Home Efficiency Upgrades

High Efficiency Air Conditioning Systems - the efficiency of air conditioning systems has improved significantly over the last 10 years. If your AC system is more than 10 years old, you may be able to significantly reduce your cooling bill by installing a more energy efficient system. A 10-15 year old system probably had a 10-12 SEER (Seasonal Energy Efficiency Rating) when new, and now is operating at at an 8-10 SEER level, due to efficiency loss over time.

If your current system is operating at an 8 SEER level, a new 16 SEER system would reduce your cooling bill by 50%. That's right. going from an 8 to 16 SEER level of operation will cut your electrical consumption from cooling in half. With the heat of Austin summers, this can result in significant savings to you over time.      


Attic Insulation - insulation is the key factor in reducing the rate of heat transfer from the hot attic into your house. It's not uncommon for temperatures to reach 130-140 degrees F in Austin attics during the summer. The only barrier between these high attic temperatures and the inside of your house is the sheet rock ceiling and attic insulation. Insulation values have an "R" rating - or Resistance to heat transfer. The higher the R value the more resistance to heat transfer. An insulation value of R38 is recommended for Austin attics. This translates to approximately 14-17 inches of blown fiberglass insulation, which really slows those high attic temperatures from entering your house!    

Duct Sealing - the number one energy saving measure in most Texas homes is sealing the duct work to reduce duct leakage. It only makes sense to minimize the amount of conditioned air escaping from your ducts to the attic and outside. You've paid good money to cool and heat that air, so don't let it heat and cool the county! Duct mastic (often called "Pookie") is a thick, viscous sealing material used to seal common duct leakage sites - at duct connections, between the register and sheet rock, and at the supply and return air plenums. A good goal is to reduce leakage below 10%, but the lower the better!

Solar screens or solar film - the biggest source of heat infiltration in Texas homes is through the windows. Solar energy (which is energy transmitted from the sun via radiation and consists of both Ultraviolet (UV) and Infrared (IR) wavelengths) enters the home through the window glass. Clear glass doesn't block radiant energy. However, solar screens and solar film do an excellent job of blocking solar energy before it enters the home. Depending on the screen or film material, 70-90% of the IR energy (which heats things up) and 95-98% of the UV energy (which fades curtains, sofas and carpet) is blocked and prevented from entering your home. Blocking solar energy from entering your home is one of the most important factors in reducing your air conditioning bill.  

 
Radiant Barrier - so why does your attic get so hot in the summer? It's because the sun heats your roofing materials (shingles and wood decking), which in turn radiates energy into the attic. Your attic is an enclosed area, thus creating an oven effect. So how can you prevent an attic from getting so hot? One way is to install a radiant barrier (RB). Radiant barriers are thin, shiny metal surfaces that reflect a high percentage of the energy that hits them and only emit (or transfer into the attic) a very low percentage of that energy. There are two popular types of radiant barriers: foil and paint based. Foil radiant barriers (think of a 4' wide roll of very tough aluminum foil) reflect about 97% of the radiant energy, and radiant barrier paints (think of water based house paint full of aluminum dust) block about 78% of radiant energy.

Technically, radiant barrier paints should be called reflective coatings. Which is better? Foil starts off with a higher reflectivity rating (97%), but supposedly degrades over time with the collection of dust. Foil can also have problems tearing away from the roof rafters, thus loosing 100% percent of it's ability to reflect radiant energy. RB paint starts with a reflectivity of 78%, but supposedly doesn't degrade over time, and RB paint doesn't have the problem that foil has of coming loose and falling out of place. I use the word "supposedly",  because I can't find any objective studies in the industry that have studied the degradation over time of foil and paint applications. I installed RB paint in my attic, but either product is effective in our hot Texas climate.

Weatherization - Houses must "breathe" in order to provide healthy indoor air quality (IAQ). Current ASHRAE (American Society of Heating, Refrigerating, and Air Conditioning Engineers) standards recommend that approximately one third of the volume of air in your house exchange with outside air every hour. In Texas, most houses breathe naturally because of air infiltration around doors, windows, plumbing penetrations, base boards, fireplaces, etc. The only problem with this natural form of ventilation is that it allows unconditioned and unfiltered air to enter the home. There's an old energy adage which says, "Build it tight, ventilate it right." Proper ventilation is provided by ducting in outside air, filtering it to remove dust and allergens, then passing it through an Energy Recovery Ventilator (ERV) to pre-cool/heat and humidify/dehumidify the incoming air. Most older homes need "tightening up", and exterior doors and plumbing penetrations are some of the key places where weather stripping and caulk can help reduce the natural infiltration of air.