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HVAC Registers - Page 2

post #31 of 53
I thought the one I selected was adjustable to provide some directionality. I guess I'll keep looking around...
post #32 of 53
EH Price also make these. They are directional with different core options. I could have the air coming down, or out, or whatever I choose.

Has anybody installed such a beast?

http://www.price-hvac.com/catalog/C_...eRequest=SMD_1


post #33 of 53
In theory those should work OK, jsut keep the face velocity down as Dennis directed.
post #34 of 53
Is there a decent place to buy the Hart and Cooley registers online?
post #35 of 53
Reviving this old thread with perhaps a stupid question....how do you verify a specified NC rating once a home theater is completed? I've spec'd an NC rating to my HVAC engineer and he's asking how do we know the requirements are met. Reading through all these threads I've made it clear the other best practices wrt velocity, damper placement, diffuser placement, etc.
post #36 of 53
Use a dB meter to measure how loud it is, then compare it to the predicted measurement furnished by your engineer.

Tim
post #37 of 53
After going through this process.............................here's my take,.............

Giving the HVAC contractor's NC-20 specs I received quite the puzzled look...............it's not like these contractors construct systems with extensive levels of sound abatement like I was suggesting. What we did lock on together was air velocities, volume of individual rooms with specific heating/cooling heating requirements and additional measures to insure sound from air exchanger would not enter the dedicated room.

Was helpful I had personally known owner of the Lennox dealership I contracted......... so putting our minds together we were able to come up with some solid solutions. My build used a Harmony 4-zone system with one branch soundproofed and modified way beyond most installs. The real issue was getting all 4 zones balanced to some degree with spec-ed equipment.

Make sure your air exchanger is variable............or at least 2 staged. Yeah, you pay more.........but well worth the significant increase in $$$$.

Tim, has alluded to the ultimate test ie. using an SPL meter for measuring final results...........................I wouldn't worry too much about it if you've done your homework. In my application, my projector reads louder on the SPL meter than my supply/return ducts. With my projector being extremely quiet in low lamp mode...................no issue..................besides, after a few months enjoying your room..........the tinnitus will have a higher noise floor than your HVAC system!!! biggrin.gif
post #38 of 53
To Learn about NC and NR go to this link
http://www.engineeringtoolbox.com/nr-noise-rating-d_60.html
Near the top it mentions NC and has a link for that as well.

also note that NR goes an octave lower than NC.
post #39 of 53
Quote:
Originally Posted by dlbeck View Post

Reviving this old thread with perhaps a stupid question....how do you verify a specified NC rating once a home theater is completed? I've spec'd an NC rating to my HVAC engineer and he's asking how do we know the requirements are met. Reading through all these threads I've made it clear the other best practices wrt velocity, damper placement, diffuser placement, etc.

Most of the commercial firms I talked to wanted to consult with an acoustic engineer / acoustician. FWIW, that's not EG. What you see posted for free on AVS is essentially what you get with an EG Signature Plan for HVAC. Their HVAC "design" is actually a set of requirements intended for you, your HVAC engineer, or a 3rd party acoustician to design against. An acoustician will have the equipment to measure noise level, know how to conduct the tests, and interpret the results. It would be his professional call if the system met the noise level requirements.

Prices can be high, though. In my area, established firms with a decent portfolio charged ~ $150/hr minimum. One group had a retainer fee of $5000 just to start, and time to work up a price estimate / proposal would come out of that $5k retainer. The best group I found was KYDG out of California. They do real engineering and can provide detailed plans for HVAC. But west coast price premium + real engineering + top of their game in HT design = pricing that is cost prohibitive for most.

So for practical purposes, most people just use the guidelines for FPM with the slotted bar type diffusors and hope for the best. The only person I've seen report a measured NC rating after their theater was built was Mike (Mike's Money Pit). Everyone else just gives some subjective opinion, which usually amounts to "good enough" in most cases. The 250 FPM is an ASHRAE (HVAC standards body) recommendation for auditoriums. They also have recommendations for fresh air exchanges, so don't forget to take that into account. Also consider that you may need cooling in the HT during the winter when other parts need heating. Last, if you're doing a basement HT, I would consider a "whole house" dehumidifier. The AC will dehumidify, and they will try to sell you a 2 stage unit to help with humidity, but in a cool basement it's not always desirable to cool further just to dehumidify. It was a $1,000 option when I was building and I wish I had done it. I have portable unit down there now, but it isn't as efficient, quiet, or as transparent as a built in unit would have been.
post #40 of 53
Great post Rabident. Thanks. Any benefit from an HRV or ERV in this application? This theater is in the basement and I'm also incorporating the low ambient option on the AC.
post #41 of 53
just a data point on this discussion, I've had clients that popped for the Nailor linear bar grills, and the last batch I used where a little sloppy. I did some looking around and I've had good luck with these cheaper alternatives:

http://www.hvacquick.com/products.php/residential/Grilles-Registers/Bar-Linear-Grilles/Dayus-Shallow-Bar-Linear-Grilles#price

sloppy Nailors looks like the machine used to assemble the corners mushed up the corners a bit. I would have had my client send them back but he was anxious to get the theater completed.





Edited by BIGmouthinDC - 12/17/13 at 9:46am
post #42 of 53
Seems like ERV or HRV's aren't easily understood. I haven't been able to find much good info on incorporating them into the home theater and integrating them in a multi-zone HVAC. My concern is cooling the theater in the winter and keeping the relative humidity at 40-50%. Of course, keeping in mind the velocity and fresh air exchange requirements.
post #43 of 53
I am going to use one (an ERV that is). The manufacturer told me it was best installed with seperate supplies and returns (seperate to AC). You can integrate them (supplies and returns, but you can get "short circuit" problems. They tell me that running one improves the efficiency of the AC by up to 50%, but I dont know/cant explain how.

I found this article to be useful:

http://www.buildingscience.com/documents/insights/bsi-016-ventilation-top-ten-list
post #44 of 53
Quote:
Originally Posted by dlbeck View Post

Any benefit from an HRV or ERV in this application?

I bought a couple Broan ERVs from Newegg. They're better than nothing, but not perfect. They work reasonably well in the winter, but bring in too much humidity during summer. I think they claim 70% energy efficiency, but I doubt it's that good. The lack of efficiency causes the main HVAC to run more. It's also louder than my main HVAC system, making it somewhat of a tradeoff between noise pollution and air pollution. It would help if they were programmable, but they're not. They're meant to just run constantly, exchanging air for 20 min of every hour and filtering recirculated air for the other 40 min. This happens 24x7 regardless if anyone is in the room. No integration options either, so you can't set the Broan and the HVAC air handler run at the same time. If I had it to do over, I would look harder at different options. Bringing fresh air in is nice. Doing it efficiently makes sense. But the off the shelf systems are surprisingly limited in what they have to offer.
post #45 of 53
The Broan has a HEPA filter doesn't it? whilst a nice idea in theory it reduces efficiency big time as the force required to drive air through the filter is significant (compared to a non-HEPA)
post #46 of 53
Quote:
Originally Posted by Dennis Erskine View Post

You could use the soffits as a plenum.
They would need to be lined with duct liner.

Quote:
Originally Posted by Dennis Erskine View Post

Where code allows, it works fine and the technique of blocking the soffit internally to create supply and return plenum works well. As to velocity...the bigger noise problem is velocity at the diffusor, not within the duct itself.

This is the direction I took and works like a charm................

During construction, I had the HVAC contractor order a 36" X 6" Nailor diffusor but was not happy with the look......................at that point I decided to build my own due to the look I was after. Was it more cost effective...............NO! Blew up many pieces of Knotty Alder which I had spent long hours gluing together 1'' X 6" X 3ft pieces while routering the grooves................destroyed over $100 is raw wood just for experimentation. Finally, found a method that worked and found 1/2 grooves worked best while still holding structural integrity of Alder. The registers are extremely quiet.............hard to tell if air is even flowing. Have done many sound tests along with having large groups of people in room................room maintains a steady temperature of 70 F.

Will check with HVAC contractor what he did to replace fresh air in our HVAC system. We installed a 1200 cfm Wolf 27" vent hood which is wired to a make-up air damper. That same damper is also hooked up to bathroom vents and vent I have in AV rack. I was concerned with maintaining air quality so I do know something was done for air replacement...............but I can't recall exactly what we agreed upon. I'll check.............for now, here are the register vents in theater room.............

4 return registers in two back row columns- front and back of each column


2 supply registers at front near screen
post #47 of 53
Quote:
Originally Posted by rabident View Post

If I had it to do over, I would look harder at different options. Bringing fresh air in is nice. Doing it efficiently makes sense. But the off the shelf systems are surprisingly limited in what they have to offer.

So I guess thats my question. What's the best way to bring in fresh/outside air without an ERV or HRV and get the fresh air exchanges that you need?

I have a meeting with the HVAC guys today so hopefully they have some good ideas as well but they don't have any experience with sealed up tight home theaters.

Thanks.
post #48 of 53
open a window outside the theater room and exchange air with the rest of the house.
post #49 of 53
Quote:
Originally Posted by dlbeck View Post

So I guess thats my question. What's the best way to bring in fresh/outside air without an ERV or HRV and get the fresh air exchanges that you need?

I have a meeting with the HVAC guys today so hopefully they have some good ideas as well but they don't have any experience with sealed up tight home theaters.

Thanks.

10" make-up damper attached to return hub which is also wired to all exhaust fans/vents
post #50 of 53
Quote:
Originally Posted by doublewing11 View Post

10" make-up damper attached to return hub which is also wired to all exhaust fans/vents

That's what my builder originally suggested, but it isn't perfect either. It doesn't solve the humidity problem in an otherwise cool basement. Pulling fresh air directly from outside would be worse in terms of injecting humidity into conditioned space vs using an ERV. It's also 0% efficient (no humidity or energy exchange between outgoing & incoming air).

It would be best to remote mount the exhaust blower. You need something to control when the exhaust vents turn on/off (temperature, timer, program, manual switch, etc). Then you also need the additional wiring & control to activate the main AC blower & open the make up air damper. Running the blower without cooling can create humidity problems on its own, without even factoring in outside air.

An ERV packages all that, and adds some degree of efficiency. The efficiency helps with the humidity problem, but not 100%. It also avoids circulating air over the wet HVAC coils from the prior cooling cycle (adding humidity back into the air). My main complaint with the Broan ERV is the lack of intelligence for turning exhaust on/off, and their lack of support for any 3rd part intelligent controllers. They're not necessarily a bad solution, but could be better. Not saying the 10" make up air duct is bad either, just that it has its own problems as well.

Another forum member was considering bringing fresh air in through a dehumidifier. The Ultra-Aire XT105H has a fresh air intake and a built in exterior damper. He would still need to exhaust the theater air outside to make room for the fresh air. It would solve the humidity problem, but is also 0% efficient. Ideal would be to combine products in a way so the ERV handled ventilation, then passed the fresh air to AC, then to de/humidifcation, and finally onto distribution. But that's complicated and not something I would want to try to cobble together.
Edited by rabident - 12/18/13 at 11:04am
post #51 of 53
Quote:
Originally Posted by rabident View Post

That's what my builder originally suggested, but it isn't perfect either. It doesn't solve the humidity problem in an otherwise cool basement. Pulling fresh air directly from outside would be worse in terms of injecting humidity into conditioned space vs using an ERV. It's also 0% efficient (no humidity or energy exchange between outgoing & incoming air).

It would be best to remote mount the exhaust blower. You need something to control when the exhaust vents turn on/off (temperature, timer, program, manual switch, etc). Then you also need the additional wiring & control to activate the main AC blower & open the make up air damper. Running the blower without cooling can create humidity problems on its own, without even factoring in outside air.

An ERV packages all that, and adds some degree of efficiency. The efficiency helps with the humidity problem, but not 100%. It also avoids circulating air over the wet HVAC coils from the prior cooling cycle (adding humidity back into the air). My main complaint with the Broan ERV is the lack of intelligence for turning exhaust on/off, and their lack of support for any 3rd part intelligent controllers. They're not necessarily a bad solution, but could be better. Not saying the 10" make up air duct is bad either, just that it has its own problems as well.

Another forum member was considering bringing fresh air in through a dehumidifier. The Ultra-Aire XT105H has a fresh air intake and a built in exterior damper. He would still need to exhaust the theater air outside to make room for the fresh air. It would solve the humidity problem, but is also 0% efficient. Ideal would be to combine products in a way so the ERV handled ventilation, then passed the fresh air to AC, then to de/humidifcation, and finally onto distribution. But that's complicated and not something I would want to try to cobble together.


There is a huge difference in regard to HVAC needs in South and Pacific Northwest.........

The suggested path for an ERV package here in my location is like taking a sledgehammer to combat a flea.......................matter of fact, for the most part, injecting moisture into homes in Pacific Northwest can be as important/needed than visa versa..................yeah, makes no sense in monsoon country, but it is...........what it is.

With energy ratings as such............and with homes now sealed tighter than a drum..............bringing outside filtered air in home from any source is extremely helpful considering most home owners never think about negative pressure and its effects. Think about it......................go to great lengths to achieve Energy Star Certification yet with one flipped switch on a 1200 cfm blower can ruin and throw all efforts out the window. Speaking of windows.................."Big" has a good idea about opening up a window............though I do see through his sarcasm. We're all making this replacement air/quality issue bigger and more complicated than it has to be........................JMHO
Edited by doublewing11 - 12/18/13 at 4:46pm
post #52 of 53
Quote:
Originally Posted by doublewing11 View Post

There is a huge difference in regard to HVAC needs in South and Pacific Northwest.........

The suggested path for an ERV package here in my location is like taking a sledgehammer to combat a flea.......................matter of fact, for the most part, injecting moisture into homes in Pacific Northwest can be as important/needed than visa versa..................yeah, makes no sense in monsoon country, but it is...........what it is.

With energy ratings as such............and with homes now sealed tighter than a drum..............bringing outside filtered air in home from any source is extremely helpful considering most home owners never think about negative pressure and its effects. Think about it......................go to great lengths to achieve Energy Star Certification yet with one flipped switch on a 1200 cfm blower can ruin and throw all efforts out the window. Speaking of windows.................."Big" has a good idea about opening up a window............though I do see through his sarcasm. We're all making this replacement air/quality issue bigger and more complicated than it has to be........................JMHO

Yes I agree. I just met with the HVAC guys and they are going to put together a plan tonight. Thanks for all the input....it was beneficial during my conversation today.
post #53 of 53
Quote:
Originally Posted by doublewing11 View Post

There is a huge difference in regard to HVAC needs in South and Pacific Northwest.........

Right, and dlbeck's profile says he is in Des Moines, IA. Wikipedia lists the climate as hot, humid summers. What worked for you, apparently in an arid climate, isn't necessarily going to work well for him.
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