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ReadyToRetire
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Posts:185
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| 04/20/2008 5:25 AM |
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We're idea shopping, and recently looked at new homes in S.C. Many -- if not most -- had high ceilings; some went to 11-12 feet. I didn't like the look or feel of the high ceilings, especially on smaller rooms, but they got me wondering:
If a house is well insulated and tight, does ceiling height effect comfort or utility bills?
Thanks for any comments that you can offer.
Larry
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vhehn
Registered Users
Posts:104
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| 04/20/2008 9:36 AM |
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| in a cold climate a high ceiling will be harder to heat. |
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ReadyToRetire
Registered Users
Posts:185
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| 04/20/2008 11:10 AM |
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Vhehn,
I know that's true in a generic house, and that it would tend to be an advantage in a warm climate. But I was wondering what happens if you build with quality: Well insulated and tight so that there's low infiltration; you'd then need mechanical ventilation, which should mix the air and prevent stagnation or layering.
Would ceiling height still matter?
If so, why?
Larry
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glenfotre
Registered Users
Posts:14
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| 04/20/2008 11:10 AM |
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| If you install a ceiling fan, and set it to slowly blow UP toward the ceiling, the difference should not be great, but I can't get my wife to do that! Otherwise, I do agree that it will be less comfortable and cost more to heat. |
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cmkavala
Registered Users
Posts:754
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| 04/20/2008 11:38 AM |
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Typically you want the fan body at 8-9ft. AFF for max. efficiency for higher ceilings attached is a down-rod chart |
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Chris Kavala
chris@southernsips.com
1-877-321-SIPS |
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Alton
Registered Users
Posts:285
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| 04/20/2008 5:16 PM |
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Larry,
Tall ceilings increases the amount of air that has to be circulated. Tall ceilings also increases the amount of exterior wall that has to be heated or cooled. These increases should be taken into account when sizing the hvac. |
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ReadyToRetire
Registered Users
Posts:185
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| 04/20/2008 5:32 PM |
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Glenfotre, Chris, Alton,
That all makes sense, and it's consistent with traditional wisdom -- which Vhehn had cited.
The reason I asked is that I'd read (nope -- I don't recall where) of a living room with a cathedral ceiling in a SIPs house; there were only a few degrees f difference in temperature over the room's entire height. If a tight, well insulated house can do that, it wasn't clear that there would be a noticable difference in comfort. Yes, the utility bills would vary with the total wall area, but with little infiltration and good insulation, I wonder how it would compare to a traditional, leaky house with 8' ceilings.
Very respectfully,
Larry
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cmkavala
Registered Users
Posts:754
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| 04/20/2008 6:35 PM |
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Larry;
Tha tis true about the constant temp, even in the dropped ceiling areas where the ducts run thru in my own house there are no supplies there , but the temperature above is only 2 deg. different.
Our whole house thru-out has no "hotspots" in the summer |
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Chris Kavala
chris@southernsips.com
1-877-321-SIPS |
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DickRussell
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Posts:12
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| 05/07/2008 1:46 PM |
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[post deleted] |
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DallasBill
Registered Users
Posts:119
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| 05/07/2008 4:34 PM |
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Ready2retire... You make a interesting point.
We have a 28ft vaulted ceiling in our ICF home. The ceiling-rafters are Sealection500 foam insulated and there is sheet rock over top. No ducts run through it. It has a metal roof on the other side with the two faces being NE-SW. There is an 24" round A/C return vent on one side wall at about the 20ft level and 4 "in-stud" returns along the bottom of same wall, at the 1 ft level. There are 4 6-in supply ducts at the 14-ft level on that same wall.
When I shoot the ceiling with an infrared thermometer gun, the highest parts of the ceiling, including the cross beams, are 79-80F. The walls, from about the 12 ft level on down, are 77F -- just like the rest of the room (floor, furniture, etc.). The t-stat is set to 77F. This is regardless of whether the outside temp is 85F or 98F. |
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Mark Fleming
Registered Users
Posts:185
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| 05/09/2008 4:52 PM |
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Short answer is yes. You have more volume to heat, but the same amount of floor space, where most of us live. You have more wall area and, if cathedral ceilings, more ceiling area. You have more temperature differential, maybe 8 or 10 degrees difference, at the peak, so you'll lose more heat up there where it isn't doing you any good anyway.
You can pay for a fan and the electricity to run it to help offset the problem. Then you get a draft and more dust blowing around. But wait, there's more! You also get the constant droning of the fan and the distraction of something whizzing around and around up in what might have been an interesting space. The solution for most is to turn up the TV and turn up the heat. Sort of an "ignore the man behind the curtain" solution.
Mark
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ReadyToRetire
Registered Users
Posts:185
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| 05/09/2008 9:17 PM |
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Mark,
Two of the oft cited advantages of SIP construction are its superior insulation and lower infiltration. I agree fully that higher ceilings in [i]traditional [/i]construction -- in a heating zone -- will be harder to heat. But your 8-10 degree temp difference at the peak avoids the question: [i]IF [/i]a SIP construction could limit the temp difference to only 2 degrees, would there be any disadvantage? If so, what would create that disadvantage?
Very respectfully,
Larry
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Jelly
Registered Users
Posts:239
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| 05/11/2008 8:50 AM |
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Interesting thread.
Maybe it boils down to a feeling of comfort. You know when you step out of the shower it feels like you're freezing when it's really pretty warm inside of the bathroom. If you have a climate that predominantly requires you to heat your interior, then I bet 12 foot ceilings would feel drafty and chilly, especially with forced air heat, even though the temperature difference isn't that great.
On the other hand if your climate predominantly requires you to cool your interior, then 12 foot ceilings would be an advantage comfort-wise when the hot air rises and displaces the cool air to the bottom of the room.
Now if your climate were so moderate that you could cool your house for a significant part of the year by having high ceilings and using transoms, like in antebellum homes, then it could actually be more energy efficient if it were combined with radiant heat for the winter.
What I'm trying to say is that in a tight house, like SIPS construction for example, the perception of comfortable temperature may be more the issue than the actual temperature. |
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GeorgiaTom
Registered Users
Posts:122
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| 05/11/2008 3:45 PM |
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If the thermostat is set at 72 or 80 that is what the temp will be where your body is at. it doesn't make any difference if the ceiling is 8ft. or 20 ft. if the house is tight you will have no drafts and if the air handler is sized for air volume of the house,everything will be OK.
you guys are overthinking this thing too much! |
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DallasBill
Registered Users
Posts:119
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| 05/12/2008 4:59 PM |
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I guess my IR temperature gun is wrong, then, and 28 ft up it's more than 2-3 degrees hotter.
Except it's not. |
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Mark Fleming
Registered Users
Posts:185
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| 05/17/2008 10:49 AM |
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Larry said
"I agree fully that higher ceilings in [i]traditional [/i]construction -- in a heating zone -- will be harder to heat. But your 8-10 degree temp difference at the peak avoids the question: [i]IF [/i]a SIP construction could limit the temp difference to only 2 degrees, would there be any disadvantage? If so, what would create that disadvantage?"
It isn't the construction technique that makes it harder to heat, it's the shape and volume. SIP construction can mask the effect, but not eliminate it. A high peaked ceiling will use more energy, period. It creates a dead air space that traps hotter air that is "wasted" because it doesn't serve any useful purpose where people live, i.e., on the floor.
There are several ways to mask the effect. SIPS can provide superior insulation overall. If you have an effective R50 SIP ceiling/roof, there's less hot air wasted in the peak than with conventional construction and an effective R30 roof. If you have tight construction, it's less likely that you'll have 40 degree air leaking in and lying on the floor. If you have forced air heat, you may circulate that air and not notice the heat stratification. Same result with a ceiling fan. But the physics remain the same. A high peaked ceiling creates more volume and will have higher temperature at the ceiling, where nobody gets any advantage from that heat.
That being said, high ceilings may have aesthetic advantages that outweigh the negatives. If you like the gymnasium look or the Montana McLodge look, high ceilings are required. If the construction is tight and well insulated, you can reduce the inefficiency, but never eliminate it. It's sort of like when I "hot rod" my wife's Prius. I get horrible gas mileage. It drops down to 35mpg. It's only horrible as compaired to her "normal" driving and 45mpg. High ceilings will be less efficient, but it may be something that you can live with.
As to temp differential, when you measure with an IR thermometer, you get a 45 degree slice of what's happening 28 feet above. You're not shooting just the peak. It may show an average temp that may be only 2 or 3 degrees higher than the floor temp, but if you were only one foot from the ceiling in the peak, you'd likely see the 8 to 10 degree difference, especially with the fan or forced air heat turned off for an hour. If you can circulate that heat, you can mask the effect and maybe benefit from the heat, but you're not changing the physics.
My solution was to place an intake for the ERV right in the peak. When it comes on, it takes the warmer air and passes it through the ERV, which effectively provides warmer incoming air that is distributed at floor level. It eliminates the stratification without a visible fan. Can't hear it or see it, but it reduces the heat stratification from more than 10 degrees to a couple degrees.
Mark
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cmkavala
Registered Users
Posts:754
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| 05/17/2008 11:15 AM |
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Mark;
The geographic location make a difference as well, vaulted ceilings make more sense in the south
Using an ERV to redistribute air is an expensive up front cost (and misuse) to just blow air back down and is accomplished better with a ceiling fan, the fans in my house are not "whizzing around"(they are quit and un-noticable)
and serve to redistribute air in the cooling and heating season.
Granted it doesn't get fridgid here but, does occasionally gets into the 20s. I have never experienced any drafty-ness in a SIPs house and the dust is way less using an unvented roof.
I you don't like vaults ....Another solution is to run the ceiling panels in the flat http://southernsips.com/residential_lechenier.html
with a conventional roof framed over the top. I have done this twice for customers with an aversion to vaults, but again it is wasting money with the initial costs
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Chris Kavala
chris@southernsips.com
1-877-321-SIPS |
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williamnaegeli
Registered Users
Posts:5
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| 05/18/2008 3:19 PM |
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| it would matter ... but it depends on the type of HVAC system, radiant heat works well in high celing applications because it only heats the area you are living in, if your talking about a heat pump system ..well no because youare back to heating AIR, which is fundamentally flawed in my book. if you want to build quality you have to use ICF wall systems, they are superior to SIPs i install both, SIPs are very good, but ICF is better...wow i can hear you SIPs rep blowing up right now. Back to high ceilings , what are you using for heat...in the summer high celings are GREAT all the hot rises and the house is very cool...open your windows. The history of low ceilings began with heat pumps .... because they couldn't heat that much air...think about it ... how fast does air loose heat(that should get the technos going? haha). |
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PanelCrafters
Registered Users
Posts:1291
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| 05/18/2008 5:29 PM |
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Posted By williamnaegeli on 05/18/2008 3:19 PM
...if you want to build quality you have to use ICF wall systems, they are superior to SIPs i install both, SIPs are very good, but ICF is better...wow i can hear you SIPs rep blowing up right now.
Um, why is that? The R-50 myth? |
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....jc
If you're not building with OSB SIPS(or ICF's), why are you building? |
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williamnaegeli
Registered Users
Posts:5
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| 05/18/2008 5:36 PM |
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| ha ha ha no its the wood myth? |
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