Fresh Air is Almost Free

At 3/15/2024, look for naivete that might be criticized in overlooking cost of conditioning moisture in the air. Google: air conditioning: air conditioning: the relative cost of heat gain and humidity regulation. Choose this result: https://www.achrnews.com/articles/146975-nrel-discovers-humidity-is-why-a-c-units-consume-so-much-energy Find that for a portion, perhaps all,  of Cooling Degree Days, air conditioning cost should be doubled. The math gets messy, but this is a moot point. Whatever the cost, we must have that fresh air exchange. It doesn't matter whether air to be expelled, then somehow replaced, is driven by a clothes dryer, or a bath fan, or holes in walls of an otherwise airtight home. Where few of us will ever have opportunity to invest in expensive HRV or ERV, the neglect is not a dominant concern. The cost of comfort will still be mostly from defects of insulation perfection and window placement. The cost will be directly regulated by generation efficiency as in upgrade to heat pump technology.

At this post of February 23, 2023, Costs of Running A Miele Heat Pump Clothes Dryer

I share a surprising finding that conditioned air dumped outdoors in USA  ordinary clothes drying is replaced at very modest cost of about $6 to $16 per year, dependent on HVAC efficiency.  The very simple math for average-USA climate, is indisputable.

Healthy provision of fresh air in our homes at required 0.35 ACHnat, 7 ACH50, is at very small cost. That cost, about $100 per year for a well-built 1000 sf home, is unavoidable. If a home is more-expensively built to Passive House standards, less than 0.6 ACH50 , fresh air must be drawn in by other means, to a total of at least 7 ACH50. Those means can be absurd, perhaps with net increase of operating costs. Powered means may be unreliable with expense in operation and repair/ replacements. Occasional reporting of false economy in air tightness, in this blog , is not kindly regarded by readers.

The physics fact in this is that air has extremely small heat capacity, rising or falling in temperature without much gain or loss of thermal energy. In-home air-to-air regenerative heat exchangers save little energy vs. operating costs including maintenance. The value in regenerative heat exchange is related to the heat capacity of the moved fluid, mattering a lot for high delta-T liquid systems, and little for small delta-T gases.

I was not heard, when I spoke out to the full assembly of March 2016 hearings of proposed 2018 revision of the International Energy Conservation Code, Louisville, KY. I was dismayed by the many proposals sought to surrender the enforcement of construction quality, to  numbers in blower door tests. I call that Blower Door Madness.

In a few words I stated an Insulation Math finding that for  my Portland, Oregon 1000 sq ft single-story home with 8 foot ceilings, 4400 heating degree days, natural gas heat at $2 per therm, each ACH50 of fresh air brings a conditioning cost of only $10 per year. Tightening a home is almost irrelevant to the total of typical HVAC costs. The attention should instead be upon perfection of a complete home insulation envelope with thoughtfully-placed windows. The best insulation envelope is fully filled, precluding air convection, air-tight all-around, not determinant by a blower door.

Where it is accepted that a healthy home should have minimum 0.35 ACHnat,  times-twenty, 7 ACH50, air exchange in my home is at natural gas cost of a modest $70 per year. Home HVAC cost is very little related to provision of healthy fresh air. Don't we all know that pulling makeup air through gaps of ordinary good construction 24/7, is better than pulling outside air at a pipe to the HVAC return, only when the air handler is running? Those odd pipes in so many new homes, are not part of any regenerative heat exchange or of thoughtful filtration of the the outside air.

Where annual usage of natural gas might be at cost of $400 per year, the healthy fresh air cost $50 at estimated 5 ACH50 tightness, is about 12% of that total, and is unavoidable.  There is a gas clothes dryer perhaps accounting for 15% and reducible by about $50 per year by the investment in HPCD.  It will make sense for sure, when all natural gas service is terminated, with heat pump HVAC. Heat pump HVAC is interesting now, from need for summertime cooling not now provided.

I have no further possible savings in adding of insulation. Recent gas usage of about $470 per year are probably with comfortable temperature setting near 70°F. Where I lived alone in the house under its reconstruction, thermostat at 55°F, I demonstrated the potential of about 50% savings in a bearable life of dressing very warmly to be comfortable.

My Observed ACH50 Numbers in Pre-1990 Existing Home Weatherization

This review of my blower door experience is in challenge of numbers near 30 ACH50, found in example Home Energy Score Reports, issued by US Department Of Energy, Better Buildings Program in years 2015 and 2016.  The reports are both for fictitious homes in Arkansas, built 1970, perhaps with little consciousness of energy efficiency.

 2015 Example:
v2015_HEScore_BB_example_12-15-15.pdf ,  a two-story home 1800 sf with 8-ft ceilings, testing in at 4200 CFM50, 17.5 ACH50. I did not remember confronting so large a number, before.

2016 Example:
Home Energy Score Report Example.pdf , of about November 2016, a single story home with ten-ft ceilings, 1500 sf, testing in at 6500 CFM50, 26 ACH50.

If such large numbers are not fictional in lax construction for milder-weather Arkansas, it does not suggest that huge savings from air sealing justify blower door madness, in Portland, Oregon. Few weatherization contractors in this area will accomplish real tightening of more than 3 ACH50, and some with their building scientist pedigree as blower door believers, will charge more than $2000 for the deed. Yes, at such unjustified cost, it is not worth doing. For a 1000 sf Portland home with an inefficient gas furnace, even with $2 per therm applied cost of natural gas heat, the savings per ACH50 reduction, in preheat cost of fresh air, are only $10 per year. Please see my Insulation Math . Annual savings of 3*$10 = $30 per year at cost of $2000 are a poor investment. At best, the present value of savings through a twenty year horizon are 44*$30 = $1320.  Please find that *44 payback multiplier (vs. *20) in this blog post .

At fair sealing cost of $300, the return is excellent. Abhor a blower door and test-in, test-out , with this. A blower door is almost never employed as the guide of important sealing measures. The value in tightening a home is in just acting in a permanent way, upon every sealing opportunity one sees, in dealing with evident drafts, and in the course of preparation to add insulation. Preparation must include all treatment of home integrity including plumbing, wiring and roofing deficiencies, that would be obstructed by the added insulation. Wiring includes anticipated communications wires and upgrades to permit most-efficient LED lighting.

Where I have spoken out as an Energy Trust Trade Ally, I have asserted that blower door testing with public support should be done rarely, for a stated purpose. Results should then be freely shared, so that we can accelerate consensus on further testing investments. This narrowing of test practice and sharing of paid-for results, never happened. My own sharing here, from my own investment, is a start.
My Test Results
I owned a Minneapolis blower door from 8/15/2008 to 5/16/2009, to dutifully employ it for air sealing test-in and test out in qualification of customer rebates. Finding no other resource, I trained myself with measurements in my 1955 single-story ranch home, 986 sf. I quickly found a stable, repeatable 1330 CFM50 Baseline result. This is 10.1 ACH50, a bit more drafty than the 7 ACH50 target for a healthy home. Tightening my home would take more than three years of staged effort, never to need or to again employ a blower door.

Higashi, October 2008:
The first test in a customer home was done 10/17/2008, a larger single story home, testing in at 1625 CFM50, 14.4 ACH50. The home tested out 11/10/2008 at 1410 CFM50, 12.5 ACH50,  with $27 per year saving of cost to heat makeup air. This was in sealing and insulating of poor solid-steel HVAC ducts of both attic (return) and crawl space (heated), with no other evident opportunities. An air sealing rebate of $215 was paid at a foolishly-offered $1 per CFM50 reduction. The work did not include any discovery under blower door conditions. The crazy ducts block crawl space access and are likely to be detached and again to leak, soon. I did not feel good about this, but always seek the maximum offered rebate for a customer.

Bronner, November 2008:
The second test was done 11/24/2008, testing in to check work of one notorious HPwES crew. who failed to do any apparent sealing, missing quite-large opportunities including a garage wall holed by long-ago car impact of a wood pile. The test-in was 3740 CFM50 in a complex 1937 two-story home, 11.8 ACH50. The test out 1/19/2009 was 3050 CFM50, 9.6 ACH50, but this large improvement, not earned, is thought to be due to closing the door to a conditioned basement, not likely the condition in other tests. I became fatally disenchanted with my blower door here. A blower door show would never be of any use to me in finding anything, and only wasted a half day of progress. I immediately sensed that prior testers in a home always used their blower door only as a marketing scam, not understanding readings at all and doing nothing useful by the testing; always spending more time in testing than in crude and unguided “sealing.”

Costello, December 2008:
The third test in a customer home was done 12/12/2008, testing in at 760 CFM50 in a small single story ranch home, a tight 7.0 ACH50. There were no sealing opportunities and no test-out, where the attic was insulated and the crawl space was sealed and conditioned.

Levine, February 2009:
This is a typical bungalow home with top half-story weirdness, with result 2300 CFM50, 12.0 ACH50. There were no sealing opportunities in my attic access and insulation work, and no test-out.

Three jobs have shed light on other contractor’s misuse of a blower door, and the magnitude of home leakage that might be found in the majority of existing homes, which were built before 1990.

Wheeler: (January 2010)
This is a 914 sf single-story home built in 1951. It was evaluated as one of 200 homes in a 2008 pilot program of assigning Energy Performance Scores, EPS, in existing homes. The assigned EPS score of 80, was done with PTCS duct sealing  and with R30 insulation of the crawl space by an independent contractor. A blower door test-in of 3670 CFM50 was reported. Extremely large 30 ACH50 was not computed, and was not attributed to a fallen-down duct in the crawl space. That duct was simply reattached by the CS insulation contractor, who may have needed to remove and then reset, all ducts. At May, 2010 and no longer owning  a blower door, I just thoroughly fixed things in the attic of this home. Fixes included replacing broken HVAC solid steel ducts much in the way and frequently stepped-upon, that had been gauze-wrapped and gooped as evident teaching of PTCS that goop fixes anything; the goal is cheapness independent of durability and safety against traffic hazards. I would hereafter have complete disdain for PTCS and EPS.

Weigand: (May, 2010)
This is a 1400 sf single-story home built about 1970. It was  my second confrontation with one notorious HPwES crew, which reported 4220 CFM50, 22.6 ACH50. This extremely large infiltration, not flagged for concern, is in part the result of construction with exterior walls open to the attic. I thoroughly insulated the attic of this home, with preparation including replacement of many poor solid-steel HVAC ducts, sealed air tight. I was not allowed to cap the exterior walls.

Chamberlain: (October 2011)
This is a 1590 sf single-story home built in 1973. This was  my third confrontation with one notorious HPwES crew. The home tested in at 3392 CFM50 (20 ACH50), and tested out at 2248 CFM50 (13.2 ACH50). The very large CFM50 change, 1144 CFM50, at paid cost $450, might have qualified an air sealing rebate of more than $1000, but in the end this home owner did not get any air sealing rebate. The achievement not rewarded, was fraudulent, with perhaps-deliberate misuse of a door to generate most of the reduction. Negligible sealing was achieved in the attic, leaving test-in of about 20 ACH50. My very thorough and imaginative sealing surely reduced leakage by more than half, less than 10 ACH50, but in this Energy Trust did not care. I could not engage a volunteer to do the test out as a learning exercise.


More than 30 ACH50  is possible then in pre-1990 existing homes, where testing is with detached HVAC ducts. Absent detached ducts, numbers much more than 12 ACH50, are not in my experience. I did try to employ my blower door just before it was sold, in a 3500 sf three-story home in Northeast Portland, and found I would have needed several blowers to generate minus fifty pascals test conditions. The evident problem was balloon frame construction, and my interest in testing was over. I can ony suggest that this home with hydronic heat, no heat ducts, was well under 30 ACH50 test-in.


In the course of this exercise I discovered writing by Allison Bailes III PhD, Energy Vanguard, upon discoveries in his Atlanta condominium, built around 1970. Higher infiltration numbers are to be expected in multi-family homes, but his blower door numbers surprise me. 
(At July 18, 2016)
http://www.energyvanguard.com/blog/how-i-achieved-a-21-increase-in-airtightness
Here find test-in at 29.6 ACH50, where part of a bathroom ceiling is missing. Ceiling patched, and with some air tight sealing of exterior walls, the number is down to still-large 20.8 ACH50. Despite advocacy for and practice of blower door testing, Mr. Bailes seems to despair of further reducing his condo fresh air supply.

He had previously found that Celotex exterior sheathing under a brick exterior of the complex was severely buckled. 
(At April 26, 2016)
http://www.energyvanguard.com/blog/air-flow-pathways-in-a-leaky-bathroom-wall 

Here is the report of fixing the exterior sheathing leakage, at a bathroom wall only.
(At May 23, 2016)
http://www.energyvanguard.com/blog/how-to-fix-a-leaky-underinsulated-exterior-wall 


Also in the course of this exercise I found that homes built from 1994 to 2004 are notoriously leaky, due to cheapening of exterior sheathing, at least in New Zealand . The leakiness refers first to rot problems. We in USA too have cheapened exterior sheathing in reliance upon house wrap, and have had lapses in provisions to screen and drain falling water. Where this is thought the concern of building science, a blower door operator will not be depended upon for solutions.

Better Math On Weatherization

We see in an article in the Oregonian Newspaper, on 8/3/2014   that Energy Trust Of Oregon , my local handler of public funds for weatherization, has found that weatherization doesn't pay, even when computed for a 45 year life of a measure. I prove that wrong, always. There are very good returns even in a home where Energy Trust saw  nothing to be done, with firm no-bid by a competitor. It's a post at this blog generally challenging Energy Trust's policies:
Math Of Under-R12 Attic Floor Insulation Rule, For Incentives 
The good returns are far more than a matter of adding floor insulation and have no resort to a silly blower door. They include attic floor sealing, thorough R30 insulation in attic walls and installing LED lights, all rejected as profitable measures, by Energy Trust. A five-year payback is computed for hard-covered R30 attic wall insulation in a further blog post for this home:
A Skylight Insulated >R30, With Plywood Hard-Covering 
There is similar under five year payback for upgrade to LED lighting in most cases, and even faster payback for air sealing.

As local enabler and enforcer of US Dept. Of Energy’s Home Performance With Energy Star, HPwES, Energy Trust teaches that a blower door is the engine of weatherization, finding energy-saving opportunities and verifying their completion. “Weatherization” is first about tightening our houses in ways that measurably decrease “infiltration.” The tighter, the better. Little-trained fools are building scientists, who infer what must be done from the blower door numbers. Without the numbers, solutions can not be found. The captains of weatherization under leadership of Building Performance Institute, shall be BPI certified  believers in the testing in and testing out every home, with a blower door. Air sealing shall be trusted and supported with public funds, only where done, very poorly, by the BPI liars. This is baloney. It must not continue.

Work under HPwES is done poorly, in part, because a blower door generally reverses flow in leakage paths, inviting repair only in living spaces, along a carpet, say. Repairs must instead be done in the attic, never with, or needing, clues from a blower door. Specific needed repairs, perhaps difficult, will never be included in a HPwES estimators' authorized work list. Where a diligent worker might volunteer, unhappily in darkness and danger, and it is not expected, why should he bother?.

Despite the notions about infiltration, Energy Trust does not require  that such "prep" must be done before rebate-offered addition of insulation. This is madness, with "weatherization" very often doing more harm than good. Money to be saved in the prep, then barred for decades, is commonly double that to be saved by added insulation.

Fresh Air Math
One problem in tightening up houses against exchange of fresh air, beyond the obvious in quality construction, is that it does not save much money in fuel costs. That is what Energy Trust is now awkwardly and confusedly admitting. Little energy is needed to raise or lower the temperature of air. All gases have low specific heat .  One might excessively tighten a house, but there is no money in it, that would offset excessive cost in extreme tightening. Further, significant tightening in existing homes, promised with HPwES, has almost never been delivered.

A healthy home should be refreshed with 0.35 air changes per hour, 0.35 ACHnat.  In a 1000 sq ft home with eight-foot ceilings, this is 0.35*1000*8/60 = 47 cubic feet of fresh air per minute. In a Portland, Oregon year with 4400 heating degree days, heating with an old gas furnace, and with $1 per therm consumer cost, this air is heated at cost of $35 per year. Say the real cost of natural gas counting irreversible depletion and environmental ruin, and military adventure, is $4 per therm. The cost of the fresh air is still only $140 per year. Of this fresh air cost, little is controllable. 

In corresponding bigger numbers, times twenty, now consider blower door test numbers. A blower door measures infiltration with the home strangely exhausted at the rate thought to occur if a twenty mph wind were blowing on all sides, driving air inward. The odd air flow measurement is labeled CFM50, cubic feet per minute at fan pressure differential of fifty pascals, 0.0073 psi. CFM50 and ACH50 are roughly twenty times larger than reverse-flow rates at natural conditions. I think that all payback math for weatherization should be computed with natural gas cost of at least $2 per therm, and use that number in my math. The math  of fresh air cost is: Annual Heating Cost = 0.074 * CFM50, $70 per year for that 1000 sf home with 47 CFMnat. I hope you are still with me, and see the consistency and bases, in the math.



Now talk of the range of control of infiltration. It is rarely more than 1.0 ACH50, 0.05 ACHnat, 7 CFMnat and 140 CFM50, for that 1000 sf home. Annual value in this range of control is $10 per year, at $2 per therm for natural gas. I have known this for years, and have alerted the fact to Energy Trust in hope they would cease promotion of blower door scams. 

In a reasonably tight home where obvious drafts have been controlled, we feel winter cold of air not from infiltration, but from convection of air against cold walls, floors and ceilings. Cold surfaces, felt especially at floors, exist because of poor insulation and because of bathing of back sides with outside air. Stopping that bathing of backsides, and thorough placement of insulation, are what weatherization is about, not some pretense with a blower door.

Where Energy Trust now salutes disappointing returns in weatherization  they fail to understand their error and to be ashamed. They will happily go on with little residential work to do, and more money to misspend on utility and business payouts. Creepy blow and go contractors they love and award their top Three Star rating, who have refused to do air sealing, are hereafter and forever more, defended against criticism.  In all of this there is yet no admission of blower door stupidity. In Portland this Summer we saw distasteful door to door pushing by HPwES/ CEWO  blow and goers claiming to offer free Energy Trust money. I accuse that these kids in new Company shirts with Energy Trust logo, were paid with “cooperative marketing” dirty money, with nothing free for a home owner. It seems HPwES, Clean Energy Works Oregon, EPS, all the programs promoting blower door scams, are alive and well. How can they persist against declared uselessness of actions purportedly guided by a blower door?

The City Of Portland is shamed through endorsement of CEWO, which was hatched in a pilot program of its Bureau of Planning and Sustainability.  BPS stationery has been applied in annual CEWO bulk mailings, a letter, and a follow-up postcard. It appears that Portland taxpayers have paid the cost of this mailing campaign.

I have gotten a letter like this every year, for three years, mailing costs totaling a half-million dollars I reckon. I find the letter scandalous on many counts, starting with offensive foot-in-door threat about deadlines, wanting reckless action. This one arrived 8/13/2014. If a million have been sent, and there are 3500 takers, it proves the offer is correctly judged a very bad deal. We hear instead that 3500 unusually willing and able to take on an inflated $20,000 pile of fifteen-year debt, proves that it is not a bad deal. If you need $3000 of very important work and need up-front financing, you are out of luck. If you are a renter, too paying into our Public Purpose Fund, you can just pay the higher bills, perhaps demeaned with public support. Your landlord knows that helping out, doing the right thing against bleeding of energy and personal suffering, is not expected or rewarded in our City.

So, what shall we do with blower doors? They shall not be used in many of our homes. In our homes, in the matter of sealing wall headers , we have expended the testing budget. There might yet be some academic testing as we defend the real reasons all wall headers must be sealed. I would like to buy mine back , at dimes on the dollar, to be part of the academic effort. My own home is a test lab, testing in at 10.1 ACH50, and probably now down to less than 7.0. I would share my findings on what works. From all of the BPI blower door madness, we have learned nothing about what, in controlling air circulation, contributes to a healthy home. It was only about rewarding and enforcing the reckless HPwES believers, all results confidential for protection of scammers.

We shall go on tightening our houses against attic floor pits and air-barrier encapsulation of all insulation, knowing it is not a game of blower door numbers. We must act with knowledge added insulation does pay, after measures of sealing, upgrade to LED plate lighting and safety modernization of wiring and plumbing are done first. Insulation cost is repaid in much less than twenty years even at modest $2 per therm energy cost. Regulators such as Oregon's Public Utility Commission may be commanded to employ fifty-year cost of energy in the administration of public funds for weatherization. Cheap and evil fracked natural gas will expire in less than ten years , evident to any responsible person, and government must act responsibly. We are not done with weatherization. For the poor especially, and especially for meanly-neglected renters, we have hardly begun.

A Silly Test Of Wall Header Sealing, In Oregon

Here is the report of a silly test of air sealing in Oregon new-home construction:

(Gone!  The subject of this post was pulled down in 2016, replaced by a Pilot II study.)

Perhaps I am responsible for this. I discover the amendment only in August 2023 upon seeing that a reader in Tualatin Oregon would have been frustrated by the missing link.)

The newer report now at the link below, produced by an outside consultancy, Evergreen Economics and SBW Consulting, Inc.. Methods tested remain impractical and inapplicable to an existing home, thus dumb and irrelevant in my judgement. Please scroll to the bottom of this post to find review of this Pilot II report.  Still want use of sealing grout, and intelligent gaskets offered by Resource Conservation Technology. Want sealing in many existing homes to involve room-by-room 

wall drywall demolition and replacement, along with wiring and plumbing modernization.

Final Evaluation Report - New Homes Air Sealing Pilot II 

Photo Caption:
Figure 1. Photograph of sill sealer (pink band at top of wall) installed on the top plate prior to drywall installation (courtesy of Fluid Market Strategies; Manclark, 2013).

I judge that pink material in this photo is OWENS CORNING  FoamSealR Sill Gasket - 3 1/2 inch x 50 feet. x 1/4 inch,  roll polyethylene foam, sold in Home Depot stores  and elsewhere. Thickness might be as little as 3/16" in a less-available roll 4" wide and 86' long. Either is too thick, too wide and too incompressible, not imagined for this application.

I found edges of this material in November 2013, in a new Hillsboro, Oregon DR Horton home, both sides of each interior-wall header, upon installing a needed attic ladder. I couldn't reach out to exterior walls, those shown in the photo. I infer that all walls were treated, at top header only. The report of the air sealing test admits unhappiness of involved drywall installers. Drywall panels are placed with sliding action that tends to grab and roll the strips, and a deservedly-angry installer will rip out the damnation. The non-flat panel edges show, and that can't be hidden with ordinary mudding. There are better ways, of course.

The better ways to seal wall headers in wall construction include use of building gaskets by Conservation Technology, Baltimore, MD .

Here is copied descriptive text by Conservation Technology:


DRYWALL GASKETS: BG32 drywall gaskets are stapled to wall studs, top plates, and bottom plates before drywall is installed in order to prevent air flow between the drywall and the wood. They can be easily installed in any weather, even when wood is cold, wet, or dirty. The head of the seal compresses easily to less than 1/8”, so there is minimal pressure on the drywall. Always screw the drywall where gaskets are used.

Please know that Conservation Technology also offers best rim joist and sill plate gaskets:

At the associated Picasa web album , please find photo excerpts of the Conservation Technology products, and of exterior-wall header sealing achieved without gaskets where Swedish Tenoarm air/ vapor barrier material is employed. Buy the Tenoarm too from Conservation Technology.


Please see discussion of wall header sealing as weatherization retrofit, in the attic floor, at posts including this:
Sealing Wall Headers 
There find report that where my flexible grout is not commercially available, I offer free samples, and find that Custom tile grout is chemically very similar, and is available anywhere. Learn that spray foam is always inferior.


Silliness of the test accused? That a blower door measures effectiveness , and that a better sealing means was not found. Anything that requires a bribe for delivery, is wrong. No one should mind working with BG32 gaskets. They cost no more than the roll foam. Close to board ends, they do not affect drywall fit-up, shape and mudding. Wall header sealing must be made mandatory. The gaskets are an easier way, and can be delivered at outside walls not accessible from the attic. We don't need to retool, and do more stupid play with blower doors. Sealing will stop action of attic floor pits, far more than it affects exchange of outside air. Testing might instead consider the thermodynamics of interior wall flooding through wall header gaps of variable size. "Experiments" should never be conducted where conditions are not controlled, and where instruments are insensitive to results.

This goes beyond silliness, to deceit. There is a budget and strong intent , to continue the madness of the Energy Trust/ DR Horton Homes program despite now knowing better, where all involved are aware of my criticism.

It isn't only that wasteful experiments take place employing inappropriate gaskets. High-end new homes are being built in Oregon, where foolish gasketing is done as taught good practice. I found this gasket scrap under insulation on the floor of a new home attic. It was ripped from stapling as a probably-angry act. If by drywallers as is likely, no other sealing was offered in its place. This is not a less-expensive way to seal wall headers. Please, let us commit to sealing in all new homes and tear-down remodels, using good gaskets from Conservation  Technology.

Working in customer existing-home attics, I have not had opportunity of wall header sealing other than as forcing of flexible grout from the attic, upon interior walls. My practice in this is detailed in the advocacy web site, Plaster Repair How To, search Label: Wall Header Sealing . Gaps found have sometimes been huge, up to 1/4" and not possible of sealing with any practical gasket. I found such gaps even in my own home, well built by my uncle and oldest brother. Here are drippings from wet grout that penetrated stuffed-in fiberglass insulation, revealed in demolition for a kitchen remodel. I will always believe that surest sealing of headers is from the attic, before a careful manual placement of batt insulation.

Although I can do right again in my attic, at last buy a coil of BG32 gasket from Conservation Technology. 

A 100 ft coil serving 100 lineal feet of wall at both top and bottom, is inexpensive. This coil cost me $40, plus $23.25 shipping. A local wholesaler could have sold the coil for $50. This is fully affordable and must be mandatory where cost is repaid with savings in about one year.

The gasket material is tough EPDM. Know that EPDM has 5 to 10 year shelf life and will remain serviceable indefinitely while not disturbed.

Split lengths for two gaskets, with scissors.

Attach with staples. Here on an interior wall, I will back up gap filling in the attic. See that I have sealed the existing drywall of the opposing room, with flexible grout. I have stuffed annuli around electrical wires, with Rockwool scraps.

On an exterior wall stuffed with insulation and with windows and doors, value of the BG32 gasket is uncertain. I didn't apply it before placing drywall to the right of this door. At 25 cents per ft, top-only, the cost is trivial. I got more placement practice, learning that 3/8" staples are needed.

The Evergreen Economics and SBW Consulting, Inc. Pilot II Report, April 21, 2016

Once again, it was thought wrongly that sealing effects could be observed with meaningful precision in blower door testing, to discriminate between homes  sealed and not sealed. Delta values were in the desired direction, but by only one standard deviation. These were not at all a test of insulation wind washing.

Tested Knauf Eco Seal was a by-gun goop-gasket application failure especially if applied with ambient below 60°F.

Available only in full truckload quantities.

Owens Corning Energy Complete is a messy and unreliable two-component foam application.

For each product,  half of homes in a study were sealed and half were not; mean for those not sealed.

Recommendation at report page 15, as wished:

Given the results, we do not recommend that the New Homes program move forward with the whole home and attic sealing measures tested in this pilot.

Energy Trust expensively justifies doing nothing with home air sealing. No incentives are offered.

 I am biased against the program intentions.

Air Sealing Is Not Cost-Effective?

This post has been under construction for about two months. Completion  is prompted by a disturbing article in the Oregonian Newspaper, on 8/3/2014 . The article is by staff writer Ted Sickinger, and it wrongly states as fact, that many weatherization measures, especially air sealing, are not cost-effective where computed only for savings at consumer cost of natural gas.

Proceed then, to refute Energy Trust's conclusions about air sealing:

Air sealing is not cost-effective as stated by Energy Trust Of Oregon Director Of Energy Programs, Peter West, on December 2, 2013, at PDF page 71 of 173, in Energy Trust of Oregon 2014 Annual Budget and 2014-2015 Action Plan .

Here are excerpted statements by Peter West:

Subject: air sealing

CAC members and participants,

At the October and November Conservation Advisory Council meetings we addressed 2014
program strategies and incentive changes. At those meetings there was significant discussion
of the recommended incentive changes for air sealing for existing homes. Thank you for your
participation in that discussion. Energy Trust values the input and ideas that you bring to this
forum. I want to take a moment to provide an update on the staff direction after the feedback.

As you recall we have looked at this measure over the last two years. We noted last year that it had fallen well below cost-effectiveness standards and agreed to additional analysis. After more review and a look at more data, we found it had deteriorated further in cost-effectiveness. The payback period for the consumer now far exceeds the expected life of the measure. In October we brought the issue forward for comment with a draft proposal to end the measure for all existing homes. After initial feedback we agreed to consider retaining it for those electric-heated homes where it could be cost-effective. We brought that idea forward in November.

After hearing from Conservation Advisory Council members in November about the loss of the measure for gas customers, and consulting with the Oregon Public Utility Commission, Energy Trust further modified its proposal. We have chosen to maintain the 2013 incentive of $150 for air sealing in gas and electrically heated homes through the remainder of the 2013-2014 heating season with a modification: starting in 2014, in addition to previous measure requirements, homes must have been built during or before 1982 to qualify. This quick, simple, screening step will focus air sealing efforts on homes built prior to the first major code modifications and where air sealing appears to have the most savings impact.

We will continue to pilot new approaches as proposed and will conduct further analysis of this
measure in 2014, in an effort to improve its cost-effectiveness. We plan to work with the trade ally stakeholder group on additional requirements and revisions to current standards that can be applied to improve the cost-effectiveness of this measure in 2014.

As required, Energy Trust continues to identify measures that are not currently meeting the
cost-effectiveness threshold. We will work with the Oregon Public Utility Commission to obtain their guidance through the open docket expected to conclude in mid-2014. We encourage Conservation Advisory Council members to be actively engaged in that docket. We will continue to engage Conservation Advisory Council regarding subsequent program changes.

Thank you for your time and contribution to this discussion.

Peter West
Director of Energy Programs
Energy Trust of Oregon, Inc.


This statement is not before challenged. The backpedaling to retain $150 customer payout in 2014 was praised. The notion that math proves measure ineffectiveness, to me, is absurd. Surely the math can not and will not be offered. Yet, I think I know how it is done. It comes from the absurd lie that benefit is a measurable difference in before/ after blower  door readings, where those numbers are presented in each rebate application, not for public disclosure or interpretation. Since the most important sealing is of attic floor pits, a flooding of interior walls with attic air, "air sealing" is not measurable by a blower door.

I have persisted in criticizing Energy Trust, when they claim a mathematical basis for policy decisions on air sealing. My persistence led to this email message of June 23, 2014:

Hello, Phil:

I appreciated your polite and honest approach when we sat down to talk for a few minutes during last week’s roundtable. These are clearly frustrating problems, and you seemed to put that aside when we talked. I’m sorry we didn’t have more time before I had to answer other questions and restart the meeting.

Although I wasn’t able to answer your questions thoroughly at last week’s meeting, I have more information that will help. I discussed the air sealing numbers, and conclusions, with our evaluations group. The air sealing numbers and supporting documentation are in the 2009 Existing Homes Gas Impact Analysis, in the reports section of our website. You will find other useful information in that section, which provides access to impact and process evaluations.

Briefly, process evaluations look closely at how we deliver our programs, while impact evaluations look at how much was actually saved, at what cost, compared to our estimates. Impact evaluations go heavily into statistics, and the reports include an explanation of how data were gathered and analyzed, and what assumptions were made.

That’s what I can provide. The evaluations and planning department has a wealth of knowledge and experience in this area, and their conclusions are sound – and serve as the basis for our program decisions.

Cost effectiveness seems like an easy topic on the surface, but the conclusions depend heavily on what one chooses to measure in the ratios. Again, that’s not my area of expertise, but I’ve had the discussion often enough that I can clearly see the source of the confusion. One of the biggest debates – how to quantify and measure non-energy benefits (or if they should be measured) – has continued for as many years as there has been energy efficiency programs of any type. Our director of planning and evaluations and others on the CAC have discussed that topic in their various roles for 30+ years.

Again, I hope this is helpful to you.

The offered documentation, 2009 Existing Homes Gas Impact Analysis is this:

http://energytrust.org/library/reports/2009_HES_gas_impact_eval.pdf 
This is relevant but is marked DRAFT and is unofficial.

The referenced Reports Section had no relevant content before June, 2014. 

On 6/13/2014, the following was posted:
Existing Homes Process Evaluation 
This is irrelevant.

On 6/17/2014 the following was posted:

Energy Efficiency Resource Assessment Report 
This is irrelevant. 

On 7/4/2014, the following was added:

The Cost-Effectiveness Review for Specific Gas Measures and Programs 

Seems significant, but only has ratios with no stated bases. A Total Resource Cost, Benefit Cost Ratio, TRC/ BCR for air sealing is given as 0.2. If the resource cost includes $500 for blower door foolery in $5000 per home CEWO overhead vs. common air sealing savings of $200 per year, just eliminate those costs. Fire all of the sucker-baiters at CEWO. Strongly discipline the program fools at Energy Trust and send them on a new mission. Separate ourselves from national madness in HPwES forced by US Department of Energy through their bottomless funding. Require every weatherization contractor to do full sealing at usual cost per home of $200. This is then payback in one year. The TRC/ BCR of 0.2 has meaning only if the ridiculous and avoidable program costs are admitted.

Consider now whether these pdf documents are the stated proof. They are not. The failure of proof is through conceptual error, that savings are calculated only as cost of make-up air associated with measured change in air infiltration. In fact, even with newest homes, air sealing is far more a matter of closing attic floor pits, large openings in an attic floor not matched by leakage paths through walls and floors below. Attic temperature, hot or cold, is transmitted to rooms below by air convection. Think of attic floor bare-area equivalents as developed in this blog post , to see that even small floor-continuity defects multiply in their significance. There is a churning of attic air up and down even through narrow wall header gaps, where I propose that bare-area equivalence might be on average 10% of attic floor area. This can and should be proven experimentally.

Here are some new examples of attic floor pits, illustrating that very new homes are not less needful of air sealing, than older homes.

Combing through the reports, find that the grand measure of sealing wall headers in the attic floor by installing foam gaskets to top plates before wall drywall application, reduces ACH50 by less than 1.0.

Simple math finds dollar cost of heating make-up air, Annual Heating Cost = 0.074 * CFM50. This is with natural gas heat at $2 per therm, about double the current consumer cost in Oregon, and still far below actual cost including expiring availability and environmental destruction.

A 1000 sq ft home with eight foot ceilings has air volume 8000 cubic feet, and 1.0 ACH50 is 8000 cubic feet per hour, 133 CFM50. Associated savings at 0.074*CFM50 are $10 per year.  Air has tiny heat capacity, and the energy required costs very little.

Most homes, old and new, will have air sealing opportunities more valuable than sealing wall headers. But, say a 1000 sf home has only wall header gaps, sealed. Say the sealing also stills an attic floor pit, fully-exposed wall area 10% of 1000 sf. The additional convection-heat savings are more than $70 per year, with heat of an ordinary gas furnace, in metro Portland, Oregon, at that $2 per therm gas cost, by posted math . A combined savings of $80 per year would be weighed against perhaps four man-hours of labor, and no material cost. We don't need to do laboratory testing, to convince ourselves the work is worthwhile.

For a number of purposes, let's state the above wall header sealing savings numbers for a 1000 sf home in Portland, Oregon, in therms, taking out the question of fair cost of natural gas. $10 at $2 per therm is 5 therms to heat exchanged fresh air. $70 at $2 per therm is 35 therms for attic pit effect, an excess of attic openings.

Air sealing is very important and is very cost-effective, but it must be assessed with consideration of attic floor pits . Savings opportunities must be delivered by a diligent and empowered worker who creates safe, lighted work conditions, and gets to the bottom of concealing insulation. Savings opportunities are not discovered by the clean-shirted fool with a blower door. Savings are not delivered by an honest worker lacking instructions, where needed work was not  somehow imagined by the estimator and is not in-contract.