Where Can I Find Good Advice?

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Where Can I Find Good Advice?

A new book repeats discredited ideas on the best way to build an energy-efficient house

Posted on Jun 15 2018 by Martin Holladay
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Donald Wulfinghoff is an energy consultant who works in Maryland. In 2015, he published Super House, a 700-page book that explains how an ordinary person without architectural training can design a superinsulated home that (he claims) will use only 10% to 20% as much energy for heating and cooling as a conventional home.

The book is lavishly illustrated and comprehensive. Right off the bat, the author shares his lack of respect for architects: on the first page, he writes, "Is it really possible for a person with no prior experience to design a home that is far ahead of contemporary residential architecture? It certainly is."

Even for readers who are put off by Wulfinghoff's exaggerated energy savings predication or his architect-bashing, the book (at first glance) shows a lot of promise. Wulfinghoff is a big believer in superinsulation. Much of his advice aligns with recommendations from energy-efficiency researchers and experienced builders. For example:

  • He advises that home builders should aim to “virtually eliminate air leakage.”
  • He advises against cramming mechanical equipment into a small closet, and instead advises that mechanical rooms should be generously sized.
  • He explains that designers shouldn’t expect energy savings payback from a so-called “airlock” entry (a mudroom).
  • He advises against flat roofs.
  • He debunks the hype surrounding thermal massHeavy, high-heat-capacity material that can absorb and store a significant amount of heat; used in passive solar heating to keep the house warm at night. : “Thermal lag is not useful if the weather stays too cold or stays too warm for several days or longer.”
  • He correctly notes that south-facing windows shouldn’t be viewed as heat-collecting appliances: “Make your windows and other glazingWhen referring to windows or doors, the transparent or translucent layer that transmits light. High-performance glazing may include multiple layers of glass or plastic, low-e coatings, and low-conductivity gas fill. no larger than necessary to satisfy your needs.”
  • He gives good advice on shading windows: “During warm weather, all the glazing in your house should be shaded. … Interior shading is the least efficient method of rejecting solar heat.”
  • He understands the limits of building regulations: “Surveys have shown that most parts of the United States do not enforce their building codes entirely, especially the more complex parts, such as energy efficiency requirements.”
  • He warns readers to be on the lookout for R-valueMeasure of resistance to heat flow; the higher the R-value, the lower the heat loss. The inverse of U-factor. scammers: “Be aware that R-values of certain kinds of insulation may be wildly exaggerated. This cheating happens most commonly with materials that use a reflective surface, such as window films and foil-faced bubble wrap.”
  • He is appropriately skeptical about efficiency claims for so-called “radiant” floors: “Floor heating is advertised as being especially energy efficient, but it’s not.”
  • He’s done his homework on solar thermal systems: “Realistic payback period exceed ten years for [solar] water heating systems, and they exceed twenty years for [solar thermal] space heating systems.”
  • He provides good advice on ground-source heat pumps: “Your super-efficient house will require so little energy for heating and cooling that an earth-coupled [ground-source] heat pump can’t be economical, even if it works properly. Therefore I can’t recommend a soil-buried geothermal system.”

A cranky uncle?

So far, so good. The advice quoted above resembles advice from many experienced builders of high-performance homes.

But once readers dig a little deeper into the book, they start to notice that much of Wulfinghoff’s advice is idiosyncratic. He’s like a cranky uncle with firmly held but arbitrary opinions:

  • He advises readers to build a “strong room” to store their guns.
  • He hates tub/shower units, preferring walk-in showers. He advises that “a bathtub is primarily an esthetic feature,” a statement that leads me to conclude that Wulfinghoff never raised children.
  • He assumes that only men will read his book, advising readers, “You will need a workshop for manly pursuits.”
  • He notes, “Almost everyone wants a swimming pool.” Really?
  • He rejects common terminology for roof types, and introduces his own vocabulary. He explains that a shed roof with solid lumber rafters should be called a “beam roof,” while a gable roof with solid-lumber rafters should be called a “triangle-frame roof.”
  • He doesn’t like walls with exterior rigid foam or conventional double-stud walls. Instead, he advises readers to use site-built wall trusses — structural cousins of the Larsen truss — that use 1/4-inch plywood webs to join 2x6s with 2x3s. He writes, “Your carpenter can easily fabricate these wide studs at the construction site.”
  • He advises readers to always use plywood sheathingMaterial, usually plywood or oriented strand board (OSB), but sometimes wooden boards, installed on the exterior of wall studs, rafters, or roof trusses; siding or roofing installed on the sheathing—sometimes over strapping to create a rainscreen. — never OSB.
  • Instead of installing triple-glazed windows, he advises readers to install two double-glazed windows — “tandem” windows — in each rough opening so that each opening is quadruple-glazed. He never mentions whether this advice is limited to cold climate zones, so readers must assume that the advice applies to all climates.
  • He advises readers to install a hydronic heating system rather than a forced-air heating system.
  • He succinctly answers a question about when it makes sense to install a central air conditioning system: “Never.”
  • He advises readers, “‘Zero energy’ houses and ‘going off the grid’ are romantic notions without real merit.”

Some of these opinions are defensible, of course. But after a while, readers get the impression that Wulfinghoff’s personality is a little — how shall I put it? — inflexible.

Advice that's just plain bad

So far, we’ve discussed Wulfinghoff’s good advice and his cranky opinions. There’s a third category of advice in the book, however: bad advice. Wulfinghoff’s advice is so often bad that his credibility evaporates as quickly as dew in Las Vegas:

  • Although he provides advice on sealing air leaks, his book never mentions blower doors or blower door testing.
  • His understanding of residential ventilation is abysmal. Wulfinghoff writes, “Windows are virtually ideal for ventilation. … In most homes, windows are the prime source of ventilation air that is needed to eliminate pollutants from the interior.”
  • He writes, “In most locations, glass and mineral fiber batts are the best all-around insulation for frame walls, floors, and ceilings.”
  • He writes, “The best insulation for the interior of the basement wall is glass or mineral fiber, in the form of batts or fiberboard.”
  • He advises against the use of cellulose insulationThermal insulation made from recycled newspaper or other wastepaper; often treated with borates for fire and insect protection. in walls. His explanation makes it clear that he has never heard of the dense-pack technique: “Don’t use cellulose insulation in ordinary frame walls, where it would settle and leave an uninsulated band at top.”
  • He falsely advises readers that the R-value of all three types of rigid foam insulation declines over time.
  • He advises readers that XPSExtruded polystyrene. Highly insulating, water-resistant rigid foam insulation that is widely used above and below grade, such as on exterior walls and underneath concrete floor slabs. In North America, XPS is made with ozone-depleting HCFC-142b. XPS has higher density and R-value and lower vapor permeability than EPS rigid insulation. is always preferable to EPSExpanded polystyrene. Type of rigid foam insulation that, unlike extruded polystyrene (XPS), does not contain ozone-depleting HCFCs. EPS frequently has a high recycled content. Its vapor permeability is higher and its R-value lower than XPS insulation. EPS insulation is classified by type: Type I is lowest in density and strength and Type X is highest..
  • He writes that “Water vapor moves into the structure by diffusion,” when in fact far more water vapor moves via air leakage than diffusion.
  • He falsely claims that “An airtight exterior sheathing will do nothing to reduce the rate of condensation.” In fact, reducing air leakage helps lower the risk of condensation in wall assemblies.
  • He advises all builders except hot-climate builders to install interior polyethylene on walls and ceilings.
  • He never explains why water-resistive barriers (WRBs) are needed, nor does he even define “water-resistive barrier.” Instead, he launches a diatribe against housewrap. He explains that housewrap is “superfluous,” and he laments, “Unfortunately, even some building codes now require housewraps. … My opinion is that housewraps are useless…”
  • He advises readers that it’s a bad idea to install a continuous horizontal layer of rigid foam under a slab. Instead, he advises readers to install rigid insulation above a slab.
  • He advises readers to encourage moisture in basement walls to evaporate inward.
  • He has an imperfect grasp of technical terms. For example, he confuses “subfloor” with “underlayment,” and he seems to think that “split-system heat pump” is a synonym for “ductless heat pump.” (In fact, a conventional American heat pump connected to a forced-air distribution is also a split-system heat pump.)
  • He advises readers to install insulation in the floor assembly above a crawl space.
  • He misunderstands the science behind continuous wall insulation: “Don’t use foam insulation board as sheathing… Foam board insulation acts as a vapor barrier. Any vapor barrier must be installed on the warm side of the wall to avoid moisture damage to the structure. But foam board used as exterior sheathing is on the cold side, inviting moisture damage.”
  • He falsely notes that attic ventilation can help keep a house cool.
  • He advises readers that vinylCommon term for polyvinyl chloride (PVC). In chemistry, vinyl refers to a carbon-and-hydrogen group (H2C=CH–) that attaches to another functional group, such as chlorine (vinyl chloride) or acetate (vinyl acetate). windows deteriorate quickly, generally lasting only 20 years.
  • He provides advice on window installation without ever mentioning that window rough openings need flashing.
  • Why is bad advice so common?

    There’s no need to flog a dead horse. After reading this review, I don’t imagine that many GBAGreenBuildingAdvisor.com readers will want to waste $60 on Super House.

    But Wulfinghoff’s book raises two perennial questions:

    • Why is bad advice on the topic of energy-efficient construction so common?
    • Where should homeowners go for good advice?
    • The answer to the first question is complicated, but the three most important factors are these:

      • Many existing code requirements have no basis in science.
      • Building science is a relatively young field, and many important research findings in this field are only two decades old.
      • Many builders and architects harbor misunderstandings about such topics as condensation, vapor diffusionMovement of water vapor through a material; water vapor can diffuse through even solid materials if the permeability is high enough. , air leakage, and attic venting.

      The answer to the second question isn’t simple. Homeowners who have heard conflicting advice from contractors or architects often post questions on GBA, asking, “Who should I believe?”

  • Advice published on the Building Science Corporation web site is trustworthy.
  • Energy-related advice from the following three magazines is trustworthy: Fine Homebuilding, the Journal of Light Construction, and Home Energy.
  • Most advice from the U.S. Department of Energy is trustworthy, although information for homeowners and builders is scattered on a variety of web sites and therefore hard to access.
  • Homeowners in search of information on energy retrofitting an existing home can trust the information in Bruce Harley's book, Insulate and Weatherize.
  • Energy nerds in search of technical information can trust the information in John Krigger's book, Residential Energy.
  • You can always trust GBA.

Martin Holladay’s previous blog: “Growing Weed Indoors is an Environmental Disaster.”

Click here to follow Martin Holladay on Twitter.


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Image Credits:

  1. Energy Institute Press

1.
Jun 15, 2018 9:10 PM ET

Book reviews
by Malcolm Taylor

These are among my favourite of Martin's blogs. I imagine him shouting indignantly to his wife in the other room: "Listen to what he says about insulation!". His wife probably replies (much like mine does when I do the same) with a "Yes Dear" and continues what she was doing.


2.
Jun 17, 2018 11:14 AM ET

Really appreciate the book reviews
by Andy Kosick

"The answer to the first question is complicated" is the answer. It is complicated and most people (builders even) fail to recognize that. There are usually several ways to do something correctly and even more ways than that to screw it up.

For some reason this reminds me of how some years back it seemed like every other issue of Fine Homebuilding had some structural engineer write in about a previous article saying what amounted to "no builder or carpenter should ever cut a single 2x4 in a house without consulting an engineer", at least that's what it sounded like because it just ticked me off at the time. How stupid did they think we were? As time has passed and I've delved deeply into building science, I have a great deal more respect for the concern of those engineers but still feel they would have done better using the platform to argue for more stringent licensing of builders rather than talk down to the many good builders that read the magazine.

Anyway, I think it's still fair to say that the desire alone of an individual to build a truly high performance home makes them more qualified to do so than the average builder, but they should maintain a great deal of humility throughout the process.

Lastly (but certainly not leastly) is there a detailed wall section of a "tandem" window available, because I would pay to see that. This could potentially end the innie vs outtie debate; best of both worlds. May I suggest a companion volume "The Window Washers Guide to Tandem Windows"


3.
Jun 18, 2018 8:46 AM ET

Edited Jun 19, 2018 8:35 AM ET.

Response to Andy Kosick
by Martin Holladay

Andy,
I agree that finding the right tone when advising builders can be tricky. No one wants to be treated like an idiot -- but I was certainly an idiot when I started building (which is why my own house is so leaky). I'm sure I occasionally strike the wrong tone, but when I'm being mindful, I like to approach advice this way: What would I have wanted someone to tell me when I was starting out (and about to make 12 mistakes)?

I'm not sure whether your tongue is in your cheek or not when you ask for tandem window details. I'm sure there is a right way and a wrong way to do it. Among the most important things to think about:

1. Which panes are likely to suffer from condensation, and how can this condensation be avoided?

2. Are tandem windows safe in an emergency, when sleepy people are looking for an egress window?


4.
Jun 19, 2018 7:48 AM ET

Definitely Tongue in Cheek
by Andy Kosick

Sorry it didn't come through clearly, but of everything you mentioned, I found the idea ridiculous to the point of humor. The more I thought about it the worse it seemed and I hadn't even thought about emergency egress. Setting aside whether or not this could be done successfully (unlikely without vinyl and a WRB), with such a variety of window performance and price available who would intentionally install a permanent storm window. It makes me think the author has never tried to keep a house with storm windows clean.


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