Studio Design for a 28' by 22' garage

sharward wrote:

Hey everyone -- catch Mike playing keys this week on Last Call with Carson Daly on NBC! 8) (He's too modest and preoccupied to tell you, so it's up to me!)

• Monday's episode -- Mike didn't play
• Tuesday Night's Episode -- I could only hear Mike play a little :x
• Wednesday Night's Episode -- I could see and hear Mike play a little
• Thursday Night's Episode -- I saw Mike playing a lot! 8) But he was hiding behind his hair quite a bit! :lol:
• Friday Night's Episode -- airs in a few hours -- I'll try to watch it tomorrow

Mike, is this the first time you've been on national TV? --Keith :mrgreen:

Tonight you should see alot, keith its an hour. Actually, weve been the host band there before as well. Believe it or not, we've been on Leno more times than any band ever, something like 7 or 8. As for the hair, it needs to go, but not till the studios done. I might need that 20 bucks for some nails. I havent watched any of them yet. My neighbors tevoing that shit though. ...Well back to the glitz and glamour of drywall.

Hey everybody, just checkin in. I was hoping someone could answer my questions on suppoting ceiling beef up alternatives. Can anyone tell me if.. a)I didnt make any sense? b)My ideas arent even close to working? c)I'd need to consult an engineer? The sistering of the garage roof rafters with steel "L" beams, that serve as beef up cleats and rafters sisters, seems like it could have some merit. As well as putting extra collar ties in above the 2 8.5' ceiling rooms seems like it could help. Compine both? It may seem a little cumbersome, but if it owuld work, thiswould allow me freedom to have that high ceiling. Other than that crazy crap, I'd like to know how and what insulation to use. If I remember correctly, Steve said during phone consultation, that I could use standard "pink stuff" insulation, if I cant afford deluxe stuff like roxul AFB at $0.81/sp.ft.. I checked home depot and R19 is like $0.41/sq.ft. If bought in bulk can I expect to see this go down? Id like to review what I think Id use for insulation (w/ no ROXUL) 1)Between roof joists(2x6) I need UNFACED R19. The UNFACED, if Im correct, is necessary because of the unvented ceiling. The facing would stop vapor from passing through, trapping plywood roof sheathing between roof paper and insulation facing. This would tend to rot plywood. a)If r19 is correct than in spots where I have more space between roof and a rooms ceiling, do I fill that space too? With what? how tight? etc? 2)Between outer leaf studs. Since this is stucco,paper,stud. I believe the walls should be FACED. FACED side goes toward vapor papor and stucco a)These are 2x4, but since the airspace is 12" until inner leaf. Do I use R19 and let it hang past stud? I would think so . but just checking. 3)Inner walls(2x6) gets R19 as well. But Im not sure that would be FACED or UNFACED. On inner walls in front of outer walls(2x4) the 2 layers of R19(6.5" thick)will compress slightly since cavity is 1'. On inner walls in front of another rooms inner wall, would I treat this the same? 4)In between joists, above all 3 rooms.(2x8) Do I use R-(whatever number is for 2x8 {like R-28?}) or R19 or R38 and let it sit higher. R-38 would totally fit above 8' ceiling rooms,but not vaulted live room. Is this faced or unfaced. 5)Any large cavities left over, do I fill? In this case would rigid insulation be better to do some bass trapping. Is the density number Im lookin for 2.5 lbs per square inch.(im gona research post for this now) Other than this and beefup question, the only real question left to at least know this plan will work is if I use HRV for mechanical ventalation, do I vent the 'unvented attic' with return and supply ducts like the rooms? Does this make it a vented attic? Thanx for everybodys help

The steel you're referring to is just called Angle; older term was Angle Iron, but it's not iron any more, steel is an alloy. Least size angle that might be effective would be 3x3, 3/8" thick; that weighs about 3 TIMES what a Doug Fir 2x8 weighs, and wouldn't be noticeably stronger - a lot of bending resistance comes from DEPTH of the piece. For a simple example, support a 2x6 across two blocks off the ground, with the 2x6 held on EDGE; try standing on it (sober :wink: ) and see the deflection. Now, lay the 2x6 on its SIDE and repeat ('nuff said) A 12' length of 3x3x.375" angle would weigh about 94 pounds, and steel has tripled in price in the last two years to around $1 a pound - so each rafter's sister, even based on ONE side only would cost around $200 - this doesn't include the collar, or finding someone to weld it that won't burn your building down. Yes, tubing is stronger in some ways - again, cross-section counts. if you were to take the amount of steel in that 3x3x3/8" angle and form a hollow 2x6 with it, placed on EDGE it would have about TWICE the support capability. But it would still cost about 10 TIMES as much as doing this beef-up with Doug Fir. Insulation - I doubt HD will give you a break on any quantity you would be able to use. And for anything EXCEPT acoustic treatment INSIDE the room, the "fluffy stuff" will get you within 1-2 dB of the high price stuff; for walls, you need complete fill + slight compression. For ceilings, you need either complete fill or, if there's room, at least a FOOT. Under NO circumstances do you want to compress insulation FIRMLY, with the possible exception of a wooden floated floor. I'm still trying to get caught up on more than a year of neglect on my own life before bad weather hits, so I've still not had time to "suss out" all the ramifications of unvented space; If, in all your postings you've included a labeled sketch of your existing roof layers, please point me to it and I'll try to finally clear this up - I also need to know for sure whether you'll be heating or cooling the space more of the time. Read this through before answering, and try not to miss any points I need answers to; hopefully I can get to it in the next few days... Steve

thanx steve for responding and Ill be as thourough as I can ULTIMATE QUESTION. IF I ABSOLUTLY SHOULD beef up ceiling, How can I do this without the extreme measures of halfway collar ties on every rafter. ULTIMATE SITUATION: IF I ABSOLUTLY SHOULD beef up ceiling, Id love the outer ceiling to be as high as possible, even high enough to sheath inner ceiling to a 'V'. Exposed collar tie in for inner ceiling OK. Id prefer halfway up, And if theres a way to use something lower profile, any material, would be great. I AM NOT EXPECTING THESE RESULTS, SO LETS SEE WHERE WERE AT.

Least size angle that might be effective would be 3x3, 3/8" thick; that weighs about 3 TIMES what a Doug Fir 2x8 weighs, and wouldn't be noticeably stronger - a lot of bending resistance comes from DEPTH of the piece

I only mentioned this because I thought it would be the opposite.(cheaper,and lighter). How 'bout steel studs? Personally, I'd put sugarcane or legos up there if it was lighter, cheaper, safer, most effective.

'm still trying to get caught up on more than a year of neglect on my own life before bad weather hits, so I've still not had time to "suss out" all the ramifications of unvented space;

I feel ya steve, and I do appreciate.

labeled sketch of your existing roof layers

plywood is 1/2"

I also need to know for sure whether you'll be heating or cooling the space more of the time.

Its hot here in the summer(100, and up to 110 but usually only 105)Never snows, well once every 20 yrs, but it dont stick, Does get cold in winter, (lows of high 30's extreme lows to 30 max. winter days are 45-60.) Average to light rainfall. Im 50 miles from keith. Im guessing with a foot of insul and a realtivley small studio, I will be cooling WAY more. Im definitely considering an AC only, system and have a couple of space heaters for the sissies. What I dont know is...if Im right about heat and if I should heat some regularly because of unvented attic system.(or anything else I havent thought of). If sistering rafter(steel or wood) can be used as a cleat, or not, can I aplly the same technique on the inner ceiling instead? Actually Id line up new smaller rafter to top(or whereever suggested) of inner ceiling 2x8, leaving gap on bottom. Then attach 1st layer on new rafters, flush with 2x8 rafter bottom edge(ill go 2 layers like this if its a good thing) then attach 3 layers below 2x8 rafters.(2 if I do 2 inbetween). This might be easier, and since Im willing to expose and drop these collar ties it could be much safer. Isetting layer 1 would make connections even with 3 layer wall(if even neccessary). SInce 1 layer is like 5/8" Id also be open to 2x8 sisters on 2x8 inner ceiling rafters and hanging all 4 under, If preferred.

Insulation - I doubt HD will give you a break on any quantity you would be able to use. And for anything EXCEPT acoustic treatment INSIDE the room, the "fluffy stuff" will get you within 1-2 dB of the high price stuff; for walls, you need complete fill + slight compression. For ceilings, you need either complete fill or, if there's room, at least a FOOT. Under NO circumstances do you want to compress insulation FIRMLY, with the possible exception of a wooden floated floor.

I can check around more than home depot, I also have a bro in law thats a foreman on a site, he said I should be able to save a bunch. Imn sure specialty products could get more difficult but we'll see. Is there any benefit to a half n half system?(Roxul on inner walls, pink on outer, or since outer is 2x4, I could get 4" roxul and let pink stuff fill from the inner 2x6 frames). On 8' ceilings do I always(generally) thake gap and split in half? Like 1 foot on inner ceiling, 1 foot hanging, or fill both and where gaps gets bigger, fill that loosely? I have a couple of dead spots in airspace where gap gets big. If I fill extra gaps with rigid, will it act like a bass trap? What do I do if just in a corner ceiling gap is less than a foot, shave it? What about staggered rafters, will this compress insulation at edges? I think I generally got it, but I thought of these questions so here they are... I think thats it...Remeber the live room is only 10'6" to 15' wide, and 20' long. The ridhe board is about 12' wide. Thats not a whole lot of span that way. And I can build walls srong to support ridge board. From 12' to 15', the wall goes diagnol and supports both subsequent inner ceiling rafters. Also the ISO is coupled, and will support old garage door beam about half way through. I dont know what that all does, but the outer structure will have mere than just collar ties holding it. thanx, thanx thanx

Gotta go build a wall before I give up for the day, but one question - please, please, tell my you have NOT yet added a second vapor barrier on your roof - to quote a favorite TV series (Highlander) "There can be only ONE"... Steve

Im pretty sure theres nothing to worry about here, steve. For one Ive done nothing internal, and especially not under that plywood. In our phone call, Im pretty sure we covered this, and you didnt see a problem. Maybe it just sounded wierd in writing. When the garage was reroofed, we went over the old roofing. So technically yes there is a second vapor barrier(basic roofing paper), but its above any sheathing. The old one leaked in spots as well, so that old barrier is probably not sealed well. Bottom to top its 2x6 rafters, then 1/2" plywood sheathing, then old roofing(paper then roofing)follwed by new paper and roofing. I hope this isnt a problem, for Ive never seen it as one. what do you think? A summary of what I remember you said is roof is fine, but make sure to use UNFACED insulation under roof sheathing. DO NOT TRAP PLYWOOD BETWEEN 2 VAPOR BARRIERS(faced side of insulation is vapor barrier), IT WILL ROT. ps Im not so sure about this part, but did you say," Hang as much as you want from the roof, it will hold, but if you didnt hang anything, it would be okay too because, your coolness will create a inpenatrable sound proof field around your abbey road quality studio youve designed.". If you didnt, it sure would be nice of you to say..

Got about 5 minutes before rushing off to the "DDJ" - yes, you're OK on the roof - building felt/tar paper isn't actually a VAPOR barrier, because it's overlapped and can let vapor through; it sheds water for the same reason shingles do (shit runs downhill) - You need to put collar ties (wood ones) on EVERY rafter pair, as LOW as you can STAND it or mid-length, whichever comes first. And I would NOT hang anything extra on your roof until you accept the fact that wishing won't make your framing any stronger; I gave you the answers I felt would keep you alive. Now you just have to decide whether that's a priority, or you'd rather become a Goth hero (down in flames) :cry: Gotta run, I've not forgotten the unvented attic just still swamped... Steve

Mike, don't shoot me for asking this question. It's a legitimate question, even if the answer shows that the option is completely impractical. For the answer to this question becomes the extreme upper limit of what you should consider doing. What if you had that entire garage of yours bulldozed and removed, and you had the freedom to construct from the ground up? How much would that cost? What benefits would you realize? I can think of several benefits:

• It would be built to today's code, which is much more structurally sound than the current building, particularly from a seismic point of view.
• Ceiling height would no longer be an issue -- "sky's the limit."
• You'd have no choice but to do it "by the book," and it would be easier to do so because you wouldn't have to worry about retrofitting.
• Your design would no longer be hindered by "the nook" or "the original doorway thing" or anything else. You'd have a clean canvas from which to work.

Another option would be to reclaim your garage as a garage (which, I realize, means redoing or undoing much of the work that's already been done in that 4' extension), and entertain the possibility of taking advantage of all that land behind the garage. (I don't think Mike has mentioned it, but he's on an especially deep lot.) I know that you've talked about this with me/Dan in the past as sort of the "ultimate" and possibly future plan -- what I'm suggesting you think about is doing the "ultimate" now. This may be way off-base, I realize... But I think it's worth at least looking into. Find out what the costs would be. Do the math. Maybe, just maybe, you'll discover that it is more expensive but the value of the investment makes up for it. Consider resale in your equation. The worst that can happen is you'll do the research and the math and conclude that it's too expensive to execute. Then at least you'll know and it won't be hanging over your head all the while. Just think... No beef-up effort. No retrofitted collar ties. No worrying about unvented attics. No worrying about "nooks." No vacillating over "to pull permits or not to pull permits" (because you will pull them). Think about it. --Keith :mrgreen:

es, you're OK on the roof - building felt/tar paper isn't actually a VAPOR barrier, because it's overlapped and can let vapor through; it sheds water for the same reason shingles do (shit runs downhill) -

Do i need a vapor barrier up there then?

You need to put collar ties (wood ones) on EVERY rafter pair, as LOW as you can STAND it or mid-length, whichever comes first. And I would NOT hang anything extra on your roof until you accept the fact that wishing won't make your framing any stronger; I gave you the answers I felt would keep you alive.

Is this to beef up outer roof with one layer of drywall? Or just to support roof as is? Really Steve, dont take my ideas as doubt of your judgements, Im not trying to be a hero. In our origial talks you said I must sister 2x6 rafters with 2x8 and keeping current raised collar tie(2x10, every other or 48"), but adding 2x8 collar ties to every new sister. This was to hold 1 layer of 5/8" drywall beef up and support 3 layer ceiling hanging off of kinetics clips over live room only. I agree, with your warnings of beefing up with missing collar ties over live room( even with bars or straps). But I was under the impression that the 2x8 sisters were necessary to hold the 3 layer ceiling, not just an added layer of drywall. Also, with the sistering/collar tie add method you origanally told me. The 2x8 live room raftered ceiling in the new plan should hold 3 layers of drywall. I cant see why sistering 2x8 with steel 2x4(or whatever is the proper size) would not hold 4 layers. Thats 2x8 rafters 24" spaced sistered with steel rafters, and if neccesary sistered on both sides. Thats every rafter is 1 2x8 and 2 steel 2x4 rafters. That wont hold? In the new live room, collar ties can be anyway you want(exposed). This room is only 10' to 15' wide, suppoerted by strong 2x6 rake walls(gable walls?). Now if this is possible then I could not beef up roof, just have better live room ceiling. If this would work what would you suggest I need to support the old 1/2" wood and roofing. Will high straps be ok. Or return collar ties the way they were. Things that would be easy to do if they helped. 1)adding collar ties(lower than the 2x10s over CR and ISO) every rafter or everyother? 2)sistering new 2x8 rafters of live room since its new construction.(wood or steel)to hold 4 layers. Again Im really not that hell bent to have every wish on this ceiling height of the live room. Its just you keep telling me th only way is to add collar ties to every rafter even with 2x10 or as low as possible. But, and I know Im a rookie, my ideas seem totally plausible as well. sistering new rafters is the same as sistering old rafters and that would hold 4 layers(1 beef,3 ceiling) QUESTION: If I added collarties to roof, every rafter, as you suggest, and beef up 1 layer. I would have to flatten ceiling top, which is accecptable. The way I would do this, would be to add collar ties to live room's 2x8 rafters just below colar ties on roof rafters. The drywall would flatten 1-2" below roof rafter collar ties, not touching roof collar ties. IF I INSTEAD MADE LIVE ROOM COLLAR TIES EQUAL TO ROOF COLLAR TIES, HOW DAMAGING TO ISOLATION WOULD IT BE TO ATTACH DRYWALL TO BOTH ROOF RAFTERS AND LIVE ROOM RAFTERS FOR FLATTENED AREA. THIS WOULD BE MORE POINTS TO HOLD FLAT PART OF CEILING, BUT THE DRYWALL WOULD BE COUPLED TO BOTH INNER OND OUTER LEAF FRAMING?(JUST CURIOUS) I read a report saying if you use a beam like a 4x4 connected at wall top plates crossing the whole span(20'). Every 48". This would replace the need for collar ties since beam secures walls. Is this true? I know its just like a low collar tie, but it doesnt need to attach to rafter and can be located nearer to walls edge to get out of the way?. check this out... http://www.diychatroom.com/archive/index.php/t-911.html Can I succesfully expose a collar tie from outer roof through live room with succesfully decoupling drywall on new rafters? Simply, Can I expose all the collar ties in the live room, without losing my room in a room, decoupled framing. In regards to bulldozing and startin g new or going deeper in yard and start new suggested by Mr. Sheward....Keith, I hear you friend, but sadly that is not possible right now for me. Again I know it sounds like im trapped, but I can lower my ceiling to accomidate Steves suggestions, Live without beefed up roof? Im just checking because in my mind, it seems possible. I can live with 10' flat section for ceiling. Unfortunatly, I have to move on the best I can, but until I commit, I want to keep options open. Keith, I have some queations about the HRV. Did you contact company with questions of your own, and were they helpful. I really think this is best for me as well, my only question I would ask them is if I supply and return duct the "unvented attic" does this now make it a vented attic, just mechanically controlled be me? I could probably install a stop valve if sometimes I should not ventattic while venting rooms, or stop valve controlled by humidity or something. This could be good for me as far as having 2 sealed leaves, but not totally relying on "unvented" aproach to be structurally sound. Ya? PS...Ive been looking at posts for putty pads. It seems confusing to me whats the BEST isolation method. 1)exposing outlets and cable on wall, very little penentrations 2)plastic boxes cut in with putty pads 3)metal boxes cut in with putty pads. In this situation looks are not totally important if exposed boxes perform much beter. If equal, Ill judge by price and look and conveniance.

mikeklooster wrote:

Keith, I have some queations about the HRV. Did you contact company with questions of your own, and were they helpful.

Nope, I sold myself on the product just from the literature and from Florian's experience with a similar European product.

I really think this is best for me as well, my only question I would ask them is if I supply and return duct the "unvented attic" does this now make it a vented attic, just mechanically controlled be me?

Perhaps... I don't know. But I would think that you would not want to have one unit do both jobs (habitable and non-habitable spaces). I would suggest separate ventilation units if you go that route, and I don't think you'd need to do the fancy HRV for the attic.

PS...Ive been looking at posts for putty pads. It seems confusing to me whats the BEST isolation method. 1)exposing outlets and cable on wall, very little penentrations 2)plastic boxes cut in with putty pads 3)metal boxes cut in with putty pads. In this situation looks are not totally important if exposed boxes perform much beter. If equal, Ill judge by price and look and conveniance.

Low-end TL probably won't be affected much with any of the above methods. I'm personally fond of Option #2. --Keith :mrgreen:

Nope, I sold myself on the product just from the literature and from Florian's experience with a similar European product.

Well, Ill shoot the question out there, if you know, until I get a chance to look deeper. The installation manuel says it does not recommend attic installation. My idea was to install in upper "nook" area. (If you remember I asked about this earlier, for it is above the CR and I was worried about noise. You said should not be problem.) I want to make the closet area a small as possible, to use the remainder as an open loft for storage. I notice though, I have choices here. I can make the closet a real closet in the iso. Or, I can let the iso end at the closet wall, and the closet could be open to the attic area. I understand the attic installation would be hotter and summer intake air would not cool as easy, but I dont know if this is exclusivly a height thing. 1)Do I make the closet a closet in iso to possibly benefit from conditioned space? 2)Do I make closet part of attic so I dont have to worry about more wall penetrations for duct. 3)I have a corner spot below attic open where HRV could hang lower in wall cavity? same as (2) but hung lower. I like idea 2, its out of the way, where I want it. But Ill put it within the inner leaf if conditioned space is better, just a bit more work.(1). Are these differences what they are worried about or is it in a more typical attic setting this is crucial? [quotePerhaps... I don't know. But I would think that you would not want to have one unit do both jobs (habitable and non-habitable spaces). I would suggest separate ventilation units if you go that route, and I don't think you'd need to do the fancy HRV for the attic. [/quote] A mechanical cut off on attic ducts wouldnt cover this? In a traditional "unvented attic" the space is conditioned so would mixing habitable non-habitable apply here? With mechanical ventalation, is this still "unvented"? other wise I can totally get with this idea. I guess it would still be better with less oenetrations, but right is right.

Low-end TL probably won't be affected much with any of the above methods. I'm personally fond of Option #2.

I know you like inwall boxes, and you feel it looks cleaner. I personally, from the image of exposed in my head, dont think id mind, but i guess if they are equal, id have to compare price and ease. you sure that puddy makes up for a hole in tha wall? thanx for your help, and if you have ideas on this great, but dont worry too much, ill research this before moving. Steve if your poking around I still have questions on my last post, so dont fret this crazy stuff if your limitewd on time. thanx all

well ive read more and there is information saying attic installation of HRV is a common practice as well. I guess theyre just warning it will be hotter up there. As for ducting attic with HRV as well as rooms. I presonally cant see why it would be wrong, but I can also understand it very well could be. Fantech makes many simpler fan units that could easily mechanically vent attic independantly. Am I right, does this give me a vented attic again? A controllable vent would definitly solve any risky assumptions on my plan. Do I insulate the same way as I was...unfaced pink stuff? Im not sure of all these specifics. But I feel in these combinations I will have a really well ventelated studio. I've been debating whether to get a dual zone cool only mini split or a dual zone heat/cool minisplit. The heat/cool unit is $1600 more than the cool only. Other than moisture issues, if any, space heaters seem the most logical choice. Any know if I will be OK without heat. Im in central california where its relatively dry, hot and as cold as 32deg.. f at night in winter, maybe a little less on the extremes. Also I found a panasonic dual zone cool only mini split for 1500 as opposed to 2065 for the mitsubishi. The fan has only 2 speeds as opposed to 3 but the db ratings are the same. Other than seer how do I determine if its really worth it to save 500 bucks.

mikeklooster wrote:

Fantech makes many simpler fan units that could easily mechanically vent attic independantly. Am I right, does this give me a vented attic again? A controllable vent would definitly solve any risky assumptions on my plan.

It seems that would be the best of both worlds: unvented attic on demand for isolation purposes, vented attic at all other times for safety/health/structural integrity purposes. Obviously you'd want to verify with local building officials that it would be acceptable.

Any know if I will be OK without heat.

Mike, I debated this for a while too. The heat pump option isn't cheap. And the place will be so well insulated that I doubt the rooms would chill that much even during the coldest times of year. I really think space heaters are your ticket to taking the bite off of a room if and when needed. It won't take much, since the heat will "stick around."

Also I found a panasonic dual zone cool only mini split for 1500 as opposed to 2065 for the mitsubishi. The fan has only 2 speeds as opposed to 3 but the db ratings are the same. Other than seer how do I determine if its really worth it to save 500 bucks.

Take this with a grain of salt, because I very well may chicken out and save money by downgrading the brand name. Not that I have anything against Panasonic in general... But the Mitsubishi brand stuff is made in Japan and from all accounts I can see, it's the standard by which mini-splits are measured. If you're still undecided, maybe talk with some HVAC folks in your area to see what they prefer. All three of the companies who gave me quotes were absolutely in love with the Mitsubishi line. My advice to you would be to save the heat pump money and buy Mitsubishi cool-only units.

im withb you all the way keith. AND only one question. In your opinion, will it be wise to have a space heater on a timer through late nights in coldest conditions? Its sounds completely unsafe and rediculous to me, but I guess in a theoretical world ,would the applied and moderated heat be good thing for the building?

mikeklooster wrote:

completely unsafe and rediculous

you said it :lol:

ya, i know. but i guess id like to be SURE without heat in the coldest times Ill be OK.

Nah. The heaters are for human comfort, not building comfort. 8)

sweet, so cool only, mitsubishi, and the only one left is 2 or 3 zone. I like the idea of the 2 zone. 1 unit in CR and 1 unit in live room, doors to iso from live open all the time exept when needing isolation. It seems fine but if theres any reason i should get a 3 zone and have a unit in ISO booth as well. It would be over powered but I dont necessarily have to use it until absolutly neccessary. Any opinions?

I think two zone will be just fine for your needs. The door can be left open and opened on demand when air is needed. If the iso room is air conditioned, then it becomes habitable, and then you must ventilate it. (At least, that's my interpretation of code.) Save yourself the trouble, and the money. I wouldn't even bother with preplumbing for unit #3 just in case. Confirm this point of view with your HVAC contractor interviewees. I'm confident they'll concur.

thanx keith, another check off the list. As for venting iso, hrv's got that. so i guess theres only one debate left in this situation. THe best way to mechanically vent attic. Any ideas on how I can find out if I should use HRV for attic. If not, I will use seperate fan unit. Any ideas on where and how to do it. Side question, with the HRV there is a cheaper unit called an air changer. Its similar to the HRV but I think it doesnt feature the temp control of incoming air as well. The problem is the vague description sounds so much like the HRVs that its hard to tell if it would work or not. Its $300. http://www.fantech.net/aev_inst.pdf compared to $700. Keith are you using the HRV with defrost option?

I would suggest you use the $300 unit for the attic. You don't need to worry about "recapturing your heat" up there since humans aren't up there. I'm not getting the defrost option. It rarely gets below freezing in my area. If you (or anyone else) disagree with my take on that, please straighten me out. --Keith :mrgreen:

two things I dont like, keith. Questioning your advice, and questioning your advice when its the cheaper path. But I must ask. Is the attic placement the reason to not use HRV? It says it changes temp as well, Im assuming just not as well. When I thought about it, I did think if its hot up there wouldnt the HRV temp control give that extra help to keep incoming air as cool as possible? I hope not, saving money is right up my alley right now.

Whether or not you place the unit in the attic isn't the issue. (I would imagine that in the case of the unit for the attic, it wouln't matter much, if at all.) The fact that you need to ventilate the attic itself is. You don't have to worry about air quality or comfort up there. The advantage of HRV is that it saves energy by warming the incoming air when it's cool outside, and warming the outgoing air when it's hot outside (thereby, in theory, cooling the incoming air somewhat). These are things that you care about for as far as habitable spaces are concerned. Bottom line, you don't care to make the air in the attic comfortable. What you do want is a flow of air to prevent moisture build-up. The cheaper unit should be able to do that for you. --Keith :mrgreen:

so maybe the HRV is better with the lack of heat. Using space heat less. Or is $400 dollars better?