QuietCool Systems

The Problem with Spray Foam Insulation


The Sealing Obsession

In the realm of building science, one of the most pervasive misconceptions today revolves around the idea that it’s better to have a completely sealed attic than a well-ventilated one. This belief is so widespread that it has even led to the extensive use of controversial spray foam insulation in attic spaces. However, in this blog post, we’ll unravel the truth behind this attic sealing myth and emphasize the importance of proper ventilation in creating high-performance homes.


The obsession with sealing attics is unmistakable, and you can find evidence of it almost everywhere in modern construction. The notion that an airtight attic is the key to energy efficiency has gained substantial traction. However, the most prevalent quote within the building science community is, “Seal it tight, ventilate it right!” This adage suggests that the most energy-efficient buildings are those tightly sealed to prevent temperature fluctuations while being adequately ventilated to expel toxins and prevent moisture damage.


The Problem with Spray Foam Insulation

When it comes to spray foam insulation in attic spaces, the reality is that ventilation becomes practically nonexistent. This is where the misconception takes root. Many homeowners, in pursuit of a sealed attic, turn to spray foam insulation, inadvertently creating a major drawback – the need to use the air conditioner to keep the attic cool due to the absence of ventilation. However, it’s important to remember that air conditioners are designed to cool living spaces, not non-living areas like the attic.

While insulation is undeniably crucial for regulating indoor temperatures, relying on your costliest appliance, the air conditioner, to cool the attic is far from the most efficient approach. It may effectively maintain a cooler attic temperature, especially when compared to traditional attics that can reach scorching temperatures of up to 160 degrees on a 100-degree day. Nevertheless, the problem lies in the significant financial cost and strain on your AC unit.


Consider a practical test: Turn off your air conditioner for a day and measure the attic temperature. You’ll likely find that even with spray foam insulation, the attic can still reach temperatures of 120 to 130 degrees. This reliance on the air conditioner for attic cooling can result in higher energy bills and unnecessary stress on your AC unit.

On average, air conditioning systems last around 13 years, and in hot climate zones, their lifespan may be even shorter due to nearly year-round operation. Subjecting your AC to this constant demand is avoidable, especially when active ventilation in the attic can be achieved effortlessly and affordably.


Ventilation as the Solution

The solution lies in proper attic ventilation, which can be provided by whole house fans and attic fans. These fans cost only pennies per hour to operate, making them a cost-effective alternative. Furthermore, the price tag associated with spray foam insulation, ranging from five to ten thousand dollars, pales in comparison to the affordability of a whole house fan (typically $600 – $1400) or an attic fan (usually priced between $150 – $400).


When it comes to cooling your home efficiently without overburdening your air conditioner and maximizing airflow, whole-house fans and attic fans emerge as the most practical and cost-effective choices. The attic sealing myth can be dispelled by embracing the importance of proper ventilation in creating comfortable, energy-efficient homes.