Just a heads up to anyone sucking air out of your garage or shop.
Remember that air that goes out, has to come back in somewhere. If you don’t open something somewhere it will pull air from anywhere it can, like a furnace vent (depending on type). It can suck out pilot lights, pull furnace exhaust back inside your shop and so on.
The smaller the space the more effect it has.
The more CFM the fan has, the the more it effects the space.
i built a filter/fan using a 20x20 filter box for a furnace, and an 8" hurricane duct fan. just drew up a transition piece from rectangle to round and cut it out on the crossfire. put some angle brackets on it an screwed it to the ceiling above the plasma table. with the hurricane fan i have the option of ducting it outside if needed. if i open the garage door it blows directly outside. but mostly i use it when its too cold out to open the garage door. it works good for painting inside as well.
i use my old used filters from the house, usually MERV 13 or higher. they will filter out most of the particles in the air. clears out the smoke pretty quick. i also turn this thing on when blowing the dust off of shit in the garage with the air hose.
I also have the heating problem here in Oregon. I use one of these and it works great with no heat loss and good filtration. Its mounted to a hood over my CrossFire XR with no problems.
I just got my new ventilation fan.
It is a beast.
PLYMOVENT TEV
https://www.plymovent.com/us/welding-cutting-fume-removal/fans/tev
Mine is the little two horse model.
Here’s a link to the spec sheet of anyone’s interested.
Is that to vent outside or to filter?
I’ll be venting out side. I have a large make up air duct that come in right by my table.
I also plan on it suck from the sanding table and from the welding area.
I will be adding a dust collector before the fan
Air make up heated?
I cant afford that. I placed the make up air right under the plasma table so that cold air make up doesn’t really mix with the room’s air.
I keep my shop at between 2.5-4.5 C during the winter.
And if working hard is not keep you warm enough then its time to go home.
The shop I apprenticed at did not heat the shop at all so you could see your breath and your hands would stick to the sheet metal sometimes in the winter … 
work there for 11 years
Not sure any of my stuff would run at that temp and I know I don’t 
my friend Arthur Itis and his cousin Burs Itis says i have to heat my shop… 20 years ago i would have agreed with you TinWhisperer.
I recently emptied my water tray for the first time. I have only cut maybe 30-40 signs and a bunch of misc stuff. Very light usage compares to others.
I scraped up over a gallon of fine dust out if the tray. Man, I am really glad my system has the water table. I’d hate to deal with all that, especially if I get really active with it.
That stuff really glues itself to the pan doesn’t it! the first time I cleaned mine out I was surprised how much effort it took to get it all!
I have a small shop, 36’x24’, but it is pretty well insulated. I have a big powerful 24" exhaust fan at the peak of the end wall. a few feet away from my plasma table is the door to my compressor shed, which is ventilated to outside air.
When I cut I crack the door open, and turn on fan. It does an amazing job of sucking it all out - or most of it. When it was 19F outside a week or so ago, I lost about 5deg F cutting for 20min. so my shop temp dropped to 40F or so. But it is still comfortable when actively working, and very cheap method,
Just get busy cleaning the shop while it is cutting and you’ll be warm in no time 
So I recently purchased a HRV…heat exchanger…and mounted it in my garage…it does around 150cfm at full speed…
I have it on a control that runs either on L, M, H or based on outdoor temps…
it is also auto balancing to make sure the room stays away from being negative or positive pressurized
.
I have supply from the HRV blowing in my direction when welding and on the far side of the garage.
My exhaust line runs over the compressor to pull air across from the front of the room which clears the air around where I weld…
I also have a duct ending right above my table as I am planning to try a 6" flexible duct from the ceiling down to the Z axis to help draw up some of the fumes.
now to try the room ventilation I set a piece of paper on fire then set it to smoke/smudge…filled the room with smokes and then did ventilation tests to watch the air flows and to see how fast it clears up the space…
I was pleasantly surprised…
the supply kept fresh air where I weld…and drew the smoke across the room to clear the air…
and the entire room was cleared of a heavy smoke in around 1 hour…
I am very pleased with the unit…in running it for a few hours I only dropped about 2 degrees…it was -10c outside and I keep the shop at 13c…
I do expect @TinWhisperer to chime in on my amature ductwork…but it is a work /test in progress…lol…
Not much keeps me warm @40 anymore!
nice HRV ! V160H65RS? . I installed about 30 of that exact type this year but the top port version V110H65RT. its is a great unit.
Thanks @TinWhisperer
that means a lot coming from you…
picked it up for around $700…I really like the core HE as it looks easy to clean…
$700 is a really good price. I was having a hard time getting enough units for my contracts earlier this year. I ended up having to get a few units from Saskatchewan ship to British Columbia. The stock is all good now but it was quite pressing for a bit.
