General House Description - I

The 'green' house I designed is relatively simple. Simple enough that I was able to build it with my own hands and with the help of my wife and brothers. It is relatively small, with about 100 m2 of interior usable space. It is basically the shape of a shoe-box, as a neighbor once pointed out. Some 17 meters by 7. The entire flat top surface is a terrace. And under the house there is a useful crawl space.

I used passive solar design principles to design a house that would require a minimum of energy to keep warm and cool and that would maximize use of onsite renewable resources to meet those minimized needs.

-The house is small. This not only reduces the need for energy to keep it warm and cool, but it also reduces electricity, construction materials needed, site impact, and resources needed to keep it clean. And it has a number of other 'green' benefits.

-It is highly insulated and air-tight to keep heat in during cold periods and hot air out during hot periods. I had originally planned to use strawbale insulation but was unable to due to inadequate construction codes. I settled on autoclaved aerated concrete as an appropriate solution to my case. It is a high insulation building material that achieves good insulation values in the walls, roof, and floor, while eliminating thermal bridges and enhancing the ability to make the envelope air-tight. I have installed high-efficiency double-paned, low-e coated windows and high-efficiency doors. While the windows and doors are good, their insulation values are low compared to the walls. As such I have also made and installed special insulation curtains. I plan to increase insulation levels by eventually applying a special ceramic based insulation paint both in the interior and exterior.

-The house is elongated on an east-west axis with a considerable number of large windows on the south-facing wall and a few smaller windows on the remaining walls. This helps maximize solar heat capture while minimizing both unneeded heat loss and interior overheating on relatively sunny, warm days. The number and amount of window space and their careful distribution also ensure adequate daylighting throughout the day, eliminating electric use for artificial lighting during the day.

-Inside the house envelope is a large quantity of thermal mass. Thermal mass acts as a heat and cool battery which absorbs excess interior heat during the day and releases it during the night when the interior temperatures drop below a certain level, thereby keeping the interior warmer than the outside during cold periods when exterior temperatures drop. The process works in reverse in summer when windows are left open at night to drain the heat from the thermal mass so that during the day it can keep interior temperatures lower by absorbing large amounts of excess heat. The floor system is comprised of AAC interlocking panels with a slab of reinforced concrete on top and a finishing layer of dark colored ceramic tiles. The concrete and tiles have good heat absorbtion and retention characteristics and function well as thermal mass. The AAC also has small but useful thermal mass characteristics. Interior walls are also masonry with those exposed to solar light having a dark color to facilitate radiation absorption. Walls are stuccoed with a one cm layer of special cement, futher adding thermal mass. The house does not experience significant temperatures swings on a daily basis. Interior temperatures rise and fall very slowly from winter to summer to winter.

-Room layout is designed to keep living areas, such as the living and dining rooms and kitchen, on the south half which is warmer during the day, and bedrooms and bathroom, which are infrequently occupied, in the colder half. The south half is one large long basically open area which is comprised of a combined living, dining and kitchen area. This helps maintain unimpeded air flow to balance out temperature differences in this area. The north half of the house also has good access to the warm air of the south half.

This post is getting a little long. I will continue it shortly. I will try to include a floor plan in my next posting.

I hope anyone who has any comments to make - suggestions, ideas, criticisms or questions, absolutely whatever - will find some time to write them down and pass them on. I will be extremely grateful.