How to Prevent Heat Loss with 4 Examples-Diagrams-Drawings for your Building Projects

In recent conversations with customers and peers about reducing energy loss in buildings & structures and how heat and cold are transferred into a building via conduction, I explained and made reference to using a metal cooking utensil to stir a pot of chili.

 

If the utensil is left in the pot of chilli for any length of time. The heat will eventually transfer heat up the utensil handle and will usually burn your hand or fingers.

Heat and cold enter a building in the same way; unless, there is some form of insulation or thermal break to prevent the conduction of energy.
Cooking utensil manufactures solve this issue by adding handles made of wood, plastic, etc.

The building and remodeling industry combats this energy loss/gain in various ways. Here a few examples, diagrams, and drawings that show how this loss or gain is minimized.
 

When this heat/cold gain and loss is minimized you will save money on your heating and cooling bills.
By renovating and building using these examples and basic design principles you will save money and reduce global warming / climate change.


  • EXAMPLE 1. ADDING INSULATION ON THE EXTERIOR OF THE BUILDING NORMALLY BEHIND THE EXTERIOR WALL FINISH. THIS IS NORMALLY USED IN CONJUNCTION WITH INSULATION IN THE WALL CAVITIES.

  1.  
    • Example 1 top view
      Example 1 Top View
      ISO View Example 1
      Example 1 Adding Insulation on the Exterior of Wall Framing
  • Example 2 – Staggered Wall Studs

  • 2x4 Staggered Studs to prevent Energy Loss and Gain
    Top View 2×4 Staggered Studs to Prevent Energy Loss and Gain
    2x4 Staggered Studs
    2×4 Staggered Studs Prevent Energy Loss and Gain
  • Example 3- Double Wall Construction

  • 2x4 Double Wall Construction
    2×4 Double Wall Construction to Prevent Energy Loss and Gain
    2x4 Double Wall Construction
    2×4 Double Wall Construction to Prevent Energy Loss and Gain
  • Example 4- Creating a Thermal Break by Adding Wall Channels

Thermal Break created by Wall Channels to prevent energy loss
Thermal Break created by Wall Channels to prevent energy loss
Thermal Break created by adding Wall Channels to prevent energy loss and gain
Thermal Break created by adding Wall Channels to prevent energy loss and gain
The above illustrations are just a few examples of how to prevent Energy Loss in a Building by adding: Insulation, Providing a Thermal Break, and Creating Dead Air Space. Examples 1 and 4 are used mostly in Remodeling and Renovation Projects. With examples 2 and 3 are used mainly in new construction of Buildings. For detailed information, proven scientific facts, about how energy is transferred I suggest reading the Article at Wiki on Heat Transfer at:http://en.wikipedia.org/wiki/Heat_transfer.

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Tags: Energy, Framing, Insulation, Louis, St, Wall

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Comment by Bud Poll on November 5, 2011 at 6:39pm

Let's focus on just the staggered stud issues.  A rough calculation for a 2x8 wall filled with R-3.5 cellulose and covered with 1 inch of r-5  rigid, sheetrock, sheathing and vinyl siding came in at about r-30 for a given wall area.  Shifting to staggered 2x4's with the same coverings and fill came in at 31.24.  Now some qualifications.  Window framing, top and bottom plates, corners and T's for walls need to use some full 2x8's in many places so we cannot obtain all of the isolation we would like.  But, the net gain for shifting from a simple 2x8 wall to a staggered stud, double 2x4 equivalent thickness wall, was just over r-1. 

It is a project to specify all of the details and then run two sets of calculations, but I can do it if necessary.  The 31.24 was a number obtained from a super stumper problem we worked out on another forum.  I simply repeated that wall configuration with 2x8's and used 10% and 90% (studs vs cavity) coverage to calculate the R-30. 

Even if the improvement had been a bit more, it wouldn't have been huge, thus a simple addition of another 1" of rigid would have been more effective.

The issue here is not the double wall, but the effort to achieve a staggered configuration.  If a wall can be built with standard materials, ie 2x6's or 2x8's use them.  If you want more r-value than can be achieved in those dimensions, then the double wall becomes a necessity, ie 12" to 24" walls. 

As for cold sneaking into our homes, that is certainly the perception, however, it is actually the heat leaving that feels cold.  There is lots of reading on the science of energy transfer and it helps a lot as you get into the calculations and understanding of how insulation, air gaps, and radiant barriers all work.  I don't claim to be an expert on any of this, but I do take a technical approach to what I do so I can understand the underlying principles. To geeks like me, this is fun :).

There's one more detail that is important.  It has been know for many years that a foam filled walls performs beyond their rated r-value.  The difference, IMO, is that of air sealing and a perfect cavity fill.  When we build a new wall today, even without the foam, we can fill the cavity with cellulose of mineral wool batts and detail the installation to be near perfect.  The result is, even a simple 2x6 wall will provide exceptional performance.  Add a couple of inches of rigid on the outside to cover from foundation to above the top plate and you get one very good wall, and at a reasonable price.

You are correct, there are places for double walls, they are just very thick walls.

Bud

PS, if that old church is brick or stone, let's talk.

Comment by scottscontracting on November 5, 2011 at 5:04pm

Thanks again for the reply.  Let me start off by saying: "I'm not too old of a dog to learn something new" and look forward to any information you can supply in re and if you would like the extra publicity I'll gladly share the info on my web sites with links that direct the info back to your organization.

 

I've also read about the extra studs needed to stagger or double wall frame; yes they use more: energy in labor, materials, and the costs are increased; but in the article I read (I don't remember the source) the increase in  $$$$ amount was offset in time by: 1) the reduced Energy needed to heat and cool a building.  As energy prices increase the ROI will offer a faster return. 2) also the Pollution from the Electricity Plants is lower.

 

The staggered stud wall framing was first introduced to my by a Drafting Teacher in college.  The college was located in North-West IA, (and were the coldest winters I can remember- snow drifted over the tops of the power lines in one storm).  I don't think the system is applicable for every situation but has its place.  I also like the added strength aspect.  

 

Just recently there were a rash of Tornadoes that tore Missouri up.  And when I viewed the destruction of the homes I believe stronger wall frames are needed.   Granted a bigger percentage of homes were built before "hurricane bracing" and the braces may or may not have helped with the F4 Tornadoes.  But when I build a new home for myself and can afford a staggered stud wall- I will implement this system in the wall framing- if for nothing else I would sleep better-and the added energy savings would just pad the pocket and help the environment.

 

My second choice would be the 2x4 wall with 2in of Exterior Insulation (ISO)-  under the siding.  I think this is good system as the exterior temps reaching the wall framing would be nil with little or no conduction of energy, either in or out.

 

I'm still on the fence as to the conduction of cold transferred via the framing members.  There has to be some reason that interior walls are cold to the touch on these old homes in St Louis and I doubt it is all from Air Infiltration.  I have yet to do an experiment myself, but remember while I was working my way though high school: "The mechanics in the shop would use the AC re-charge gas to make metal tools brittle so they could break or bend the metal" to get a free Snap-On replacement tool.  From experience I couldn't hold onto the end of the tool (with-out gloves or a vice) while the cold liquids were being applied.  I know that wood does not conduct cold like metal does; but, I'll bet it still does-just not as fast.

 

I'm going to snoop around the Oak Ridge Laboratory for some studies and experiments I'm sure they have done on the subject.  If time allows I'll plug some numbers into the Equest system I use to evaluate building envelopes.

 

On an Green Energy note: I'm working on a project for a local church...original request was for a solar system to provide the electricity...until they realized that it could cost $68-125 K...when I mentioned there were other things to do that would cost less (weatherization) that would reduce the energy needs. We're now going to work on making their building more efficient and reduce the number of solar panels needed...I'm also doing my best to lead them into "Buying American Solar".

 

Whats the temp in Maine?  Its starting to get chilly here.

 

Build Green,

Comment by Bud Poll on November 4, 2011 at 9:23am

Hi Scotty,

I like the diagrams/illustrations and was hoping to carry what they represent to the next level, the actual energy savings and the added costs to achieve them.  Terry Davenport commented on this web site "I have found the double stud walls to be quite labor intensive and it feels like I have built two houses," http://homeenergypros.lbl.gov/group/bestpracticesresidential/forum/...

I tend to agree.

As for my picky point, there are no equations for cold transfer,  Heat gain or heat loss, but cold is simply a by product of heat loss.  As for St Louis, I rarely get that far south, so I do know what cold feels like and I know what you are saying.  But when it comes to calculating the actual r-value of these optional configurations, we need to follow the science and avoid the conventional thinking.

The question is, have you calculated these options to determine the increase in r-value and then estimated the added labor and material costs?

 

Bud

Comment by scottscontracting on November 4, 2011 at 7:11am

Thank you Bud for the Reply.  The article is meant to show people just a few of the available options for building energy efficient wall framing to reduce energy costs.  There are drawbacks and benefits for each example.  I personally prefer 2x4 either staggered or with exterior Insulation. 

I'll disagree with the comment of 2x6 instead of 2x4 walls, (1)-because a 2x4 wall with R13 Ins and exterior insulation will give a higher r-value; while preventing the conduction of heat to cold.  This also reduces the number of trees needed to build a building.  (2)-A 2x4 staggered stud wall framing will almost have the same sq ft of insulation that a 2x6 wall does and will create a stronger wall frame.

If you don't think cold is not transferred by conduction come feel the interior walls of the older homes in St Louis that are not insulated.  Granted some of the cold is from Air Leakage but not all.

 

Build Green,

Scotty 

Comment by Bud Poll on October 24, 2011 at 10:15am

Hi Scott,

A couple of points before this one falls too low on the list.  One, I can't read any of the details on your pictures.  However I kind of know what you are illustrating and have a question.  On a double studded wall, have you calculated the savings vs added cost of construction for staggered studs vs 2x6 or 2x8 construction?  Materials go up, labor goes up and the net increase in r-value seems minimal considering.  Thus there is a SIR for this approach which will vary by location. 

In many cases a simple 2x6 or 8 wall, well sealed with a detailed installation of insulation will performs so much better, that the extra cost of staggering is not necessary.  Those dollars could be better spent elsewhere.  If someone is looking for an extreme wall, say 12 plus inches thick, then it is simply 2 walls and not staggered.

 

If I could read the labels I could comment on eac diagram, but not sure that is possible

One last picky detail, cold is not transferred by conduction, just heat.

Bud

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