Maybe I am doing some math wrong or something, but it seems that adding XPS for $5,000 and then the interior insulation, studs, OSB, more expensive brick/stone ties, and framing labor; I am in the ballpark of ICF or SIPs. Would you agree? I haven't received hard numbers from ICF or SIPs, but estimating I would think there is not much difference. I like the XPS route, but it seems to be cost prohibitive to the point where there is not that much savings over going ICF or SIPS.

I guess the problem I see with ICF and SIPs is #1 I can find very few contractors in my area. #2 There is always the excuse for giving estimates - Why so many variables? I can look at a set of plans and say, this is the lumber/material I need, this is the insulation, framing is $4.25 square foot or less, etc... You should be able to do the same things with ICF and SIPs!


Sorry, for that rant.

The cost effectiveness of ICF depends a lot on the local cost of the concrete relative to framing, and the R value you're looking for. R for R (whole wall, thermal bridging of timber framing accounted for) the installed cost of EPS (the insulation on ICF) costs about 2.5-3x that of spray cellulose, and only slightly less than XPS sheathing.

Have you priced out a Z or omega steel-furring + cheap masonry tie solution for foam clad timber frame? Pressure-treated wood furring through-screwed to the studs also works, and you can use just about any tie that you would have used with without the foam.

Please share them if you get more details on the costs for ICF or SIP vs framed walls. I get $1200 + labor for 2" XPS foam, but of course that depends on the house size. It isn't exactly hard to lift or to cut. Guys that can frame 2x4 walls are easy to find right now. OSB is optional if you use plywood at the corners. Maybe not even that with the brick/stone.

Posted By Dana1 on 15 Jun 2011 11:45 AM
The cost effectiveness of ICF depends a lot on the local cost of the concrete relative to framing, and the R value you're looking for. R for R (whole wall, thermal bridging of timber framing accounted for) the installed cost of EPS (the insulation on ICF) costs about 2.5-3x that of spray cellulose, and only slightly less than XPS sheathing.

Have you priced out a Z or omega steel-furring + cheap masonry tie solution for foam clad timber frame? Pressure-treated wood furring through-screwed to the studs also works, and you can use just about any tie that you would have used with without the foam.

I guess I was referring to the foam board itself being too expensive. Payback is my goal. I like comfort, I want to save energy, but even with energy costs rising, the payback of $5,000 intial cost takes a long time. The houses I typically build are between 3,100-4,000 on one level with either a full basement or second level. So overall ~6,000 of HVAC space. My electric bill (Heating and cooling) maxed out this winter at $320. The typical month is $220.  Lets say I use the higher $320 and say 90% is heating and cooling. If I save 30% by doing these upgrades, it takes 5 years before I see any benefit (not including loan interest). I guess this is why I do research. The idea of putting foam boards up to increase R value, save energy really appeals to me, but the uncertainty and unusual high cost will always turn any consumer off.

If 5 years is your time frame, then just build to code minimums with the cheapest equipment and materials. But I encourage you to think longer term. And build somewhat smaller but better houses :-). Hopefully the gov will start taxing energy heavily (and give the average $ amount back as a refund) so that people will care more about saving energy.

Posted By jonr on 15 Jun 2011 12:23 PM
Please share them if you get more details on the costs for ICF or SIP vs framed walls. I get $1200 + labor for 2" XPS foam, but of course that depends on the house size. It isn't exactly hard to lift or to cut. Guys that can frame 2x4 walls are easy to find right now. OSB is optional if you use plywood at the corners. Maybe not even that with the brick/stone.

I would never skip on the OSB wrap or better. We are not considered to be in a high wind zone or anything, but in homes that use foam board and wrap the corners. You can hear walls popping and my friends who own drywall are always going back on repair because walls bow. 

What does the $1,200 cover? Material? 

I have contacted any ICF people that have given me pricing. "Depends on the plans, and labor." is the typical answer. Basically, a we won't know until after we start attitude.

For SIPS for one house I built, the cost was $10,500 for one story of exterior walls not including labor, delivery, or custom cut outs for windows and doors. The lumber for that story including the interior, exterior walls, house wrap, and ceiling rafters was $5,000. Foam and Batt, and attic insulation for the entire house (which included another 1500 feet upstairs and 1000 feet in garage) was $7,000. I went with the stick framing.

Posted By jonr on 15 Jun 2011 01:45 PM
If 5 years is your time frame, then just build to code minimums with the cheapest equipment and materials. But I encourage you to think longer term. And build somewhat smaller but better houses :-). Hopefully the gov will start taxing energy heavily (and give the average $ amount back as a refund) so that people will care more about saving energy.

I would think that $320 for a 4,000 ft2 beats most.

I work for the gov. I actually work for part of the energy side of the gov. And we do tax energy heavily. There are heavier taxes and costs on the horizon though.

There are heavier taxes and costs on the horizon though.

Don't forget the tax credit to make up for it part :-). I want less energy use, not higher overall taxes.

Posted By jonr on 15 Jun 2011 02:13 PM

There are heavier taxes and costs on the horizon though.

Don't forget the tax credit to make up for it part :-). I want less energy use, not higher overall taxes.

The tax credits are pretty significant right now. The reason I want less energy use is that I see what can happen when energy production is maxed out at peak hours. I have always had programmable thermostats. I use a system of really cooling/heating the house at certain times, using solid wood, countertops, tiles, and good insulation to hold temperature through those peak use hours. I believe we will evetually get to the point where the charges we see on our power bill will be hourly based on the time of use.

Back on topic....So I can go with 2x4 and 2" of board or spray foam, and increase r value to 20? I will have to weigh these different approaches. But at least I do not necessarily need 2x6 walls.

By the way, I tried foam and batt this last time, and I do like cellulose much better.

To properly calculate payback you also have to consider the reduction in mechanical system costs etc. But even with bottom of the line least-cost heating & cooling systems and single-pane windows there isn't even an economic rationale for even HALF the code-minimum in a net-present value calculation.

At any R value greater than ~R3 the biggest ROI on any of it is defining and implementing the primary air-barrier, monitoring those details carefully during construction, and at least one blower-door verification/rectification cycle. It takes a plan and an air-barrier-Kommandandt to get there, but the costs of getting it under 2ACH/50 aren't huge, and very straightforward when the lines of the house are simple enough. Something with 18 corners, 3 cantilevers, kneewalls, and 9 dormers will take more than a house with simpler angles and fewer independent flat surfaces. The Canadian R-2000 spec for < 1.5ACH/50 has proven to be relatively straightforward to achieve, but there are some learning curves for the builders. If you can get it down to under 3ACH/50 that's probably "good enough", but know that with the right builder and a simple enough house 0.5ACH is readily achievable with builders experienced with air sealing. (The PassiveHouse spec is <0.6ACH/50, with literally thousands of examples of varying complexity in Europe meeting or exceeding that spec.)

The fact that above a very low R-value there's no payback in ANY 5-6 year financial analysis despite pretty good 25 year or lifecycle value is only one of the many reasons building codes exist. In states with no codes, low cost housing can and is build with R7 econobatts, and those houses have an operating cost well out of proportion with their size.

Air-tight R20 walls with appropriately downsized mechanicals can be NPV+ in 25 years in some parts of Zone-4, but it's more about comfort/$, and whether you're in the mood to build something and move out of it before it falls apart vs. something that's comfortable and reliable for the long term. The recommended R values in the table on P10 in this document work financially in the longer term, if achieved in a carefully considered way:

http://www.buildingscience.com/documents/reports/rr-1005-building-america-high-r-value-high-performance-residential-buildings-all-climate-zones

Read at least the first dozen pages, (the entirety of Chapter-1), if nothing else.

BTW- For the record, what's the payback on brick veneer vs. vinyl siding in a 5-year simple or NPV analysis? :-)

Yes, 2x4 16" o.c. with cellulose fill and 2" of exterior foam comes in at ~R20 with a 25% framing fraction (typical window & door framing & size, doubled plates, etc) at and is a good performer. That can be boosted a small amount if you use some of the "advanced framing" or "optimal value engineering" techniques (google those terms for full-on descriptions) on the framing design. (you can at the very least design placement of windows with studs to minimize extra studs with no skinny cavities, , and the lengths of walls that work for the stud spacing, etc. If you use foil-faced iso or 2" of 2lb foam and advanced framing you'll hit ~R25 ish.

If you're really looking to optimize payback on every energy use aspect, tweak your design with a decent building modle (the DOE-2 freebie isn't bad, but there are others. See: http://www.doe2.com/ ) and do your own cost/benefit analysis.

Some basic approaches that make a difference:

The smaller (particularly narrower) you make the windows, the lower you drop the framing fraction, which increases the whole-wall R since there is simply less lumber thermally bridging the R12-R13 (center cavity) cellulose.

Casement & awning windows seal better than double-hungs or sliders, and offer more egress & ventilation area per square foot of glazing. (Push-outs are more reliable than crank-outs, but better crank-outs aren't bad.) Fixed windows leak even less. At R20+ whole wall, the total amount of glazed area begins to dominate the total heat gain/loss numbers. Shrinking glazed area and using simpler window designs is usually cost-negative (saves upfront cost) way to squeak another 10% or more out of the envelope efficiency. Every square foot of U0.34 window is an R3 hole in your R20-something wall, so a 10 square foot window conducts as much heat as 65-75 square feet of wall. A 20% reduction in overall glazed area can easily be a double-digit reduction in peak heating load & heating energy use.

But doors are usually worse than windows (at least half-decent windows) A 2" paneled oak doors with etched glass decorative sidelights have that great look and feel, but they're a big R1.5-R2 hole in your building envelope. There exist good/better/best insulated doors available starting at about R3.5 that don't actively suck in look & feel- at least think about it. (A project I'm advising on locally used some not-butt-ugly Jeld-Wens with a U value of 0.18, or about R5.5, but there are others.) At R4.5-R5 you've cut the heat transfer of that hole by 2/3, and it makes a difference.

But it feels like I'm repeating myself (broken record syndrome, I guess. :-) )

With air-tightness and attention to detail beating "typical' construction heating loads by more than half is pretty straightforward. With air-tightness and higher R in many designs you can then do high-efficiency mechanicals on the cheap with mini-splits, (or multi-splits) saving the cost & complexity of ducting. (This works better with smaller homes open floor plans and somewhat higher-R, but it still works OK with R20 overall average whole-wall and reduced glazing in the rooms doored-off from the rooms with the interior units.) If you can get your design-condition whole house heat load down to 20KBTU/hr or less (which is a realistic goal, with a bit of design, unless this a huge house) there are numerous ductless heat pump options that won't break the bank, and deliver superior comfort compared to typical hot-air systems, and provide both heating & cooling. (At Gatlinburg winter temps you should be able to run at an average COP well-north of 3 in heating mode.)

Greetings,

Posted By Dana1 on 06 Jun 2011 04:01 PM In bang per buck you'll usually get more performance out of adding more insulation than with RB, the exception being if you have ducts & air-handler in the attic. Response This is a common perception.  If you consider the fact that RB reject 97% of the heat energy (HE) and FG/Celluose about 5-10% and foam about 20%, then if you add the RB to the existing insulation it becomes the primary insulation. Adding more bulk insulation can actually increase summer heat loads (attic).  This has been a common complaint of FG.  It is common knowledge that about 4" of any bulk insulation is going to save the greatest amount of energy vs cost.  Going above that is iffy at best.  For instance if you have 6" FG in attic and add 6" more then the increase in efficiency is about 7.6% ( not 7.6 fuel savings).  Since you have already saved the most of the energy that this material can save, 7.6% is not very attractive.  In fact it may never pay for itself in energy savings. It has been my experience that adding a RB over the existing insulation will reduce the ac run time 50% or more.  There is no way bulk insulation can match that.  Reduce winter costs are usually lower because the heat transfer loads are different.  At the least customers say winter comfort is better. You must remember that the super "R" craze was generated by the bulk insulation industry.  In  fact the "R" value BS was generated by the insulation industry.  Look at the science.  Check who is backing the tests.

if you have 6" FG in attic and add 6" more then the increase in efficiency is about 7.6%

No, you cut the attic conductive heat loss by a little more than 50%. What percentage of your entire house that is varies. If you think that adding a radiant barrier to an insulated attic reduced AC use by 50%, then you didn't do the test correctly.

Greetings,

QUOTING jonr If you think that adding a radiant barrier to an insulated attic reduced AC use by 50%, then you didn't do the test correctly.

I don't have to test. All you have to do is compare utility costs and increased comfort of the house. I have been comparing for over thirty years. Besides you can't trust the manufacturers, they all LIE.

Until you do a RB retrofit, PROPERLY, and see the results you're not qualified to challenge me.

Besides the lower bills you have a substantial reduction in ceiling drywall temp. Since ceiling temps with, say FG can easily get to 110 dgs on a 95 deg day, no shade, then reducing the ceiling temp by 15 to 20 means less radiant heat radiating into the room.

This is why I say ALL the bs formulas are meaningless. In order to know the eff of you attic insulation, you have to know its temp on a hot day. That tells you the btu's being radiated into the house. That is your REAL DATA.

Now a drywall temp of 110 deg radiating to a 75 deg floor will radiate 35 degs/hr/sq ft. Now a retrofit will vary, BUT a new home with 3 layers of RB, installed per my instructions will give you about 2 btu/hr/sq ft. Which would you rather have.
If there is that much difference then I think we can safely say the retrofit will give a substantial savings despite what the so called experts say.

Just remember, insulation manufacturers lie, the government lies, and just more than a few engineers sell their degree to make money. It's not a pretty picture. And we and the environment are the victims.

Posted By rbisys1 on 23 Sep 2011 01:43 PM
Greetings,

QUOTING jonr If you think that adding a radiant barrier to an insulated attic reduced AC use by 50%, then you didn't do the test correctly.

I don't have to test. All you have to do is compare utility costs and increased comfort of the house. I have been comparing for over thirty years. Besides you can't trust the manufacturers, they all LIE.

Until you do a RB retrofit, PROPERLY, and see the results you're not qualified to challenge me.

Besides the lower bills you have a substantial reduction in ceiling drywall temp. Since ceiling temps with, say FG can easily get to 110 dgs on a 95 deg day, no shade, then reducing the ceiling temp by 15 to 20 means less radiant heat radiating into the room.

This is why I say ALL the bs formulas are meaningless. In order to know the eff of you attic insulation, you have to know its temp on a hot day. That tells you the btu's being radiated into the house. That is your REAL DATA.

Now a drywall temp of 110 deg radiating to a 75 deg floor will radiate 35 degs/hr/sq ft. Now a retrofit will vary, BUT a new home with 3 layers of RB, installed per my instructions will give you about 2 btu/hr/sq ft. Which would you rather have.
If there is that much difference then I think we can safely say the retrofit will give a substantial savings despite what the so called experts say.

Just remember, insulation manufacturers lie, the government lies, and just more than a few engineers sell their degree to make money. It's not a pretty picture. And we and the environment are the victims.

The condensed data from some people who DO actually test and compare utility costs, and have a large body of published empirical data to support their models:

http://www.ornl.gov/sci/ees/ets...et2010.pdf

Yup, the facts & data are all still a big conspiracy to screw ol' rbisys out of a well-weaseled buck, thatzit!

Greetings,

If you are planning to use RB on the exterior of the house it will become your primary insulator. Would recommend 2 layer RB sys between studs and single layer over inside like a VB, which it is. 1/2" stl "z" strips across the studs and then drywall.
You can use the same sys in the attic. This will give you about 2 btu/sf/hr in mid 90's summer and about the same for winter.
Use perforated materials.

This will out perform all other sys and is not prone to mold or condensation which cause fiber types to increase heat transfer up to 72 % .

Still more BS.

To meet code-max U values in any European climate zone with a mostly-RB product without additional foam or fiber insulatoin takes 7+ layers, not 2:

http://www.comparethemultifoil.com/

In cooler Euro climes with a 0.18 max U value you need to add 3" of rigid polyiso (PIR, iso) in combination with any of the multi-foil products that have fewer than 7 (8 really).

Airflex (3 layers) doesn't count, because it specifies 80mm (3-1/8") of mineral wool insulation in their installation procedure.

What they don't tell you in that chart is just how little extra thickness of iso it would take to be equivalent to the multi-foil RB ('taint much.)

But clearly 19 layers is pretty good stuff, eh?

Greetings,

QUOTE> To meet code-max U values in any European climate zone with a mostly-RB product without additional foam or fiber insulatoin takes 7+ layers, not 2:

The RB manufacturers gave up on manufacturing any more than 3 layers. There was no additional savings. Question is, since ONE layer reflects 97% of the energy, how much do you want to spend trying to control the other 3 % ?

The problem the RB industry is facing is the adoption of these ridiculous "R" factors based on the fact that the bulk insulation are so ineff.

When the RB people come in and show that you can do a better job with less they can't comprehend that and that is what the bulk insulation cos are banking on. The mentality is, you need a blanket. And what happens when blankets get moisture in them? They get useless. They other problem is, more is better.

In the thirty yrs I have been installing RB I have never found a house with any type of bulk insul that performed as good as the RB. Some better than others but not as good as RB. If there was a material more eff I would be promoting that material.

If you haven't seen any homes with bulk insulation outperforming 3-layer RB in the last 30 years, you clearly haven't been looking.

The 97% energy blockage of RB is solely for the radiated portion of the heat transfer. Only in an empty cavity would the majority of the heat transfer between wallboard & sheathing be radiated, and even then that fraction changes with delta-T. It's not even a huge majority in empty-cavity walls except on walls directly heated by the sun running temp several 10s of degrees above ambient. And 97% blockage of only the radiated portion insufficient to meet code for whole-wall U-values anywhere that has codes.

The methods of managing moisture issues in bulk insulation in timber framed construction is well understood by designers and building code developers (if not necessarily by all builders) despite a lot of misinformation and mis-understanding of vapor barriers/retarders prior to 1990. The IRC 2009 is pretty good about defining minimum standards for avoiding moisture issues related to insulation and vapor permeability in timber framed structures by climate zone, no rocket-science required.