It is a proven method of producing a stable temperature within a building by controlling the natural heat flow on an annual basis by means of materials placement and building design. As a result, the home can maintain a nearly constant comfortable temperature. In the summertime heat is extracted naturally from the home and stored in the earth about the home. In the winter that stored heat comes back out, also by natural heat flow, to keep the home warm. Essentially, PAHS, when properly applied, produces a home with a built-in temperature.
How well has PAHS been shown to work since 1983?
PAHS is really just a down to earth explanation and application of natural heat flow: the laws of physics. Consequently, in order to produce the best performance, the principles of PAHS must be adhered to. When major compromises have been made in the past, the result has always degraded performance. Some have worked very well and some have been disappointments. Since nearly all of the homes have been owner built, there has been little supervision over design and even less over construction. Yet, the method has proven its worth and to this day PAHS provides the only practical way of producing a home with a built-in, constantly comfortable temperature.
Will PAHS work on earth sheltered buildings other than domes?
Certainly. The heat transfer characteristics do not vary noticeably with shape, except that the shape may affect the PAHS design and layout of its components. We offer our Building System Plans. These are not round and have had good success.
Can I use the Building System Plans with other buildings?
Certainly. Many purchase them specifically so that they can use the PAHS parts with their own designs.
How much data has been collected?
Enough to show that PAHS works, and works well, but not nearly so much as we would like. One reason for this is that the numbers change so little or not at all and so soon become boring that people simply stop taking them. Before and after measurements have been taken that show clearly that the application of the insulation/watershed umbrella quickly stabilizes the underground temperature and it begins to rise up to a comfortable room temperature of about 70o F. (21o C.)
What kind of compromises have degraded performance?
Cost cutting on earth covering, the size and thickness of the umbrella, solar widow input sizes and thermal breaks. In cold climates, the house must still take in heat in the summer in order to store it for winter. If that heat source is cut off, then the average annual air temperature created in the house is too low and the earth around the home will assume a lower temperature.
What kinds of problems have been encountered?
Water is a big one. The instructions in the PAHS book and the Building System Plans and Manuals are given for specific reasons. Umbrella drainage and selection of materials are important. If the drainage system is incorrect, the umbrella can't drain properly. If it fills up with water, it's thermal properties will be compromised. The principle is simple. If you don't put sand or gravel etc. at the proper drainage points at the periphery of the umbrella, it won't drain, but will full up like a bucket. The house won't work as it was intended.
How do the attitudes of the builders affect performance?
One of the most common problems is that people who have not read the PAHS book, or don't pay attention to it, are allowed to make decisions. Because above ground structures are the typical experience, people tend to make decisions based on the way things have always been done. The problem with that is that above ground performance has typically been very poor, so the earth sheltered project suffers. Also, there are many who will make decisions based on something they heard or the way they imagine things to work. The problem is that the laws of physics do not care what our personal opinions are. Sadly, some homes have had their PAHS systems completely ruined by design changes that compromise performance based on untrained or indifferent attitudes. In order to have a high performance home, we have to have a high performance design and stick to it.
How well have the earth tube ventilation systems worked?
When applied according to the directions, they have worked very well. Some have enough flow to blow out a candle placed in front of the opening.
Does PAHS work on above ground homes?
PAHS can be used to improve the performance of many types of homes including above ground ones. Many have talked about it, planned, and some been built. We have not received much feedback from those who did. We wish they would contact us. But in theory they should work well. The catch is that convection takes heat up. Therefore, some mechanical device, usually fans, must be used to force the heat down into the earth below the building. Many have included fans with their earth tube ventilation systems, especially where the pipes are smaller than recommended.
Have there been any revisions in the PAHS book since 1983?
There really hasn't been a need. Between the PAHS book and the Building System Plans and Manuals, a revision would need only some small additions. This is because they all teach PAHS based on elementary physics, but with easy, down to earth language. The laws of physics don't change. So the books are still just as up to date as when they were written.
Are there any homes available to look at?
No, sorry. But after a short time, the novelty of having visitors wears off. People want their privacy. Because of that we are not able to even recommend, or contact owners. They want and have a right to their privacy. We wish there were some we could send you to, but at this time there are not.
Why doesn't everyone have a PAHS home?
I don't know. Why do people in Tornado Alley still live in mobile homes? It doesn't seem logical to me, but I'm sure they have their reasons. When the price of oil goes down so does interest in conservation. Homes built with PAHS incur some added initial costs. Most of the people who are truly concerned about the price of energy are those who don't have a lot of money in the first place. Most people who have enough money don't worry about conservation and, therefore, don't build PAHS homes. But around the world people are still interested in PAHS, judging from our continuing book sales. The original PAHS book has been sold in 25 countries around the world, every province of Canada and every state in the U.S. Over the past 20 years many have been built and the vast majority of them have been successful because they follow the instructions.
