Tuesday, November 29, 2005

An Example of a Passive Solar House Plan

Designing and building a passive solar home in the far north isn't all that difficult. One needs a compass and a way of measuring exactly what angles the sun shines at various times of year. There are books containing this information. This new sub-blog will try to provide this sort of information. For today, I wish to share my own house plans. Living in this sort of house does require some labor, opening and shutting windows, doors, turning on or off fans or reversing them, eventually, I might computerize this whole thing but that will be a while yet. Besides, I am home all the time, anyway.

Just like computers make our cars burn fuel much more efficiently than previous engine incarnations, computers can make our homes run much more efficiently if we preset them with the proper air circulation/sun/shade cycles. The ideal is to be able to totally obscure windows at night in the winter and to make them reflect outwards the sun in summer, of course, tall skyscrapers that do this make the environment much worse because the air around them heats up intolerably. Walking in Manhattan in summer can be brutal. This is why using awnings and various shade devices is so enviromentally friendly. Many middle class and upperclass Victorian homes used awnings, especially on the western windows. Often, I find artifacts of these awnings when I do repairs or restorations of such buildings. Obviously, since they couldn't use electricity to create an artificial enviroment, they used passive methods that work pretty well for I use the same, myself, today.

Often, finding out how to cope with rising energy costs involves understanding how our ancestors dealt with it in the past, they were awfully clever, no?

By Elaine Meinel Supkis

It took me several years to build but I finished the main work on this house in 2000. These floorplans show how a building, oriented to get maximum sun exposure in winter and minimum in summer, works.

The problems are several fold. If you have many windows, the heat loss in winter at night is severe. To deal with this, I made buffer zones of the sun rooms. Namely, at night, I can close all the interior sliding glass doors, isolating the rooms. To keep them from dropping in temperature, there are heat ducts from both the basement coal/wood stove and the main floor's coal/wood stove.

So the temperatures at night in the core of the house remain quite high while the exterior buffers drop, but not more than 15-20 degrees, so if the core is at 75 degrees, the buffer zones are at 45-50 degrees. The sun, when it shines, heats up the sun rooms so much that if the doors leading to them are not opened, the temperature can rise to over 90 degrees. Even if it is below zero outside, the sunrooms still heat up tremendously. Since severe cold days tend to be very bright days, we often use the least heat on hypercold days. It is the gloomy, rainy or snowy days we use the most energy.

In winter, the sun reaches deep within the house which is why we have so many sliding glass doors, both on the outside buffers and the interior. The rays come inside, our home being in the higher latitudes, that it goes in at least 15 feet into the rooms. The outer buffers are 6 feet wide by the bedroom and 10 feet wide by the livingroom yet the sun shines into livingroom and bedroom, it is very bright on sunny days. Even in winter, the sun shines into the western sunroom so the whole house continues to heat up until 4:00 EST. The tree planted by the western windows is decidious so it sheds its leaves in fall and lets full sun shine in winter but in summer, shades the same windows.

The western windows can be quite brutal in summer unless one does something about it. We found that 8-10 foot awnings works great, we have vines growing on the ornate metal posts as well as bamboo shades which cuts down on the sun while letting air flow and inviting hummingbirds to visit. The south eaves are 18" deep which keeps out the summer sun entirely in our latitude. Each house must take into account, when building, what the actual sun angles are. The further south one goes, the less the difference in summer/winter sun angles.

In summer, the eastern windows have small awnings for it is nice to wake up to the sun peeking in, only after around 10 am does it become an annoyance. So 2 feet of awning is all one needs. When I was building the house, Bargain Outlet, my favorite guys, they sell odds and ends at very good prices, had a shipment of sliding glass doors which I got for very little. I wasn't expecting to have 11 sliding glass doors! This inspired me to design the house so the basement as well as upstairs has not only excellent ventilation in summer but a zillion fire exits! We use all of these doors in summer, the dogs and cats love going in and out of them and children are fascinated by them. Most of the time, being on a mountain, we don't have all of them open all the way because the wind just roars through the house.

So we stagger them, opening doors at 45 degree angles to each other. Right now, tonight, the wind is over 50mph and thanks to the strength of modern sliding glass doors, I hardly hear the wind unless it rattles something outside like my ladders which just gave a knock. Of course, when building, one must double-seal everything. I use Grace Wycor sealing tape which is a foot wide and very airtight.

The windows on the north are all much smaller than the south. The south windows all go floor to ceiling. On the west side, from ceiling to waist, on the north, only three feet tall or shorter. In summer, when it is hot, the prevailing winds are from the south so if I open only the north windows and the attic top vent, the cooler, shaded air on the north side pulls up from the basement to the attic. We reverse the heat duct fans in the sunrooms which blow downwards in winter to upwards in summer. This way, the entire house is brought into harmony with each other's parts so various parts aren't excessively hot or cold.

The heating and cooking stoves are all on the north side of the house. Usually, we only have to run the stove in the livingroom. When it is very cold, we light up more and more stoves, sometimes, when it is 20-30 below zero, all the stoves are roaring hot at night.

One has to take into account oxygen depletion when heating a very sound, insulated, airtight house. I ran airducts to the cold air at the top of the house, this is fed into the woodstoves and shoots out as very hot air. This causes the fires to burn very nicely as well as healthy air in the house, proper. A lot of people living in modern houses forget about this factor. People die or their heating systems burn inefficiently or badly due to lack of oxygen.

In older homes our ancestors lived in, everything was very drafty. In Germany, after WWII, I once lived in a house built in the 1600s. The bedroom Beate and I used was so cold, we put our school clothes under the coverlets to keep them warm and you could see the frost on our breaths, in bed. When I returned to America, the bedrooms at night at home were insufferably warm. I felt like I was going to suffocate!

So if you are in an airtight house, check out the air return system to see if you can improve it. Usually, installing a vent to a heating system isn't all that hard depending on where it is and one's skills (I find it very easy to do, but then, I do this sort of thing all the time so it isn't fair assuming other people can do it!).

If anyone wants to submit their floorplans (include which way south is!), I will be happy to analyze them and make suggestions. There are many things one can do to make one's home more efficient.

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