A solar concept is anything that can help make using solar energy more practical, whether by causing the house to require less energy or by making more effective use of the sun. Certainly a highly insulated shell is important, but so are many smaller details such as your home’s entrance. This concept has an impact on energy used, but also on comfort and convenience. For a new house or improving your existing home, it is well worth planning your entrance.
First, if possible, locate your entrance away from prevailing winds. A boon to comfort is an entrance on the south or east side, where wind will not invade your home every time you open the door.
Second, minimize the spread of cold air when people enter the house by including a vestibule or better yet a cold basin. A vestibule is simply a smallish room between the outside and the inside, like an airlock. People enter the vestibule, close the outer door, wipe their feet, perhaps take off coats and boots, and then enter the house. The vestibule need not be heated, just a tempered buffer between outside and inside. It is uncomfortable to the inhabitants, especially those lying on the floor watching TV or playing, to have a blast of cold air pass by every time a person enters the house. Plus, for all the cold air that enters, hot air leaves!
Another approach is to have the entrance to the vestibule down a half flight of steps. This cold basin works well if entering from a garage, as we had in our previous house. The area at the bottom of the steps is always cold (no heat is being sent here and it is adjacent to the unheated garage), but when you enter the cold stays down and you leave it there as you climb the stairs. However, please note that while this is a great way to address invading cold streams, it is also a series of steps which may become more of a problem as you age, as it did for my wife and me. Still it works very well for the young and nimble!
Another aspect of Entrance is: How many to have? For safety purposes, doors on opposite sides of the house are important, but beyond two you are adding a thermal weak spots (typically 20 square feet with an R-value of about 5 with good doors and much less for many doors that are not so good, and seals that will often leak and fail over time).
Maximizing on this concept was quite simple for us - we have one primary entrance. Almost all entering the house will come in via the garage (east) or the front door (south). In both cases, this is through a small porch that will be insulated but not heated, where wet clothes and shoes can be removed before entering the home, into the Active Area.
This winter the ceiling of the vestibule was not insulated, so it was not as warm as we expect it will be “normally.” However, it did not freeze during February when outside temperatures dipped as low as 14, inside temperatures never went below 37. Still, we will have to experiment a bit on how to deal with wet clothes and snow packed boots in this environment. Worse case, we will bring these items into the house on occasions they need drying.
Incidentally, a little fresh air from outside is nice, but less is better. Air quality is assured mechanically to and from areas of your choice – see Ventilation in a later blog.
We have just one other entrance, a door on the west end of the house that opens to a screened (someday) porch. This entrance is hardly ever used during the winter.
In our previous house, we had a formal central foyer that opened to the second floor with an open staircase and balcony. This foyer had a solid door, sidelights, transom and a small chandelier, as so many have. But, all this elegance was hardly ever used! We made a choice to build smaller and eliminated the foyer, formal dining room and living room with its heat sucking fireplace! Except for passing through and heating the area, we didn’t use this space more than 6 – 10 times a year!
Admittedly, our “energy focused” view of house design with just a utilitarian entrance is not the apex of fashion, but it is practical and convenient. Plus, Simon has a plan to make the vestibule porch much more “pleasing to the eye” by building a set of oak lockers and boot draws to capture all the clutter one would normally find when entering our home! Simon, Judy thanks you!
Finally, we used fiberglass, foam filled doors without windows for as much thermal barrier as we could achieve.
Picture taken at Solar noon. Note even shadow under, indicating house is facing exactly solar south.
Dan Gibson is Reporter and Chief Coordinator of Our Energy Independence Community and Chief Energy Auditor and Solar Designer for www.HomeEnergyAdvisors.com. He previously spent 5 years performing home energy audits in NYSERDA’s Home Performance program. He is also currently “finishing” their 100% Solar Home – no, three years in the making and it's not finished yet. He can be reached at DanG@OEIC.us or at (518) 899-2400.