New Posts  All Forums:Forum Nav:

New Home Build - HVAC Advice

post #1 of 29
6/21/10 at 11:41am
Thread Starter 
Hello,

We are in the process of building our custom home. We are not finishing the basement right away, but I have designed it have a HT in the future. My desire is to have something similar to Swithey's build (http://www.avsforum.com/avs-vb/showthread.php?t=620108) as our rooms are similar sizes (his being 14.5 x 17.5 and mine being 15'8" W x 18" L with 8'1" ceilings.

I have attached a copy of the basement layout. The walls with the vertical lines are load bearing walls so I can not change the current layout.
Just to give you an idea of what I am planning on doing, I was thinking of having speakers behind an AT screen of ~125" and 2 rows of seats with a riser. The screen would be on the north side of the theatre (if the top of the drawing is north) and having the equipment/server in the maintenance storage are near the mechanical room.

My big question is the HVAC. I am able to tell the HVAC guys what I want to do with regards to runs for the house so I am trying to get everyone's opinion. I live in Alberta and it gets as cold as -40 C and as hot as +40C. Sound isolation and sound proofing are my big concerns. I do not want sound to travel to the upstairs levels via ductwork. From what I have read, mostly from Dennis, is to tell the HVAC guys what temperature you would like it and what you want the sound of the air flow to be at certain points from the vents. I have a lot of time to plan the little details, but the big, unfixable things need to be addressed now. Please weigh in with any and all advice. Thank you.

 

Basement.pdf 393.9384765625k . file
Reply
Reply

AVS Top Picks

post #2 of 29
6/21/10 at 12:25pm
We have a couple of projects in your neck of the woods. How about that?

First, you want to be certain they keep the ceilings in the proposed space as clear of of stuff hanging below the joists as possible. Second, you want the system zoned so you can run the A/C for that room only, in the winter. Third, you want the ducts (supplies and returns) run to the space; but, not into the space at this time. Fourth, since the room hasn't been designed yet and you have no clue about the BTU cooling load (in the winter) you cannot tell them that; but, you can tell them to treat it as though it were a kitchen with a two hour duty and the kitchen is completly closed, sealed and air tight.

They will push back, btw, because they fully understand the impacts of what it is you are doing.
Reply
Reply
post #3 of 29
6/21/10 at 1:14pm
Quote:
Originally Posted by mikelaevlaev View Post

I was thinking of having speakers behind an AT screen of ~125" and 2 rows of seats with a riser.

Just a FYI that is a going to be tight but not impossible in an 18 ft room. You need to minimize the loss of room length on the screen wall by using quality in-wall speakers. You need to consider the style of chairs for the second row. Fully reclining Berkline style reclining seats require 6 1/2 feet of riser depth, more if you want some breathing room for the speakers at the rear of the room.
Reply
Reply
post #4 of 29
6/21/10 at 1:31pm
Thread Starter 
Quote:
Originally Posted by Dennis Erskine View Post

We have a couple of projects in your neck of the woods. How about that?

First, you want to be certain they keep the ceilings in the proposed space as clear of of stuff hanging below the joists as possible. Second, you want the system zoned so you can run the A/C for that room only, in the winter. Third, you want the ducts (supplies and returns) run to the space; but, not into the space at this time. Fourth, since the room hasn't been designed yet and you have no clue about the BTU cooling load (in the winter) you cannot tell them that; but, you can tell them to treat it as though it were a kitchen with a two hour duty and the kitchen is completly closed, sealed and air tight.

They will push back, btw, because they fully understand the impacts of what it is you are doing.

I imagine most of the stuff you are dealing with is in Calgary as it is the big center. I am 3 hours south in Medicine Hat.

Thanks for all the advice. I know I am in a spot a lot of people would envy so I don't want to screw it up. I've read too posts on AVS where people have spent small fortunes to re-route ducts and it's put a scare in me to do things right the first time.

When you say run to the space, but not into; how far away should it be? A foot or so?

Thanks
Reply
Reply
post #5 of 29
6/21/10 at 1:35pm
Thread Starter 
Quote:
Originally Posted by BIGmouthinDC View Post

Just a FYI that is a going to be tight but not impossible in an 18 ft room. You need to minimize the loss of room length on the screen wall by using quality in-wall speakers. You need to consider the style of chairs for the second row. Fully reclining Berkline style reclining seats require 6 1/2 feet of riser depth, more if you want some breathing room for the speakers at the rear of the room.

I realize it's going to be tight. It's still up in the air, but if space is too tight and it compromises audio quality then I have no problems going to a single row without a rise. I am sort of in a grey zone regarding 1 row or 2 with the length of my room. I can't recall the last time I have had more than 5 people over at my place to watch a movie, but I imagine that would change when I build the HT. Still lots of time to decide, though. Thanks for the advice, Bigmouth.
Reply
Reply
post #6 of 29
6/21/10 at 4:19pm
I am most interested in this thread because your room size is similar to mine and this is the area I need the most help with right now. Like you I don't want to screw it up and have to redo later.

Dennis - I can't say it enough that I am glad that you are a member of this forum. Thanks you.
Reply
Reply
post #7 of 29
6/21/10 at 4:36pm
If I build a house again HVAC will be a major, major point of interest/design.

This House for example is very special.

It is completely sealed (all doors, windows etc) and has a very special fresh air exchange system - basically the ambient temp is maintained year round in quiet, peaceful harmony. This house in particular has been run over by all sorts of Academics (Cambridge University for example) for what it achieved, its quite special from what I understand

Something to have a think about....I am a bit partiular about air quality
Reply
Reply
post #8 of 29
6/21/10 at 4:38pm
Quote:
When you say run to the space, but not into; how far away should it be? A foot or so?

Right up to the framing.
Reply
Reply
post #9 of 29
6/21/10 at 5:10pm
Quote:
Originally Posted by Dennis Erskine View Post

Right up to the framing.


Do you do the HVAC outside the home theater room before framing or after? Or does it even matter due to that portion of the ducts will be up in the ceiling joists?
Reply
Reply
post #10 of 29
6/21/10 at 8:02pm
I plan the room so the diffusors (registers) do not penetrate the drywall unless behind a secondary barrier. While the ducts could enter the secondary area from above, they could also enter from the wall. If the ducts are brought to the space; but, not in the space, the flexibility with respect to where the supplies/returns are placed exists without the need to redo previously paid for work. Until you have designed your space, how would you know where they would be placed and how you'd route the ducts to those locations?
Reply
Reply
post #11 of 29
6/21/10 at 11:18pm
Is the foundation poured already? Like BIG said, space is tight, better goes 24' long and 16' wide if you could. Also, do 9' ceiling if it is not too late. What is up with the unexcavated space there? That is a perfect space for a very nice size home theater.

As far as HVAC goes, I have to deal with mine be that relocating one main trunk from center to the side wall. So, my advice would be,
1. Don't run two main trunk together in the center of the basement, you will have a huge bulk head that you need to frame soffit to box them in
2. Use flex duct cross the theater space in joists
3. Run every duct in the joist cavity
4. Plan ahead where you want your basement (including theater room) supply and return vents go and have the HVAC guy pre-install take-off fittings so you don't end up with having to cut holes on main trunks later.
5. Install duct liner in main trunks
6. Do a dual zones if possible
7. Put the HVAC main unit and hot water boiler somewhere near the corner so you don't wast space.

Another non-HVAC but related point, all the pipes (gas, cold & hot water and waste water) should run as clean as possible, you do not want to deal a lot of obtrude pipes here and there, a lot of headache dealing with those pipes when you finish basement, framing is more challenging.
Reply
Reply
post #12 of 29
6/22/10 at 5:22am
Quote:
Originally Posted by theWalkinator View Post

What is up with the unexcavated space there?

I'm betting a garage
Reply
Reply
post #13 of 29
6/22/10 at 8:47am
Quote:
Originally Posted by BIGmouthinDC View Post

I'm betting a garage

Most likely.

Although there is always the option for a pre-cast concrete floor in the garage. I will absolutely be doing this in my next house. The theater will be going in under the garage.
Reply
Reply
post #14 of 29
6/22/10 at 8:53am
In my house, the builder did not evacuate the space under the family room (which is next to the garage) which is 23x15', would be a nice theater space, but they just poured concrete slab and is a step down from main floor, the room is always colder than other rooms in the house and the floor is always cold, especially in the winter and no one really want to stay in that room. I am thinking to put dricore subfloor over existing engineered hardwood floor after this basement project is done.
Reply
Reply
post #15 of 29
6/22/10 at 11:34am
Thread Starter 
Quote:
Originally Posted by theWalkinator View Post

Is the foundation poured already? Like BIG said, space is tight, better goes 24' long and 16' wide if you could. Also, do 9' ceiling if it is not too late. What is up with the unexcavated space there? That is a perfect space for a very nice size home theater.

The wall at the back of the current room is a load bearing wall so there is nothing that can be done about the size of the room. We looked at 9 foot ceilings and I know it would be great, but the builder was going to charge us quite a bit more to do it. I am content with the current dimensions.

Like Big guessed, the unexcavated space is the garage. It's a side entrance garage from a private lane.

Thanks for all the advice. I am really new to home construction world and it's been a huge learning curve.
Reply
Reply
post #16 of 29
8/18/10 at 12:06pm
Thread Starter 
Hello.

2 months later and the tin bashers are finally doing their work. I made them a list saying my priorities were to isolate sound from the rest of the house, prevent any sound from ventilation system, and to keep the room cool when the projector is going as the room will be sealed tight.

I can't zone the furnace as they had already ordered one. All duct work in the HT will be between the floor joists so I won't have to build any soffits which is a bonus. I asked them to put plenty of baffles and turns after entering and exiting the room to diffuse the sound. I asked him to use flex ducting for any ductwork above the ceiling. He said that flex ducting would not move the air out of the room so he said he won't use it. He said that he would have to be called back to fix the room after it's all done. So we may have to compromise here. I will ensure that the duct is lined with acoustic insulation to decrease as much noise going out as possible.

I told him to put the supply near the front of the room and near the bottom of the wall. I told him to put the return near the projector at the back of the room.

I also told him not to put the end of the duct right into the room and to end it at the frame.

It didn't seem like he understood the scope of the project, but we will see how it turns out. I think it won't be 100%, but it will be pretty good.

I'll post some pics later tonight.
Reply
Reply
post #17 of 29
8/18/10 at 7:28pm
Did a mechanical engineer design the system? Did they show you a heat load calc? Most hvac shops will have no idea
Reply
Reply
post #18 of 29
8/18/10 at 7:31pm
Flex duct will move the air you just have to make it bigger
Reply
Reply
post #19 of 29
8/18/10 at 7:49pm
The more I think about this I just don't think you can cool that room with out a zone system or a mini split.Maybe Dennis or BIGmouthinDC will chip in cause they know better than me
Reply
Reply
post #20 of 29
8/18/10 at 9:23pm
Flex duct even pulled out has double the resistance of ridged pipe per ft of run. The penalty for excessive use with regards to air flow is considerable.
Reply
Reply
post #21 of 29
8/19/10 at 7:50am
Thread Starter 
I think no matter what this HVAC does or doesn't do I am going to have to tweek it myself later on. I think the room will always be on the colder side since it is in the basement and basements stay cold in my part of the world. My main worry is sound traveling to the kitchen. I don't think the HVAC guy has ever built a house with a dedicated theatre so I have a feeling it's going to require some work later when it's time to finish the basement. I wish the Pro Theatre deal was happening when I designed the place. Live and learn.
Reply
Reply
post #22 of 29
8/19/10 at 12:23pm
He said that flex ducting would not move the air out of the room so he said he won't use it. He said that he would have to be called back to fix the room after it's all done. So we may have to compromise here.


This is exactly what I have heard. I have had two different HVAC guys look at my basement and future home theater area and both disrespected the flexible acoustic duct, both giving stats on the inefficiency of the stuff etc.

One of the guys is my cousin, and he is already familiar with my various crazy ideas, so I can probably talk him into the flexible stuff, I just have to wear him down.
Reply
Reply
post #23 of 29
8/19/10 at 12:44pm
Regardless of the efficiency, or lack thereof, of any ducting method, one must go back to the original objective ... reduction of sound transfer. Therefore, you may care to look at an insulated duct board or lined metal ducts.

In this area, if you ask to use something other than insulated flex duct, they tell you to take a hike and call someone else. It's a geographic thing as well.

Quote:


He said that flex ducting would not move the air out of the room so he said he won't use it. He said that he would have to be called back to fix the room after it's all done. So we may have to compromise here.

Anyone who threatened me like that wouldn't get within a 100' of my home much less be allowed to work on it.
Reply
Reply
post #24 of 29
8/19/10 at 1:29pm
I love the way HVAC contractors (as well as other services) strong arm clients when it comes to home theater build criteria. I suspect it's typically because they don't understand what you want, don't want to learn it and don't want to deal with it so they tell you it won't work.

I'm speaking from experience since I went through the same thing when we built our home theater. Several service contractors told me they wouldn't do what I wanted done and said I didn't know what I was doing. I held my ground on the HVAC and electrical issues I was dealing with. THIS IS WHAT I WANT, CAN YOU DO THIS? It was very frustrating and somewhat exasperating. I wish I would have found someone like Dennis Erskine back then.

The bottom line is that it's your house and your hard earned money so find a contractor that will do it the way you want it done.
Reply
Reply
post #25 of 29
8/19/10 at 1:34pm
Thread Starter 
If it was me doing the contracting then I would have more of a voice, but my builder uses only certain vendors and i don't think I have much choice in the matter. I don't have enough construction know-how to come back at them with anything besides what I have learned through the build so far and things I've learned on AVS.
Reply
Reply
post #26 of 29
8/19/10 at 1:37pm
Wait a minute. This is a "custom home", yes? You are paying the bills (ie, you are the contractor's employer). You will be living in the house when it is done, or his he living in the house? You might want point that out to him.

Alternatively, get a professional on your side. You wouldn't go to court without an attorney would you?
Reply
Reply
post #27 of 29
8/19/10 at 2:13pm
Thread Starter 
It's true. I just need to be more assertive. I'll at least have them line with duct lining.
Reply
Reply
post #28 of 29
8/19/10 at 2:15pm
Thread Starter 
Also, the only home theatre people we have in our town are not "true" home theatre professionals, but more-so equipment salesmen and installers. The local guy didn't know much about room treatments when I asked him so I couldn't trust him.
Reply
Reply
post #29 of 29
8/19/10 at 2:36pm
There are not many "pros" in this field in the country ... they are used to dealing with issues by phone.
Reply
Reply
New Posts  All Forums:Forum Nav:
  Return Home

AVS Top Picks