The Just-Right House in Lake Chapala

If you want low- or no-heating/cooling bills, what should you look for in a home in Ajijic?

Barbara Harwood, Adjunct Professor
Frank Lloyd Wright School of Architecture

As part-time residents of Ajijic who bought our perfect home because I had seen it in a dream when I was 12, you may not think I should be advising you on how to select a house that is perfect for this climate. But, dreaming aside, I still teach sustainable architecture, so I’ll give you the basic rules I give students about designing for this mile-high mountain climate in the lakeshore tropics of Mexico.

Our white (walls and roof) U-shaped hacienda, opening on the south with a fountain in the courtyard center, is the ideal style, shape, color and direction for a house in Ajijic.  

A solid white wall on the west prevents overheating in the hot months of April and May. West windows are a no-no in any tropical or desert hot climate because low afternoon sun shines directly into west windows, either making the house unbearably uncomfortable, or forcing shades to be closed, making the house dark.

The east side of our U has only two, high windows to allow for ventilation in a bedroom and a bath. East windows can heat a space early in the morning – when sun is low in the east. In cold climates, east windows can flood a kitchen with cheerful morning sun and add natural heating to a home. But in our climate, there is almost no time of year when early morning sun is an advantage, so it is best to have high windows under an overhang.

The north side, with a view of the mountains from our high boveda-ceiling living room, has several operable windows for natural ventilation. South floor-to-ceiling sliding doors open wide enough to create an uninterrupted space flowing from the courtyard into the living room. The large, operating fountain provides a fine spray on summer breezes for natural cooling. North and south windows are perfect in every climate for flow-through ventilation. In our climate, as in all warm desert climates, north windows are indispensable for daylighting and natural ventilation.

South windows must have a properly sized overhang (70^o angle from the tip of the overhang to the bottom of the window in this climate), first, to allow winter sun into the home to warm it, and second, to keep summer sun out during the hot months.  Ajijic has two-three chilly months, and people often lug expensive-to-operate gas or electric heaters around from room to room to be comfortable. In our hacienda, we have no need for that. The sun penetrates our south-facing windows, flooding our home with heat and light. Bricks on the courtyard surface, protected from chilly north winds by our south-facing hacienda-style house, heat during the day, reflecting their heat into our living space and warming it. When you buy, look for south windows protected by an overhang. If you have no overhang or terrace roof covering your south windows, during April and May, you will roast in south-facing rooms.

I encourage you to have a properly-vented, recirculation fireplace in the room(s) where you will do most of your living and entertaining. If there are several cloudy days in a row during the cool months of December-February, you will find it’s a whole lot cheaper than a portable heater.

Do not be rushed into a decision about a home here. Oil/gas prices – and thus utility bills - will only go up from this point, and they are already the highest in the world. You do not want to be stuck with a lemon that costs you a fortune every month for comfort.

Comments

[Rick Cowlishaw]

Hi Barbara;
I am writing a Green Group presentation for passive solar and cooling of homes located on the north shore of Lake Chapala. Would you be willing to review it? :)

Rick Cowlishaw
rcowlishaw@comcast.net