A home efficiency rating tells you how much bang you're getting for your energy buck. There are quite a few factors experts consider when setting these scores, including where you live. To better understand how well your HVAC equipment uses power, it's wise to know something about the lingo. Read on to learn the five home efficiency acronyms you need to know.
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R-values is one of those terms you frequently hear tossed around the home improvement store. It describes an insulating material's resistance to heat flow. The higher the R-value, the more insulating properties a substance offers. The R-value of traditional fiberglass batt is 3.1 to 3.4, while a closed cell spray foam rates up to 6.5. Your home's ideal thermal resistance or R-value depends on your climate.
You may have heard your HVAC technician mention SEER levels. Seasonal energy efficiency ratio (SEER) is a figure used to measure an HVAC unit's efficiency. SEER ratings range between 10 and 18, with 18 being the highest energy conserving option that offers homeowner's the best savings over time. Heating and cooling units with a SEER of 12 or higher use as little energy as possible — as much as 20 percent less than a 10 SEER unit.
To get a better understanding of the productivity rating for your HVAC unit, it's helpful to know its annual fuel utilization efficiency (AFUE). AFUE measures how efficiently your appliance converts energy into heat over a typical year. If your HVAC system scores an AFUE of 90 percent, that means that most of the fuel is burned to become heat or AC, while the other 10 percent escapes up the chimney or leaks through your windows and doors.
Air leakage (AL) is the amount of air that passes through a window or door frame. It's calculated using cubic feet per minute, per square foot of the open's area. The standard building code for air leakage is 0.3, and the lower the number, the more airtight your house.
Air leakage changes as materials expand or warp over the years. The best time to compare AL measurements is when you're in the market for new windows or doors. Most new products include a label with its AL rating so that you can choose the best windows and doors for each room.
Solar heat gain coefficient (SHGC) refers to the solar radiation a window allows inside. The score ranges between 0 and 1, and windows with a SHGC of 0.3 or less may be eligible for a tax credit.
The best choice of SHGC value depends on where you live. If your home is in a warm climate, choose the lowest possible rating to minimize air conditioning costs, so you don't bust your summer budget. If you live in a cold area, consider windows with an SHGC up to 0.55, and take advantage of the sun's warmth to help heat your home.
It's easy to get confused by energy-rating acronyms. With this handy decoder, you'll know how to decipher these top five terms.