Malcolm 116 "A series of bellicose responses to anyone who doesn't share your views isn't furthering the discussion either. The questions that still go begging are at what price and what is their efficiency compared to other options? I think it's fair to say, apart from generalities, the proponents have been coy or mute in answering those points. Why is that and why are you getting so mad?" I apologize for the seeming 'bellicosity' of my responses, not intended to be that. What's bothersome is when radiant comfort systems (in any climate) are 'tried' and the results are unsatisfactory and needing forced air mitigation (and the costs associated thereto), they then categorically claim radiant comfort systems are a poor choice for cost, efficiency and comfort. Most people, yourself included I presume, have never "visited", lived in even for a few days (weekend) any successful radiant comfort system. I guess this is not very likely, possible or desired by those who are curious or like to opine. Oh, and being able to 'compare' two system's (radiant & forced air) operation in real time, apples to apples so to speak, not likely - who is going to build two “identical houses” with one incorporating radiant and the other incorporating forced air??? This is unfortunate but is the reality. Therefore, all in this group (most everybody) have to rely on second hand information, data, technical reports and opinions of others from all sources - radiant and forced air opined examples. My "views" are like others who have personally experienced successful radiant comfort. BUT, unlike these others, my "views" are based on first-hand knowledge and experience in conjunction with DOE Building America Program research engineers testing and monitoring with embedded sensors in, on and below the concrete floor, and elsewhere for real time data monitoring temperature, thermal comfort, humidity mitigation and ERV whole house ventilation. Construction was completed in late spring, 2011 with move in and testing protocols occurring for the next 2-3 years. Moreover, and I can’t be 100% sure, but I think nowhere else has there been created a high performance thermal enveloped prototype new home that has BOTH a whole house radiant floor comfort system AND a whole house forced air comfort system to research. These two systems were tested independently and togethe, monitored, experimented with and (live in) experienced for almost three years now. The radiant system has three independent thermostat controlled zones, one for the main living area and one for each bedroom wing (split bedroom floor plan, single story). The ability to test so many combinations of thermal performance and electricity usage and humidity-dehumidity performance with set point thermostats and setback thermostat settings... a wealth of REAL TIME information (objective and subjective) has been gleaned. All of these reports, stories, presentations, and abstracts will be chronicled soon at our website. Plus, this summer at the annual ASHRAE conference and the biennial ACEEE conference the most recent evaluation and assessment abstracts will be presented. No offence intended, but the opinions and experience of Mr. Holladay’s are antiquated and outdated. Sort of like musing about picture tube TVs when high def’ flat screen LED TVs have fully replaced the ‘old order’; smart phones compared to analogue phones? Which would you prefer moving forward into the future?
Posted: 11:53 am on May 5th 2014
Southern Arizona slab on grade with radiant tubing To insulate or not; to steel reinforce slab or not; wire fabric in slab or not; radiant floor (heating) pex tubing attached to suspended #4 at 2'oc each way or not; what about potential (some say inevitable and the only thing one can do is mitigate) cracking slab; sandwich the vapor barrier or not; on compacted base or under........ How about the following proven concept (DOE Build America testing, monitoring and 3 year lived-in experiencing) compact sub-base, compact AB or similar, 40 mil plastic liner (vapor and radon restrictive; perhaps too much but one time expense), 2" R10 Creatherm (pex ready snap-in plasticized topped eps foam), pex tubing at bottom of 4.5" slab with no steel reinforcing, finished concrete floor, no cracking, year round radiant floor thermal comfort It's called the KIS (keep it simple) principled way of building.
Posted: 02:37 pm on July 10th 2014
40 mil correction Sorry readers, I misread the old invoice from 2010. The poly vapor barrier is 10 mil, not 40. It's called Perminator a product from WR Meadows. Comes in different widths and lengths so it's easy to economize and minimize seams. Great stuff. Burke- it's great to hear your prepour installation method in wet, coastal environment in Canada. Your sequence is identical to what we did in hot/dry climate of southern Arizona. It seems like the only difference is in the particular foam product choice. We used 2" R10 Creatherm product because it had the plasticized 'reversed muffin tin contour' (my description for visual perception) in which PEX just pops in place perfectly uniform in position. Do you do any hydronic radiant heating?
Posted: 01:27 pm on July 11th 2014
WR MEADOWS white paper on vapor retarders/barriers definitely worth reading: http://www.wrmeadows.com/concrete-vapor-barriers/
Posted: 01:44 pm on July 11th 2014
Hello Anneal, If you are still interested in design/building a cost effective high performance energy efficient home, the Dept. of Energy (DOE) Build America Program has been doing extensive real world research in all climate zones including our southern Arizona hot/dry climate. You might want to explore the 2013 Build America Top Innovations for net zero ready homes: http://apps1.eere.energy.gov/buildings/publications/pdfs/building_america/ba_innovations_2-1-6_zero_energy_homes.pdf Go to page 2 top left picture and read brief description on right about ARBI research on the home(Left) The ARBI team, led by Davis Energy Group, worked with La Mirada Homes on this SIP prototype home in Tucson that uses an air-to-water heat pump to heat water for radiant floor heat and chill water for fan coil and radiant floor cooling. There is a lot more published and (news) story info on this home. Bottom line is that it attained Passive House performance (31.6kBtu/ft2-year, 38.1kWh/ft2-year is PH min threshold) with off-the-shelf design build features producing R34 SIP composite wall, R41SIP roof and R10 under slab. The structural and thermally isolated concrete floor is temperature controlled which results in controlled ambient temperatures hovering around 75F all the time.
Posted: 12:33 pm on July 15th 2014
When you're hot, you're hot, EXCEPT... Its summertime in southern Arizona and, yes, it gets hot just like northwest Phoenix area. Is it possible to be cool in a home where ambient temps ALWAYS hover around 75F? without a forced air system cycling intermittently throughout the 24 hour day? How could this be? A well insulated ice chest with a block of ice will maintain cool temps for a longgggggg time. It's as simple as that. The same is true for a house (ice chest) and the temperature controlled concrete floor (block of ice). The enormous thermal mass capacity of a 4.5" thick slab for the entire home does just that, noiselessly, consistently, evenly and everywhere in the home - no varying and intermittent micro climates created by a blowing forced air system. And, with a 3kWh PV system the electric bills have been April, May, around $12 each month. June was just under $28 (almost half was standard customer service charges). July is coming soon but probably will be around $40.
Posted: 08:31 pm on July 17th 2014
poly placement and radiant heating Excellent points on the poly placement location Regarding tubing placement for radiant heating, I have always been concerned about potential problems with the pex tubing being tied to rebar mat: (1) uniformity of placement both horizontally and more importantly, vertically (2) potential known and UNknown damage to pex occurring during concrete pouring, (3) just so many potential what if's with so many laborers trying to maneuver around during the pour. With the use of Creatherm product almost all the above mentioned concerns are just taken out of the equation. Additionally, I used poured stem walls and a 'floating' slab (thermal and structural isolation) and NO rebar in the slab. The only add to the 4.5" pour was fibermesh. I had NO cracking at all. I personally think there were four reasons for this easy, non-cracked floor: fibermesh, pouring in shade (SIP walls and roof were up) and most significantly the physical embedded reverse muffin tin shape of the Creatherm product: 4" oc, 2" diameter, 1" tall knurled protrusions into the bottom of the concrete and finally NO uneven water wetting the subbase just prior to pour thereby NO uneven drying or curing.
Posted: 01:03 pm on July 18th 2014
Shading exterior walls... Do you need to shade a highly insulated ice chest that has a block of ice in it? No.
Posted: 11:36 am on July 30th 2014
Air sealing or insulation? To really understand the relationship between air sealing and insulation-R value one can think about the following real world analogy: (assuming a cold climate context), air sealing is akin to zipping your jacket up on a cold wintery day but, if you are wearing a wind breaker shell like jacket as opposed to a down jacket, you're going to be cold. Conversely, if you are wearing a down jacket and it is NOT zipped up, well you're going to be cold. Bottom line is you can't have one without the other because with either one by themselves you will be paying much more in lack of comfort and higher utility costs. Bottom line, is you 'should' to do BOTH, it's a ONE time expense that absolutely determines your daily comfort and monthly cash flow. It is as important as the structure itself.
Posted: 05:40 pm on August 28th 2014
Jenz Yoder- I wish I had come on board this debate/discussion a couple weeks ago because of all the misinformation, erroneous predictions, etc., etc. Most, if not all, the opining and consulting you have endured with your realistic questions have been answered from those who have not, in fact, done what you are doing; those who only rely on conjecture. They have not been in the 'trenches" as your are doing and have not "been there, done that" in the real world where the proverbial rubber meets the road. I have been living in a passive house quality, proven home with radiant floor heating AND radiant floor cooling in the desert southwest, Tucson, AZ for four years now. One that was tested and monitored by the DOE Build America Research Program. I can say without hesitation that radiant floor heating in a passive house quality or qualified home is by far and away the best heating, and cooling system you can have for this "ice chest" like home. What these 'experts' do not realize is that in this kind of "ice chest" like home, the insulated and thermally isolated 5" thick concrete slab equates to the "blue ice" that one puts in the ice chest except it is "plugged in" to a typical wall thermostat and corresponding heat/cool source for the water. By keeping the surface temp of the slab at 75 degrees (or whatever you choose), the entire living space both horizontally and vertically stays whatever floor surface temp you have chosen. The entire volume of space is the same temperature within degree or so. The enormous amount of thermal mass that the concrete floor contains trumps anything else, period. And, by the way, the time for "recharging" the floor is during the day when the sun shines and having a modest size PV system will be all that's needed for heating. No electric storage needed. And because of the superior quality of your thermal envelope your heat loss will be immaterial and there will be no lag time between heating days.
Posted: 11:01 pm on September 16th 2015