Building workers perspired in midwinter — without a fire! That started the solar house, in which the sun is part of the furniture
John Caulfield SmithJanuary151946
HOUSE THAT SUN BUILT
Building workers perspired in midwinter — without a fire! That started the solar house, in which the sun is part of the furniture
John Caulfield Smith
IT WAS different from any house I’d ever seen, and, as an architect, I get inside more than most people.
It was low—only one-story—and its walls were practically all plate glass on the south, but almost windowless on the north. And it had something else I’d never seen in an ordinary house—an eave so wide it was just like a hatbrim hanging over the southern windows.
On closer scrutiny I found the windows weren’t like normal windows either. They were set right into the wall—not on a movable sash—and even the glass was different. I didn’t quite know how different at first, but it seemed to have two sheets of plate glass, separated by an air space.
It was my first view of a solar house.
Howard M. Sloan, real-estate developer, erected it as one of a group near Chicago, and because it was designed to use the sun as a heating aid, Sloan dubbed it “solar.” The name stuck, has since been applied to all residences planned on the sun-heat principle. At least two have been completed in Canada.
Sloan’s architect, George Fred Keck, first became acquainted with application of the sun to heating problems when he visited a job under construction for the Century of Progress Exposition. In below-zero weather he found the furnace out and workmen perspiring from sunshine streaming through the windows. The idea that the sun could be used in modern home heating was born there—and its first North American showing was in the Sloan development.
When I got inside one of the Sloan houses I noticed that although no sunlight entered (it was summer, and the wide eave kept it out) the living room was bright and free from glare. The huge expanse of glass gave me as complete a view of outdoors as though I had been sitting on a porch. Yet this intimacy with nature was not accompanied by a sense of invaded privacy. I experienced a delightful feeling of relaxation. My eyes had been tired by travelling. Now, looking toward the horizon through sparkling, crystal-clear glass, they felt rested and refreshed.
I mentioned this to the owner of the house and he informed me that mine was a common reaction. “When we moved in,” he told me, “my wife wore glasses. Within six months she was able to do without them. The walls of a room, unless they are more than 20 feet distant, cramp vision. Distant views counteract eye fatigue.”
“Why is there no glare?” I asked. “With so much glass one’d expect it to be blinding.”
“Not at all,” was the reply. “Glare is caused by too sharp a contrast between light and shade. Everyone knows how objectionable oncoming automobile headlights can be at night. Small windows, which give a spot of brightness, surrounded by comparatively dark wall surfaces,offend in much thesame way. Large windows furnish even illumination, eliminate glare.
This house had three characteristics which since have become definite requirements for any house called “solar.” All its principal rooms had southern exposure, with large glass areas; its “hatbrim” eave was designed to keep the sun’s rays out in summer, admit them in winter; and by use of insulated glass, heat gained from the sun was retained and efficiently employed.
The wide eave helped the insulating glass in this last function. In summer, when the sun is high in the heavens, it keeps out ail direct rays. But in winter the sun’s slanting rays get under the eave, warming the house.
Despite this help from the sun in heating a solar house, an automatic heating system of normal capacity is required for cold days
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when the sun is entirely hidden by clouds. Thus there is no saving on heating installation costs. The economy comes in operation. On bright sunny days the furnace can be shut off for hours at a time.
“How much fuel is saved?” I asked Howard Sloan.
“Some results are remarkable,” he replied. My own bill has been as much as 38% lower than the heating engineer s estimates, but each house must be considered as an individual case. On the whole, I would say that extravagant claims for fuel saving cannot be justified. What is definite is that solar heat received through large glass areas compensates for room heat |ost through these areas.” Sloan’s internent is in line with official V mgs.
;*.. Over a one-year period tests were made on a typical solar house by ^■ngineers of the Illinois Institute of "lecanology. During that time the building was occupied by its owners, a young married couple. No restrictions were placed on their use of the property. They lived normally, entertained guests, adjusted heating facilities at will.
One January day, when thermometers recorded 17 deg. below zero, the thermostat inside was set at 70. It’s amazing but true: the heating plant stayed off from breakfast till after eight o clock at night. Such spectacular
results are most uncommon, however.
Credit for minimizing heat loss goes to the type of glass used. Windows have been compared to a “glass sandwich”—two sheets of polished glass, separated by a dehydrated air space, with its edges fused together by a metal seal.
Using the trade name Thermopane, this unique glaas was invented about 15 years ago by a refrigeration engineer. He first thought of it in terms of the commercial applications with which he was familiar. It soon appeared in stores, in meat display cases and cabinets for dairy products and frozen foods. When Admiral Byrd undertook his 1939 expedition to Antarctica he took the glass with him for use in the windows of his laboratory. A radiogram reported, “No condensation took place . . . almost perfect visibility at temperatures down to at least 75 deg. below zero, with a room temperature of 75 deg. inside.”
The captive air space between the sheets of glass is the key. Dry as the Sahara, it prevents fogging or frosting of interior surfaces. The manufacturer’s guarantee in this respect recently was raised from two to five years.
It Was the Answer
Before insulating glass appeared on the market, storm sash provided the only means of reducing heat loss through windows. Large glass areas were impractical in northern climates because of difficulties involved in handling and storing suitable storm
sash. When big picture windows were used they usually consisted of a single sheet of glass. Solar heat was admitted but quickly lost. The glass was cold to the touch, moisture in the room air condensed on its surface, and heat loss constantly drained heating plant and pocketbook. With insulating glass the surface is no colder than the wall in which it is installed. The glass remains clear, and in double-thickness form has as much insulation value as a brick wall eight inches thick. For residential windows two thicknesses are usually sufficient, though triple-thickness units may he needed in exposed locations.
Actually, as many sheets of glass and corresponding air spaces may be employed as are required to do any specific insulating job. But insulation is not. the only function of multiple glass. It also provides insolation. You see, the radiant infra-red rays of the sun have a short wave length. They pass through the glass, strike an object in the room and are reflected from it. But enough of their warmth is absorbed to lengthen their wave length so that the glass—unlike ordinary windows-— will not retransmit them. Instead of the heat being lost it is trapped and utilized. Ultra-violet rays are not transmitted to any extent by the glass; but it is possible to get sunburned through it.
Fading of fabrics and carpets by the sun cannot be prevented, except by use of an expensive special glass. Drawing the drapes or blinds is a solution, but doing so eliminates the benefits of solar heat. However, with large windows, fading is so uniform it can hardly be noticed, whereas fading with small windows is apt to be streaky. Furnishings in a solar house need not be renewed more frequently than those of ordinary dwellings.
Is it difficult to keep large areas of insulating glass clean? No. Because edges are sealed, dust and dirt cannot filter in between the individual sheets. There are only two surfaces to maintain spotless and shining. It’s easier to cope with them than to fuss with a window divided into many panes, each having four corners. All that is required is a pail of hot water, a brush and a squeegee: standard equipment of professional window cleaners.
Cost of insulating glass is not excessive but is somewhat higher than two single sheets the same size. Of course the more windows there are the less wall area there is to pay for.
At this stage you’re probably thinking, “All very well in winter. But who wants to live in a solar house during the summer? The heat would fry you alive!”
Not at all. The wide eave does much of the cooling by keeping out the direct sun rays, and heavily insulated roofs and walls do the rest.
Ideal location for a solar house is on the south side of an east-west street, with main rooms enjoying correct exposure while overlooking the rear garden. Lots on north-south streets present a problem. In the interests of privacy they generally require fairly wide frontage. On a large lot the house can be laid out all on one floor, on narrow lots two-story houses are indicated. Any conventional building materials may be used.
No Goldfish Bowl, Please
Great care must be taken in locating windows. Far better to sacrifice some solar heat than allow activities within the house to become the focus of inquisitive eyes. No one wants to live in a goldfish bowl!
The usual municipal construction code requires the window area of any
habitable room to be at least one tenth that of the floor area. In solar houses main room windows represent an area about one half the floor area.
The two completed Canadian solar houses are both in Ontario. Toronto claims one, Dundas the other. The Toronto dwelling, located on the south side of Dale Avenue, overlooking a wooded ravine, is the work of architect Gordon S. Adamson. It has kitchenbreakfast room, living-dining room, bedroom and dressing room facing south. On the north are two other bedrooms, entrance, recreation room, utility room and child’s playroom. There is no basement.
I designed the Dundas house. Its site is on a ridge encircling the town. Living-dining room and two bedrooms face south; kitchen, entrance and attached garage are on the north. There is a full basement. The Toronto house is built oí stone, the Dundas one of clapboard.
Both dwellings have pitched roofs. The Toronto one uses sheet aluminum to ward off heat of the summer sun. T he same purpose is served in the Dundas house by light-colored asphalt shingles. The eave of the Toronto house projects six feet on the south. I hat of the Dundas house projects only 30 inches, hut for another 30 inches beyond that there is an open framework on which an eave extension can be placed when required. This removable sun shield is used generally only in deep summer, and the shorter permanent eave means that the sun’s heat can he used well into the spring.
If you plan erection of a solar residence you must know the angle at which the sun’s rays strike the earth on June 21 and Dec. 21, the days when the sun is respectively highest and lowest in the heavens. This information, which enables you to calculate the correct eave projection for the latitude in which you live, is obtainable from the department of astronomy at the nearest university.
It’s essential that the heating system of a solar house be flexible. It should he possible to kill manufactured heat as soon as the sun’s rays penetrate the rooms; revive it just as fast when natural heat is no longer available. To ensure most efficient and satisfactory results, mechanical firing and some method of automatic control are required. Gas is the fuel used in the Toronto house, oil was chosen for the one in Dundas.
The Toronto house makes its own weather. A complete air-conditioning system is combined with one of the first residential radiant heating installations in Canada. In radiant heating, not to be confused with solar heating, the entire floor of the house acts as the source of heat. In it are laid coils of wrought-iron piping through which water at temperature slightly higher than that of the human body is circulated. The Dundas house has a forced conditioned warm-air system ofll conventional design. Â j
The glass in the Toronto house is! permanently set in the walls: there are no windows to open and close. Th^j air-conditioning system provides fête round ventilation. It not only tempers and humidifies the air, but even removes tobacco smoke from it! Windows are immovable in the Chicago houses too, hut ventilating louvers are provided. On the south side of the house they are placed under the windows, on the north on top of them. In the Dundas house ventilation is supplied by a casement sash located between fixed windows.
Solar houses need not cost more to
build than dwellings of conventional design. Much depends on the individual tastes, needs and income of their owners. In Howard M. Sloan’s development near Chicago prices run from $12,000 to $20,000. The two Canadian examples differ widely as to cost. The one in Dundas was several thousand dollars less than the cheapest Chicago house. The one in Toronto, definitely of the super de luxe class, is expected to exceed considerably the most expensive one in Chicago.
While houses based on traditional
architectural sty'les can be designed in the solar manner, such treatment is not entirely “honest.” The small window panes associated with Tudor and Georgian residences resulted from primitive methods of manufacturing glass, taxes on windows, and lack of adequate heating systems. Now we have the know-how to make large sheets of insulating glass, windows are not taxed, and heating methods are highly efficient. “Honest” solar design should take maximum advantage of both modern methods and materials.
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