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Heat, Cool, and Power Buildings

Information about the mechanical systems in our buildings, including advice on maintaining, repairing, and replacing furnaces, water heaters, air conditioners, and ventilation systems. Also includes information on renewable energy options.


Indoor Ventilation Systems
Maintaining a balanced home ventilation system is essential for providing healthy air to the home's occupants, controlling moisture within the home, and maximizing energy efficiency. Indoor ventilation serves two purposes: it exhausts pollutants, moisture and odors from the interior of the house, and it brings outside fresh air into the house. Home ventilation systems work year-round to maintain a balanced level of air pressure inside the home that provides the proper amount of air exchange for both its occupants and its combustion appliances.

In houses where the inside air pressure is too low the home can become depressurized, causing combustion equipment (like furnaces and water heaters) to backdraft dangerous gases (such as carbon monoxide) into the home rather than out through the chimney. Under-pressurized houses can also contribute to indoor air quality problems by encouraging the growth of molds and mildews in areas with poor air circulation, leading to health problems, including allergies and upper respiratory infections.

In houses where the inside air pressure is too high, there is the possibility that moisture could be driven into the walls and attic and cause damage to insulation and the building structure. Overly pressurized homes can also lead to wasted energy for heating and cooling losses.

One solution to creating a balanced air system in a house is through the use of mechanical air exchanger equipment. Heat Recovery Ventilators (HRV) provide an adequate supply of fresh air while extracting most of the heat from the indoor air before exhausting it to the outside. Energy Recovery Ventilators (ERV) work the same way, but they have an additional feature that maintains a humidity balance, as well.

In homes that have home ventilation systems installed, it's important to clean the fans, clean or replace the filters and clear the intake openings at least once a year or according to the manufacturer's instructions. The ventilation system, as well as your heating system, should be inspected annually by a heating contractor or other service technician.

In older homes that do not have a specialized home ventilation system installed, there are several areas that should be checked. In bathrooms, exhaust fan propellers and vents should be cleaned yearly to maintain maximum efficiency. Kitchen fan hoods should also be cleaned of any buildup, including monthly washing of the metal grease filters.

The clothes dryer vent is another area that requires annual cleaning. The exhaust tube and vent need to be cleared of excess lint and debris, both to increase the dryer's efficiency and to prevent a fire hazard. In addition, the combustion air supply vent for the furnace (it looks like a dryer vent only larger) should be cleaned and checked that it's in working order.

Public Buildings

School Energy Guidebook
This guidebook provides detailed and practical guidance on how K-12 school districts can plan and implement enhancements to their current O&M programs that can successfully maintain their facilities while also reducing energy costs up to 20 percent.