I declare I have never seen a home where weatherization problems demanded detection with a blower door test. This is in exceptionally competent practice as an individual, over five years, dealing mainly with attics. My practice does include walls and crawl spaces. For walls, I once found a garage wall driven-through, hidden by paneling, behind a wood pile, very leaky through insulation batts not-covered by the opposite face, and not detected by a home performance tester.
I charge that there are no weatherization problems to be solved in typical American homes, not best detected visually by a diligent worker. I do admit that a blower door can deepen temperature gradients, to improve detectability of hidden problems by infrared inspection, but note that infrared inspection is with expensive tools, not afforded by many Home Performance inspectors, and not demanded of them in Oregon.
My criticism of blower door testing is posted for comment to inspection professionals at Saturn Resource Management, Inc., in Montana. SRMI is an especially competent organization and source of training. SRMI publishes the best books I have found, teaching weatherization details.
Here are comments to my blog postings, by SRMI bulletin-board readers, Saturn Online:
http://srmi.biz/forum/YaBB.pl?num=1276355506/1#1
I further invite Saturn Online postings of examples that contradict my findings.
Monday, June 28, 2010
Saturday, June 19, 2010
My Home Performance Test
While I owned, and competently operated a blower door, I of course applied it to my own house, typical but extraordinarily well-built, 1950's ranch-style.
In this, apply my Insulation Math.
Here is the text of the Blower Door Test Certificate I produced:
Date: August 25, 2008
Baseline, My House
In a baseline test, all outside doors and windows are closed. If there are storm windows, they are closed. All interior doors are open. Fans and furnace are off.
Result: Airflow at test pressure (CFM50), 1330 CFM.
Results Commentary:
Desirable Air Exchange: Look at air changes per hour, ACH.
Consider ACH50, that at the minus fifty pascals test condition.
ACH50 = CFM50*60/House Volume
where house volume = 8 ft height times 986 sq ft floor area, 7888 cu ft.
ACH50 = 1330*60/7888 = 10.1.
Compare this to a minimum value of eight for a healthy home. Some further reduction would be desirable.
A reduction from ACH50 =10.1, to ACH50 = 8, is 280 CFM50. The value of that reduction, in annual heating cost, is 0.074 times change of CFM50, or $20 per year.
The estimated leakage under natural conditions (ACHnat) is approximately the result of dividing the test result by twenty. ACHnat = 10.1/20 = 0.506. Compare this number to a value of 0.35 to 0.5 for a healthy home. A target blower door test result is about 921 to 1315 cfm, for the target 0.35 to 0.5 ACHnat. A reduction of 280 CFM50, to 1050 CFM50, is a shift to ACHnat from 0.506, to 0.40.
A 280 CFM50 change corresponds to 14 CFM at natural conditions. Compare that to accelerated fresh air exchange while running a bath fan. A good bath fan for a 100 sq ft bathroom will be rated at 80 CFM. If I ran that fan four hours a day, it would average 14 CFM.
I have a typical house, and this is a typical result. Nothing motivating. Just a sick feeling about wasted time and effort. It is a typical home performance test overall. No other step to assess the "science" of the personal comfort and health in a home, offered in the typical hopeful "holistic" baloney. No offer to look for hidden problem areas with an infrared camera. No thought about Radon. No thought about control of relative humidity. No duct blaster test or furnace assessment competently at-offer, if not done by a rare professional home inspector or HVAC mechanic. Just the blower door show.
The commentary is above and beyond what most home owners receive. For most, there is nothing. A number might get written on a scrap of paper. It might appear in a report. There will be no offer of "fixing" anything. A particularly diligent tester might have tsk-tsk'd at a squealing window edge, and might have even done an impermanent and inappropriate repair, with a caulk tube. Anything serious is for another contractor, who will not likely see any of the tester's report.
If the testing is by an interest-conflicted blower of loose-fill insulation, repairs such as the so-often needed covering of attic floor pits, and bringing in an electrical contractor to deal with safety and convenience issues, will be precluded by immediate burial. In my area, that crook can then submit a fudged blower door report, and pad his bill with the rebate I would have been denied for my real, diligent, hard work. The home owner will then suffer unsaved heating costs, for many years. This is a crime of the incentives programs that exalt home performance testing. The awful wrong-headedness is well illustrated in a flyer from Energy Trust of Oregon, perhaps from a national template for "training."
Weatherization Boot Camp will teach you how to:
Reduce uncontrolled air movement by installing blown insulation materials to correct density.
What does that mean? For an attic floor without buried problems, it is absurd. For an attic floor with buried problems, it is criminal.
2016 Update
At 3/24/2016, add to this with goal of addressing IECC actions for 2018 revision, R402.4.1.2(old) R402.3.4(new) Testing Envelope Air Leakage.
The building or dwelling unit shall be tested and verified as having an air leakage rate not exceeding five air changes per hour in Climate Zones 1 and 2, and not exceeding three changes per hour in Zones 3 and colder. We talk of such "air changes," tending to forget such are for artificial conditions as if a home were subjected to static pressure everywhere outside the home, that of 20 MPH wind. The artificial condition is set by a "blower door" mounted in an exterior door, pushing air outward, at static head of 0.2 inches water column. The air flow through the fan for those conditions is about twenty times the rate of actual home fresh air exchange.
I believe I am now below 5 ACH50, saving $50 per year in cost of make-up air, from accumulated home improvements. There was no possibility a blower door would have guided those improvements. I will own a blower door again someday, and will use it honestly. It will never be lied-about as guide and measure of weatherization. A blower door is useful only as verification of needed fresh air exchange, upon very rigorous completion of obvious improvements that tighten a home. If a controlled amount of air exchange is volunteered, as through continuous powered, regenerative heat exchange, a test may again have no value.
I am contributing to the 2018 IECC revision process as an unpaid volunteer, and hope to address applicability of rules, to existing homes, Chapter 5. Chapter 4 rules apply only to new homes unless referred into Chapter 5, and that referral for home sealing has not yet happened. That failure is associated with the continuing blower door madness that misguides weatherization. Important opportunities for sealing are found by sight, and should be addressed by each worker, not restrained by test-in, test-out foolishness.
Proposed changes to the International Energy Conservation Code Of 2015, will be considered at the 2016 Committee Action Hearings, April 17-27, in Louisville, Kentucky. In my preparation for this, I see a foolish continuing commitment to tighten our homes without limit, then needing to provide fan-driven fresh air.
I summarize thus, further exercising the Insulation Math for my 1000 sf home:
About that radon concern I now monitor my house continuously with an affordable Corentium Model QRI, a very nice Product of Norway .
At Amazon $200 it isn't for everyone, but it is more affordable than I had hoped ever to find. It came to my attention in a post by friend Corbett Lunsford .
How to Test for Radon at Home: Proof Is Possible - YouTube
I thought I would observe readings for a couple of weeks, and then let my customers share it, but instead it has been recording away for three months now, and the long-term average has not held steady at 2.5 pCi/L. It has drifted up now to 3.5 pCi/L, moving toward the action level of 4 pCi/L . I will continue to watch this for a few more months, before sharing the monitor.
Further radon monitoring and a very successful passive solution is reported in my blog post Success: Passive Control of Radon in My Single-Family House, April 10, 2021.
September 2024 Update
Here is the text of the Blower Door Test Certificate I produced:
Date: August 25, 2008
Baseline, My House
In a baseline test, all outside doors and windows are closed. If there are storm windows, they are closed. All interior doors are open. Fans and furnace are off.
Result: Airflow at test pressure (CFM50), 1330 CFM.
Results Commentary:
Desirable Air Exchange: Look at air changes per hour, ACH.
Consider ACH50, that at the minus fifty pascals test condition.
ACH50 = CFM50*60/House Volume
where house volume = 8 ft height times 986 sq ft floor area, 7888 cu ft.
ACH50 = 1330*60/7888 = 10.1.
Compare this to a minimum value of eight for a healthy home. Some further reduction would be desirable.
A reduction from ACH50 =10.1, to ACH50 = 8, is 280 CFM50. The value of that reduction, in annual heating cost, is 0.074 times change of CFM50, or $20 per year.
The estimated leakage under natural conditions (ACHnat) is approximately the result of dividing the test result by twenty. ACHnat = 10.1/20 = 0.506. Compare this number to a value of 0.35 to 0.5 for a healthy home. A target blower door test result is about 921 to 1315 cfm, for the target 0.35 to 0.5 ACHnat. A reduction of 280 CFM50, to 1050 CFM50, is a shift to ACHnat from 0.506, to 0.40.
A 280 CFM50 change corresponds to 14 CFM at natural conditions. Compare that to accelerated fresh air exchange while running a bath fan. A good bath fan for a 100 sq ft bathroom will be rated at 80 CFM. If I ran that fan four hours a day, it would average 14 CFM.
I have a typical house, and this is a typical result. Nothing motivating. Just a sick feeling about wasted time and effort. It is a typical home performance test overall. No other step to assess the "science" of the personal comfort and health in a home, offered in the typical hopeful "holistic" baloney. No offer to look for hidden problem areas with an infrared camera. No thought about Radon. No thought about control of relative humidity. No duct blaster test or furnace assessment competently at-offer, if not done by a rare professional home inspector or HVAC mechanic. Just the blower door show.
The commentary is above and beyond what most home owners receive. For most, there is nothing. A number might get written on a scrap of paper. It might appear in a report. There will be no offer of "fixing" anything. A particularly diligent tester might have tsk-tsk'd at a squealing window edge, and might have even done an impermanent and inappropriate repair, with a caulk tube. Anything serious is for another contractor, who will not likely see any of the tester's report.
If the testing is by an interest-conflicted blower of loose-fill insulation, repairs such as the so-often needed covering of attic floor pits, and bringing in an electrical contractor to deal with safety and convenience issues, will be precluded by immediate burial. In my area, that crook can then submit a fudged blower door report, and pad his bill with the rebate I would have been denied for my real, diligent, hard work. The home owner will then suffer unsaved heating costs, for many years. This is a crime of the incentives programs that exalt home performance testing. The awful wrong-headedness is well illustrated in a flyer from Energy Trust of Oregon, perhaps from a national template for "training."
Weatherization Boot Camp will teach you how to:
Reduce uncontrolled air movement by installing blown insulation materials to correct density.
What does that mean? For an attic floor without buried problems, it is absurd. For an attic floor with buried problems, it is criminal.
2016 Update
At 3/24/2016, add to this with goal of addressing IECC actions for 2018 revision, R402.4.1.2(old) R402.3.4(new) Testing Envelope Air Leakage.
The building or dwelling unit shall be tested and verified as having an air leakage rate not exceeding five air changes per hour in Climate Zones 1 and 2, and not exceeding three changes per hour in Zones 3 and colder. We talk of such "air changes," tending to forget such are for artificial conditions as if a home were subjected to static pressure everywhere outside the home, that of 20 MPH wind. The artificial condition is set by a "blower door" mounted in an exterior door, pushing air outward, at static head of 0.2 inches water column. The air flow through the fan for those conditions is about twenty times the rate of actual home fresh air exchange.
I believe I am now below 5 ACH50, saving $50 per year in cost of make-up air, from accumulated home improvements. There was no possibility a blower door would have guided those improvements. I will own a blower door again someday, and will use it honestly. It will never be lied-about as guide and measure of weatherization. A blower door is useful only as verification of needed fresh air exchange, upon very rigorous completion of obvious improvements that tighten a home. If a controlled amount of air exchange is volunteered, as through continuous powered, regenerative heat exchange, a test may again have no value.
I am contributing to the 2018 IECC revision process as an unpaid volunteer, and hope to address applicability of rules, to existing homes, Chapter 5. Chapter 4 rules apply only to new homes unless referred into Chapter 5, and that referral for home sealing has not yet happened. That failure is associated with the continuing blower door madness that misguides weatherization. Important opportunities for sealing are found by sight, and should be addressed by each worker, not restrained by test-in, test-out foolishness.
Proposed changes to the International Energy Conservation Code Of 2015, will be considered at the 2016 Committee Action Hearings, April 17-27, in Louisville, Kentucky. In my preparation for this, I see a foolish continuing commitment to tighten our homes without limit, then needing to provide fan-driven fresh air.
I summarize thus, further exercising the Insulation Math for my 1000 sf home:
Each ACH50 for my home is 8000/60, 133 CFM50, and corresponds to makeup heat cost of $0.074*133 = $10 per year. The size of a hole that could carry this flow is 9.86/0.555 = 17.8 sq in, a circle 4.8" diameter.
Every ACH50 I may covet, could come through its 5" hole. 5" holes! No big deal. Driven by natural pressure differential without cost of electric power and with measurable increment of good health. The flow at natural pressure differential 133/20 = 7 cfm. is a small fraction of the flow of a bath fan.
Think about this please. Math is for fuel cost bumped up to truer cost at $2 per therm. It's a 1000 sf ft home in a moderate climate formerly 4400 65° HDD and already down to 4000 HDD with global warming. If in silliness I have tightened my home to 3 ACH50, from 0.5 ACHnat, I am paying less for cost of heating the air from ambient to 65°F, to the tune of $10 * (10-3) = $70. Now I need to pay for the driven fresh air. Say it is 25 watts, continuous, six months per year. I will be erratic in regulating the system while mindful of opening windows more in mild weather. 25 watts *24 hr * 365/2 * KW/1000 watts *$0.11/KWH = $12 per year. Maybe the draw is closer to 100 watts. There are maintenance costs. I am not saving anything, really. I admit though, I have an unmentionable reason to be on this path. I have a radon problem largely solved by letting ample fresh air in at bedside windows at night, and will be happy to relax that some if I achieve a plan to exhaust stale air through-roof, via a sealed, conditioned crawl space. With this solution, I don't visibly and audibly display the radon problem. I think I have answers and not many problems. Silly people with blower doors know none of this. They think they know better. They cause us so much trouble and expense. We are made to feel guilty about opening windows a bit, letting in the evil coldness.About that radon concern I now monitor my house continuously with an affordable Corentium Model QRI, a very nice Product of Norway .
At Amazon $200 it isn't for everyone, but it is more affordable than I had hoped ever to find. It came to my attention in a post by friend Corbett Lunsford .
How to Test for Radon at Home: Proof Is Possible - YouTube
I thought I would observe readings for a couple of weeks, and then let my customers share it, but instead it has been recording away for three months now, and the long-term average has not held steady at 2.5 pCi/L. It has drifted up now to 3.5 pCi/L, moving toward the action level of 4 pCi/L . I will continue to watch this for a few more months, before sharing the monitor.
Further radon monitoring and a very successful passive solution is reported in my blog post Success: Passive Control of Radon in My Single-Family House, April 10, 2021.
September 2024 Update
Discover this tool at https://basc.pnnl.gov/redcalc:
Here is the report I get for my house before any "improvements." The basis is ASHRAE 62.2 of 2016. DOE report, https://basc.pnnl.gov/redcalc/tool/ashrae-622-2016
Unstated, this calculator employs a house-specific n-Factor, the ratio of air exchange driven by a blower door fan at head 50 pascals, 0.2" water column, to natural infiltration.
Infer the unstated n-Factor of the RedCalc report to round out our understanding of analysis methods. ACH 50 is 60min/hr times 1330 cfm, divided by house air volume 8*986, 7888 cuft. A blower door test result of 1330 cfm is 1330*60/7888 = 10.1 ACH50.
The ASHRAE 62.2 (unstated) required ventilation rate is 0.35 ACHnat.
RedCalc and US DOE dare to try place a more accurate n-Factor than the number 20,
at 7.0 ACH50. Sure, specify home-specific actual ventilation flow rates, as if they could be known, and of superior meaning.
If the effective annual average leakage rate is 34 cfm, the n-Factor is 1330/34 = 39. Surely this is in error by nearly a factor of 2. No such number is presented for my Zone 3 conditions.
In error, I am told that I need more fresh air than 10.1 ACH50, not less! The total of wanted leakage and mechanical exchange is 10.1 * 44.58/34 = 13.2 ACH50. And, I am forgiven if I have only 10.1 ACH50.
I am about to own a Minneapolis Blower Door tester again. I will soon test my house now-a-very-superior-rental, and will get the bad news that at about 6 ACH50, I am in much bigger trouble. Anticipate the new DOE report: https://basc.pnnl.gov/redcalc/tool/ashrae-622-2016
Now, I suppose my renters shall be scared into maddening periodic running of a bath fan, choosing that of the half-bath in the corner of the beautiful new kitchen, Panasonic 80 cfm FV08VQ5. I will not do this. Again, raise a flag so very hard to believe, that the RedCalc method is incorrect. If the effective annual average leakage rate is 15.5 cfm, the n-Factor is 600/15.5 = 38.7.
Whatever the correct math upon blower door numbers, it has been absurd that we are compelled by building codes, to achieve near-zero natural fresh air in badly-built new homes quality-tested for energy efficiency only in madness tiny blower door numbers.. It is more absurd that we are now guided to constant running of mechanical air exhaust in all homes, where many homes will not have such a fan. Most of us have silly bath fan noise makers that discharge little through bad ductwork, just wasting electricty. A not-stated compulsion is that we shall get the added fresh air through a HRV or ERV not compatible with existing HVAC and possibly generating ductwork mold. The payback on a $1000 HRV or ERV is - never. The real compulsion is to inaction and to disdain for energy saving in general. My now-a-rental home demonstrates the honest wish: that full insulation shall be tightly packed in airtight enclosed spaces, and the house shall be isolated from ground by a dry conditioned crawl space. These honest wishes are not verifiable by numbers in a blind, quick test.
At 9/25/2024, still trying to understand a factor of two greater need of ventilation with REDCalc, also choose number of occupants as Num Bedrooms plus 1 = 4, Get this REDCalc result;
Now think the factor of two increase of needed ventilation is in the WSF, Weather & Shielding Factor, 0.5 for my location. I am nearing a recommendation for full-time operation of an 80 cfm bath fan. Try out the two Solvers at bottom of the window, and see a very wild wish for draftiness of my house. 2390 CFM50 in a blower door test. I can still convert this to ACH50 by the math I have seen as true, 60*2390/7888 = 18.2. Still thinking make-up heat for this fresh air cost $10 per ACH50, I am adding (18.2-7)*$10 = $112 to annual olperating costs. This is kind of affordable, only because fresh air is nearly for-free, as I pointed out, and was ignored, at the 2016 IECC Conference in Louisville.
Find useful discussion here:
All infiltration is a good thing now.
In ASHRAE Standard 62.2–2016, the minimum required outdoor ventilation rate (Qtot,62.2) is determined by Equation (1):
Qtot, 62.2, L/s = 0.15 * Afloor, sq meters + 3.5 * (Nbr + 1)
Nbr +1 = 4, Afloor = 1060 sf
Apply units conversions:
1 liters per second = 2.11888 cfm
1 square meter = 10.7639 square ft
Qtot, 62.2, L/s *( 2.1188 cfm / L/s) = 0.015 x Area, sf * (sq m / 10.7639 square ft) + 14.
Qtot , cfm = 53 cfm, (at 0.35 ACH50?)
vs. 61.8 cfm by REDCalc?
Let it suffice that wished 2390cfm in a blower door test is absurd. If the wish in a blower door test is absurd, is there any value in a blower door test?
Saturday, June 12, 2010
A Larger Appeal Against Home Performance Testing and a BPI Mafia
Thanks to this news item:
http://energytrust.org/trade-ally/updates-and-events/insidernewsletter/?article=id_46
I learned who in Oregon has interest in the competent service of home performance testers.
The following, one-sided, so far, conversation results:
Sent to State of Oregon, on June 10th, 2010:
Hello Craig,
http://energytrust.org/trade-ally/updates-and-events/insidernewsletter/?article=id_46
I learned who in Oregon has interest in the competent service of home performance testers.
The following, one-sided, so far, conversation results:
Sent to State of Oregon, on June 10th, 2010:
Hello Craig,
My experience through five years of extremely diligent service as an Energy Trust Trade Ally is that a blower door test never beats diligent sight inspection, in finding the problems needing repair in a house. Money should never be wasted in testing distraction, by people with no competence or interest in the repairs. All sponsor and consumer money should be spent on just doing the work. I speak out on this at my blog:
Please do not hold interest-conflicted and often dishonest home performance inspectors, to a lower standard than professional home inspectors.
My Signature Here
Sent June 12th, 2010:
Hello again, Craig,
My post to you has inspired fine-tuning of this web page:
Please find me a competent critic of the snake oil as a national problem, in the clean-shirt job creation, and terrible waste and diversion from real work, of home performance testing. Someone must speak the truth. It will not be a suckered home performance tester. We learned at the last Energy Trust Residential Round Table, that despite the interest conflicted activity of groups like Energy Trust, the volume of testing is at an all-time low. Consumers see the truth. Professional home inspectors are right to fight the dilution of their opportunities to serve and survive, by people who know little and do not deserve credentials. They do cheat, to crank out that expected-but-impossible 300 CFM50 reduction. They know little else than possibly the setup of a blower door.
I sought defense of testing at BPI, and think I was consciously given a runaround. Here is the reply to a phone call, asking for examples, and reporting-for-comment, heard assertion of a "BPI Mafia."
Do you find any examples of usefulness in home performance testing by the links? I surely will not talk with econtc people, the worst creators of excess and marginal testers.
Good morning Mr. Norman, I would like to direct you to Jeff Catlin jeff.catlin@econtc.com
Vikki Murphy
Director of Affiliate Development
Building Performance Institute, Inc. (BPI)
877-274-1274 Ext 106 (Toll Free)c.com
518-899-2727 Ext 106 (Office)
518-899-1622 (Fax)
518-331-8965 (Cell)
Training, Accreditation, Quality Assurance
My Signature Here
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