# Dust collection venting



## John_G (Jan 12, 2011)

Hey everyone,

I'm looking to purchase the ever popular Harbor Freight 2HP dust collector. I'm currently just using a large shop vac hooked up to a home made thien serperator on a steel trash can. It's works ok i guess, the shop vac obviously can't keep up with some larger tools as it just doesn't have the power. So i'd like to upgrade and i know there have been sooooo many rebuilds on the HF Dust collector but i still have a questions.

I usually see everyone talking about getting a cartraige filter to put on it. This reduces the amount of fine dust back into the room. I have a different approach. I would like to just run out line out/vent directly outside, just like a dryer vent. This way i will get ZERO dust back into the shop. This seems like the best move and i'm just wondering what you all think and why no one else seems to do the same.

Thanks in advanced everyone.
John


----------



## hydro (Aug 9, 2013)

You will be blowing a lot of heat outdoors up there in the cold NY winter. Keep that in mind when designing the vent system.


----------



## John_G (Jan 12, 2011)

The vent would exit my basement a few feet above grade through the rim joist. I could add an elbow on the outside if i wanted to direct heat/dust but idk if it's really neccisary. Not sure what the heat would do, i can't imagine it's like a dryer vent that puts out a lot of heat.


----------



## hydro (Aug 9, 2013)

Heat as in $$$$$


----------



## Dal300 (Aug 4, 2011)

Hydro is correct…. You are paying to heat and condition that air that you are just throwing away.

I use the 1HP HF unit, rated at 660cu.ft/min….. about 10 times what your dryer puts out. I think the 2HP unit is rated at 1100cu.ft./min…. probably equal to what your furnace blower can produce on it's best day.

Next question, (And I'll answer it, thankyouverymuch), where are you going to get air to make up what you are pushing outside? Ummm, the only place available….. The outside.
That means that you will have to intake unheated, unconditioned air to make up for what you paid to condition and heat in the first place.

Good luck to ya, I hope it works out.


----------



## JJayzon1 (Oct 20, 2012)

Hey John,

I did this with my HF DC it works great. I used 5" stove pipe (I sealed all the joints with silicone caulk) for my exhaust because I didn't want to restrict the exhaust. The only problem with using the 5" pipe was that there is no exhaust vent like the dryer vents, so I got a cap and drilled a bunch of 1/2" holes in it leaving just enough material to keep rodents out. Here is a pic of my set up. 









I used the original ring and made a thein baffle so the larger material falls into the trash can. I attached the blower & motor on top. I have a small leak somewhere around the exhaust but have not had the time to address this yet. Even with the small leak my basement is almost dust free it's great. Oh one other thing to think about is the location of your exhaust because a lot of the fine dust will can collect on your cars and other stuff ( I learned this the hard way, My wife thought there was some weird pollen on her car LOL)


----------



## John_G (Jan 12, 2011)

OK so my shop is in my basement, so it's not really a heated space. The intake for the vac would be from my machine, to the thien seperator on a steel can then to the blower and out the vent outside. So are you saying that the new fimes i have it turned on a week that it will pull sooo much air through my tool (planer, table saw, bandsaw) that it'll suck all the warm air out of the room and cool the space? just want to make sure i'm following along here.


----------



## Smitty_Cabinetshop (Mar 26, 2011)

John, I believe that's the concern being stated. I'm with you, though. When the DC is run only intermittently, it's not a significant factor.


----------



## a1Jim (Aug 9, 2008)

I have run my dust collectors out side for years,you avoid the expense of filtration systems,using up valuable floor space. I just built a litte shed to hold the barrel and bag that's normally connected to the DC unit inside,this stops dust from blowing around outside .Unless you are running your dust collector all day I don't think you have a signifacant heat loss.


----------



## GShop (Dec 7, 2013)

Another issue to consider is location of water heater and furnace. If they are located in basement and you do not have sufficient intake air, you could create a negative pressure causing CO risk. Or, safety features on more modern appliances may shut down the unit.


----------



## Dal300 (Aug 4, 2011)

*Edit*. I give up. Whether the DC is on for 3 minutes or 3 hours it will cost money to re-condition the air you use.
All of this is up to you. Personally I like efficiency and hate spending money that I don't need to.
My filter cost $130, I have used it over a year, no need to clean it yet. I may need to clean it next year sometime. 
How is that more expensive than throwing conditioned air outside?

*OK so my shop is in my basement, so it's not really a heated space. The intake for the vac would be from my machine, to the thien seperator on a steel can then to the blower and out the vent outside. So are you saying that the new fimes i have it turned on a week that it will pull sooo much air through my tool (planer, table saw, bandsaw) that it'll suck all the warm air out of the room and cool the space?*

Essentially, yes, although if you are working in your basement in New York in December and it isn't heated, you are a better man than I Gungadin!
You say the intake for your vac would be from the tool. Hunh? You have a tool that can make it's own air? Or are you saying that the tool is an opening for the ambient air to pass through so the DC can draw air from the area?
The air that passes through the tool, (the DC actually sucks air from the low pressure area of the tool to the exit). 
Think of it this way… if your basement were perfectly sealed and you sucked all the air out, could you survive? Wouldn't the basement implode? 
Any air you take from the basement is being made up from someplace, probably from the heated spaces above because houses are not sealed internally, they must breathe from top to bottom.
The house can take in unconditioned air in a number of ways. 
through the roof vents.
through the fresh air return of the furnace
through leaks in the building itself.
Or all of the above plus others.


----------



## mbs (May 8, 2010)

I have one that I run outside but weather isn't an issue for me. It is very noisy though. Do you have neighbors nearby?


----------



## JJayzon1 (Oct 20, 2012)

Unless you are going to run it for long periods of time I think you wont have a problem. I have been running mine for 3 or 4 months now and I have a gas hot water heater. My DC is not on the entire time I am in my basement only the short period of time my tools are running. Also not sure how much room you have in your basement but if you are like me space is at a premium, the way I have set up my DC saved me a ton of space.


----------



## bondogaposis (Dec 18, 2011)

The big problem with that is the loss of heat in the shop. Say the typical 2 car garage workshop is 7200 cu ft and the HF dust collector is rated at 1550 cfm. Even if you cut that in half due to manufacturer optimism and friction loss due to duct-work, separator , etc. to 775 cfm you will completely change the air in your shop every 9 1/2 minutes. If your are spending a lot of money to heat your shop in winter, you will soon realize that this is an expensive idea. If your shop is in a climate where the difference between outdoor and indoor air temps are not great it is a good solution.


----------



## John_G (Jan 12, 2011)

JayMade
That is exactly what i'm talking about, perfect. The vent will actually go into my backyard where there's about a quarter acre of nothing. Glad to hear it's working out for you.


----------



## JJayzon1 (Oct 20, 2012)

John,

If you have any questions let me know. While working on this I made a quick and easy circle jig for my router that worked wonderfully. I can send you pictures if you need them.


----------



## Dal300 (Aug 4, 2011)

Basically you don't want actual information, only someone who will agree with your thoughts.

Not a problem for me, but from now on please state it that way so some of us don't waste our time giving you an honest answer that you don't want to hear.


----------



## John_G (Jan 12, 2011)

WOW someone's obviously a bit grumpy. The fact that there a varrying opinions on here from people actually doing this totally debunk what you want to push off as fact. No worries though, i'll average out the opinions and then make my own.


----------



## Smitty_Cabinetshop (Mar 26, 2011)

Bondo's math was an eye-opener for me.

Math: A four letter word.


----------



## Dal300 (Aug 4, 2011)

Show me the facts. 
Do you have historical data related to the question?
Probably not, but that is your problem.

Am I a grump? nope, I'm a curmudgeon. (Big word you might have to look up).

I did look at all your answers, a number of times… It still doesn't change my mind that you only want to listen to answers that agree with your original question. 
Why would you ask the question in the first place if you only want an answer that agrees with you?

If you want to exhaust the dust outside, do it. but don't ask anyone that has experience with HVAC to agree with you.


----------



## crank49 (Apr 7, 2010)

I was about to chime in and agree with Dallas, because I am an engineer with 40 years experience with these types of problems. And, I was just thinking the same thing when Dallas gave you, free of charge, a lot of useful and valuable information. Which got completely ignored until another poster chimes in and says no problem, I been doing it this way for 3 months. Now that's the solution you wanted to hear. I don't blame the curmudgeon, that kind of thing gets my drawers in a twist also.

Good luck.


----------



## a1Jim (Aug 9, 2008)

John
Bondo almost always makes sense as far as I'm conserned. so I would say if heating cost is an issue don't vent outside. I have used my units when it's cold outside and I have not noticed a marked difference in room tempiture but I have'nt focused on that point ether.I have also found Dallas to be very well informed on such subjects too.


----------



## John_G (Jan 12, 2011)

OK OK, math is math i do agree, add this to the equation. Your talking air changes an hour. I'm not sure my dust collector will bu turned on a total of an hour every few weeks. I can see in a shop that's running all day that leaves the machine on and uses blast gates that the air changes in the room could be a problem. Maybe i should have explained the usage in the beginning. I get in the shop maybe an 1-1.5hrs a night and maybe a few on the weekends. And of that time my current vac is only tunred on for the seconds to minutes that a machine is on. So as i don't not agree with your prediction of loss of heat and $$$, with the frequency of use i'm guessing i will see little to no change. I'll let you know.


----------



## JJayzon1 (Oct 20, 2012)

I'm with Jim, I have no doubt that Dallas has forgotten more stuff that I have learned. I can only speak to my personal experience. When I set up my DC I gave a little thought to heat loss, but my basement is almost always 62 degrees year round. I have not noticed any temp drop, but again I have not been focused on it either. I was just in my "shop" last night it was in the 20 outside and it was just as comfortable as always in the shop. Like I said I don't run the DC the whole time I'm down there mainly because I don't want to listen to it (albeit so much quieter then the shop vac). @Dallas I really hope you don't feel you are wasting your time. This site is so great because of people like you willing to share there thoughts and experiences (even if someone does not take your advise).

Just my 1 1/2 cents.


----------



## Dal300 (Aug 4, 2011)

Hmmmm.
Maybe cost isn't a factor to you. 
However it is to me and many like me.

think of it this way:
If your DC moves 1100cfm and you are sending that air from a conditioned space to a non conditioned space, the air must be made up with fresh air in the conditioned space somehow.
Now, Consider this:
Would you open your living room windows (provided they are around 3X5), wide open and put box fans in the openings that push 200cfm turning them on high for a 3 minutes a number of times per day?
2-3X5 windows, fully opened = 15 square feet. Taking into account losses from a 20" fan and a 36" window approximately, a lot of heat is going to be escaping. 
Just because the pipe is only 4"/5"/6" at the exhaust doesn't mean that it isn't putting out a lot of air. It is just being forced out faster.
A1Jim's use is somewhat commercial I believe. His costs are included in his CoDB and CoG.

Here's another way to think of it:
The first summer I had my shop in the other half of the house, (heated/cooled by the same heat pump), I ran my little DC out a window, covering the hole with cardboard with a hole for the pipe.
Now, Our house isn't energy efficient, and in fact is scheduled for replacement in the next couple of years but, this will demonstrate heat loss/gain, I hope, Using a smoke stick, (a tool that makes smoke) and holding it up to the kitchen and bedroom window, a steady stream of smoke was being poured toward the fresh air return of the furnace. Since this air was well over 100°F, it only took a couple of minutes to warm the ambient air in the house by 4°F which the heat pump had to work harder, eg: longer to compensate for.


----------



## bondogaposis (Dec 18, 2011)

When I set up my DC I gave a little thought to heat loss, but my basement is almost always 62 degrees year round. I have not noticed any temp drop, but again I have not been focused on it either. I was just in my "shop" last night it was in the 20 outside and it was just as comfortable as always in the shop.

Jay, the reason you don't notice it, is because you are pulling warm air from your house into your shop. That air has to be made up somehow and 20° air will be entering your house somewhere causing your furnace to kick on to make up for the heat loss and causing dollars to evaporate from your wallet while you work blissfully away. If you are alright with that, there is no reason to change.


----------



## JJayzon1 (Oct 20, 2012)

Hey Bondo that totally makes senses. I told you i didn't think much about it  But unfortunately in my situation I have to be more concerned with space. This setup allowed me to have a DC and fit it into a 2X2X4 space. Now in a few years when I convince my wife to build a 12X20 building in or backyard I will have to reevaluate my setup.


----------



## Finn (May 26, 2010)

Like A1Jim :::I also have my dust collector outside in it's own little closet. Yes there is heat loss when it runs but I get zero dust in the air from the discharge of this unit. I get plenty enough dust in my shop that is missed by this system. I do not want to add to it.


----------



## MrRon (Jul 9, 2009)

I vent my DC to the outdoors. For the amount of time it runs, the loss of heated air is insignificent. I live in the hot deep south, so maybe my DC helps cool my shop. If it is real cold, I won't be in the shop, but being in a basement does pose a potential problem if you have gas fueled appliances.


----------



## Hotpuppy (Aug 14, 2013)

Thank you for the pics JayMade…. exactly what I was looking for.

@Dallas - you raise an important and valuable point. However, I think you are missing the purpose of venting particulate dust. The vast majority of the "dust collectors" on the market are simply "chip collectors". From what I have read most of them simply don't get this dust. Most of the filters are only rated when loaded, which takes time, in the meanwhile they pump particulate dust into your shop.

So yes, heating and cooling costs money… but so does screwing up your lungs.


----------

