What is the benefit of ultra high R values? If you are insulating at R 80 you block only a small percentage more heat than at R 40. I would bet that a sip house with R 25 walls properly installed with R5 windows, would out perform a house with r80 walls and only double pane low E windows. When you get past R30 or so I don't see where extra R value makes a cost effective difference. Is it just a "more is automatically better" philosophy?

I don't see where extra R value makes a cost effective difference

What will the price of energy be next year?

HylandTF: In 1990 a couple of scientists got together in Germany to find out the answer to that very question. They studied various buildings and started to develop a thesis which then developed into a house, then more houses, then a philosophy for how to build the best low energy house. Their project, still led by that scientist (in Germany), is now a non profit called Passive House. It's named after the idea that you should not need to be splitting wood or raising and lowering shades, but that if built correctly the house should passively heat itself - or close to it. And it works. Now there are hundreds of builders, architects, and interested people across the US who have studied his ideas and have learned the methods he used in his buildings. And there are a number of PH's built in the US, and thousands in Europe. No, it is not as easy as adding more R value, and it is a somewhat complicated process to design one to his standards, but it is not a "just a more is automatically better" philosophy. Look it up. Read about it. Learn the techniques; they'll help your business. http://www.passivehouse.us/passiveHouse/PHIUSHome.html

You are right that at some point, windows become a major factor. Maybe someone will come up with shutters that work well enough to become popular.

If you are going to build efficient buildings, you need to be thinking of the building as a system. You are correct in that windows are a huge factor.
In my mind the object is to build a durable building that does not cost too much to build and consumes as little energy as possible. There are many ways to get there, but it all starts with a systematic approach to building. It also has to be tailored to the microclimate you live in. A good building in Santa Fe New Mexico is not a good building in Fargo North Dakota. It is not trivial to do it right and most new buildings do not.
It is also hard to justify anything more than code min insulation if you are a builder, unless you can make efficiency a selling point to differentiate you from other builders. The average person lives in a house 7 years and will not see much of a return.
If the consumer drives the discussion then things change to what reduces the overall costs for house ownership. Today with interest rates very low, the incremental costs of energy efficient improvements are lower. If you pay 20$ more in a mortgage but spend 30$ less on utilities, then you are ahead of the curve. The question is how do you spend your money on efficiency measures smartly to get the biggest return for your buck. You also have to carefully look at the cost of energy and what sources are available in your area. Where I live, options are Electricity at ~$0.17 kwh, home heating oil and propane. All are costly.
If I take my house and the 2 houses closest to me you can see the extremes for the building trend. All were built in the last 8 years.

House 1 1100 sf ranch with 1100 sf insulated basement. IE 2200 sf inside the heated envelope. Well insulated, icf foundation under slab insulation mostly triple pane windows, passive solar design, solar hot water, wood stove, efficient propane boiler total yearly utility costs ~800$

House 2 3000 sf colonial insulated basement with minor mold problems code min insulating and windows, 6.3 kw solar PV system on roof fixed angle mount, 6 ton Geothermal Heat pump, vertical wells. Paid for a enery audit and air sealing. Near Zero Utility costs ~80,000$ upcharge for geothermal and solar.

House 3 4300 sf mcmansion + finished basement problems with mold in the finished basement dehumidifier running all year long, Oil heat. Code min insulation, crappy windows lots of them sited poorly so little solar gain is possible. Owner admitted they use about 6000$ per year in oil (1500 gallons) and electricity as high as 600$ month in the summer. AC and pool heater being the biggest loads. Owner considers these expenses “normal” they are quite happy with their house and have nice granite countertops and shiny fixtures. Wicked stove with massive 1100 cfm vent, triple ovens


Cheers,
Eric

Cost effectiveness on high-R has many factors, but on some level should be view on the lifecycle cost of energy-use avoided. Code-min is roughly 20-30 years to break-even in a net-present-value calculation using modest assumptions on energy price inflation and discount rates. But the cost of financing upgrades beyond that can often be rational since the total cash flow of that somewhat higher-R building can be lower, and the cost of heating/cooling utilites are paid in after tax dollars, while mortgage interest is subsidized in the tax coded, etc.

It's fairly easy to calculate the impact of construction & window types on energy use. In the US you can get good relative numbers (and even decent absolute numbers) for your house design at your specific site & site factors using DOE2 or BeOpt, freebie download tools courtesy of the US D.O.E. (google 'em).

At typical glazing fractions U0.30-0.34 windows start to dominate the wall-losses at whole-wall R of R20-25, so going to R50 whole-wall with a crappy window doesn't make a lot of sense, since the window could then be over 75% of the loss out that wall. Less obvious but still substantial is the heat gain of the windows both when the heat is and isn't needed, but that too is fairly well simulated with the DOE freebie tools. If you relally want to know the relative performance of PARTICULAR houses in a PARTICULAR climate using different R, mass, and window types, that is now readily knowable, no speculative bets required.

Also less obvious is the air leakage rates. A well-insulated wind-tunnel is still pretty expensive to heat & cool, which is why most higher-R standards that have been codified have max leakage specs (0.6 air changes per hour at 50 pascals ""ACH/50" max for PassiveHouse, 1.5 ACH/50 for the Canadian R-2000, etc.) While it's easier to air-seal ICF than stick-built it's by no means a done-deal. Many ICF houses where air sealing was mostly a shrug will run an ACH/50 of 5+, whereas it's neither difficult nor expensive to hit below 3ACH/50 with stick-built (which is the new recommended upper bound for most of the US under the IRC 2012. See: https://www.energycodes.gov/sites/default/files/documents/BECP_Buidling%20Energy%20Code%20Resource%20Guide%20Air%20Leakage%20Guide_Sept2011_v00_lores.pdf )

How you get to high-R has huge cost differences- doing it all in closed cell spray foam or an ultra-fat ICF is far more expensive than double-studwall or Larsen Truss with dense packed cellulose, etc. Air-sealed sheathing on 2x6 framing with 4-5" of exterior polyiso has a lifecycle cost rationale in most places with 7000 HDD+, and will knock the socks off R22.U0.30 ICF construction, provided the rest of the R values & U-values move in proportion, but would be absurd in places with 3000 heating degree days.

A rough guide on R-values by climate zone can be found in Table 2, p.10 of this document:

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

Note that those R values are whole-assembly averages with all thermal bridging factored in, not center-cavity R. Those values aren't engraved in stone, but are a starting point, since the cost of that R will vary by construction type, and the cost of heating/cooling energy isn't the same everywhere. In some locations with some methods even 1.5x those values have a clear lifecycle-cost rationale, but in places with cheap energy and high construction/material/methods costs it won't.

A persistent background criticism of the PassiveHouse approach (particularly on under-slab insulation, which has few super-cheap options), is that beyond a certain point the lifecycle cost of the higher-R go beyond that of the energy costs of photovoltaic solar expended in air-source heat pumps even at current PV pricing and HP efficiencies. The trend of PV price/HP efficiency over the lifecycle of the insulation makes some of those expenditures on the building envelope questionable on a lifecycle basis, even considering the costs of maintenance & replacement of the equipment.

For the time being in most of US, those hooked up to the natural gas grid are paying even less for heating & cooling energy than PV + HP, but over the lifecycle of the insulation that is unlikely to be the case. PV + HP will continue to become cheaper, and gas pricing will have quite a bit of volatility over the next 100 years, no matter how many holes they poke in the ground.

Hate to be Pollyanna and Dr. Doom in the same post, but ...

We have no earthly idea what state of the art will be in 100 years. It is instructive to remember that electricity was a luxury in 1912, and best-case then was coal delivered by wagon and shoveled into your basement. Even then, we're assuming your insulation survives until 2112. Could be a future owner 60 years from now rips out your "crap" for the fancy new phase-change stuff.

It's equally possible that your neighborhood in 60 years has sunk so far into decline that no one cares how much foresight you had. Unlike Germany, we live in a throwaway society. While my crystal ball is as worthless as the next guy's, I think I can say with some certainty that my children will never live in the house I'm building. Or their children. Unlike Germany. If it won't pay for itself in your expected tenure, forget it.

It's unlikely that energy will cost more in 60-100 years than PV + heat pumps do right now. Current technology wind-power is already in the same levelized cost as cheap natural gas in standard thermal plants, and is on a cost & efficiency improvement track to be competitive with cheap natural gas in combined-cycle power plants. PV is only 2-3x as expensive on a lifecycle basis, with manufacturing technology improvements in the pipeline to drop by more than half in the next 10 years, let alone 60.

Which means there would be no cost-incentive for pulling out that crap you installed today for the 3rd generation phase-change gunk (at any price for the gunk).

Even 1980 code min R values won't pay for themselves in the average 6-7 year tenure most 'mericans stay in their homes if they're heating with min-legal efficiency equipment, even if heating with high-priced BTUs like propane.

If it all needs to show a positive net present value in under 6 years, buy a tent a propane or kerosene heater, and a 600 board foot foam kit. Spray the exterior with an inch of closed cell foam and be done with it.

And if PC in 20 years is so cheap that superinsulation is irrelevant...? Back in the mid 90s, at the height of Japan's asset bubble, homebuyers were signing 100-year moirtgages. I believe they will tell you that making a bet on that kind of timeframe is a fool's errand.

Posted By toddm on 07 Sep 2012 12:51 PM
And if PC in 20 years is so cheap that superinsulation is irrelevant...? Back in the mid 90s, at the height of Japan's asset bubble, homebuyers were signing 100-year moirtgages. I believe they will tell you that making a bet on that kind of timeframe is a fool's errand.

That's the very argument some critics of PassiveHouse are making- the cost of the sub-slab insulation required to hit PassiveHouse has a higher lifecycle cost than PV + heat pumps at TODAYs HP efficiencies & PV costs, let alone the anticipated 2025 or 2050 costs & efficiencies, and current PV is still substantially more expensive than most other energy sources.

Even at half the current cost of PV going well beyond code min has a lifecycle-cost rationale if implemented using a lowest-cost methods. But yes, the error bars on future energy costs are large, and cheap energy supplies that begin with exponential growth DO have limits on capacity:  Even if wind power or PV were free the size of the resource is finite, and would not be enough power to run the entire US economy at current efficiency levels at predicted future population levels & energy efficiencies.  The capital costs of load reduction beyond some level may be more expensive relative to wind that can garner a 30% capacity factor (average output relative to max power over a year), but that mark gets moved WAY back for marginal wind developments with only a 10% capacity factor. 


There's bets and there's bets- not all need a short term positive return to be rational.  Some (like going 1.5x code on R) can be viewed as an insurance policy against future price volatility in the energy markets. Even if in the short or intermediate term there is energy deflation, making it arguably a poor investment from strictly an ROI point of view.  But if in fact there turns out to be a period high energy inflation, you are protected.

Just because plans may have to change in the face of evolving facts doesn't mean you shouldn't have a plan.  When building a house many efficiency opportunities are only available (or only come relatively cheap) during construction.   Superinsulation at PassiveHouse level isn't a hedge or  a bet- it's a philosophical point of view. 

At about R30-R40 whole-wall R it's pretty straightforward to get to Net-Zero Energy with PV on a house using mini-splits in much of US climate zone 5, and the project as a whole isn't outrageously expensive considered in a 50 year heating/cooling cost context of a code-min house. Still if you buy the PV today a un-subidized rates it's still a philosophy, not a bet.  But building an R30-40ish house with future PV in mind could still be considered a hedge if you're planning to live there for a coupla decades.  At the current cost of money the increased mortgage of the more expensive build is significantly offset by the reduced energy use even at today's energy costs, but not completely.

Simply bumping the thermal performance of R20 (center cavity) 2x6 construction by 50% with a couple inches of exterior foam can be viewed as a both a hedge & as an investment in comfort, even if it's never fully offset either  up front in reduced mechanical system sizing  or in short-years energy cost savings.  Building to R25-R30 whole-wall performance just isn't all that expensive compared to US zone 5 or 6 code-min on new construction when done using least-cost methods.  But it'll never "pay off" in 5 years or on resale value.

So it's really up to YOU to decide what's important to you, and what's worth paying for (and not.)  Green building isn't by it's nature is never going to be a pure present-value-of-money-invested proposition. There is implied value propositions beyond the mere cash, yet cash is still important. And not all efficiency upgrades will have the same impact per dollar, short term or long.

The philosophical arguments aren't all pure BS- the externality costs of most heating/cooling energy are not incorporated into the price per BTU or kwh, and some of those (like climate change) simply aren't easily quantified.  Some people are pretty comfortable about paying more now to offset those impacts of a house that will probably be around for another century or more. Even if their kids'/kid's/kids aren't living in it, they're probably still going to be on the same planet or at least that's the plan.  Clearly YMMV.

the material cost of isolation used in 2,152.8 sq. ft house in sweden ( 2 story building with frost protected shallow foundation) would be roughly 16000 dollars 300mm eps in slab 45mm + 220mm + 70 mm stonewool batts in walls and 500 mm blown in stonewool in roof.. not really that expensive imho .

And buildng in Sweden must be much more expensive than Usa ... for example we have to pay 25 % construction vat ..

As Don Rumsfeld said famously, there's what you know, what you don't know and what you don't know you don't know. In the latter category, in 1912, were fiberglass, stryrofoam, polyiso, spray PU, aerogel; in barriers, poilyethylene, Tyvek, radiant; in windows, multipane, gas fills, coatings; in hvac, nat gas piped to homes, AC, heat pumps, modcon furnaces. It's ludicrous to think we might know what 2112 will look like. Ergo, the 100-year argument for super insulation is also ludicrous.

Hedging is a different question. My goal is to build a house I won't be priced out of in my lifetime, or roughly 20 years. But that includes frugal use of my retirement funds. "It's only money" if you have it. To the OP's question of whether it pays to chase insulation down the curve of diminishing returns, the answer is no.

But few outside of the PassiveHouse/PassivHaus community are making the 100year argument for SUPER insulation. The (sometimes much-maligned) Building Science Corp folks are making the argument for roughly half PassiveHouse R-values, and suggesting that you sharpen your pencil around local energy costs, based on some relatively un-controversial future energy cost and current insulation cost assumptions.

BTW toddm: Even in 1912 full-wall-height air-barrier products available, as was blown-in cellulose and other fiber insulation (if not fiberglass), and storm windows. Natural gas and "city gas" coal gas had been long-since piped into homes for lighting/cooking/space-heating/water-heating use, hydronic boilers were also available (both pumped & gravitational systems) that ran with better than 70% combustion efficiency. Panel radiators for liquid hydronic heating already existed, as did steam-based radiant floor- not sure when the first liquid-water radiant floors showed up, but it wasn't much later (Frank Lloyd Wright was a fan of radiant floor technology well before 1950). Sure there have been a lot of improvements in materials, and but the actual performance improvements in homes have been primarily from code prescription for actually USING the stuff, not from some magic new technologies with no 1912 precedents.

Heat pumps had been invented prior to 1912, and air conditioning was already in use to control temperature & humidity inside printing & textile mills (mostly for the benefit of the product, not the employees), but wasn't used for residential AC or heating until a bit later. The toxicity of SO2 & ammonia refrigerants limited residential use of heat pumps mostly to food refrigerators in the 1912 time frame, but HFCF refrigerants came along in 1928 (less than 20 years after 1912) and residential heat pump use expanded rapidly- for food refrigeration initially, but rapidly expanding into air-conditioning in hot-humid climates.

For the most part the materials & technology used for heating & cooling and controlling heat/humidity transfer in building assemblies have been incremental improvements on that which preceded it. Many of the technologies have predictable limits based on the raw physis, some of which have been pretty much hit (such as 95%+ efficiency condensing boilers) but there's still plenty of room for large incremental improvements in heat pumps. The study of heat & moisture transfer in buildings didn't get really serious until energy become more expensive about 40 years ago, but that is now far better understood than it was in 1972, and the physics won't be different 2172, even if better materials for handling the issues are developed. Short of some amazing new energy source (nukes didn't exist in 1912, nor were they foreseen), 2112 solutions would only be incrementally better performance versions of currently available stuff- glass windows have been around a long time, and a state of the art triple-pane would be readily recognizable as a window by a 17th century person.

My expectation is that fossil fueled hydronic boilers might look a bit quaint in 2112, but there may be bio-mass boilers around, unless heat pumps make such rapid strides toward the theoretical limits by then that any home sized combustion-boiler would be expensive oddity. The theoretical limit of the coefficient of performance of a heat pump running a delta-T of 40C is about 7, and most 2012 heat pumps are running half that or less. There's room for improvement, but it will most likely be incremental with time, not big breakthrough type epiphany that changes the world forever. It won't be an order of magnitude better, but may follow a track similar to that of the combustion efficiencies 50-70% boilers available in 1912 to the 80-95% boilers of today.

warimoto: Sweden is a bit cooler than most of the northern US (but not a lot colder), and IIRC Swedish building codes related to energy use are based on performance rather than prescriptive U-values/R-values the way it is done in the US. If the energy use numbers can be met with heat pumps or other methods rather than more insulation or high-performance windows, that's acceptable under Swedish code, whereas in the US the building elements meet a (not very stringent specification) independent of the efficiencies of mechanical systems. Swedish code puts a lot more responsibility for performance on the architects & engineers than the people doing the actual construction, but oversight of construction on features that affect performance is pretty intense since the architects & engineers are responsible for fixing it if it fails to perform. By focusing on performance rather than prescriptive values of sub-components it drives the designers toward lowest-cost solutions.

That said, insulation levels for new homes in Sweden are much higher than in comparable climate zones in the US (if still lower than PassiveHouse levels), which indicates to me that higher insulation levels are a cheaper and more reliable way to hit the performance numbers.

"Everything that can be invented has been invented," Charles Duell, U.S. patent commissioner,1899.