How Attic Ventilation Affects the Efficiency of Your Air Conditioner

Choosing and installing an efficient air conditioner in your Roseville, California home is an important step towards lowering your energy bills and reducing your carbon footprint. However, even the most efficient cooling system is guaranteed to under-perform if your attic isn’t properly ventilated.

Heat Collects in the Attic

Heat rises, and if your home has an attic, this is exactly where your indoor heat is rising to. Attic spaces also collect and retain heat from the sun’s rays as they beat down on the roof. During the hottest portions of the day, your attic can collect massive amounts of heat in the form of solar energy. Worse still, this is heat that will eventually migrate to other areas of your home.

Proper Ventilation Removes Attic Heat

Good attic ventilation keeps heat from building up in these spaces and then leaking into other areas. Ventilation routes hot air out of the topmost portion of your home and back outdoors before it ever has the chance to affect the ambient temperatures in your actual living spaces. Ventilation additionally allows cool air to circulate throughout the attic after the sun sets so that your home’s roof becomes cooler, problems with mold and mildew are kept at bay, and the upper portion of your home doesn’t have a dank, musty smell.

Insufficient Attic Ventilation Diminishes the Lifespan of Cooling Systems

Most homeowners don’t pay a tremendous amount of attention to their attics. In fact, unless yours is fit for storage, you probably never visit this space at all. Unfortunately, even when it isn’t being used, your attic can still have a tremendous impact on your indoor comfort and on the health, lifespan, and efficiency of your air conditioner.

If your attic is collecting heat and releasing it into your home, it’s causing your cooling system to work far harder than it’s meant to. This is especially true on the hottest days of the year. This extra wear and tear shortens the lifespan of home cooling equipment. More importantly, as AC systems sustain progressive wear, their efficiency rapidly declines, and they’re more likely to develop serious repair issues.

Signs Your Attic Isn’t Well-ventilated

During the summer months, there are several ways to tell whether poor attic ventilation is causing AC system stress. For instance, if your air conditioner is still relatively new, and if it’s been well-maintained, your cooling cycles should last about 15 to 20 minutes.

On hot days, there should be approximately three to four cooling cycles every hour. If you’ve set your thermostat at a reasonable temperature, there may even be relatively long stretches of time where your air conditioner never cycles on at all. However, absent of attic ventilation, you may find that your AC system’s cooling cycles last 25 minutes or more, or that your air conditioner never cycles off at all during the hottest portions of the day.

Higher-than-normal energy bills during the summer months are another strong indication of ventilation problems. Many people schedule AC repair thinking that their cooling systems are under-performing. In reality, their air conditioners are often over-working instead. They simply have the odds stacked against them in the form of excessive attic heat. Putting your air conditioner to the task in unfavorable conditions will eventually lead to major functional problems.

During the winter, you may notice ice damming at the edge of your roof. Heavy build-ups of ice along the roof’s eaves is a clear, cold-weather sign of poor attic ventilation. This is a problem that can additionally undermine your roof’s substrate and cause the entire roofing system to fail before its time. Thus, improving ventilation in your attic isn’t just about cutting your home cooling costs, saving energy, and creating a more comfortable living environment. It can also preserve the integrity of your roof and stave off the need for a total roof replacement.

Poor Attic Ventilation Can Affect Your Indoor Air Quality Too

In winter, when your air conditioner is at rest, poor attic ventilation can affect your indoor air quality. During the cold season, most families keep their windows and doors sealed shut to trap warm air in. They also tend to spend more time indoors, take longer baths and showers, and engage in steamy cooking projects. Much like heat, excess moisture has a tendency to rise, and not surprisingly, its final resting place is the attic.

Excess moisture in attic areas dampens the attic insulation. This undermines the efficacy of insulation, causes heating costs to rise, and sets the stage for mold and mildew development. When mold forms in the attic, it isn’t long before it starts affecting other areas of the property, negatively impacting resident health, and diminishing building aesthetics.

Too Much Attic Ventilation Is Also a Problem

Too much attic ventilation increases the likelihood of ceiling air leaks. This frequently occurs when too much insulation is used or when attic insulation has higher-than-necessary R-values. The result is an issue known as the stacking effect. With the stacking effect, warm, low-density air moves upwards at an accelerated rate and creates a dramatic air pressure difference. Air pressure in the living environment is low, and air pressure in the attic is high.

Why Do Homes Have Poor Attic Ventilation?

There are a number of reasons why attic ventilation may be insufficient. For instance, some houses are built with kitchen and bathroom exhaust fans that are vented to the attic rather than outdoors. This inflow of warm, moisture-heavy air adds heat to attic spaces and makes normally acceptable levels of ventilation inadequate. Changing how these exhaust systems are laid out can make a major difference.

In California, there has also been a push to create completely airtight homes. In theory, airtight buildings are more efficient than buildings that allow outside air in and inside air out. Many builders have long surmised that the tighter a home’s envelope is, the more efficient the structure will ultimately be. Unfortunately, excessively tight home envelopes don’t account for solar heat gains, rising moisture and heat, and poorly designed ventilation systems. They also fail to take indoor air quality and the air pressure effects of using HVAC systems into consideration.

Some homes with poor attic ventilation have been modified by homeowners themselves. These modifications might be as major and complex as turning basic, unfinished areas into bedrooms or offices. They can also be as simple as using attic storage areas in a way that blocks attic vents. At times, even adding too much insulation or the wrong insulation types can cause problems with venting. Both the cause and the best methods of correction can be unique for every home.

Priming Your Air Conditioner for Efficiency

Buying an efficient air conditioner is only one step towards minimizing your environmental impact and cutting your home heating and cooling costs. It’s also important to streamline your home’s envelope to ensure optimal HVAC performance. This includes creating the conditions for good airflow. With the right level of ventilation, your attic will retain less solar heat and limit strain on your AC system. In some buildings, this requires the installation of powerful attic fans that clear hot, stagnant air out.

Since 2010, Environmental Heating & Air Solutions has been proudly serving residents of Roseville, California and the surrounding areas. We’re committed to helping our clients save money while making the most of their HVAC equipment. We offer heating, cooling, plumbing, and indoor air quality services. We also provide air ventilation, blower testing, and home insulation services. If you need help optimizing the performance of your AC system, we’ve got you covered. Give us a call today.

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