Indoor Air Quality

 

In many tightly constructed, energy-efficient homes, air quality and ventilation can be a concern. While heat recovery ventilators recover most of the heat from exhausted air, a home automation system can control the ventilation system to operate only when the house is occupied. Additional sensors can control the humidity as well.

Air Cleaners/Purifiers

Air cleaners or purifiers reduce pollutants that detract from the quality of indoor air. Most models will filter dust, pollen, pet dander and other common allergens—great for people who suffer from asthma or allergies—as well as cigarette smoke and unpleasant odors. Efficient and versatile, they come in portable models or whole-home systems. Prices can vary significantly, depending on size, technology, special features and filtration stages.

For more information about the various types of air cleaners and how they work, read the U.S. Environmental Protection Agency’s Guide to Air Cleaners in the Home.

Types of Air Cleaners/Purifiers

Electrostatic Filter

The filter of an electrostatic model has a static charge that attracts airborne particles. When air passes through the unit, particles will “stick” to the filter, thereby cleaning the air.

ESP (Electrostatic Precipitator) Filter

ESP (Electrostatic Precipitator) filters generate opposite charges that attract airborne particles. When air passes through the unit, pollutants adhere to the metal plates or wires in its “filter” assembly, which can be washed and reused.

High Efficiency Particulate Air (HEPA) Filters

HEPA (High Efficiency Particulate Air) filters remove 99.97% of airborne pollutants 0.3 microns or larger. Particles of this size include household dust, pollen, pet allergens and tobacco smoke.

Ionizers

Ionizers, which are sometimes combined with other types of air cleaners, attract particles with a small electric charge. When air passes through the unit, a magnetic-like attraction causes pollutants to adhere to its filtering mechanism.

Ultra-Low Penetration Air (ULPA) Filters

Ultra-Low Penetration Air (ULPA) filters remove 99.999% of airborne pollutants 0.3 microns or larger. Particles of this size include household dust, pollen, pet allergens and tobacco smoke.

Whole-House Air Filters

Whole-house air cleaners are installed in the ductwork of a home’s heating, ventilation and air conditioning (HVAC) system. Every time your system runs, air passes through a filtering mechanism that removes household dust, pollen, pet allergens and other particles.


Dehumidifiers

Dehumidifiers remove excess moisture from household air, which reduces the growth of mold and mildew and protects your home from rot. In addition to improving air quality, dehumidifiers deter pests like fleas, roaches and dust mites, since they prefer an environment with higher humidity. Energy-efficient models can save consumers about $20 per year. Over the life of the unit, that’s more than $220* in savings.

* Source: ENERGY STAR® -www.energystar.gov

Types of Dehumidifiers

Basement Dehumidifiers

These dehumidifiers are designed specifically for use in basements, where dampness and mold are often major issues. Some models offer convenience features like a direct drain-off hose, which eliminates the need for a water tank (and the necessity to empty it on a regular basis). Before investing in a dehumidifier for your basement, you should first address contributing factors like cracked floors or walls, existing mold or mildew, broken windows, poor insulation and air leaks.

Dehumidifying Ventilators

Ideal for attics, crawlspaces and basements, dehumidifying ventilators feature an exhaust fan that is automatically turned on or off by a sensor set to a specific humidity level.

Heat Pump Dehumidifiers

Often the most effective way to remove water from the air, a heat pump dehumidifier is perfect for homes where flooding is an issue. Robust and comparatively affordable, these units run cyclically and use a heat pump, fan and heat exchange coil to eliminate moisture.

Portable Dehumidifiers

In some houses, only certain rooms are susceptible to excess humidity. Here, a portable, plug-operated dehumidifier can be the best option. There are several types of models, some much heavier than others. When purchasing a portable dehumidifier, be sure to consider the size of the room in which it will be used as well as the weight and capacity of the unit.

Whole-House Dehumidifiers

While they can be expensive and require proper maintenance, whole-house dehumidifiers are ideal for homes located in very damp climates. Unlike their smaller counterparts, these units can remove large quantities of water—about 100 pints daily—and also provide special features like humidity evaluation and automatic adjustment. If you’re looking into purchasing a whole-house dehumidifier, consider a high-efficiency model, which will save you money and energy.


Humidifiers

Designed to increase the moisture in your home’s air, humidifiers are typically used during winter months when conditions can become excessively dry. In addition to making one’s house more comfortable, a humidifier helps reduce static electricity and protects moisture-level-sensitive household structures and furniture.

Types of Humidifiers

Portable Humidifiers

Varying in size and capacity, portable humidifiers are plug-operated, freestanding units that use their own water supply. Medium-sized models are often capable of humidifying one to two rooms, while their larger peers can often keep several rooms comfortable at once. There are also desktop models available, but these are only designed to humidify the immediate area.

Whole-House Humidifiers

Integrated into your HVAC’s blowing system, a whole-house humidifier draws moisture directly from your water supply. There are a few different models available, all of which use different mechanisms to achieve the same goal: increase your air’s humidity to an acceptable level (typically 30-50%).


Ventilation

In addition to reducing indoor air pollutants, proper ventilation helps control moisture in the air. There are several options available, from natural ventilation—air that moves through structural cracks or through open windows, for example—to whole-house and spot ventilation systems.

Read what the U.S. Department of Energy has to say about home ventilation.

Types of Ventilation

HVAC (Heating, Ventilation & Air Conditioning Systems)

As its name indicates, an HVAC (heating, ventilation and air conditioning) system is a single unit that can meet all of your home ventilation, heating and cooling needs. A qualified dealer in your area can service your existing equipment or, if you’re considering installing a new system, recommend the best one for you.

Localized Exhaust Fans

Ventilation or “localized exhaust” fans—like those used in bathrooms and kitchens, for example—are designed to augment a home’s other ventilation systems. They are most helpful in areas where moisture, steam, smoke and odors build up temporarily. There are several on the market that can economically and effectively meet your ventilation needs.

Natural Ventilation

Natural ventilation can help reduce air conditioning costs and, in some areas of the country, eliminate them entirely. When the outside temperature is at or below 77°F, ventilation can provide much of the cooling needed to make a home comfortable.

When using natural ventilation, keep the house closed up and do your best to limit heat gains, such as sun coming through un-shaded windows and the use of heat-generating appliances. Then, ventilate the house at night. In breezy locations, natural ventilation can be provided simply by opening windows. Even when the air is still outside, it can be used to ventilate homes. Because warm air is less dense than cool air, it rises naturally. Therefore, air will move by itself if low and high openings are created in the home. For example, with a two-story house, windows on the top and bottom floors can be opened. This will create a natural cross flow as warm air escapes out the upstairs windows pulling cooler air in the downstairs windows to replace it.

Whole House Fans

Although they can cost three or four times as much as other models, whole-house fans provide the combined cooling effects of portable, ceiling and window fans. They do this by drawing hot air from inside the home and exhausting it into the attic. In so doing, they cause air movement across the body and they pull cooler, outside air into the home.

A whole-house fan should be located centrally in the home—in a top-floor hallway ceiling, for example—where it can easily pull air in open windows. The fan is mounted in the ceiling and is usually covered on the interior side with automatic louvers that open when the fan is on, and close when it is turned off. When the space is air conditioned or heated, heat gain or loss can be reduced by covering the fan with an insulating blanket—like those made to wrap water heaters—or by installing an insulated, weatherstripped box around it with a detachable or hinged lid. Be sure to remove any insulation before operating the fan.

Whole House Ventilation Systems

A whole-house ventilation system is ideal for airtight, energy-efficient homes where natural ventilation cannot provide sufficient air quality, with or without the support of localized ventilation means. Featuring one or more fans and duct systems, whole-house ventilators enable controlled, universal air exchange throughout a home. There are four types of these systems:

1. Exhaust ventilation systems – move interior air outside the home
2. Supply ventilation systems – bring exterior air inside the home
3. Balanced ventilation systems – move equal quantities of air inside and outside the home
4. Energy recovery ventilation systems – transfer heat from outgoing or incoming air to maximize energy conservation