Cold breeze tickling the back of your neck in winter? Don’t be in a hurry to seal around that window.
The point of ventilation is “to get fresh air into a room,” Robert Dadras, of Liberty firm Dadras Architects, said. “People don’t realize that [in a house] they still need air from outside.”
Old buildings leak. You may have noticed, if you moved into an old Victorian, or even a pre-1970s, house here.
The alternative is modern buildings, where, without the influx of fresh air, problems can develop. Uncirculated indoor air builds up moisture, odors, dust and air pollutants, according to the American Lung Association. Too much moisture inside can lead to mold or rotting wood.
“It can be stuffy. You’re sensing there is no oxygen,” Dadras said.
Sometimes the repercussions can be worse than a little discomfort.
Sick Building Syndrome was first identified in the 1970s; people had headaches, nausea, dizziness, dry coughs and more. Inadequate ventilation is the most common cause, according to the Environmental Protection Agency (EPA).
Up until the 1970s, they say, building ventilation standards “called for approximately 15 cubic feet per minute (cfm) of outside air for each building occupant.”
But starting in 1973, oil prices shot up. Ventilation standards were tightened to conserve fuel; the EPA says that the levels were tightened to 5 cfm per occupant. “In many cases these reduced outdoor air ventilation rates were found to be inadequate to maintain the health and comfort of building occupants.”
A 1984 report by the World Health Organization found that “up to 30 percent of new and remodeled buildings worldwide may be the subject of excessive complaints related to indoor air quality.”
Carbon monoxide can build up indoors too, says the ALA. So can radon. Both can kill. So can COVID-19, which spreads through the air.
“Everyone seems to love the Victorian era for style,” said Victor Dadras, partner at Dadras Architects and Robert’s brother. “But much of it was functional.”
Double-hung windows, for instance. “The upper sash was more important in order to have air circulation.” You opened the upper window, you opened doors or transoms over the doors, and let the air flow through. And it mattered for health. “Indoors, people breathed out germs.
Outdoors, even in the slightest of breezes,” the germs dissipated.
Higher ceilings helped air circulate, Robert Dadras said.
So you’ve bought a house and you want more ventilation but you’re concerned about your heating and cooling bills too. What can you do?
“HVAC systems condition the air,” said Robert Dadras. (They cool and heat the air, but they also treat it, removing moisture, smoke, airborne bacteria, and more. The “V” by the way, stands for “ventilation.”)
It saves money to keep warm or cool air inside, Victor Dadras said, but new systems can mitigate an abrupt temperature change as you bring outside air in.
UV light can be used to sanitize at home, as hospitals do, Robert Dadras said. The bulbs have to be replaced when needed for it to work properly though.
“Keep the windows open as much as possible,” he said. If you have double-hung windows, open the upper sash.
In winter, it may drive up your heating bill. In summer, it may let in some warm air. But keeping your home ventilated will go a long way toward keeping you healthy.
We’ve gone back to the old ways of doing some things; the new standard for ventilation rates is 15 cf per minute per person, according to the American Society of Heating, Refrigerating and Air-Conditioning Engineers.
ASHRAE also calls for our homes to get .35 changes of air per hour. That, says the EPA, gives you acceptable indoor air quality and minimises all the problems you can get from your building.
The rate at which outdoor air replaces indoor air is called the air exchange rate.
Fireplaces and cookstoves might need supplemental ventilation, and bathrooms and kitchens might want some kind of exhaust system.
It’s important, says the EPA. “Increasing the amount of outdoor air coming into the building helps to control pollutant levels, odors, temperature, humidity and other factors that can impact the health and comfort of building occupants.”
In the 19th century, Catherine Beecher, in her “New Housekeeper’s Manual,” protested tightly-caulked homes in the North, where people lived in one room, carefully sealed against the weather, for the six months that winter lasted. No wonder people have spring fever and biliousness, she said. “All these things are the pantings and palpitations of a system run down under slow poison.” Carbonic acid from heating stoves, undiluted by fresh air, killed people, she said.
Respiratory disease killed people too. Take tuberculosis.
To fight TB, which often transmitted through the air, we brought in fresh air. We slept on sleeping porches. We went to the Catskills for the high altitudes and clean air, Robert Dadras said. “People came here with TB and didn’t leave,” because returning to the city could kill them.