Most home owners only consider energy related audits during the coldest seasons of the year. This is when they feel the most uncomfortable in their homes and are keenly aware of the one factor costing them money during these months... their heating bill.
But the factors grossly skewing their heating bills are also significantly contributing to their cooling costs during summer months as well! Most home owners simply overlook this fact as the rise in electricity is seemingly gradual, but oh so sneaky! Only a few homeowners become slightly aware of exorbitant electrical costs when something begins to fail... usually their air conditioner.
This high end home had no outwardly visible indications of anything amiss. In fact, the wall with the three yellow stud bays was an interior partition wall separating one bedroom from another. This is a wall where we don't expect to find any insulation as there really is no need to thermally isolate an interior wall from one conditioned room to the next. But why would there exist a significant thermal concern at such a wall as this?
The answer is in the attic! When interior partition walls are constructed, rarely is any thermal barrier installed within the wall... or on top. Wait... isn't there any insulation in the attic you ask? Well yes there is. About 14 inches of loose fill fiberglass. That helps protect the ceiling from the extreme temperatures experienced in the attic, but provides very little barrier to actual air movement from the attic and into these walls. You see the top plate of this wall was never sealed. They rarely are during construction. Air can essentially move freely as it pleases following the laws of thermodynamics. In layman's terms, warm travels to cold naturally unless physically altered or forced in the other direction. With the empty partition wall colder (due to the operating air conditioner) than the apparent temperature of the attic, the hot air from the attic is naturally drawn down through gaps at the top of the wall and into the empty bays. 
In fact. the insulation that lays on top of these walls merely performs as a glorified air filter as can be witnessed from the discolored insulation in the image to the right (from a different home). The warm drywall inside the room now contributes to the increase of the temperature of the room, the air conditioner tries to compensate, and a vicious cycle is created. Albeit a gradual cycle, but a costly one nonetheless which often goes overlooked by homeowners during summer months.
The solution:
- Have a heat loss energy survey performed by a qualified and competent service provider. The cost for this service is quite affordable as compared to the wasteful spending of "out of sight, out of mind" cooling costs. Utilizing such equipment as blower doors, infrared cameras, and other specialized equipment, the service person can quite literally show you what you otherwise can't see of your home.
- Install gaskets and air barriers at all penetrations inside the attic. These include the tops of partition walls, vent penetrations, recessed lighting, and all other areas identified during step one. Some of these repairs may indeed be performed by the homeowner, but due to complexities and potential safety hazards of attic areas, a qualified contractor is best hired and money well spent. Besides, when it comes to air sealing potential combustion sources such as ceiling lights and exhaust flues, these tasks are best left to the professionals.
- Perform combustion analysis of all fuel burning appliances within the home after significant air sealing repairs have been completed. Again a qualified service contractor should perform this very important task. They use special instruments and meters to evaluate proper combustion of all appliances (including your gas stove) to make sure everything is vented and operating properly so your home remains safe and comfortable.
- Perform a second survey to make sure the contractors addressed everything properly. The smallest of details can become quite obvious in the infrared spectrum.
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