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.