Marc's Patio & Garage Studio

Well, I've been working on the HVAC thing, looking at options, talked twice to my HVAC guy, showed him all the posts and I'm still in the same position. 1st Thank you Rod amd Sharward for pointing/posting all this out, the info is valuable. I am going to hook my room up to my house HVAC system. All air ventilation/exchange will be through house. I'll have a mechanical damper (manually controlled) on the supply duct, and a switch to turn my HVAC variable speed fan to on while in the room. No thermostat zone control set up, the house gets it's temperature and I get a damper. I've decided to keep this short, been writing a post for a day now. I’ve read or in fact followed recent threads over the past months about HVAC & ventilation and DO NOT WANT my thread to "deteriorate" because… I’m going to stay on my plan with some revision; I’m going to break code for ventilation with reasons (mostly short and long term financial). I mean no offence to anyone. I may change the ventilation later. Big reason is cost short and long term. A separate HVAC/ventilation system for just my room will cost to much money right now maybe down the road. This would be over $3,000. Adding in fresh air take to my current HVAC is not possible. I would need a bigger air handler, mine is 3.5 ton now, I would need a 4.5 ton to handle conditioning the extra humid air coming in. Average AM humidity hear is 89% year round, average PM humidity is 60%. This would turn into a $6,000 to $10,000 cost. I had written a longer post with more reasons but bottom line is I know I am going to break code, I do not think I will suffocate, I think exchanging air with my 40 year old house will be good enough, arguable not healthy enough. To some up my HVAC guys opinion on all this, he's seen to many buildings in Florida that have ERV, HRV or other fresh air ventilation systems that have the vents plugged by the owners to stop the humid hot air coming in, in order to save on cooling costs. Marc

Marc, I have no problem with this............ I know sometimes I seem to come down hard on people- but it's mostly when they get defensive - and ESPECIALLY if in the process they try to defend themselves by presenting that I don't have a clue....... I would point out is that your conrtractor still doesn't seem to get it He can't compare this to what he sees being done at residential homes across Florida..... I believe him- and if you wanted to do this to your home I wouldn't have a problem with it - heck it isn't required for your home in the first place,........ The issue is with a room that has no other manner of gaining fresh air...... not with a home that will get it anyway......... He is also wrong on how much load this would add to your system. If you followed my suggestion and provided (directly into the room) just the air you needed for that room (or rooms as the case may be) (which can't cost more than a couple of hundred dollars at the worst) you would add 0.07 tons of load. He must be think of adding it to the entire house. You say you'll only use it yourself - so playing safe - adding fresh air (15 cfm per person) for those times that you and a buddy are working a mix - that would be 30 cfm........ which would be (I don't know exactly where in Florida you are - so I am using the Miami figures here) as follows: this is 2 simple 4" pipes - one with a tiny fan -one with a barometric damper - running from avoe your room to the outside air through the roof of your building. My math, which comes from The ASHRAE Journal - entitled: Dehumidification and Cooling Loads From Ventilation Air is as follows: The VLI (Ventilation Load Index) for Miami FL is 17.8 latent and 2.7 sensible Ton per year per CFM...... which adds up to .07 tons of added cooling (0.070205479 top be exact). I don't know exactly where you're from - so I ran the Miami numbers - which are on the high side......... only Key West has higher numbers. That's 20.5 year tons of cooling (per cfm) * 30 CFM = 615 added tons of cooling pr year / 8760 hours per year = 0.070205479 per hour of actual added load. I have to believe your system could handle that seeing as it's handling all of the added sensible load from your gear, lighting and body - plus the ........ latent load from your body........ already. Now- having said that - my responsibility is to educate - once I have done that and that I know that the people really got it - and they are making an informed descision - then I let it go......... If you choose (after knowing everything) - to take a chance - at least I can rest assured that your descision wasn't based on bull..... but while understanding the facts.... We all take chances in life - every time we walk along a street- or drive a car........ I've taken my share - hell I've walked on the top of unbraced 2x4 walls 30 feet in the air while laying out floor joist.......... backwards......... I wouldn't let my men do it - but it was the fastest way I could get the job done- I made an educated descision - and decided to take my chances....... I wouldn't do it today - but today isn't yesterday........ So do what you have to do......... you'll have no problems with me....... Sincerely, Rod

Rod, Again thank-you. And a note to others, Rod and I have PM'd on this briefly. I am not trying to disrespect Rod (or Sharward) at all, I'm just trying to deal with this the best I and my finances will allow with out stepping on anyone's toes or come off on this forum as an A-Hole.

He is also wrong on how much load this would add to your system. If you followed my suggestion and provided (directly into the room) just the air you needed for that room (or rooms as the case may be) (which can't cost more than a couple of hundred dollars at the worst) you would add 0.07 tons of load.

Well now you got me swaying my thinking again. :D

He must be think of adding it to the entire house.

Well yes... the room can not go without cooling so it has to be hooked up to the existing central air OR have it's own HVAC cooling system. If the room (as planned) is hooked up to the existing central air and the room is vented to the outside then all the conditioned air and fresh air with 89% humidity would get mixed via my room... essentially adding the fresh humid air to the house.

You say you'll only use it yourself - so playing safe - adding fresh air (15 cfm per person) for those times that you and a buddy are working a mix - that would be 30 cfm........ which would be (I don't know exactly where in Florida you are - so I am using the Miami figures here) as follows:

Yes playing safe numbers are a good idea for 2 people and also sure my 4 year old boy will want to spend time with me in room. Playing safe with Miami numbers is good also, my exact location is right beside Kennedy Space Center, due East of Orlando close to Atlantic ocean. On "maps of numbers" Daytona or Melbourne Fl are the closet for climate averages, Miami is one climate zone higher then Cocoa, the town I live in.

this is 2 simple 4" pipes - one with a tiny fan -one with a barometric damper - running from avoe your room to the outside air through the roof of your building.

That is simple, but it would bring in that humid air and then mix it into entire house. I could easily afford this and if I do, it may be worth while to add a mechanically controlled straight off and on damper to the intake in order to keep the pressure in the room while not in use so that conditioned air does not exit this duct.

The VLI (Ventilation Load Index) for Miami FL is 17.8 latent and 2.7 sensible Ton per year per CFM...... which adds up to .07 tons of added cooling (0.070205479 top be exact).

.07 tons is not what my HVAC guy said, he said it would add 1 ton. Got to run this past him again SO, I'm now not done with this decision. I have to dive into the numbers and do more research. Actually I guess I have to run this past other HVAC guys locally to double check what my friend/neighbor/HVAC guy is saying. Marc

It is physically impossible for 30cfm of outside air to add a ton of cooling load to a home....... Heck - your bathroom exhaust is probably 50 to 75 cfm by itself - and a house built in the 1960's were not built that tight (in the 70's we used to deliberately construct homes so that they would receive at least 1 complete air exchange per hour). By todays standards- extremely tight homes are around ...6 or less.......... well kept older homes 1.0...... somewhat loose older homes 2 to 3...... Now lets put that into perspective........ .6 represents 6/10 of a complete house fresh air exchange PER HOUR....... in a 1,000 s.f. home with 8' ceilings - that is air infiltration of 4,800 cubic feet of air PER HOUR..... that's 80 cfm......... and that's in a new tight home built today in the 2000's. Let's suppose your house, that was built in the 1960's - had an exchange rate of 1.5..... which would be pretty reasonable if it's in decent shape..... if it was just 1,000 s.f with 8'ceilings, that would be complete air exchange of 12,000 cfh..... or 200 cfm....... Now let's look at this calmly for a minute- because that looks like an awful lot of air - I mean you'd feel a wind blowing on you right? Actually - if you take a 24 x 42 ranch - slab on grade........ that's 132 linear feet of outside wall------ and with just a 1/16" crack at the base for air to filter through - which is much better than average from a construction point of view..... that's the equivilent of a hole in the wall 99 inches square.......... that's almost 10 x 10 clear opening - AND THAT'S JUST THE SILL........ if you moved 200 cfm through that it would hardly feel like a soft breath.... Add to that the air infiltration straight though walls- through small cracks around the edges of windows - from opening and walking in and out through doors........ and you should quickly come to see that these numbers are not far off...... Doors - now there's a biggie...... you suddenly open up a hole in the side of your house that is 20.01 s.f. in area - and picture the air that can move in a minute through that baby........ So now you're talking about moving the air at a rate of 200 cfm and having to cool that..... let's see - at one ton per 30 cfm that would be 6.67 tons for 200 cfm. ...... and we haven't begun to talk about passive solar gain - cooking heat - showers - cleaning clothes - never mind the BTU output from people themselves- having to dehumidify the moisture from their breathing...... having to cool off the heat produced by their bodies in general........... for crying out load- by time we were done you'd be installing 10 ton units for old 1,000 s.f. homes........ Sorry - taint being done......... even when remodeling older properties - you have perhaps a ton and a 1/2 of cooling for 1,000 s.f. - maybe 2 tons if the contractor really wants to over size it............ Yes - have him look at it again.......

Hey Marc, Don't be silly -- I'm not offended/disrespected. :-) But I do think you're making a mistake though... :roll: ...I have to be honest. Although, you're in the very best of hands with Rod here, so obviously I defer to him. If I were you, I would at least consider doing the HRV system, and also pre-wire and pre-plumb for a mini split that you can opt to install later if you wish. Up until now, your being quasi-code compliant (having a permit for uninhabitable space was due to the lame septic tank certification requirement, which we can reasonably see is bureaucratic nonsense in the context of your project. That was and is not a safety issue. However, this ventilation requirement is a safety issue. Have you seen eruss' "air duct silencer" thread (now locked) and his subsequent "Ventilation and code" thread? The above referenced threads give some context to Rod's remark about people getting defensive, but they also contain a wealth of information about ventilation. Many thanks to Rod for his generosity of time on this subject! I'm very close to implementing my ventilation plan myself, so I will obviously be doing a lot of reading and rereading of his words and (sorry Rod!) I'll definitely run the details by Rod before I begin to buy/build it. 8) --Keith :mrgreen:

guitardad72 wrote:

Well yes... the room can not go without cooling so it has to be hooked up to the existing central air OR have it's own HVAC cooling system. If the room (as planned) is hooked up to the existing central air and the room is vented to the outside then all the conditioned air and fresh air with 89% humidity would get mixed via my room... essentially adding the fresh humid air to the house.

Marc...... like I said- tie a 4" directly to the 12" supply entering your room - install a fan capable of 30 cfm That mixes with the air in the12" supply - so if you were feeding 100 cfm from the supply - it would now be 130 cfm -= with 23% of that being fresh air............. now install another 4" - tie it into your return - and duct outside - install a barometric damper on it - set to dump 30 cfm when the room pressurizes......... Now you're back to 100 cfm returning to the unit - of which - worse case - 77% is fresh air- whic means you have to dehumidify 23.1 cfm of un-blended air............... Heck- you bring morethan that into the house - for your system to deal with - if you even THINK about opening a door......... Please show him the numbers, then him I would love to see his calculations if he woud be kind enough to let me. Sincerely Rod

Wouldn't an HRV connected in the same fashion be more efficient in the long term, Rod? Of course, my understanding is that HRVs tend to be much more efficient in preserving heat on cold days, rather than preserving cool on hot days... :roll: --Keith :mrgreen:

sharward wrote:

Wouldn't an HRV connected in the same fashion be more efficient in the long term, Rod? Of course, my understanding is that HRVs tend to be much more efficient in preserving heat on cold days, rather than preserving cool on hot days... :roll: --Keith :mrgreen:

Not when you're talking about this small a quanity it wouldn't......... and I believe that for cooling loads it's an ERV that you us - they have dissacant dehumidifiers in them...... But still not cost effective for this - they are intended as whole house systems..... or at least for large zones with much larger amounts of fresh air than we're speaking ofhere. Rod

I did a gig last night, have 6 more in the next 3 days. Couldn't help but think about this all last night. I wanted a real life example of 30 CFM and Rod clearly posted this on my thread. THANK_YOU I'm going to add a fresh air intake to my room. but still wonder if I open every my door 15 to 30 mins to have a smoke outside, only close inner door when needed (remember I got a week outer/exterior door with window that does not open but made this choice for natural light and to break sound iso on purpose) combined with just HVAC from house if I'd be fine... besides the point I realize and I don't plan to be a smoker forever, so... just had to say it but I am still going to add the fresh air intake. Got more research to do. Only thing that's really got me is how a fan set to 30CFM is going to kick back pressure of my air handlers fan and not let air out (go backwards) of a fresh air supply duct connected to my supply HVAC duct for room. My air handler is 40,000 BTUH, 3.5 tons. The fan is really strong. My HVAC guy suggested it's pushing 600 cfm BUT I could be totally wrong on what he said/can't remember/I think he was guesing... I just know it blows real hard and then I'd have to figure out the cfm by counting my registers in my house, so on and so forth. Every register in the house moves enough air to blow dry hair... I got to figure it out. OR is this really where the barometric damper on the return kicks in? My air handler model # TWE040E13FB2 but the closet model I can find info online is TWE040E13F. It has the name American Standard on it but it's really a Trane: http://www.trane.com/Residential/Produc ... Speed.aspx Sharward, I read this (quote below) the other night. ERV would be better in my case BUT reading the last line in the following quote (have not looked up other source for 3 opinions yet), Rod's words, knowing my current HVAC removes more than 5 gallons of water from my house per day (I keep a 5 gallon bucket under the drip and use it for watering plants) and the additional cost I think NO ERV.

ERVs are especially recommended in climates where cooling loads place strong demands on HVAC systems. However, keep in mind that ERVs are not dehumidifiers. They transfer moisture from the humid air stream (incoming outdoor air in the summer) to the exhaust air stream. But, the dessicant wheels used in many ERVs become saturated fairly quickly and the moisture transfer mechanism becomes less effective with successive hot, humid periods.

Source: http://www.toolbase.org/Technology-Inve ... entilators There is more good info on that site too: http://www.toolbase.org/TechInventory/t ... tailID=797 Go to run to the next gig, hopefully I'll have this all figured out by next week and will post a drawing for review with calculations. :roll: Marc

guitardad72 wrote:

I did a gig last night, have 6 more in the next 3 days.

Marc, congrats on the gigs........

guitardad72 wrote:

Only thing that's really got me is how a fan set to 30CFM is going to kick back pressure of my air handlers fan and not let air out (go backwards) of a fresh air supply duct connected to my supply HVAC duct for room. My air handler is 40,000 BTUH, 3.5 tons. The fan is really strong. My HVAC guy suggested it's pushing 600 cfm BUT I could be totally wrong on what he said/can't remember/I think he was guesing... I just know it blows real hard and then I'd have to figure out the cfm by counting my registers in my house, so on and so forth. Every register in the house moves enough air to blow dry hair... I got to figure it out. OR is this really where the barometric damper on the return kicks in?

You got it - that is why the barometric damper is required......... As I explained earlier - where I am suggesting to place this is NOT where I would normally put it........ but you don't have a whole lot of options here..... not without messing with the existing system - and then a whole slew of ploblems because there is no wat to for the fresh air t go just to that room - so it has to tie into the durct work off the trunk line to be dedicated for your room. The trick is this - how many cfm go to your room - what size is the duct feeding it? how many feet of duct? then I can calculate the static pressure - and spec a fan that will deliver 30 cfm at just above that static....... it has nothing to do with the cfm - the static pressure is everything....... for example- 12" round duct - doesn't develope 1" of static (back) pressure until you reach about 2300 cfm for 100' of pipe - At 400 cfm - the static pressure is only (the same 100') .039"wc. So if that were the case I would spec a fan capable of delivering what was needed...... example: Duct Fan FANTECH FR-100 - grainger price 184.00 Type Centrifugal, In-line Fits Duct Dia. (In.) 4 Inlet and Outlet Dia. (In.) 3 7/8 CFM @ 0.000-In. SP 122 CFM @ 0.200-In. SP 100 CFM @ 0.400-In. SP 78 CFM @ 0.600-In. SP 55 CFM @ 0.800-In. SP 15 Max. Inlet Temp. (Deg. F) 140 Voltage 115 Hz 60 Phase Single Max. Amps 0.18 Max. Wattage 19 Motor RPM 2900 Motor Enclosure Totally Enclosed Bearing Type Ball Housing Dia. (In.) 9 1/2 Length (In.) 9 5/8 Flange Width (In.) 7/8 Speed Control 4YC44 Housing Material Thermoplastic Mounting Position Horizontal or Vertical Agency Compliance C-UL-US Includes Mounting Bracket 2 each 2C905 Roof Cap BROAN 636 $15.06 1DGV1 Fan Speed Control,3 A DAYTON 1DGV1 $20.45 And then add to that the cost of 1 barometric damper - 1 balancing damper - and what? 30 feet of 4" round galvanized duct. sequence - verify existing air flow with Lo Flo Balometer prior to running or adjusting supply air fan. assume for this exercise that yu are getting 400 cfm. Install fan w/ balancing damper on load side of fan - and tie into system..... On low fan setting - (with barometric damper wide open) adjust damper until air flow is 430 cfm measure with Low Flo Balometer

Balancing Comment regaring balometers and air balancing in general: your HVAC buddy should either have one of these - or be able to borrow one - they are much more accurate than the small handheld electronic Anemometer. Generally the techs do not take enough point readings with an Anemometer to report actual conditions - and small variances can add up to fairly large decrepiancies in actual flow rates. The balometer is a one shot deal - if calibrated properly you can't get more accurate readings. they look like this: http://www.alnor.com/products/balometer-loflo.aspx where as the anemometer looks like this: http://www.omega.com/Green/pdf/AIRFLOW_MEAS_REF.pdf

Now adjust the barometric damper to dump 30 cfm with fan on low. This will be only partly open. After this - switch fan to meduim and high - test and verify actual air at the supply register......... the 30 cfm in low setting will satisfy 2 people- for each additional 15cfm in the higher settings - you can safely add another person...... the barometric will automatically open to allow the excess air flow to escape if using higher fan settings..... See how easy that is? Sincerely, Rod

PROGRESS: The screen wall for my patio got put in today. My drummer friend (who owed me a favor or two) installed it with my help for about $100 over the cost of materials. Total cost was $450, but he would have charged $750 if he did not owe me the favor and was not hungry for gigs :D PLUS he did a great job, appears to know screen and aluminim well and went the extra mile. I am not going to confirm that, I just want to be left with a completely positive feeiling about my buddy who is a subcontractor. This part of my build has nothing to do with sound isolation and did not have to meet any real code.... if he did do something wrong I do not want to know. I'll get pics of the screen wall tomorrow when it's daylight again. Does it ever make my (new smaller) patio, seem smaller. :roll: Only other surprise was how my buddy referred to the aluminum door frame and chair rail (horizontal bar in screen, chair height) feeling really tight and steady. Compared to the 2x4 frame wall and door frame I just built... well can't compare, the screen is just for keeping the bugs out. Rod,

congrats on the gigs........

I could elaborate on that positively and show my ego OR negatively and come closer to the truth, so I'll refrain. Just glad I'm working and feel lucky to be able to support my family via playing music for a living. Not many who want to, can. I'm still working on a diagram of my HVAC but I got a couple questions: You keep mentioning 12" duct for examples. I wanted to use 8", HVAC guy said 6" and we agreed on 7". HVAC guy says smaller duct for my room will be easier to balance room to the house. 1. Do you have an opinion on duct size I should use from my air handler to and from my room? Silencer: As Sharward noted recently on his thread, previously there were not to many clear plans or pics of silencers on this forum (or in your book :D ) The best silencer diagram now seems to be yours: http://johnlsayers.com/phpBB2/download.php?id=16137 THANK-YOU :D 2. If I were to build this silencer for a 7" duct I would increase the silencer size in your diagram... basically every where you're noting 12" in box I increase to 14" and increase every other measurement proportionally (so the air moves twice as slow through the box)...or larger to be safe.... or the larger the better.... just make sure entry and exit of box is the same size? I think I'm going to build the silencer box(s) out of 3/4" plywood because I have a lot of 3/4 plywood sitting around. Going to build at least one on the outer side of room (in attic) and place just before air passes through wall. Then I'm thinking about building another set of silencer boxes in the room, or more like in between the inner and outer leafs because of the available space. I've seen you advice (I think) 1 silencer box per duct run through wall as well as 2 silencer boxes (one on either side of wall). 3. For a room such as mine: Goal STC 65, TL @ 50hz -30dB via double frame walls 2 layers (or better) of 5/8" drywall etc... Do you have a recommendation for how many/how much silencer box to use. The 4" fresh air supply duct I'm thinking on feeding directly to the silencer box instead of Y'n into the HVAC supply duct. I'm thinking this would be hard to give an opinion on unless I provide a diagram BUT I've not yet made up my mind what exterior wall, soffit/overhang or roof I am going to run the fresh air ducts to. 4. If I had a long enough run, and 2- 90 degree turns could I run the fresh air duct straight into a silencer box with out causing problems. I want the ability to "shut the window" or close off the fresh air while not in use. Fresh air supply duct gets a fan and a full closing damper. Return gets barometric damper and a full closing damper. Full closing dampers would be the ones when power is off they close so I can hook these up with fan to one switch. Goal is that when I am not in room, fan is off I close those vents so conditioned air is not flowing out them. 5. Any potential hazard with the OFF fresh air switch besides letting the occupant have control for potential suffocation? :lol: 6. I'm thinking about full OFF/ON dampers to shut HVAC/conditioned air off to the room. This way when it is cooler out I can just give myself fresh air. Sharward is planning the supply fresh air vent under a soffit/overhang on a cooler side of his house. Rod has (only) suggested I go in and out of my roof. The closest soffit on north (cooler side) of my house is right over my noisy HVAC heat pump/condenser unit. To get to another spot on north side of house away from condensor I'd have to run 30' and install duct in a spot in attic that would for sure warrant a 1,000 word post ranting on how I hate my attic. 7. Do you (or anybody) think it will make that much of a difference in temperature of air coming in to run fresh air supply to a shadier/cooler part of exterior on the house? I realize I may not have given enough info for some of above to be answered :roll: , some info I don't have. Dang I didn't mean for this post to be this long. Marc

how much air did he say he's going to supply you through that 7" duct? XXXX cfm......... ??????????????????? The reason I insert the fresh air where I do is so that it will have a chance to mix completely before entering the room............ I'll get back to you on the rest......... Rod

See pics of Screen Wall below. Still have to caulk around the perimeter. Then I can rebuild and clean up my garden area, re-install drip system, hanging plants in patio, etc... Rod,

how much air did he say he's going to supply you through that 7" duct? XXXX cfm......... ???????????????????

Don't know. Maybe he guessed at 100 cfm? BUT wouldn't I more being going for the "correct feel" number for the room... once the balancing damper on supply is in (closing to 80% max) then I will adjust that till the temperature feels right in the room, this will decrease the cfm to room (right?). Think I am going to install a manual controlled balancing damper with in easy reach of my attic access. Shouldn't I be asking him for a guess number of what cfm should be going to my room of 130 sqft/ less then 1,000 cubic feet, all based on our local temperatures, insulation of room, my air handler, etc... OR does this sound like a number I truly won't be able to measure till it's all installed? Maybe I'm over-thinking this but I will ask him tonight, I have to show off my new screen wall. BTW My HVAC guy is my neighbor, friend, our kids play together and we help each other out with house hold projects when needed. He helped me with my recent ceiling drywall, I helped him with drywall in his bath, etc... AND I've not yet told him that I am going to install the fresh air ducts.

The reason I insert the fresh air where I do is so that it will have a chance to mix completely before entering the room............

Maybe I over thought that too. Thinking was it would be an easier install and somewhat cheaper to run both conditioned and fresh air ducts to silencer box. BUT if the fresh air duct Y's into the conditioned air duct at some distance before the silencer box then it would be less likely for noise to travel from outside into room, so that's making more sense to me, even if it's only a small difference. The only other info I got right now is the conditioned air supply duct will be about 20' to 25'. The return will be 15' to 20' long. Both will have 2 90 degree turns with those lengths BUT... Question: HVAC guy said just curving the duct around would be enough to stop sound from passing through ducts. Does it have to be 2- 90 degree turns OR can the duct curve around a min of 180 degrees. I'm planning to use this newer heavy grade flex duct. HVAC guy is calling this green duct and I want to get the manufacturer name from him, tonight, hopefully if he does have time to look at my new screen wall. Marc

AND one more thought/concern. What about when the air handler is off. It would only turn the fan on when the thermostat in house calls for (conditioned) air, unless I set the fan to on while I am in the room but that would only be at 50% (I guess). Plus it's a variable speed air handler (12 speeds). Starts slow to move warm air out of ducts (in attic) then kicks in full (self adjusting for static pressure I believe). Once the thermostat has reached it's temperature it stops conditioning the air but the fan then goes back to a slow speed to move extra conditioned air out of the ducts into house. That is what really sold me on this HVAC system when I bought it 4 years ago. When the fresh air fan is on pumping air into the studio room and air handler fan is OFF there would be nothing to hold this air back from going the other way back into the supply ducts of the house UNLESS I install a automatic back draft damper on the conditioned air duct right before the Y where fresh and conditioned air get mixed. Could feed the fresh air ducts straight to room via there own registers BUT that does not seem like a good idea. More holes in the walls, more silencers and the two air supplies would not mix pre entering the room. hmmm Marc

guitardad72 wrote:

Think I am going to install a manual controlled balancing damper with in easy reach of my attic access.

Marc, NO NO NO NO NO......... with emphasis on the "NO"......... you do not want to be messing with the balancing once it's done- the right way to do this is with a pair of motorized dampers - placed on the main side of the fresh air in and outlets - wire those to a cooling thermostat - when your space is satisfied - the thermostat will close down the dampers - and then open again when you need more cooliing. Meanwhile - your fresh air fan can be running and providing you with fresh air.......... it will still work (and not effect your system) because once the rooms pressurizes - the barometrric damper will still open. The only other thing I would consider would be an humidistat that also tied into the motorized dampers - that could open them to say 50% if the humidity started getting high in the room - at least that would allow your fan coil the chance to dehumidify the air while not freezing you out........

Shouldn't I be asking him for a guess number of what cfm should be going to my room of 130 sqft/ less then 1,000 cubic feet, all based on our local temperatures, insulation of room, my air handler, etc... OR does this sound like a number I truly won't be able to measure till it's all installed? Maybe I'm over-thinking this but I will ask him tonight, I have to show off my new screen wall.

Dayam, when you read the book you never really paid attention to the section on HVAC......... you should be asking him for a hard calculated number based on gear (sensible load) ..... people in the room (latent load) fresh air (sensible and latent loads) and lighting (sensible load) I just finished designing a smallish semi-pro studio in NC - and the HVAC was a part of my contract........ the control room required 3 tons of cooling.... That was all because of gear........ his control room gets 60% of that - and he has a seperate equipment room (w/ computers and a lot of rack gear) that gets the balance...... but that's still 1.8 tons in his main room- and roughly 480 cfm of air........ all of which I keep below 100 feet per minute of flow - with 6 supply registers with 2 large returns. look at the calc sheet.........

Question: HVAC guy said just curving the duct around would be enough to stop sound from passing through ducts. Does it have to be 2- 90 degree turns OR can the duct curve around a min of 180 degrees. I'm planning to use this newer heavy grade flex duct. HVAC guy is calling this green duct and I want to get the manufacturer name from him, tonight, hopefully if he does have time to look at my new screen wall.

I am not overly concerned about fan noise traveling through the duct - AIR FLOW is a different issue........ 100 cfm in a 7" round duct is about 380 feet per minute of velocity - and with flex duct it's noiser than with hard round lined...... I like to see numbers not exceed 100 fpm.......... I don't have a real good feel about this............ I take it that he doesn't want to mess around with a custom built silencer box? Only one concern is fan noise - the other is that you have this hole cut through your iso assembly - what if a plane flies over head - or there are screaming kids around - or some kid playing his boom box? The iso chamber helps to keep that noise out as well....... that's why it needs to be installed so it becomes a piece of the ceiling or wall that is being penetrated. I hope this helped. Sincerely, Rod

I'm in a stretch of gigs again over the weekend and have a few "must do" tasks to take care of... April 15 (US tax deadline) is right around the corner. Studio work and planning is on hold for a bit even though the HVAC is warping my brain (even though Rod has implied it's simple), I really want to get the plan/diagram done. Still need to talk to my neighbor/HVAC guy. I was saying to my wife last night (who is wonderful for just listening to me rant for over a year now about my room) about the HVAC: I thought/could do this..., Sharward is doing..., others on forum are doing..., our HVAC neighbor says..., and Rod says... Her reply was simple "do whatever Rod says" Marc

I agree! :-)

taxes aren't due till april 17th this year, hope that's a relief. (i have yet to finish up my returns as well)

taxes aren't due till April 17th this year, hope that's a relief. (i have yet to finish up my returns as well)

Yeah 17th but... My desktop is doing major crashing, all my tax stuff is on there (and a huge pile of archived audio and video work) and I as of 2 days ago I can't trust it to stay on long enough to do any work....complete crash with no warning 5 times in 24 hours... It's a hard drive failure , computer has been warning me, it's just getting worse. So my relief... Desktop is 5 or more years old and I'm buying a new one :D. File an extension on taxes and send in a "good faith" payment to IRS. :twisted: It's not a relief trying to decide how much money I want to spend on how powerful of a computer for what end use... new computer could be for studio and/or office needs.. URH I plan to re-use the crashing computer with another hard drive. :cry: Oh well :cry: Marc

Just had an inspection for drywall. I passed and then asked inspector (who was the same one from my last inspection) "What else do I need to do to get a final for my storage room?" He said "Do you want one now?" I got a final inspection for my storage room!!!!!! So now I can really get to work. What I am really, really, really happy about is that I did not have to put drywall mud over the screws on the drywall I just put up. Meaning I can now easily take down the drywall on the short wall (as planned) and even reuse that drywall. I can also, if needed easily take down some of the drywall on the ceiling so that I can have an easier time installing air ducts. Also, I bought a new desktop computer HP Pavilion Media Center TV PC (M8000N) with Vista on it. It smokes... but I am weary of what software I have that worked perfect on XP will work on Vista. I really do not think I'll being using this Vista computer in the studio (Pro-tools is not yet Vista compliant), this will be my office, game and bash around computer. It sure is nice to have a super fast desktop that does not crash.

Congratulations, Marc, on your passing inspection! Now, proceed with caution as you, uh, "fly under the radar" -- be careful! 8) (You always are...) --Keith :mrgreen:

Hey Marc! What's going on? We haven't seen you here in a month! Everything OK, my Floridian friend? --Keith :mrgreen:

Eh Keith, Yup every thing's OK and no studio progress to report, have not done anything except a little research since my last post. The next task is still to caulk the screen aluminum and concrete joints. I just have stuff to take care of, & "Shameless Self Promotion" is the number one task at hand... need more gigs. Got to publicly thank BassRocks (Andy) on the forum. He used my website content for a high school state competition of building websites. The results were OK but they really did not have enough time to do a great job. None the less got to thank Andy for the opportunity as it could have saved me a lot of work not only in building a new website but also in relearning the software involved. And I uploaded a new avatar :D Marc

PROGRESS, I finally got out and did some more work on my room. Seems like every 6 months or so I have to break from even thinking about working on it for a month. I took down the drywall off my studio/family room wall which I had put up for final inspection. I removed the insulation from that wall, peeled the paper off and installed it plus the rest of the package of insulation into my new exterior walls. Now I am prepping to beef up the studio/family room wall in between the studs. I'm very happy I already have the drywall, screws, nails, backer rod, caulk Green Glue and furring strip for cleats to do this job because... I've spent twice already what I estimated. My intention was to get this room done before my 2nd child was born and wife took a break from working so that I could more easily step up my income. Working on the room, in part, steered my attention away from getting gigs. Right now I'm getting by with very little extra money to "spend on me" each month. I'm not whining, just want my "toy money" back. Another thing which recently changed is my son's health, he's got a minor heart condition (small VSD and a small sub-aortic membrane) and we have to go back to the heart doc on 6 months. Right now he shows no negative effects at all, he's perfectly OK. His condition may go away all by itself, but it may not. My wife now has to go back to work so that we have full HMO health coverage, but that won't kick in till Jan 1, 08. You can imagine how I feel about spending money on me right now. Worse case scenario I would sell my house for my son BUT it's very unlikely it would come to that. Anyways I've been picking up on my gig hunting and shameless self promotion activities, more gigs are coming in and I even got interest from a major attraction at an Orlando Theme park. I don't dare name the venue as it would be bad luck, but I ask you all to silently rout for me. I'll take some pics of the beef up. Question, Am I correct with this: I'm installing drywall in between the studs. There is 1/4" wood panel board on the other finished side. I'm planning on using finishing nails the secure the 1st layer of drywall in between the studs (nailing at an angle into the studs not the 1/4" panel board or even the drywall). I'll use some green glue on that 1st layer, just enough to fill in slightly uneven spots. 2nd layer of drywall will get 50% green glue coverage and will be secured via 1" drywall screws and then cleats , very carefully so that I can backer rod and caulk everything. Marc

Hey Mark, Wow... Too many emotions to express: congratulations (on the progress), condolences (about your son's "hopefully not a big deal" health issue, and best of luck to you (on the theme park gig potential). The only thing about your beef-up plan that has me scratching my head is the remark about Green Glue in the uneven areas... :roll: ...Surely you don't intend to use Green Glue as filler -- right? :shock: Perhaps you could clarify your intentions there. I really like the Rod's "finishing nails into the studs" idea. I definitely would have done that had his book come out a year or two earlier! :? --Keith :mrgreen: