Is your house suffocating itself and you?
In most cases, it is. Like human beings, houses need to breathe. Without a certain amount of air exchanged in a day, you and your home can get sick. It is only recently that we have begun to focus on how our living environments, both indoors and out, affect our health. A big factor in home health is proper ventilation.
In milder climates, homes are loosely built and with limited concern for energy conservation. This allows them the benefit of natural ventilation. However, in areas like Tahoe, the need for energy conservation is necessary and local building codes require that homes are insulated with large amounts of insulation and air continuous barriers to prevent heat loss. This limits the amount of fresh air a home can exchange with its outside environment.
Ventilation comes in many different forms and has different uses.
It is very common in Tahoe to ventilate attics and crawlspaces. These ventilated areas are considered unconditioned space, or space that is not temperature-controlled. If vents are not available nor opened in summer months condensation will form on cold surfaces, which can result in mold growth. Most homes should have vents running around the perimeter of the crawlspace and have the ability to open in summer months and close in winter to prevent pipe freezing. If your home has an attic you will need vents in the freeze blocks by the eaves, vents at the gable ends, or a vent in the ridge of the roof. In most cases you will need a combination of these.
Attics and crawlspaces are typically unconditioned spaces. They should be separated from the living space, or conditioned spaces. This is done with an air and a thermal barrier. The air barrier is simply the floor you walk on, or your drywall ceiling. Not much air passes between these materials, so it is an air barrier. The thermal barrier is the insulation that should be in your floor and ceiling joists. It resists the exchange of heat and is therefore called a thermal barrier. Together they create the home’s living space envelope.
If your home is working well, this barrier should be constant, with both layers intact and next to each other surrounding the entire living space. This barrier will separate the cold outdoors and hot attic from the area of the home you live in. The more holes in this barrier, the more energy loss your home will have.
The best way to ventilate your home is passive ventilation. Simply by opening windows in the summer time for at least a couple hours a day, you will give your home the fresh air it needs. The issue is, there is only a few months when keeping windows opened is feasible. So what to do the rest of the time?
In many cases if you have an old home, with limited mechanical ventilation systems, you will need to open windows from time to time in winter months. This will result in heat loss, but will be much better for the air quality in your home. More modern homes will have exhaust fans. These include the fans in your bathroom or the hood vent over your stove. When you turn these on it forces air outside of your home.
Other air needs to come in somewhere to replace the air that was removed. Many times the entry points are accidental holes in your home’s envelope. Some common breaks are electrical outlets, recessed lights, and leaky heating ducts. When these items are installed, holes need to be cut in the drywall or air barrier, resulting in air transfer between conditioned and unconditioned space.
In most cases air is provided from the least-fresh place like your attic and crawlspace. To solve this problem there is a device called a heat recovery vent. This is a simple vent with an exhaust and an intake. The fresh air comes directly from outside and is heated as it enters the home. The air that is exhausted from the home is recycled and used in the process to heat the entering air. These systems are being improved every year as the technology gets better and information about air quality gets to be more commonplace One day, these units may be used in every home.
Another reason to ventilate areas in the home is because of combustion appliances. These include your furnace and water heater, if they run on combustible fuels like oil or gas. For them to operate, many times they require a source of air to allow for the combustion process. If the room that these combustion appliances are operating in does not have enough air available, they will deplete the room of oxygen. This poses an issue for breathing and the process of combustion. If there is not enough air available for the combustion process then the fuel won’t burn properly producing harmful carbon monoxide.
Some appliances have intakes for the air needed for combustion, though for most water heaters and older furnaces, the combustion area needs to be vented to the outside. This is achieved with simple louvered vents that connect with the unconditioned space of the crawlspace, attic, or outside. If connected to the attic or crawlspace, you need to confirm that that those areas have proper ventilation to allow for the combustion appliance.
The other issue with a lack of ‘make up’ air is negative pressure and back drafting. Many combustion appliances rely on natural drafting to vent combustion exhaust. For this to work, the exhaust pipe needs to be engineered to properly allow enough vertical rising to create a draft. If the exhaust is not designed well, it won’t have enough draft to allow the appliance to be exhausted to the exterior.
In addition to improper exhaust installation, when a room doesn’t have enough ‘make up’ air it will create pressure. With fans and other appliances which exhaust air, a large amount of negative pressure is created in the appliance area and can actually force the combustion gasses into the room instead of up the exhaust pipe. This leads to a build-up of carbon dioxide that is harmful in elevated levels.
So now that you know that ventilation is important, you need to determine whether your home is suffocating. If you are interested, we offer a detailed home audit service for $150-$250.
Please call today to schedule an appointment at 530-583-6653.