Big Steps In Building: Make Natural Ventilation Mandatory
by Lloyd Alter, Toronto on 02.25.08
Hallandale, Florida's oceanfront is wall-to-wall condos; you can tell the ones built in the recent boom because they are generally huge stucco and glass monsters like the one on the left, interspersed with older, lower buildings that were just big enough to avoid being flattened. But more than size separates them.
The big building is a center-corridor design that is identical to what might be built in New York or Toronto. The corridor is air conditioned and cold. Outside it is in the mid 70's and the wind is blowing hard, maybe 20 knots off the water. We have all the windows and the patio door open. In the dining room it is stuffy and hot. In almost every other unit the patio doors are closed and the air conditioning is running.
The older building to the right does not have pressurized air conditioned corridors; it has an exterior walkway at each level serving the apartments.
The older building is slender, and the doors to the corridor have jalousie windows that crank open. The breeze can blow through the apartments and on a mid-winter day in Florida they do not need air conditioning. The building is designed with the climate in mind, in a pattern used in hot countries all over the world. There may well be air conditioning in every unit, but it is under the owner's control. It is all low-tech but also low-energy.
But in Florida density trumps energy efficiency. (dare I use that word trump? it is on every second unfinished building here.) It is hard to pack them in as tightly in a single-loaded building as it is in a double loaded one, and developers will naturally build as big as the zoning bylaws and the building code lets them.
Such densities can only be achieved by using energy, to pressurize and air condition the corridors and to air condition the apartments that are otherwise marginally habitable in the middle of February. To permit such designs to be built in this century, where the developer gets the sales and the owner is stuck with the operating costs, is unconscionable and wrong.
We are in a time-out right now thanks to the mortgage meltdown. Let's use it to re-write the building codes to ensure that every new apartment is designed so that natural cross-ventilation is a design requirement, as important as windows.
It isn't only in the South; in northern cities like New York, even the cheapest tenements were required by law to have natural light and ventilation to kitchens and bathrooms. Sometimes it might be little more than a slot, but those were the rules. Then the electric fan was accepted as a substitute. Lightwells and light slots disappeared as powered technology replaced windows.
It is time to bring the old rules back. Natural light and ventilation should be available to every room; the ones that make the smells should have as high a priority as any other.
yep. I grew up in florida with no AC. A large whole house fan sucked in the night air through open windows and could make things a bit chilly, relatively speaking, of course.
Caveat: One thing to watch for in designing these kinds of buildings is humidity. You don't want to have your ventilation system responsible for growing a nasty mildew culture. Mildew and sandspurs: the Florida state flowers. :)
My idea is that this may not be much of a problem if you cool the house at night with natural ventilation, close it up in the AM as temperatures rise, then run a whole house dehumidifier. You might be able to do without AC most of the time.
Ja lousy windows, though: invitation to criminals and leak like a sieve in the winter. May not seem important now, but even Canadians get acclimatized to Florida weather(esp. if you're not running AC all the time!) and eventually want the heat on when it gets 50-60 degrees, which does upon occasion. Jalousie windows not much help then.
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Hey, wait a minute! I just reread your post a bit more closely. OF COURSE you don't need AC in winter in Florida. Even if it's 80ish, no problem. Have you spent an August at this location? You can still get by with no or little AC(especially in a highrise), but August would be a truer test.
LA: fact is, the way these buildings are designed you do need ac in February and that is just wrong.
Well said.
This is an interesting post to me. You see, I've noted a large number of articles on this website that go to great lengths to say that we should build as densely as possible. You know, slow down urban sprawl and all. In most densely packed areas, the concern for break-ins is high enough so that doors and windows will be shut and as securely locked as possible. Many of these people likely put bars on their windows to keep intruders out. Seems unlikely that they would go to work and leave a window open for ventilation. Even if it's a jalousie window. (Jalousie windows were used in older mobile homes. They may have been good in the summer if the home wasn't air conditioned, but a very leaky way to keep your heat in when the weather turned cold.)
I went on at length and for some reason my comments were rejected. Since my efforts are not appreciated by your silly machine, I will try to summarize:
Good idea, use whole house fan, watch for humidity, but jalousie windows are not that great an idea when you're trying to heat or secure the home.
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And hit the same condo in August, THEN tell me about cooling with natural ventilation. It's possible, but you've got to acclimatize to it. AC in February, really. Wimps.
Oh, and Jaffa Kree
LA: the system requires human intervention and this human is on the beach. Sorry it took so long.
A working vacation, then. You are to be commended. About that August trip though . . . :)
health wise why do we need some of the things we put in our houses when we r building like ventlators, windows houses with long roof?