Newbie needs some help with HVAC issues!

[camistan]

At present I have not had my basement framed up yet for any type of construction. It is an unfinished basement. In the room that will become my control room there is an incoming air vent there. It is coming directly from the blower, but the same duct line is used for another vent about 25 feet further away. In my studio (live) room there aren't any air send ducts. I was wondering for the purpose of quiet air flow and air exhaust (return from each room) if it's possible to tap into my air handler to send air to the studio (live) room, along with tapping into the air handler return line for venting stuffy/hot air out of each room? Is this the proper method especially for air return? I was told it would be better to make any HVAC changes now rather than wait until framing was done. Also, I looked on this site and it seems Johns Manville Superduct is recommended for Duct ventalation. Do you use this duct strictly for air flow, or do you also put flexible duct inside it? Hey, I don't know a THING about HVAC!

[sharward]

Greetings and welcome, Camistan.

HVAC experts here are few, but there's been lots of discussion here to learn from. Try some creative searches and you're bound to find some golden threads.

I tend to agree with you that engineering your HVAC system is better done before framing is done. In fact, I believe it is better to have everything engineered before the first nail is hammered upon. I'm kind of anal about that, but I've witnessed a lot of examples of less-than-adequate planning on this forum, and I'm doing all I can to avoid the same pitfalls.

It sounds like you've got the basics down, particularly the fact that when air goes into a sealed room, an equivalent amount of air must exit the room, hence the need to tie into your return line.

That being said, I personally recommend that you have a few HVAC contractors come to your place to evaluate your situation. You particularly need to know whether or not your existing system can handle the additional load.

You may want to consider having a dedicated system for your studio space. I would imagine that your cooling needs for that room will differ quite a bit from the rest of your dwelling. If you have a single system, the thermostat in the main hall won't have a clue what temperature it is in the basement space, so you may find yourself in a Goldilocks situation (too hot here, too cold there, just right somewhere else).

Although expensive, you may want to consider a mini-split system. That is what I am planning for my space. They're expensive, but in my case it will fit the need very nicely. Full disclosure: there's some debate on the forum about mini-splits. Searching the forum for "mitsubishi" or "split" will likely return some good discussion and info.

Finally, you need to review the the "Before You Post" post, as that announcement message contains important details of how you can best help yourself here on the forum, as well as important steps you need to take to help us help you.

I hope that helps to get things started.

[PhiloBeddoe]

I'm also doing a basement studio. I'm not an expert, but the ideal system is a completely separate one including air handling and ducts. For me this was not affordable so I chose to run flexible insulated ducts everywhere. If you use long runs with a few bends the air flow noise is reduced significantly. I'm completely happy with the air flow noise, but the sound isolation performance remains to be seen.

Lined ducts such as Superduct are probably the best, because Rod Gervais says so and he's the man. He doesn't like flex duct, partly because it can be compressed and restrict air flow. This is absolutely true and the HVAC technician said the same thing. If you can find an HVAC person that knows how to install the Superduct for a reasonable price then go for it. I decided to eat the lost efficiency of the flex. Also, it is a good idea to use oversize ducts of whatever you use. This allows the air to flow at a lower velocity, which quiets it. This applies to both supplies and returns, which are equally capable of transmitting sound throughout the house.

Using the existing vent in your control room space could be a bad idea, escpecially if it is basically just a hole in the main trunk (a.k.a. plenum) as is commonly done in basements. You need distance between the plenum and the outlet if you want to quiet the flow.

As Shaward said, it is best to do as much planning as possible. This is especially important if you hire people to do work. Unless you have people that have studio building experience, they will likely not be familiar with techniques discussed on this forum. This certainly goes for HVAC. The average HVAC tech will want to install sheet metal ducts of the shortest run possible, which would be great if you weren't building a studio. They will look at you funny when you describe what you want, but stick to your guns.

[knightfly]

All good advice, especially the "stick to your guns" part - you'll find that virtually NO one in the building trades (unless you get VERY lucky) will have ANY idea of the concepts that make a room quiet (and still breathable) - so you need to learn enough about these to educate your contractor/laborers BEFORE they screw up your dream.

Ducts MUST be separate for each room, with at least two 90 degree bends; if they are metal, they MUST be damped with absorptive linings or they will make noise. Corners (at least) need to be absorbed/damped to smooth out air flow; turbulent air makes more noise.

Noise from moving air is roughly proportional to the 4th or 5th POWER of the velocity; so larger ducts will allow the same cubic VOLUME of air to flow with a BUNCH less noise, by lowering the VELOCITY.

Don't oversize the system; you want it to run with a long enough cycle time to allow dehumidification, or you'll end up with mold problems.

Don't drop cold air into the room between you and your speakers, unless you like wierd, unexplainable flanging effects - the speed of sound in air is dependent on temperature.

DO isolate air handler from structure, and use expansion joints if necessary to isolate duct runs.

DON't use a single run with two drops into two adjacent rooms, or you might as well just leave the doors open. Instead, separate the runs from air handler to/from each room, each run with at least 2 90 degree bends.

A lot of this I've picked up from Rod in the last couple years, some from other sources; bottom line is, I don't know squat about HVAC either but I still know more about how NOT to do it than your local contractor, and now so do you... Steve

[sharward]

. . . I don't know squat about HVAC either but I still know more about how NOT to do it than your local contractor, and now so do you...

Classic!!

[camistan]

A heartfelt "thank you" for the replies I have recieved so far. I will take the info and use it accordingly. You are all on target for the feeling that most HVAC guys will not be aware of what needs to be done for ventilation in a recording studio. I plan to take the suggestions and info on this site along with any expertise the HVAC person I select has, and try to make this phase of my studio construction successful. As I said, since no framing has been done yet, it's a lot easier to get around and install duct lines now rather than later. I plan on making a detailed construction "book" of my studio construction from "nothing to final completion taking plenty of pics. I'll be getting the ol' "red eye" from reading so much info on this site as I'm sure many reading this post have. By the way, if you hear a loud "BOOM-BANG", that's my wife starting up her "hurry up and finish the basement " jets. I'm in "turtle mode" taking my time to make sure things are done right, but since there are other rooms in the basement besides my "little ol' studio", her jets are firin' RED HOT. I've got my "turtle shell" in full effect when her jets revv up though. BOOM!-BANG...oh oh...did you hear that?
Thanx

[sharward]

"BOOM-BANG", that's my wife starting up her "hurry up and finish the basement" jets. I'm in "turtle mode" taking my time to make sure things are done right, but since there are other rooms in the basement besides my "little ol' studio", her jets are firin' RED HOT. I've got my "turtle shell" in full effect when her jets revv up though. BOOM!-BANG...oh oh...did you hear that?

I heard it! (Good one!)

When the jets get fired up, try to appeal to her with the following:

• I'm going as fast as possible. Starting later actually means ending sooner and saving money, since I'm avoiding mistakes on paper rather than with expensive building materials.

Turtles are cool.

[Deluks]

It sounds like you've got the basics down, particularly the fact that when air goes into a sealed room, an equivalent amount of air must exit the room...

What happens if it doesn't, will it cause a major problem in a small room? (Mines 10x14ft)

I intend to have 1 inline fan pulling outside air in through 2 metres of ducting outside the room, going into another 2 metres of flat channel in between the stud wall.

The other end of the room will have a similar arrangement, except a regular window type extractor fan will be fitted in a self contained box, again outside the room.

This is my D.I.Y. approach to ventilation, but please warn me if I could potentially hyperventilate to death by not balancing the airflow

[sharward]

It sounds like you've got the basics down, particularly the fact that when air goes into a sealed room, an equivalent amount of air must exit the room...

What happens if it doesn't, will it cause a major problem in a small room? (Mines 10x14ft)

It's really scary -- you turn on the air, and within about two minutes, your room explodes into a million pieces, destroying every object and life form within a hundred yards!

Oh, wait, that's only in cartoons.

What really happens, I believe, is that the room becomes "pressurized" in a sense, so that no more air can enter the room. It becomes "full," so-to-speak, because there's no escape hatch for air to move back into the system. In theory, the same amount of air coming in has to go out the other side in order to be effective.

In a house, where ducts feed into small rooms that can be closed off, the air usually sweeps around (and mostly underneath) the door... Although the room is generally more comfortable when the door is left open so that air can flow in (through the duct) and then back out (towards the return).

With a room that's been very well designed for isolatuion (i.e., pretty much air tight), the "around/under the door" thing doesn't work.

I intend to have 1 inline fan pulling outside air in through 2 metres of ducting outside the room, going into another 2 metres of flat channel in between the stud wall.

The other end of the room will have a similar arrangement, except a regular window type extractor fan will be fitted in a self contained box, again outside the room.

This is my D.I.Y. approach to ventilation, but please warn me if I could potentially hyperventilate to death by not balancing the airflow

I'm not sure... That seems like it would get air moving through the room, but it won't condition (cool) it. You'll probably get overheated in there, in spite of the windchill effect, unless you dedicate a new system or or tie into your existing HVAC somehow.

[Sword9]

When you try to open your door, you'll have an effect similar to trying to open a car door underwater.

[Deluks]

[quote="sharward]I'm not sure... That seems like it would get air moving through the room, but it won't condition (cool) it. You'll probably get overheated in there, in spite of the windchill effect, unless you dedicate a new system or or tie into your existing HVAC somehow.[/quote]

Heat isn't really a problem in England, we have brief hot spells in the Summer but most of the year it's pretty mild. The fact that I'll be working in a sealed box surrounded by rockwool on all sides does worry me though, especially with a drummer in there and you know how much heat they can produce
It'll be a case of suck-it-and-see, but with a minimal budget, I'm not gonna squander a quarter of it on a dedicated air-conditioning unit for what is essentially a 'jam-room'

I'll let y'all know if it works when I build the thing, (If I haven't exploded into a million pieces!)