What are the benefits of Active Solar Heating Systems?

If you’re thinking of installing active solar heating systems or are just wondering about its true benefits, all I know is that it is the most  cost-effective when they are used for most of the year. Which means that you need to have good solar resources. AZ, for example, will be a good place to have solar heating. If you currently use electricity, propane, and oil heat to heat your house, solar heating system will make the cost go much lower. You might be able to receive sales tax exemptions, income tax credits or deductions from your state government also.

It’s true that the system will not come cheap. The cost of an active solar heating system starts from $30 to $80 per square foot of collector area installed. But your fuel bills will be reduced so much even just in the first month. You can even use it to heat water and to generate electricity. If you’re also environmentally responsible, it will reduce air pollution and greenhouse gases. So if you know that you’ll stay in the house for a long time, then invest in a system.

Source: EERE

Energy Performance Testing, Certification and Labeling

The National Fenestration Rating Council (NFRC) operates a voluntary program that tests, certifies, and labels windows, doors, and skylights based on their energy performance ratings. The NFRC label provides a reliable way to determine a window’s energy properties and to compare products.

The NFRC label can be found on all ENERGY STAR® qualified window, door, and skylight products, but ENERGY STAR bases its qualification only on U-factor and SHGC ratings.

Source: Office of Energy Efficiency and Renewable Energy, U.S. Department of Energy

Energy Performance Ratings for Windows, Doors, and Skylights

You can use the energy performance ratings of windows, doors, and skylights to tell you their potential for gaining and losing heat, as well as transmitting sunlight into your home.
Heat Gain and Loss

Windows, doors, skylights can gain and lose heat in the following ways:

* Direct conduction through the glass or glazing, frame, and/or door

* The radiation of heat into a house (typically from the sun) and out of a house from room-temperature objects, such as people, furniture, and interior walls

* Air leakage through and around them.

These properties can be measured and rated according to the following energy performance characteristics:

* U-factor

The rate at which a window, door, or skylight conducts non-solar heat flow. It’s usually expressed in units of Btu/hr-ft2-ºF. For windows, skylights, and glass doors, a U-factor may refer to just the glass or glazing alone. But National Fenestration Rating Council U-factor ratings represent the entire window performance, including frame and spacer material. The lower the U-factor, the more energy-efficient the window, door, or skylight.

*Solar heat gain coefficient (SHGC)

A fraction of solar radiation admitted through a window, door, or skylight—either transmitted directly and/or absorbed, and subsequently released as heat inside a home. The lower the SHGC, the less solar heat it transmits and the greater its shading ability. A product with a high SHGC rating is more effective at collecting solar heat gain during the winter. A product with a low SHGC rating is more effective at reducing cooling loads during the summer by blocking heat gained from the sun. Therefore, what SHGC you need for a window, door, or skylight should be determined by such factors as your climate, orientation, and external shading. For more information about SHGC and windows, see passive solar window design.

*Air leakage

The rate of air infiltration around a window, door, or skylight in the presence of a specific pressure difference across it. It’s expressed in units of cubic feet per minute per square foot of frame area (cfm/ft2). A product with a low air leakage rating is tighter than one with a high air leakage rating.

Source: Office of Energy Efficiency and Renewable Energy, U.S. Department of Energy