_catalog.pdf

kas

Kas,

Thank you for your excellent reply and for the reference material. I have read a few of your old posts on this subject here and it certainly does appear that you have put considerable study into this. Given the lack of uniformity in determining how specifications are determined/measured, as well as variability in environment and cooking style and therefore requirements, isn't some of the calculation overkill?

Sorry for late reply, traveling for a few days. Thank you for the tremendously helpful approximations.

After spending probably too much time searching the web for specs and information, and getting a sample of VAH's stainless to see if it matches my old VAH - which BTW must now be made of a better grade of stainless as it doesn't quite match and is now non-ferrous while my old VAH holds a magnet, I've decided to purchase a new Wolf hood. The craftsmanship is worth the extra $$ to me.

As long as it is affordable to you, I think you will like the Wolf.

The older VAH must have used a 400 series stainless steel. These are not as "stainless" as the non-magnetic 300 series, and over time will change color a bit. A phosphoric acid wash might re-establish the original color, but I think you will be better off with the more conventional Wolf (assuming it is from the quasi-professional baffle-bearing configuration styles).

Kas,

Thanks again for your help. There were just too many issues to work around that may or may not have worked out well to make saving my old VAH worthwhile. None of this kitchen renovation feels very affordable but it had to be done and I expect it all to last for my duration in the house (hopefully many, many years) so looking at the expense in that light makes it less painful. I'll give my old VAH to a building material recycling place and I'm sure that it will make an excellent addition to someone's kitchen project.

Just to confirm your decision, I was concerned about the performance of my old hood ( A Viking badged hood with Broan motor ) and so I took it down and decided to take the squirrel cages off and clean them of years of baked on grease and grime. It was a very messy and long job, and it performed much better after, but my guess is you would have spent a lot of time and elbow grease cleaning the cages on your Ventahood.