BREAKING: Commercial Building Engineers Live in Residential Buildings

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ASHRAE commercial building engineers live in residential buildings

I've just returned home from Long Beach, California, where I've spent the past five days attending the ASHRAE conference, which focuses on heating, ventilation, air conditioning, and refrigeration. One of the things I heard there was this statement:  95% of ASHRAE members work on commercial buildings. 100% of them live in residential buildings. Seems like there's a disconnect in the system.

ASHRAE actually does quite a bit of work in the residential sphere. Two standards that I'm aware of apply specifically to residential buildings. Of course, the residential ventilation standard, 62.2, is well known to readers of this blog since I've written about it so much. It's got some traction in the marketplace, as it's been adopted for use in the US Department of Energy's weatherization program, the EPA's ENERGY STAR new homes program, and the California energy code (Title 24).

The other residential standard is 90.2, Energy Efficient Design of Low-Rise Residential Buildings. It's got no traction. No one is using it yet, partly because of confusion about its purpose. Unlike it's commercial building sibling, 90.1, this standard is not a minimum standard. According to what I heard from members of the committee this week, it's meant to provide a path to building homes that are significantly more efficient than code-minimum houses.

Or is it? If you look at the home page for this standard, you'll find this:

1.1 Purpose: To establish the minimum design and construction requirements for energy efficient residential buildings.

1.2 Scope This standard provides the minimum design and construction requirements for new residential buildings and their systems and new portions of existing residential buildings and their systems that use electricity and/or fossil fuel.

I'm not on that standards committee and haven't been to any of its meetings, but it seems clear to me that they need to clear things up.

Beyond those two specifically residential standards, ASHRAE does a lot of other work that applies to residential building. Some of it goes into standards, like the aforementioned 62.2 and 90.2. Some goes into one of the four handbooks that ASHRAE publishes. Here's a sampling:

  • Standard 55: Thermal Environmental Conditions for Human Occupancy. Discomfort is an issue in all buildings.
  • Standard 160: Criteria for Moisture-Control Design Analysis in Buildings. If a building has an enclosure, this standard applies.
  • Technical Committee 5.2: Duct Design. This committee writes some of the chapters in the Handbook of Fundamentals and the Handbook of HVAC Systems and Equipment. (I've been writing a series on duct design based mostly on ACCA's standard, Manual D, which is based on ASHRAE's work.)
  • Technical Committee 4.4: Building Materials and Building Envelope Performance. Insulation, drainage planes, air barriers... all the control layers are covered here.

And much more!

The good news is that some of those engineers who go home to residential buildings realize the need for ASHRAE to step up and do more in the residential market. A couple of years ago, they created the Residential Building Committee (RBC). This group has some momentum now and I think you'll be hearing more from them in the coming years. If you, like those ASHRAE engineers, live in a residential building, you may be the beneficiary of their work.

But here's something you may not know. ASHRAE isn't just for engineers. They seek involvement from stakeholders across the board. The residential ventilation standard committee has home performance contractors and home energy raters involved. And the National Association of the Remodeling Industry (NARI) has just started sending two members to represent their interests. So come on. Get involved.


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You made a statement that is incorrect: ". . . conference of the American Society of Heating, Refrigerating and Air-Conditioning Engineers, better known as ASHRAE" The organization's official name is now "ASHRAE" and it is no longer the American Society of . . . . Why? They are trying to broaden their base beyond America and HVAC&R Engineers. Maybe that is a good thing, maybe not. I see a lot less good technical content at these meetings now.

Now to respond to the real question. I was on 90.2 as a voting member, but quit due to a lack of progress. Since I left, they have accomplished a lot and I am fully supportive of it. As far as being a "minimum" standard, I claim that it is in terms of "energy efficiency". The current codes do have a lower energy efficiency requirement, but I would claim that they are not requiring "energy efficient buildings". The economic analysis that was used to establish the 90.2 baseline was based on the minimum energy required for a house design with the same life-cycle cost as a house meeting IECC 2015. In other words, a 90.2 house would cost more, but the money would be paid back with lower utility bills over the life of the house and the energy consumption would be considerably less.


Thanks for the clarification on those issues, Roy. I looked up the name issue on the ASHRAE website and found this:

In 2012, as part of a rebranding, ASHRAE began doing business as “ASHRAE” vs. using its full legal name of the American Society of Heating, Refrigerating and Air-Conditioning Engineers. Use of ASHRAE reflects the Society’s worldwide membership and that services will continue evolving globally.

So I guess the full name is still their legal name but they're using the acronym as a DBA. I'll revise my lead paragraph.

Your explanation of the direction of 90.2 reminded me that Philip Fairey sent me a paper they wrote about the cost effectiveness of the standard. Published by the Florida Solar Energy Center (FSEC), the paper is titled, Maximum Energy Efficiency Cost Effectiveness in New Home Construction and is available online. According to that paper, the goal now is "50% savings compared to this 2006 IECC baseline 'subject to cost effectiveness.'"

Thanks again, Roy. It's good to have your input here since you've been in the thick of things at ASHRAE for so long.

"The economic analysis that was used to establish the 90.2 baseline was based on the minimum energy required for a house design with the same life-cycle cost as a house meeting IECC 2015. In other words, a 90.2 house would cost more, but the money would be paid back with lower utility bills over the life of the house and the energy consumption would be considerably less."
This brings up a huge sticking point of mine - residential life cycle. If the duration you are speaking of is that of commercial structures, then you are talking about 30 years. If not, then I am very interested in what it is. Point being - our country (and most other developed countries) are still awash in old residential structures that (IMO) are WAY past their designed lifespans. On an order of 3x-4x. But no respected guidance group (ASHRAE or others) has put out any guidance on what to do with them. Just reset the lifespan timer? Rehab and reset? Raze, rebuild and reset? Millions upon millions of brick/masonry row homes, brick/siding-clad cinderblock sided, wood-frame aluminum-sided; they're still out there being touted (by the real estate juggernaut) as perfectly habitable and a desirable purchase. My opinion is that unless there is some reason (i.e., historic designation, outstanding architectural design, etc.) every building (commercial or residential) should either be gut/rehabbed or razed at the end of its design life in order for the most current/best building practices to be used. My guess - every recognized group will suddenly "have new shoes" so as to not upset the political and financial apple cart (status quo) for builders/remodelers/mortgage institutions. Until there is wide-scale need/demand for change, there will be no meaningful change.

Yea, STD90.2 has been a bit confusing. ASHRAE's goal for 90.2 about 10 years ago was to have a standard that resulted in a 50% energy reduction compared to IECC 2006 if it could be shown to be cost effective. Once the committee got around to doing the economic analysis, IECC 2015 was already in place, so the economic analysis was done to determine the maximum energy savings that could be cost-effectively achieved relative to IECC 2015. This maximum cost-effective energy savings relative to IECC 2015 was then compared to IECC 2006 to see if it would still meet the 50% energy reduction goal relative to that standard, and it did. Does this makes sense or are we now even more confused? Philip Fairey and others gave a great overview of this standard on Wednesday at Long Beach, but as usual, attendance was quite low on the last day of the conference.

We should keep in mind that this version of the standard is still under public review and there will likely see some changes before it is finalized. I hope that these changes are not substantial.

Standard 90.2 economic analysis was based on a 30-year economic life which was chosen to correspond to the length of a standard fixed-rate mortgage. I am pretty sure that it also assumed a salvage value at the end of that life. Life-cycle cost analysis over long time periods is tough because of the number of parameters that have to be set during that time period. All of these parameters were extensively debated on the committee. I doubt if anyone was completely happy, but that is how committees work. Some people on the committee wanted the economic analysis to be over the average ownership period of a house (about 7 years) with the discount rate being current credit card interest rates (18%). We ended up with a discount rate of 5%, roughly corresponding to 30-year mortgage rates.

I have no idea what the actual life of a house should be or who should determine it. I can't imagine a law that says you have to tear down a house after X years. People seem to pay significant prices for older houses with lower energy efficiencies so they must be worth something even if the energy bills are higher. Perhaps we should just tax utilities to the point that it would be cheaper to tear down old houses than to heat them? I guess Eminent Domain would be another option (let the government buy them and knock them down). (I am not really serious about any of these ideas, but I can't think of any better ones, can you?)

Quite a few people in the industry believe that residences should last for many decades if not centuries. I am part of that group in favor of durability. At the same time it is important that they improve over time -- particularly with respect to energy use. In the Central Valley Research Home Project we retrofitted five houses of various vintages. The oldest built in 1948. It would be a shame to tear down these perfectly viable homes for new construction with all the cost and energy associated with building new.
Myth: "You have to rebuild the house to save 50% or more of the cooling energy". NOT SO
The three oldest homes saved an average of 77.7% of the cooling energy through simple, common retrofits (ducts, HVAC, insulation, air sealing, etc.). Only the newest home fell short with a 45% cooling energy savings. That home was already well insulated, with good windows.

No real useful alternatives visible right now because of perceptions - of homeowners' that their properties will increase in value over time (unlike every other material possession); of the real estate profession (all workers) who only want to sell properties over and over; of legislative bodies that do not want to obtain the requisite funding to do much of anything revolutionary. I think that the better option is to de-fund energy generation subsidies so that all energy users will be required to pay all costs; to create a nation-wide energy grid so all generators can "play" across the entire country not just in their "fenced" location; to create/enforce nation-wide, advanced (best industry practice) building codes to avoid any local delays or interpretations that would apply to all new construction and any sale of an existing property (but current residents would not be affected until property sale) so that the quality of all housing stock would improve over time, or the true value of unimproved buildings would be evident.

John - somewhat agree, but at what cost? Just saw a YouTube video from Matt Risser the other day where he was talking about his TX renovation project and the same question was asked. Answer was that it was about 2x to 3x more expensive to remodel/re-engineer to meet today's desired living arrangements as well as safety/energy codes than to build new (labor to renovate/improve is more expensive and building methods harder to implement and are less effective). Unless your 1948+ homes had very desirable architectural details, the entire mechanical layout is best current industry practice, and the floorplan is desired in today's market - why bother?

John, Thanks for your comment! Our problem is finding contractors who understand building science.

Perhaps my past houses have not increased in value over time, but their prices have gone up, which is more than I can say about any of my other material possessions. I will agree with you that realtors have little value added to the housing market and are way overpaid due to MLS monopoly. I am surprised that MLS still exists with the current internet-based markets. I guess you still need to have some third-party to arrange house showings. Perhaps we should have Uber Realtors who just drive you to the house, let you in, make sure that you don't steal anything, and then lock it when they are done. They wouldn't provide any useful information, but most real estate sales people don't either.

But seriously, when I look at purchasing a "used" home, I would sure like to see the past utility bills. I would think that lenders would also like to see that to determine the overall "affordability" of the house.

As for a nation-wide grid, it practically exists today, but the grid is not capable of distributing electricity over long distances with low losses unless you go to expensive DC distribution trunks. Texas took the opposite approach and separated themselves from the rest of the grid and deregulated the generators and retail service providers. Prices have not really gone up and there are some interesting time-varying electricity rates available to homeowners.

I had to add 7+8 to post this comment. I hope that I got the right answer!

Partial Solution : Get rid of the mortgage interest deduction. This deduction is a taxpayer (future generations) subsidy and contributes to price inflation of the housing industry as a whole.

I'm sure you're already aware of this, but the price of all those "used" homes is directly tied to the supply and demand of the dirt they sit on. Sure, fancy countertops or an extra garage stall can help, but a good home in a bad neighborhood will still have a hard time selling.

As for the utility bills being a disclosure, I agree. In fact, I have first-hand experience on using them to help sell our "used" home 6+ years ago. That's why I applaud states like CT and CO and the city of Portland, OR who now require either a Home Energy Score or an energy audit as part of the sale process. To be clear, they don't require any improvements/upgrades, just the disclosure of the energy performance of the home.

During part of the 1970's we provided utility bills. Due to privacy the utility company doesn't cooperate in providing this information. Yes, we should have the owners provide that information on the Seller's Disclosure Statement. Yes, I would love to see the energy rating be a requirement at time of sale IF you can train people to give an enlighting report that would be meaningful to the buyer.

Hmmm. Once again this IECC vs ASHRAE issue. Sometimes it feels like a competition. It is apparent to me, having served quite a few years writing codes, that the two organizations have different goals. IECC- while builders have one set of goals and energy advocates have another, governmental voting members have the final vote on what goes into the code because they have no financial interest in the outcome. What is the goal of the energy code official? A usable, understandable, enforceable code.

ASHRAE has a goal of net zero one day and are moving towards that. Kudos to them for that. I have nothing against ASHRAE. I recommend it sometimes, depending on the project and the GOALS of the designer/owner.

Perhaps instead of constantly having to compare the two and trying to keep up with the Jones's, it is time to say that you use the code or standard based on your goals. If your goal is a minimum efficiency that is written in "code language" then you recommend IECC. If your goal is more efficiency and you are ok with a little more complexity in the scope, you go with ASHRAE 90.1. It would sure help us at code hearings to quit having to try and put provisions into the IECC "because they are in ASHRAE".

We have to keep providing flexibility and if you make the two codes/standards match then you remove a layer of flexibility and options. Write your two different books and let the designers decide which one to use, knowing that they can't go any worse than the IECC. The two don't have to be equal. They can just be different approaches. A jurisdiction could also determine which level of "minimum" they want and could always require ASHRAE as their minimum. It is just clear to me that there are different goals and so maybe it's time to make them different levels of efficiency instead of trying to keep up with each other.

No matter what, I would suggest that ASHRAE writers keep one thing in mind. There is an end user to the document. If you make the wording so complex, even though the writers understand what they are trying to say, many end users won't understand it and can't get through the complexity and they won't use it, at least they won't use it correctly. Please remember that there is an end user to this standard and they need to be able to understand what it says without having to purchase the user's manual.

Just a simple request from a simple code official who sees so many jurisdictions accepting a passing COMcheck to ASHRAE and calling it good. They don't realize the requirements for the energy monitoring and controlled outlets, etc. It's just not being used the way you intended, and to be fair, neither is the IECC. There's a lot of work to be done on both documents. They just don't have to be the same or equal!!

ASHRAE only writes voluntary standards. It is up to others as to how they use them. Some code bodies do adopt some of them in various forms. The decision was made on Std. 90.2 to not "compete" with building codes and to develop a "leadership" standard for those who want to specify a higher level of energy efficiency than the IECC. There is not expectation that IECC will adopt 90.2. Many of us hope that it will be adopted by other programs such as Energy Star or various utility incentive programs. Perhaps someday builders might just want to build to 90.2 specifications for marketing purposes.

Even though ASHRAE encourages that their standards be written in "code enforceable language" there really is no mechanism in place by ASHRAE to enforce these standards. That is up to those who use them. In other words, ASHRAE tries to lead horses to water, but cannot make them drink.

I would like to see the data on those making the standards and does their own home meet the standard they created.

I am not sure what "data" you mean. The current draft version of Std. 90.2 is new and quite different from previous versions and has not even gotten through the review process yet. If it does pass the review process and is published, only time will tell if it has any impact on the market.

I would guess that most of the current 90.2 committee members live in houses that were built before this version of the standard was under development and even before the recent IECC standards were in place. I would also guess that most of these committee members wish that their houses were more energy efficient. I have never met anyone in an existing house that wishes that their energy bills were higher. I just bought a brand new house (spec built, not custom built) that I think would come pretty close to meeting the current draft version of 90.2. I had to look a long time to find it. So far, I am quite pleased with it.

To be clear, I have experience enforcing standards (as an energy rater), but no experience creating them.

When I read this my first thought was, "in this mess of standards, where do we actually need to be" and my second thought reading the comments was, "what the heck is cost effective?" Which made me think why isn't there a ultimate standard, the mountain top if you will, this would describe where a residence needs to be on a per person basis to be comfortable and sustainable in a zero carbon, 11 billion person future (perhaps Passive Haus is already something like this). This document would have nothing to do with economics and would be updated as technology and understanding move forward. There would probably be a appendix of options to meet the standard, like double stud versus exterior foam, etc. Then, because not everyone could cost effectively meet this standard, there would be a second standard that describes the the best way to back away from the first. In other words, what needs to be done now and what can be left to be improved later. Also, what needs to be done to make those improvements feasible. Then, leave it up to governing bodies to determine what point on this flow chart of sorts is cost effective at the moment.

Crazy ideas that would fit into this scenario would be some be something like why aren't we encouraging builders to put 2 maybe even 4 inches of exterior foam and skip the cavity insulation. With vinyl siding it would relatively easy to fill the cavities later when that R-value becomes cost effective, but it would be comparatively ridiculous to add exterior foam.

Am I crazy? Let me know.

I have thought about this question too, regarding what is the minimum theoretical energy requirement for a residence? Theoretically, the goal of a house and its systems is to "cool" the occupants. We each generate around 340 Btu/hr (mostly sensible, some latent) when we are sedentary and we have to remove that heat and water vapor. If we had infinite insulation on all sides of the house (which would preclude the use of any currently available windows), then we would never need to heat the house, but we would have to mechanically cool it until the outdoor temperature drops below 70 F (depending on outdoor humidity) and then we could use "natural" cooling with outside air. So since a "ton" of cooling is 12000 Btu/hr, we need about 340/12000 (0.03) tons of cooling per person when it is "warmer" outside than inside. So the minimum energy required is practically nothing, unless you want to do something in the house. The first thing you might want to do is breath clean air, which requires a minimum of 5 cfm per person (some say 15 cfm/person) of outdoor air. That adds 200 Btu/hr per person of heating requirements if it is 0 F outdoors. This minimum ventilation also requires another 0.03 tons of cooling per person when it is 100 F outdoors in a humid climate. Of course, we could eliminate these ventilation energy requirements with an infinite ERV that required no fan power.

Any other "minimum" energy requirements the house? You might want lighting especially since we eliminated windows. Cooking appliances? Entertainment (TV, computer, cell phone charger)? All of these require electricity which in turn requires additional cooling energy unless it is sufficiently cold outside to provide it naturally. Solar PV collectors could provide the energy to power these devices, but the additional cooling energy would still be required.

Then there is hot water. We heat cold water for various purposes and then just throw the relatively hot water down the drain. We could recover some of this heat and/or generate it from solar thermal collectors.

So what is the minimum energy requirement for a residence? It depends on how much "luxury" you require and how much solar equipment you can afford.

"Crazy ideas that would fit into this scenario would be some be something like why aren't we encouraging builders to put 2 maybe even 4 inches of exterior foam and skip the cavity insulation. With vinyl siding it would relatively easy to fill the cavities later when that R-value becomes cost effective, but it would be comparatively ridiculous to add exterior foam"

I'll take a shot.

#1 Cost. Exterior foam (or mineral wool if termites are an issue) is very expensive vs. batts or loose fill. In colder climates the double-stud wall is cheaper.
#2 Labor cost. In colder climate zones especially it's expensive and difficult to attach cladding using long screws through 6 or more inches of rigid foam let along mineral wool. Never mind the challenges with having to build window boxes and flashing details of these thicker walls.
#3 Rigid foam shrinks.
#4 More difficult to design complex elevations when dealing with thick layers of exterior insulation.
#4 Industry lobbyist who stand to lose out on this are going to fight it.

My two cents.

Don't overlook refrigeration, unless you were lumping that in to "cooking appliances".

Also, vampire loads can be as much as 5% of the overall electrical load, but that could be trimmed down if you're minimizing the luxuries of the home.

RE: #2 - If building wider window & door bucks is an issue, the concrete home industry has had those products readily available for years, so they already exist off the shelf.

How much does rigid foam shrink and over what time period?

Yes, I was including refrigerators as well as laundry under appliances (I should have said all appliances, not just cooking appliances). Although the current draft of 90.2 is a "performance" standard, it does have some prescriptive requirements. One is that ductwork must be inside the conditioned space. I am all for that. Another is that all lighting (with a few minor exceptions) must be high efficiency, which generally means anything but incandescent. I am OK with this requirement also. LED's are now so cheap and have such long lives and high lighting quality that I use them wherever possible, mainly so that I don't have to ever replace them again. There is another lighting requirement that all permanent fixtures must have dimmer switches or occupancy sensors. I am not big on this requirement. I cannot think of any light fixtures in my house where I want variable brightness--I just make sure that I have the right brightness to start with. Also, I have had no luck with occupancy sensors. I think that the lighting manufacturers on the committee got away with this one based on their economics, not the homeowners'.

And on the topic of occupancy sensors, wouldn't they contribute to vampire loads? I'd love to see a study where they analyzed the load devoted to sensors over the course of a year, compared to leaving LED lights on longer than necessary (which is the function of the sensors). My guess is the sensors' benefit is greatly minimized by LEDs.

I'm not convinced about LED lighting.

#1 I've read reports that the light spectrum of typical LED's isn't necessarily good for our eyes.
#2 I have bunch of incandescent bulbs in my house that are as old as the house itself (17yrs). We just don't leave these lights on all the time. I suspect that we've saved more energy and $$ on using the lights only when needed vs replacing them with more expensive LED's.

That's a good point, is there a net energy savings? When I was on 90.2, the lighting people proposed a requirement for occupancy sensors controlling attic lights. I raised the issue of what happens if you get out of view of the sensor and it shuts the light off while you are in the attic? Instead, I think that they should require that the attic light switch be in an occupied space and have a pilot light on it so that the occupants can tell if it got left on.

I hadn't heard about any studies on the LED lights being bad for the eyes, but it doesn't surprise me. I am guessing that it was government funded and the final conclusion was that the results were not definitive and more research is needed. That's how I ended every paper or report when I was spending government research money.

I agree that the number one energy conserving strategy is to turn off stuff when not needed, and I think that most people are pretty good at that, especially with lights. I also agree that LED's may not be economically justified on low-use lights, but the government is slowly taking that choice away from us by banning incandescent lights.

See IDA (International Dark-Sky Association for information on LED lights.

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