What We Know About Building Ventilation:-
1. Indoor air can be 2-5 times more polluted than outdoor air. Click to:> Learn More
2.Outdoor air reduces indoor air pollution improving IAQ
3.Low outdoor air ventilation rates result in health risks to building occupants
4.Higher outdoor air rates not only improve occupant health, but [...]
In this “Keeping It Cool” episode of Blueprint for Home Building, you’ve learned about the basics of air conditioning, the importance of the size of your HVAC system and how zoning your system can be energy efficient and less costly. In this final segment it’s time to discuss the air quality of your new house. [...]
Characterizing how air is introduced to, flows through, and is removed from spaces is called room air distribution. HVAC airflow in spaces generally can be classified by two different types: mixing (or dilution) and displacement.
In today’s building industry there is more and more focus on occupant comfort, indoor air quality, ventilation effectiveness, energy use and [...]
The idea of letting hot summer air into your home to help keep it cool sounds paradoxical. But some parts of your house need to be well ventilated both summer and winter, regardless of the temperature outdoors. In temperate weather, a whole-house fan that pulls cool, outside air through the entire house can substantially reduce [...]
Because heat plus moisture equals mold and mildew, every bathroom needs a way to combat this combination. The most efficient way is to exhaust bathroom air outside.
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Most new homes come with a fan already installed; older homes–if they have a fan at all–usually have one that is underpowered.
Whether your home is new or old, [...]
A little humidity is important to comfort in a home, particularly in the winter.
But too much vapor, combined with fumes from synthetic materials, pesticides, cleansers and household chemicals can make a house’s air not only uncomfortable but downright toxic. The answer? Ventilation.
Houses should breathe. They should draw in fresh air and exhaust stale air. [...]
The best selling Vent-Axia HR204 heat recovery ventilation system is now available with a LoWatt ECDC motor, offering even greater energy savings for homeowners and SAP benefits to developers.
The new Appendix Q listed LoWatt HR204 provides continuous air extraction typically from a bathroom and kitchen, whilst also supplying filtered fresh air to living rooms [...]
Some homes do not have return ductwork at all, a design that assumes the air delivered to rooms will probably make its way back to the air handling unit. In such systems, the air handler is usually in a cold basement or crawl-space and has to do more work warming this cold air for delivery [...]
A home’s supply and return ducts are designed to be in balance, meaning that the amount of air supplied to the home is the same as the amount returned to the air handler, and the pressure inside the house is neutral. If either the supply or return ducts have air leaks, this balance is disrupted, [...]
Amid growing concern about the quality of the outdoor air we breathe, many homeowners have become concerned about the quality of the air in their homes. The 1970’s alarm about formaldehyde escaping into homes insulated with urea formaldehyde, combined with the 1980’s radon gas scare, have made people wonder what they are breathing in their [...]
Use outside air to cool the house when the temperature is below 77° F. That means opening windows and letting air flow naturally or giving it an assist with fans. Draw air into the home, particularly during the night when it is cool. During the day, as the temperature rises, close it up [...]
Mechanical ventilation is typically accomplished with a small fan located on a dormer vent. These fans are usually hardwired into a house’s electrical system and are controlled by a thermostat. They usually draw electricity in the range of 2 to 70 kWh per year, depending on local weather conditions and your attic temperatures. The cost [...]
Remember, the “V” in HVAC stands for ventilation.
Ventilation refers to the movement and exchange of air in the home, as performed by your air conditioning system. Proper ventilation is important because it will keep fresh air moving inside your house while removing bad or stale air to the outside.
“If you have a tighter house, a [...]
What is an ERV?
One of the main advantages of a well-insulated and well-sealed building envelope is that it takes less energy to heat and cool the home. An efficient building envelope keeps the conditioned air within the home that needs a smaller furnace and/or air-conditioner that is working less often — and this translates into [...]
If you are building a new home, you have the opportunity to make sure that the duct system will deliver “top-notch” comfort and efficiency by specifying to the builder that you want a leak-free, insulated duct system. Even better, discuss with your builder the option of locating the ducts within the conditioned space and hiding [...]
Crawl space vents keep moisture from building up under homes and damaging building materials. Don’t be tempted to seal them to save energy. Sealing them could cause costly moisture damage.
Foundation vents for the crawl space should be located on every wall, close enough together that there is at least one square foot of free [...]
The most rigorous way to locate duct leaks is with a blower door or similar analysis performed by a professional. This analysis measures the magnitude of your duct leakage and identifies its location. Some companies offer ductwork sealing services with a follow-up blower door check to ensure duct leakage has been reduced to acceptable levels.
A [...]
Occasionally found in duct systems that use joist spaces or other parts of the building structure to channel air flow, blind-alley ducts occur as a result of mistakes made during installation. A blind-alley duct leads nowhere (except possibly to the outside) while the register it was supposed to serve has no source of heat. The [...]
Attics should be ventilated year round, to reduce the build-up of heat and moisture. In winter, attic ventilation expels moisture that might otherwise accumulate and deteriorate insulation or other building materials. Don’t be tempted to seal the vents to conserve energy. Sealing them could cause costly moisture damage. In summer, proper ventilation reduces roof and [...]
The easiest answer to the question of where to seal air distribution systems is “just about everywhere.” Here are the key locations to be sealed, in order of priority:
A. Disconnected components, including tears in flex duct, and strained connections between ductwork.
B. All seams in the air handling unit. Also seal the holes in [...]
Air systems use ductwork to distribute heated or cooled air throughout the home. The duct system is a collection of tubes that distribute conditioned air to the home’s rooms. This system can make a big difference in both the cost and the effectiveness of heating and [...]
The air-tightness of a home is often indicated by air-change rate; the number of times the home’s air changes over with outside air. For example, if the amount of air that enters and exits in one hour equals the total volume of the heated part of the house, the house is said to undergo one [...]
Health effects from indoor air pollutants may be experienced soon after exposure or, possibly, years later.
Immediate effects may show up after a single exposure or repeated exposures. These include irritation of the eyes, nose, and throat, headaches, dizziness, and fatigue.
Immediate Effects
Such immediate effects are usually short-term and treatable. Sometimes the treatment is simply eliminating the [...]
Indoor pollution sources that release gases or particles into the air are the primary cause of indoor air quality problems in homes.
Inadequate ventilation can increase indoor pollutant levels by not bringing in enough outdoor air to dilute emissions from indoor sources and by not carrying indoor air pollutants out of the home. High temperature and [...]
The selection and design of air-conditioning ducts plays an important role in providing good indoor air quality. For years, conscientious HVAC contractors have been insulating the insides of galvanized ducts with rough fiberglass insulation. They had good reasons, too: The rough surfaces reduce air noise, and the insulation isn’t as easily damaged as external insulation [...]
Jump ducts are an increasingly popular method for improving the energy efficiency of homes with forced-air heating and cooling systems. They address the critical issues of equalizing air pressure in various parts of the home and of handling return air.
When managing the heating and cooling flow within any building, it is challenging to ensure that [...]
The most important step in filter improvement is to make sure that all the air that goes through the electric air handler or gas furnace is filtered. If your HVAC system is pulling air through cracks in the duct system or return air chase, it pulls the contaminates along with it. Have your service technician [...]
Out with the bad, in with the fresh. Simply put, those are the purposes of the recently introduced standards for creating acceptable indoor air quality. The standards, published as ASHRAE standard 62.2 for Ventilation and Acceptable Indoor Air Quality by the American Society of Heating, Refrigerating and Air-Conditioning Engineers, suggest requirements for new and existing [...]