Image Credit: All images from “Energy Saving Handbook” by James W. Morrison Flat-plate solar thermal collectors haven't changed much since 1979. Here's some old-fashioned advice: if your basement is cold, "add banking." What if you have a drafty house? Should you plug those big holes in your basement and attic? No — just "Add storm doors & windows and caulk around windows and doors." Where are the ventilation baffles? If you plan to install fiberglass batts between your rafters, don't use this 1979 illustration as a guide. If you don't install ventilation baffles, you'll end up with soggy roof sheathing. In the late 1970s, Steve Baer's drum wall got a lot of media attention. No one installs this type of thermal mass these days. According to this table, if your attic has 6 to 8 inches of insulation, the amount of insulation you should add is "none." This table implies that it's more important to check whether your windows are caulked than whether or not there are any holes in the ceiling below your attic.
Rummaging through the shelves of a used book store, my son Noah came across an old paperback called Energy Saving Handbook. Written by James W. Morrison, the book was published by Harper & Row in 1979.
A brief web search failed to reveal any biographical information about the author. However, I discovered that the book was published under several different titles, and was distributed by at least four state energy offices. Morrison’s book may have been funded by the U.S. Department of Energy; some of its chapters seem to have been repurposed from government brochures.
This book came out at an interesting time for the field of residential energy efficiency (1979). It was six years after the first oil price shock (the 1973 OPEC oil embargo); three years after the Department of Energy launched the Weatherization Assistance Program; and two years after Gautam Dutt, the discoverer of the thermal bypass, had his “aha!” moment in a New Jersey attic. In 1979, the Iranian revolution caused turmoil in the international oil market — precipitating the second oil price shock of the 1970s.
Back in 1979, in spite of Gautam Dutt’s 1977 epiphany, most weatherization workers still had an incomplete understanding of how air leakage affected home energy bills. That’s not too surprising, considering the fact that blower doors were not yet commercially available. (Gadsco began marketing the first blower doors in 1980.)
In 1979, most homes were leaky
By the late 1970s, residential energy experts were beginning to pay attention to airtightness. In the “Energy Saving Handbook,” Morrison notes, “To determine the heat loss from infiltration, it is necessary to know the rate of air movement through the homes. Most houses undergo from one to three air changes per hour, depending on construction.”
Morrison’s estimates of the average natural air changes per hour in older homes was probably accurate. By today’s standards, however, the houses that Morrison describes are extremely leaky. These natural air exchange rates — 1 ach(nat) to 3 ach(nat) — correspond to blower-door test results of 17 ach50 to 50 ach50. That’s very leaky.
These days, most newly built homes have natural air exchange rates of 0.2 to 0.5 ach(nat) — corresponding to blower-door test results of 3.4 ach50 to 8.5 ach50. In other words, the homes Morrison described were about 5 times leaker than most new homes built today. (Passivhaus builders do much better, of course — routinely achieving 0.6 ach50.)
Ducts outside of a home’s thermal envelope
Morrison’s book contains plenty of good advice. For example, he writes, “If the ducts for either your heating or your air conditioning system run exposed through your attic or garage (or any other space that is not heated or cooled) they should be insulated. Duct insulation comes generally in blankets 1″ or 2″ thick. Get the thicker variety.” Except for the fact that today’s experts usually recommend thicker duct insulation (at least R-8), and would probably mention the need to seal duct seams, Morrison’s advice is timeless.
Other examples of good advice from Morrison’s book include:
- “Use fluorescent lights in suitable areas — on the desk, in the kitchen and bath, among others. They give more lumens per watt.”
- “To prevent excess heat gain in the summer, provide window shading. These devices (overhangs, grilles, awnings, etc.) should shade the total glass area at noon during the hottest months.”
Morrison’s book includes an illustration of a solar thermal collector (see Image #2, below). The illustration will remind modern readers that this century-old technology hasn’t changed much over the years.
Leftovers from the 19th century
Back in 1979, I was 24 years old, and I was employed at a plumbing wholesale house where I performed heat-loss calculations and designed residential heating systems. Back then, homes were different, and Morrison’s book reflects these differences. For example, his book includes advice on maintaining a coal furnace: “Oil the inside of the coal screw and hopper to prevent rust.” Morrison wasn’t just being nostalgic; in some areas of the country, coal furnaces were still fairly common in the 1970s.
Morrison also makes several references to “banking” foundations, as when he notes that “infiltration from the foundation can be improved by adding banking materials.” (See Image #3, below.) Today’s young builders have probably never heard of banking foundations, but the practice was common when I moved to Vermont in 1974. Every fall, Vermonters banked their foundations with hay or softwood brush; once these materials were covered with snow, air infiltration into the basement was greatly reduced.
My paternal grandmother grew up in South Dakota, and one of her childhood chores during the early 1920s was to bank the house in the fall with manure from the stables. The advantage of banking with manure was that composting manure generates heat.
What Morrison got wrong
Building scientists have learned a lot since 1979. Here’s a list of a few things that Morrison got wrong.
Morrison overestimated the need for ventilation. Morrison wrote, “Any building will constantly exchange air with its environment: outside air leaks in, inside air leaks out. A certain amount of this exchange (say, one complete air change per hour) is necessary for ventilation, but most buildings have much more than is needed.” Morrison’s recommendation predates the first ventilation standard (ASHRAE 62-1989) by a decade. His recommendation of one air change per hour is three times greater than the rate recommended by ASHRAE 62 (0.35 air changes per hour), a rate which is still referenced for many purposes.
Morrison didn’t understand the need for a ventilation gap above fluffy insulation installed between rafters. Morrison’s book includes an illustration showing how to insulate between rafters to create a cathedral ceiling (see Image #4, below). Unfortunately, the illustration shows the installation of a fiberglass batt in a rafter bay without any ventilation baffles.
Morrison expressed misplaced concern about the effects of outward vapor diffusion in winter. Like many building experts who wrote during the 1970s, Morrison was a firm believer in the need for interior vapor barriers. “Vapor barriers are installed to reduce the flow of moisture through the insulation so that condensation will not occur,” Morrison wrote. “Vapor barriers should always be installed on the warm side (inside) to stop the moisture before it reaches the insulation.” These days, building scientists understand that the most important mechanism for conveying interior moisture into wall assemblies is exfiltration, not vapor diffusion, and that the problem of exfiltration is solved by an air barrier, not a vapor barrier. (For more information on the history of vapor barrier requirements in building codes, see Do I Need a Vapor Retarder?)
Morrison expressed a misplaced obsession with caulking. In the 1970s, a tube of caulk was seen as the solution to air leakage in homes. Forty years later, this misunderstanding seems quaint — but bad advice about caulking still crops up on today’s lists of energy saving tips.
The first two items on one of Morrison’s lists are appalling: “Where a house needs to be caulked: 1. Between window drip caps (tops of windows) and siding. 2. Between door drip caps and siding.” In fact, contrary to Morrison’s advice, it’s essential to keep these two cracks free of caulk.
Morrison has a section in which he explains how homeowners can reduce air infiltration. Here’s his advice: “Check to see if weatherstripping can be installed around single doors and windows. … Check to see if the infiltration through the wall can be reduced by caulking around doors and window frames.” Advice like this was common in the 1970s. Sadly, while millions of homeowners spent countless hours fiddling with weatherstripping or caulking their weep holes and drip caps, almost all of them ignored the raccoon-sized holes in their basements and attics.
Morrison had a misplaced faith in the value of storm doors. Predictably, Morrison advised homeowners to install storm doors. Remember storm doors? Sure you do. The only problem with the storm door idea is that a storm door saves only a tiny amount of energy — so that the payback period from installing a storm door stretches to 100 years or more.
Morrison’s passive solar glazing ratios were excessive. By 1979, authors like James Morrison had read dozens reports on the “solar house” fad, and had read profiles of innovative solar inventors like Steve Baer (see Image #5, below). Like most people who were intrigued by the idea of “solar houses,” Morrison passed on bad advice about passive solar glazing ratios. Here’s what he wrote: “To capture the necessary solar radiation, it is necessary to provide a minimum amount of south-facing glass. The minimal: 1/4 to 1/5 of the floor area (in temperate climates); 1/3 to 1/4 of the floor area (in colder climates).” These percentages — 20% to 33% — are nuts. Within a few years of the publication of Morrison’s book, passive solar designers had dialed this ratio back to a more sensible range of about 6% to 8%.
The first generation of so-called “solar houses” — the ones with 25% glazing ratios — created so many comfort problems (including overheating in summer and chills in winter) that they precipitated the famous “solar vs. superinsulation” debates of the 1980s.
Morrison recommended low R-values for attic insulation. Morrison told homeowners to measure the depth of their attic insulation. As long as an attic has at least 6 inches of insulation, Morrison advised, there was no need to add any more (see Image #6, below). Since 6 inches of insulation is only about R-19, this is pretty bad advice by modern standards.
In the 1970s, why didn’t energy experts understand the need for attic air sealing?
Morrison provides a checklist and table (see Image #7, below) for homeowners to fill out to figure out whether their home has a relatively low rate of air leakage (one air change per hour!), a moderate level of air leakage (two air changes per hour), or a high rate of air leakage (three air changes per hour). To make this determination, homeowners are advised to look for cracks in the basement, and to check whether there are any air leaks around water service pipes in the basement or crawl space. They are also advised to note whether their house has storm windows, and how tight their windows seem. They are also supposed to note whether their house has a storm door, and whether their exterior doors have a “loose fit” or a “tight fit.” Finally, homeowners are advised to see whether their windows are caulked.
Mysteriously, homeowners are never advised to go up in their attic to look for air leaks. Obviously, most homes in 1979 had huge leaks up there — often an open chase from the basement to the attic. Such defects matter a lot more than whether or not you can spot any caulking around your windows. But Morrison didn’t get that — in part because it’s easier for homeowners (and researchers) to notice infiltration than exfiltration.
When he wrote his chapter on air sealing priorities, Morrison — weighed down as he was by his caulking fixation — missed the boat. Still, a glimmer of hope can be found toward the end of the book. A single sentence (strangely placed in the “heating and air conditioning” section, where it clearly doesn’t belong) holds the germ of an idea that, if it had only been fully developed, might have led to better advice on which areas in the home need to be prioritized when performing air sealing work. Morrison wrote, “Seal any openings between your attic and the rest of your house where air might escape, such as spaces around loosely fitting attic stairway doors or pull-down stairways, penetrations of the ceiling for lights or a fan, and plumbing vents, pipes, or air ducts which pass into the attic — they don’t seem like much, but they add up.”
If Morrison had understood the full implications of this sentence, he would have re-written his chapter on air sealing. Alas, in 1979, a book providing good advice on attic air sealing measures was still a few years off.
Passive design principles
These days, when institutes in Germany and Illinois do battle over the definition of “passive house,” it’s interesting to read the chapter in Morrison’s book titled “Passive Energy Design.”
Morrison wrote, “An energy conscious home is one which goes beyond conventional energy conserving features such as insulation in the right places, double glazing and weatherstripping at all openings. It incorporates passive design ideas and/or solar energy systems in its planning, design, construction, and use.”
Morrison wrote, “Passive design ideas or approaches use solar energy naturally, contain little mechanical hardware, require little or no energy themselves, and tend to be low in cost.”
Morrison continued, “Sometimes it’s easiest to understand passive ideas by contrasting them with ‘active’ design examples. Furnaces, boilers, electric water heaters and air conditioners all fall into the active area: they require complex, expensive and energy-consuming equipment. An active approach to solar heating and cooling uses a carefully designed, complex and sophisticated solar collector with fans, pumps, storage or heat exchange units and sophisticated controls. In contrast, one passive approach to solar heating or cooling is a regular window, of the right size, with the right orientation to the sun, designed to capture natural breezes, with an insulated window shutter and sufficient heat storage mass.”
Morrison’s book provides evidence that the ideas that Wolfgang Feist, the founder of the Passivhaus Institut, began championing in the 1990s had their roots in North American ideas developed in the 1970s. (In fact, Dr. Feist regularly credits the Canadian and American researchers on whose shoulders he stands.)
Why does this matter?
An analysis of Morrison’s book is enlightening for at least two reasons. First, his book reminds readers that residential energy retrofit work has roots that go back forty years or more.
Second, his book helps explain the persistence of the misinformation that energy experts still have to contend with when we visit job sites. The energy crises of the 1970s were traumatic. Our country suffered serious energy shortages; drivers had to wait for hours in long lines to buy gasoline. Many families couldn’t afford to pay their heating bills. In desperation, they bought books like Morrison’s and hung onto every word.
The energy tips promulgated during the 1970s made a deep impression on builders and designers. Builders of my generation learned about caulking and vapor barriers from books like Morrison’s. Then, lulled to sleep in the 1980s by cheap oil prices and Reagan’s policy reversals, many builders never read any more books about building science. They failed to keep up with the times.
Unfortunately, many mistaken beliefs from the 1970s are still with us; the bad advice is still being passed from builder to builder like a persistent virus.
Martin Holladay’s previous blog: “Heat Transfer When Roasting a Turkey.”