Residential Ventilation Smackdown — The Battle Over Simplicity
I went to school with Cajuns in south Louisiana, and fights were a big deal. They happened frequently, and when they did, a small crowd would gather. The noise would grow quickly and soon everyone in the schoolyard would run over to where the fight was happening. One day in sixth grade, we exploited this tendency and staged a fight between two shoes at recess. Sure enough — our tight circle of boys banging two shoes on the ground and making a lot of noise brought the whole school to us.
I went to school with Cajuns in south Louisiana, and fights were a big deal. They happened frequently, and when they did, a small crowd would gather. The noise would grow quickly and soon everyone in the schoolyard would run over to where the fight was happening. One day in sixth grade, we exploited this tendency and staged a fight between two shoes at recess. Sure enough — our tight circle of boys banging two shoes on the ground and making a lot of noise brought the whole school to us.
Today, I’m making noise for a fight that broke out over the topic of residential ventilation. This is a real fight among two heavyweights in the home performance industry: John Krigger of Saturn Resource Management and Paul Raymer of Heyoka Solutions. Don’t worry; it’s not a Jon Stewart/Tucker Carlson kind of fight or something you might see on the Jerry Springer show. These guys respect each other and even teach classes together.
In this corner…
Krigger opened the fight last week with a roundhouse punch aimed at ASHRAE and the latest versions of their residential ventilation standard. “ASHRAE 62.2-2010 is a confusing jumble of requirements and choices that has wasted vast amounts of time and money in training personnel and coping with confusion,” he wrote. Krigger doesn’t like that so much time and money is being spent in the home performance and weatherization industry to train people on this standard. Now it’s about to change again with the 2013 update, “which will be different and lead to another cycle of confusion and wasted resources,” according to Krigger. He believes there’s no reason to move away from the 62-89 version because it’s much simpler.
In addition, he claims that the assumptions on which they’ve based the changes in the standard are questionable and lists four problems at the end of his article. I’ll let you go read them and decide for yourself, but I will mention one here. He wrote that, “There are millions of respiratory problems relating to a lack of ventilation.” When I posted a link to the article on LinkedIn, Bobby Rhett, an Industrial Hygienist in the Washington, DC area, replied, “We may not always have the source of asthma pinned, but there is evidence that improving ventilation improves asthma outcomes.”
In the other corner…
Raymer responded with a jab, aiming to connect quickly and thus take some of the impact out of Krigger’s blow. His article, titled, Don’t Blame the ASHRAE 62.2-2010 Standard, disputed Krigger’s claim that ASHRAE moved away from simplicity when they revised the standard from their first version, 62-89. That early version, he wrote, was 26 pages and the 2010 standard is only 14. “The ASHRAE 62-89 Standard is no longer supported by ASHRAE partly because of its complexity,” Raymer explained.
He then went into some of the details of the two versions of the standard, offering a nice contrast between how they really work. One important point that many in the home performance and weatherization field probably don’t know is that, “there is nothing in the 62-89 Standard about calculating a Building Airflow Standard, Building Tightness Limit, Minimum Ventilation Level, etc.” Those terms come from the programs that reference the standard.
How many rounds will it go?
In case you don’t know who they are, both Krigger and Raymer are heavyweights in this field. Krigger is the author of the book Residential Energy, which is used, I imagine, in nearly every building analyst and home energy rater class in the US. Raymer is the author of the book Residential Ventilation, which covers the whole topic extensively. He’s also on the committee that decides what goes into ASHRAE 62.2 and issues the new version every three years.
How we ventilate homes is a big deal and far from settled. ASHRAE 62.2 is leading the way, but as you can tell from this fight, there is pushback from some of the people who have to apply the standard in the field. The Building Performance Institute (BPI) was supposed to drop 62-89 and adopt 62.2-2010 this month but released a statement on 28 December announcing they’d postponed that change.
Both of these guys make good points, but I have to side with Paul on this issue overall. I think BPI should have dropped 62-89 long ago, and to keep postponing it only makes it worse, as more people get trained on an obsolete standard that was created in the 1980s. John definitely makes some good points, and I think we can do a better job of considering the training aspect of applying standards. Part of that falls on the organizations that adopt the standard, too. Paul’s basically right, though, that we need to go with the newer version. Yes, it needs work, but the three-year cycle is getting us there.
This is an important battle in the Building Science Fight Club. It’s not just a bunch of sixth graders banging shoes on the ground to get attention. We need to ventilate homes to improve indoor air quality, and we need to be able to do it cost-effectively. Debate and discussion are healthy, and we need to keep it going. I’d love to see John and Paul do an evening session at the RESNET conference this year and continue this debate.
I’ll give the last word in this stage of the debate, though, to Albert Einstein, who once said, “Everything should be made as simple as possible, but not simpler.”
The Two Punches
Energy Standards: Common sense Basics by John Krigger
Don’t Blame the ASHRAE 62.2-2010 Standard by Paul Raymer
Related Articles
Breathe! – Get Fresh Air into Your Home with ASHRAE 62.2
Asthma and Poor Indoor Air Quality — The Trouble with Homes
You Do NOT Talk About Building Science Fight Club
Photo of boxers by The Cosmopolitan of Las Vegas from flickr.com, used under a Creative Commons license.
This Post Has 9 Comments
Comments are closed.
Thanks for timely post on the
Thanks for timely post on the hot topic of ventilation. For attics a Hip Ridge vent systems can add much needed NFA (attic exhaust). It’s a bit risky and can be a tough install on rerto.
I’m glad I’m not trying to
I’m glad I’m not trying to keep these guys apart! While I sometimes get a little annoyed with auditors and experts discussing everything ad nauseum (as a contractor I just want to get in there and FIX it!), as a closet egghead, I’m really glad to see the discussion. This leads to better solutions and it’s fun to watch the blow by blow.
I appreciate Krigger fighting for simplicity because the changes make contractors’ lives a bit hellish. As usual, the solution is probably in the middle, John had a hypothesis, Paul the antithesis, and the synthesis should turn out well! It’s good to really like both fighters too!
To Don – do not confuse
To Don – do not confuse indoor ventilation (the subject of this blog) with attic ventilation. If you reduce interior air leakage, attic ventilation becomes a minor issue while indoor ventilation becomes a major issue.
Allison – don’t want to get into a battle of the Titans, but another Titan – Dr. Joe – has recommended for quite some time not to get tied up with the “seal it tight and ventilate right”; just “ventilate right”, which I interpret as every home needs proper ventilation by intentionally providing it rather than relying on unintentional ventilation (cracks/gaps through dusty/moldy areas) and that this design aspect might be as/more important than air sealing.
Don P.: As
Don P.: As Dave Eakin said, attic ventilation is a whole different animal, an important one, to be sure, but outside the scope of what we’re talking about here.
Nate A.: As Paul pointed out, 62-89 wasn’t as simple as it’s made out to be, and 62.2-2010 isn’t as complex as it’s made out to be. You’re right, though – A lot of the problem is because people don’t like change.
Dave E.: Indeed, Joe and BSC are spot on by claiming that we need to stop trying to use a blower door to figure out how much ventilation we need. As he says, “To me, the ventilate right part is easy: put in a ventilation system and pick a rate.” See footnote 4 in his article Just Right and Airtight for the details of how BSC does that. I’ll write more about this issue in another article because it’s a big, important topic.
Wow, I’m glad to see that Dr.
Wow, I’m glad to see that Dr. Joe agrees with me on residential ventilation ;~)
One of the dumbest things that ever got promulgated to the residential building science field is the BTL. It is a classic CYA attempt which does the occupants of a building no real good.
Repeat after me: This house needs a ventilation system. That house needs a ventilation system. Every house needs a ventilation system.
Sizing is more complicated, but not much. Low level continuous at something below the ASHRAE standard (Gee, 60% sounds reasonable) with spot ventilation for high load areas: Kitchens, baths, rooms with 15 aquariums.
Not that I have an opinion on this…
I assumed the "
I assumed the “ventilation battle” would be about the 4 different types of ventilation: a) exhaust only – easy to build in, but does it work well? b) supply only – more complicated to build in, can lead to comfort issues in shoulder months, c) balanced – combines supply and exhaust, d) balanced with heat recovery – most expensive, hardest to implement, most efficient.
It might be useful to focus
It might be useful to focus the fight in the retrofit/weatherization/home performance arena? 62.2-2010, of course, covers both new construction and existing homes, but is it really that complicated for new construction? The requirements for existing homes, however, is much more awkward and leaves room for further development.
Take just the calculation of the ventilation requirements for existing homes. The big-picture approach is better than BTL (I agree with Bill Smith here; leaving behind the BTL is certainly a positive step forward). But the calc for existing homes, while maybe not a CYA approach, still seems full of compromise.
This is my take on the procedure for existing homes:
1) Calculate an initial rate for the whole-building ventilation requirement.
2) Determine what is required to meet local exhaust ventilation requirements.
3) Adjust whole-building requirement to accommodate existing local exhaust:
–Add up local exhaust deficits (including any window credits).
–Divide combined deficits by 4.
–Add this amount to the initial whole-building requirement.
4) Find Natural Infiltration (ICFM)
–Run BD test to find initial CFM50.
–Convert CFM50 to ICFM using appropriate weather factor.
5) Calculate infiltration credit, using the formula: 0.5 (ICFM – 2 CFA/100)
6) Determine required whole-building fan capacity by subtracting the infiltration credit from adjusted whole-building requirement.
It’s the adjustment of the whole-house ventilation to accommodate existing local exhaust (step 3 above) and calculating the Infiltration Credit (steps 4 and 5) that is the awkward part.
Leakage as a proxy for fresh
Leakage as a proxy for fresh air? Maybe if you have no experience testing IAQ over time. But its little better than measuring my feet when sizing for gloves.
Some tight houses have great iaq, some lose houses have terrible iaq. A blower door measures tightness, not air quality.
Changing rules that take pretty long leaps of faith wrt what is accomplished seems pretty crazy. These programs are really fully burdened, seems adding straws is reckless and myopic at this point! Who benefit$ from such things?
Certainly not the consumer. Change adds cost in training, may add cost to the consumer beyond the imbeded employee cost, and may simply mean much smaller dispersion of better practices as more turn their backs to this stuff.
This argument will hopefully be mute shortly. We will have devices that MEASURE air quality. Shortly following these devices will control your ventilation (is becoming more common to use expensive CO2 monitors for control now, though I’m not convinced CO2 levels are great proxy for IAQ)
In the meantime, always recommend mechanical ventilation to your clients. Get them used to the idea houses need fresh air, and cya in the event it is later discovered their air quality is a problem.
I would love to see the
I would love to see the following theory proved/disproved: air follows the path of least resistance; mechanical ventilation (provided for each living space and engineered to meet the current ASHRE guidance) will be that path of least resistance so there will be no “natural infiltration”.