What can we do as a society to improve our physical environment and make our homes greener?
Those who are recent inhabitants of the City of Miami don’t know what it was like to live here or in the Caribbean in the 1950’s or 60’s. My family used to come and vacation here in the 60’s. We had come from Cuba in 1961 and moved up north, but we came here once or twice a year on vacation.
In the 50’s or in the early 60’s no one had central air-conditioning. Most people would have window or wall A/C units in their houses. And many houses did not have air-conditioning at all.
So how were houses designed then? Well, most houses were designed for good cross ventilation. They had either jalousie or awning windows. Either of these allowed the entire window to be opened for breezes to come through, as opposed to single-hung or horizontal sliding windows which only open half-way. Ceilings were high and often had ceiling fans. Although most houses had no insulation, between the high ceiling and cross ventilation the summer heat was bearable. In places like Cuba where there were always crosswinds from the ocean, the summers were even more pleasant.
I remember when I lived at the sorority house at Georgia Tech in Atlanta while going to architecture school, there was no air-conditioning in the house. We made due with a whole house extractor fan on the second floor, and honestly, most of the time, this took out most of the heat in the house, making the sorority house quite livable, even during Atlanta’s muggy summer days.
Another detail which good architects took into consideration was the orientation of the house and protection of the walls and windows. In our Southeast region of the US, the sun is almost never in the north except during some days in the winter. The sun rises in the east and sets in the west and goes a little to the south as it goes across the sky from east to west from sunrise to sunset. This means that the east, west, and south exposures of a house need overhangs. Windows on the west need to be avoided as western sun is the hottest of the day. In addition, the sun casts deep shadows. Being next to these windows is very uncomfortable in the afternoon. Windows on the eastern exposure are most welcomed as the sun in the early morning is very pleasant.
How are most houses designed now? They ignore all of this.
Air-conditioning is the biggest user of electricity in any home. The next biggest user is the water heater. If we are to make a real dent into what the typical homeowner uses in electricity, then some things have to change in home design. In essence we have to go back to the future.
Back to the Future
There are some simple things we have to change to better the energy consumption of a typical Miami residence:
- Plan the house as though it is not going to run the A/C all the time 24/7. This means making sure the house is oriented correctly with good cross ventilation. Consider designing a house around a courtyard. Plan on high ceilings and large windows. Plan on ceiling fans in each living space of the house. Then, don’t run the A/C 24/7. Open the windows and enjoy the Miami natural winter environment.
- Heavily insulate the attic space (R-30 minimum). Heat comes into a house mostly through the roof. Only about 3% comes through the walls. For the Miami are this means that modest insulation in the walls is good enough (R-6 per 2007 Florida Building Code (FBC]).
- If possible, put the A/C ducts in an air-conditioned space. This will maximize the efficiency of the A/C. The 2007 FBC, which is the code which has been adopted by the City of Miami and is enforced state-wide, requires R-6 insulation for duct in non-air-conditioned spaces.
- If the house is going to have a water heater with a tank, make sure that the water heater is installed with a timer so that it does not run all day. Miami is almost never cold, so the water heater can produce great hot water in 15 minutes. There is no need to run the water heater all day long.
- Make sure the house has overhangs where needed. In the Miami area that means in the southern, eastern, and western exposures. Sometimes shading devices, such as louvers and screens can be added as well.
- Consider putting several trees close to the house to provide shading. This is a very effective way of lessening the exposure of the roof to the sun. This, by itself, will reduce the temperature around and in the house by several degrees. And, if at the same time, we can use native landscaping for the Miami area which are drought-resistant, then water usage can also be curtailed.
- Lastly, consider putting covered terraces, trellises, pergolas, and/or porches around the house to use in the South Florida winter. So while everyone else is freezing in the north, you can tell yourself how brilliant you are for having chosen Miami as your home!