By all means. Ignore the scientists. Toss out common sense too. Why Todd's Magic Elixir grows a full head of hair, cures cancer and makes you as handsome as George Clooney! And my interior mass house is so warm I bottle heat and sell it to the neighbors.

Jonr, shudda said diurnal swings must bracket comfortable for mass to eliminate hvac. In the classic adobe/thick stone model, heat and cold never penetrate fully but rather cancel each other in sine wave cycles somewhere in the wall interior. Thermal lag in concrete is roughly an inch an hour so your approach in a dry climate, coupled with exterior insulation, could hold a house in a narrow range. The 64-dollar question is what's the daytime heat load from windows, appliances, activities, egress.... Mass helps in any case even if you need the AC.

And my interior mass house is so warm I bottle heat and sell it to the neighbors.

Yes and probably have to otherwise it overheats.

BTW Adobe is not the same as stone or concrete. It is clay with a much lower conductive value, It does not rob all the btu's from the air as concrete does but takes and gives slowly because of its insulate value. Just like ICF!

Well no. The thermal lag of adobe is slightly less than concrete at about 10 hours to penetrate a foot vs 12 hours for concrete. In a typical adobe wall two feet thick, though, the heat of the day NEVER gets inside, which is the point of old-school thermal mass. (I'm not sure how mass works in FBBPland; the physics apparently are different.) In a cooling climate I'd want walls that "rob btus from the air," as would most San Diegans. Gotta wonder how many 19th century New Mexicans said, 'gee, this interior wall is only 75 degrees. Let's cover it.'

Mass is less effective in a heating climate as both ORNL and Canadian studies show. There's some beneficial time shift. The daily low is delayed in an eight inch concrete wall from 4 a.m. to noon, when a heat pump presumably works more efficiently, but we're still dealing with the world in 24-hour segments. There are days in the shoulder seasons when mass works as advertised, again buffering diurnal highs and lows. Fact is there is a reason ther aren't many adobe houses near you in Alberta or me in Pa.

I live in a high-mass house because it also has aggressive passive solar glass, so walls "that rob btus from the air" are a blessing on bright days. God help us if you argue next that ICF is better than internal mass at buffering passive solar.

ICF is better at creating comfort in all situation. With naked mass, the days the sun doesn't shine and the mass has given up its excess heat, you need to pump in enough btu's to heat all the mass and the air just to raise it that one degree. With even a little insulation on the mass, you can get the air temps up to the comfort range quite quickly while letting the mass slowly absorb its needs (even if it is being supplied by fossil fuels.)
I can't find Dana post on it right now but I believe he suggested 3/4". Wether this is the right amount or not, I'm not sure.

Actually neither the ORNL or Canadian Studies show that and certainly don't prove that. The Waterloo study only says that the heat transfer does not reverse.

Wow. No again. A house that loses 25k btu/hour at design temp, as mine does, needs 25k btu/hr to keep it warm, high mass or low mass, icf or internal mass. The only difference is that an hvac-free hour would be barely noticeable in my house. The temperature change in 50 tons of concrete, cooled by 25k btu, isn't even a rounding error. In fact, my unheated garage settles at 55 degrees in an average winter. FBBP's icf house would also have great staying power if only he hadn't covered his concrete with insulation.
So what happens after 200 hvac-free hours? Well, I have a wood stove boiler and radiant heat that raises the slab temperature, or half of the house's mass, by one degree an hour. A major source of btus is a good idea even in San Diego. In old-school thermal mass, it was an adobe fireplace called a kiva.
Would an icf house seem warmer faster? Yes. Would it be warmer? No. Assuming equal mass, equal loss and equal r value, the recovery would take the same number of btus except over many more hours and potentially wasteful furnace cycling, because the mass is hidden beneath EPS.
That said, his home and mine don't have equal r values. More to the point, my glazing would be a comfort nightmare in Alberta. So I will cheerfully admit that r22 walls with no thermal bridging is more efficient in heating climates than internal mass at lesser R value. The rub is that r22 can be had without concrete. What the Waterloo study says is that researchers found no evidence that thermal mass (the concrete) made a difference. So call it sturdier, tighter, pest proof, whatever. But north of the 48th don't call it green.
Finally, while comfort is subjective, I suspect that most people would say my radiant slab is decadently superior to forced air. Can't even hear the pumps turning.

So that must be a fairly large house, eh?

Yes it would be warmer because the air people feel will be warmer. Will it take less heat to stabilize? No because the mass will take the same btus. And that is what we are talking about. Its good of you to man up and admit that naked mass needs a major source of btus to deal with fluctuation. Not everyone has cheap wood or the desire to burn wood so they would have to use fossil btus to save the comfort levels. Also no, there would not be wasteful furnace cycling because we can use smaller heating appliances in the first place.

So Todd, tell me, do you really believe the fact that there is no reversal of heat flow in the mass when the warm side temps are kept steady is an indication that ICF has no DBMS?

Sailaway stated and showed that performance was reduced by 33.4% if all the EPS was on the exterior building side. Best performance was with the concrete sandwiched between the two layers of EPS as observed in a standard ICF sandwich at 2.5" EPS x 6" concrete x 2.5" EPS

San Diego. You know. Padres? Chargers? South of LA? Near the Mexico border? Not Oregon. Definitely not Alberta. For the few times high mass/passive solar would fail OP, he could use resistance heat as his major source of btus and still save megabucks the other 51 weeks of the year.

Oregon is the flip case. From my adventures on the Rogue River, making sure the second time to bring along a sweatshirt in August, one wonders if R62 saves $10 a season. One also hopes that sailorrb is offended to see her analysis misused in a discussion of icf vs internal mass in the desert SW.

Rather than have this argument again, I'm simply going to urge the OP to go here: http://www.energy-design-tools.aud.ucla.edu/climate-consultant/request-climate-consultant.php Using historical weather data from the NWS site nearest to your site, it breaks down the year by the number of days that an energy strategy provides comfort. The winner will be passive solar/high mass by a huge margin. You will also see that high mass works by itself, and by high mass it means exposed, not hidden behind EPS. If you doubt that, go here: http://www.energy-design-tools.aud.ucla.edu/heed/ Applying the same weather data to a crude model of your house. oriented on the site with doors and windows in position, it shows energy consumption and cost through 365 days. ICF and internal mass are stock options in the model, so with a few clicks you can compare them unfiltered by salesmen. Be sure to return here to thank Lbear for his "help."

IIRC, California require block walls to be filled with concrete. Your local building dept will help (one hopes.) Hybrid ICF splits the difference, using low density concrete blocks that are then filled with concrete in a honeycomb pattern. You can add EPS sheathing or not. Rastra in Phoenix is the oldest of these. Durisol is the greenest -- made in Canada with cementized wood chips. No worries in SD about getting too much mass as long as you have a source of heat capable of recovery. Truth be told, passive solar will be enough by itself. Nothing happens quickly in a high mass house. HEED also guestimates how hot and cold your house will be over a year of no hvac.

http://www.energy-design-tools.aud.ucla.edu/climate-consultant/request-climate-consultant.php

toddm - Thanks for the link. I hope this will simplify matters.

I just spent some time in Mexico, Baja California. It's a desert environment with most of the recently constructed buildings and houses made of concrete and rebar without insulation and very "loose" envelopes. AC is needed in the summer and to reduce humidity at least near the ocean, but most of the year the wind keeps the buildings cool, comfortable. The temperature swings do make a difference here, without a doubt.

It becomes evident though by all this discussion, that if saving energy is truly a priority in the USA, Canada or elsewhere, there really needs to be some sort of standardization in using Thermal Mass, obviously dependent solely on regional climates. ( What is best for San Diego is not best for Alberta and vice versa.)

I think there is wide acceptance for the thermal mass modeling software developed by Oak Ridge Natl Labs for DOE with the exception of the ICF crowd. Surely the UCLA software relies on it for HEED and ClimateConsultant. It is also a component of the DOE's EnergyPlus, and as such incorporated in MIT's simulation software. Except for ICF, mass wall manufacturers follow ORNL protocols to generate effective r values for eight cities representing US climates. My building inspector accepted effective r values for DC to pass my house under the energy code.

ICF's pique is longstanding and heated -- to the point that the trade association built a test structure in Knoxville in conjunction with ORNL in hopes of setting the laboratory straight. The house performed poorly and the trade group promptly buried the study. ICF boosters have lots of reasons why it underwhelmed, such as FBBP's swimming pool in the basement. But one wonders, in that instance, if the trade group's execs were too dumb to have their own people onsite in Knoxville or if said people were too dumb to request a water table analysis when one of the issues on the table was whether or not ICF walls benefit from "earth coupling." (ORNL's answer: nope.) One might also wonder why they didn't find higher ground and start over.

You should take this as an indictment of marketing types rather than the technology. My house sits on ICF frost walls, for which use it is head and shoulders superior to standard practice block construction. And an icf basement is a winner as extra living space in heating climates.

I expect that the modeling is straight forward and accurate except for the people behavior part. Ie, how much interior temp and humidity variation will they tolerate, how good are they about opening/closing windows and is powered ventilation used.