downdraft vs rangehood

[Jimmy]

we are thinking of putting in a downdraft in the wall behind the stove rather than losing so much space to a range hood - anyone tried a downdraft?? any comments?

[SilentButDeadly]

Uncle's place has one......it doesn't work. You'd have to have a fan from an evaporative air-con to suck enough air to catch the fumes.....and that's just stupid.

[woodbe]

One of our family has one for his in-bench electric grill. It's right alongside, and works surprisingly well, but if you are thinking about replacing a range hood over a normal cooking range, I doubt it would be up to the task.

These things work by sucking an enormous amount of air, and that brings some unwanted side-effects: Noise and running costs.

Not for me, but they look neat.

woodbe.

[renomart]

Downdrafts are not the best choice. They are pretty noisy.

[markharrison]

I've always thought that what was really needed was a combination of blowing and sucking.

Oi, you at the back. Stop snickering this is serious!

Consider this. Take a balloon filled with helium to neutral buoyancy and a common drinking straw. How close do you have to be with the straw to attract the balloon while sucking? Now compare to blowing. How far away can you get to move the balloon? Believe me, blowing wins every time.

So what I think would be the most efficient method of collecting cooking fumes would be to have a "curtain" of air surrounding the cook top directing the cooking fumes towards the range hood. The curtain of air would not have to be very big or powerful to be effective.

The range hood would not have to work as hard, consequently consuming less energy, and much more fumes would be collected not to mention that the kitchen would be a lot less noisy.

[Jimmy]

a thinker amongst us, I like that!!! am thinking, thinking, will get back to you about that idea ... meanwhile our cuurent plan is that we have a 1200 m3 p hour ball bearing drum fan which has variable speed which we are thinking of using - it is very quiet, so we are told.... contemplating building the duct work ourselves

[renomart]

If you are worried about noise you can get a hood with the motor mounted in the roof space.

[woodbe]

Motor and fan noise is only part of it.

If you suck that amount of air through a slot, it's going to create turbulence and noise.

There's probably a balancing point between sucking enough air and sucking the food off the grill

woodbe

[markharrison]

Yeah, it's a bugger getting the snags off the range hood too

[RedRaven]

Rangehood.

The main reason range hoods are effective is that warm air from cooking rises. Simple convection.

So even though a range hood sucks (and is thus less efficient at moving a 'target' volume of air, compared to blowing, as pointed out by Mark), the warm cooking air is already moving upwards, all you need is a way for it to get outside before it hits the roof and spreads out. In this way, a range hood is an evolution of the chimney.

Rangehoods are also a good place for lights - I like to see what I'm cooking!

If they're metal, they're good for holding recipes using fridge magnets.

If you're worried about losing space (headroom?) go for one of the pull-out types that slides towards the wall when not in use.

[markharrison]

Your central thesis is essentially correct. I'm not arguing that range hoods are not effective. It's just that they could be much more effective without sounding like a turbo jet military attack aircraft taking off with the afterburner!

I've toyed with this idea for a while but I frankly have no interest in running with it commercially.