attenuating the noise through a filter

[Roger Feeley]

My shop is in the basement of our relatively new house. The HVAC guys were going to put a return in the basement which, in my view, would put too much dust into our system. I told them to give me two vents for the basement and no return. Instead, I had the general contractor make a 20"x25" opening into our stairwell with a nice grate over it on the stairwell side. We made it a nice tight fit for a 20x25 air filter. As I fitted out the shop, I took steps to seal any openings into the basement other than that filter. I sealed the door, around the hvac vents, around the plumbing and any electrical openings. The idea was to put air into the basement from those two vents and force it through that filter.

The plan worked pretty well. I find very little dust on that vent cover. I've had no complaints about dust elsewhere in the house. Neither of us have allergies so that isn't an issue. A further indication of success is how often I have to take the filter outside and blow it out.

My wife has never complained but the machines in the basement do make quite a bit of noise and it comes up that stairwell. I wonder if some sort of simple baffle might help. I'm thinking sort of a u-shaped thing open at the top and bottom with maybe some foam on the inside?

[Lee Schierer]

I heat/cool my shop with the house HVAC system. I have two air returns in my shop. I equipped each of them with merv 10 filters. I can find no trace of dust in the air returns back into the house. I also run a recirculating air filter in my shop when I do sanding.

[Mark Daily]

I heat/cool my shop with the house HVAC system. I have two air returns in my shop. I equipped each of them with merv 10 filters. I can find no trace of dust in the air returns back into the house. I also run a recirculating air filter in my shop when I do sanding.

I think Roger is complaining about noise not dust.

[Roger Feeley]

Perhaps I wasn’t clear. As mark said, I have no dust problem. And my bride has never once complained about the noise. I’m just wondering if I could do something.

[Stan Calow]

I would still have the return but keep it closed. Your usage of the basement area (or the next owner) might change in the future. A return in the basement helps keep it dry, IME.

[Roger Feeley]

Good thought Stan, but the ship has sailed. We did do some things in this little house with the next owner in mind.

We had plumbing for a bathroom in the basement installed. It’s all stubbed out and I had to place some machines very strategically.

we had one of those window we’ll egresses put in. That, along with the inside AND outside stairs, means that someone could put two bedrooms in the basement. With 1300 sq ft down there, it could be an apartment.

240 square feet of the basement is under a concrete patio. It would make a great shelter. We joke that about the time I’m too old for a shop, our grandson will have a band. But, this being Washington DC, that space could also be a Sensitive Compartmented Information Facility or SCFF. This is a secure room for used by a cabinet secretary or senior person in the intelligence community. Retrofitting a home for a SCFF is expensive. In my basement they would just add one wall.

we designed in a plumbing chase going frame basement to the loft. So our 500 sq foot loft could be a bedroom.

the interior spiral staircase could be replaced with an elevator.

So, as built, we have a one bedroom, one bath granny flat. But it could be a 4 bedroom, 3 bath house with three living areas. I can’t imagine anyone wanting to do all that, but the building does present quite a few options.

[Jim Becker]

Reducing direct sound transmission is they best an nearly only way to accomplish your task. This is exactly the same thing that we folks who put our dust collection systems in closets have to design for....return air back with out taking the noise with it. The answer is ALWAYS an indirect path. Mine is baffled. JKJ uses a long length of large flexible duct work to accomplish the same thing. In your case you have to work out a way to make things as indirect as you can within the space you have to work with.