Why is my attic so hot: cooling your attic

Is your attic hotter than ever this summer? You’re not alone. Attics are prone to overheating for a few reasons, and most homeowners don’t even realize the real culprits behind the rising temperatures.

Before you go blaming the summer sun or thinking your attic has poor ventilation and needs an upgrade, you should know it’s probably not either of those things causing your attic to feel like a sauna. The truth is, there are a couple of common heat sources in attics that are too often overlooked.

Keep reading to find out what’s causing your attic to overheat and some easy solutions to help you keep your attic cool all summer long.

Poor insulation: the primary culprit

If your attic feels like a sauna in the summer, the problem is most likely poor insulation. Insulation is a barrier between the hot air outside and the cooler air in your living spaces. Without adequate insulation, the heat is free to seep in — and your AC has to work overtime to both exhaust hot air and cool things down.

The most common type of attic insulation is fiberglass or cellulose.

These are loose fill insulations that are blown into the attic.

Over time, they can settle or compress, reducing their effectiveness. If your insulation is more than a few years old, it’s a good idea to have it topped off to the recommended level for your area.

Ventilation issues

In addition to a lack of proper insulation throughout, poor attic ventilation can also raise temperatures. Your attic needs vents, like gable vents, ridge vents, or attic fans to allow hot air to escape.

If you don’t have enough vents, the hot air gets trapped — and your already hot attic turns into an oven. Attic ventilation also helps moisture and condensation from accumulating, which can lead to water damage and mold growth.

Sealing up cracks and gaps

Heat and air leak into the attic through gaps and cracks in the attic floor, like where pipes, wires, and the attic access door enter the living space below. These cracks, even small ones, can significantly impact the ideal attic temperature here. Sealing and weatherstripping them can improve comfort and energy efficiency.

Providing adequate insulation, ensuring proper ventilation, and sealing up leaks are the keys to cooling your sweltering attic. Make these attic improvements and you’ll gain a more comfortable home and lower energy bills.

Lack of ventilation: trapped hot air has nowhere to go

Your attic is sweltering in the summer for one major reason: lack of ventilation. All that hot air has nowhere to go, so it just builds up, and up, and up.

To keep your attic cool, you need to improve airflow and circulation.

Here are a few ways to do that:

1. Install roof vents or turbines. Roof vents allow hot air to escape through the attic to the outside. Turbine vents use the wind to spin and draw the hot air out. Either of these options will help tremendously.
2. Add soffit vents. Soffit vents are installed in the triangular section of your attic walls. Placing a few gable vents at opposite ends of the attic will provide airflow and cross-ventilation. This constant flow of air will keep the attic temperature in check.
3. Install an attic fan. An attic fan is one of the most effective solutions. It actively pulls the hot air out of your attic and vents it outside. fans can lower the attic temperature by up to 30 degrees Fahrenheit. For the best results, place the fan near roof vents or gable vents to maximize circulation.
4. Get the proper insulation. While ventilation is key, more insulation will also help. Adding reflective insulation, especially on the attic floor, will prevent heat from the house below from rising into the attic. The less heat that gets in, the less there is to vent out.

With the soffit vent and reflective insulation, the air sealing your attic can go from unbearably hot to refreshingly cool.

Roof absorption: your roof is soaking up the sun

The main reason for your hot attic — your roof is absorbing the sun’s heat and radiating it downwards. The hotter it gets outside, the heat naturally rises, and the more your roof acts like a giant solar panel.

Roof material matters

The type of roofing material you have directly impacts how much heat it retains. Dark shingles, especially asphalt, absorb more of the sun’s rays.

Lighter, reflective materials like metal or tile deflect more of this energy. If you have a dark, asphalt roof, you can expect your attic room to be a good 10 to 15 degrees hotter than if you had a light-colored roof with installing reflective insulation.

Heat rises

As the sun beats down on your roof, the heat it absorbs has nowhere to go but up — right into your attic.

The hot air, in turn, gets trapped in your attic bedroom since it’s not well-ventilated.

This creates a vicious cycle where the attic just keeps getting hotter and hotter. The only way for the hot air to escape is through openings like vents, but these are often too small to be very effective.

The solution: more vents and added insulation

To get cool air into your sweltering attic room, you need to increase ventilation and add insulation. Install additional vents, roof vents, gable vents, or ridge vents to allow more hot air to escape.

At the same time, add more insulation between the attic and living space below. Fiberglass or cellulose insulation will help prevent the heat that does build up in your attic room from penetrating your home.

Making some improvements to increase attic ventilation and insulation can help lower temperatures in your attic room significantly, often by 25 degrees or more.

You’ll gain more comfort in your living space below and improve energy efficiency, saving on cooling costs all summer. A full roof exhaust, cooler attic, and lower energy bills — should help you rest easier, even on the hottest nights!

Excessive lighting: more light means more heat

Excessive lighting in your attic room generates heat, which contributes to the overall attic temperature increase up there.

More light means more heat for two reasons:

First, the bulbs themselves emit heat as a byproduct of converting energy into light. The more lights you have on, and the higher the wattage of the bulbs, the more heat is generated.

Second, the attics get so hot from the bulbs and fixtures that then get trapped in since warm air rises. The hot attic acts as an oven, baking everything inside. The heat has nowhere to go, so temperatures keep climbing. Installing ventilation like exhaust fans, attic vents, or radiant barriers can help vent the hot attic air and lower temperatures.

Other steps you can take include:

• Use a lower wattage for attic lights when possible. For most tasks, a 60W equivalent LED bulb should suffice.
• Turn lights off when not in use. Don’t leave attic bedroom lights on for extended periods if no one is up there.
• Consider motion-activated lights for attics with pull-down stairs or limited access. This way lights are only on when needed.
• Choose lighting with built-in fans or ventilation. Some attic fixtures offer integrated exhaust fans or vents to get air movement and prevent heat buildup.
• Add a switch at the base of the attic stairs or entryway. This makes it easy to turn lights on as you go up, and off as you come down. No more guessing if the lights were left on!

Appliances and electronics: hidden heat sources in your attic

Your attic can easily become a hot spot in the summer, even if the rest of your home stays comfortable. One overlooked source of attic heat is the appliances and electronics located up there.

Water heaters

Your water heater works hard to keep water hot for your home. In the process, it releases heat, which builds up in your attic space.

Any attic-located tank or tankless water heater should be well-insulated and vented to the outside to minimize heat buildup.

HVAC equipment

Furnaces, air conditioners, and heat pumps also release heat as a byproduct of operation. HVAC equipment installed in an attic should have good ventilation and insulation to channel heat out of the attic.

Generators

Backup generators kick in during power outages and generate heat and fumes that can fill an attic. Never run a generator in an enclosed attic – overheating and carbon monoxide it produces are extremely dangerous.

Electronics

Satellite dishes, cable boxes, wifi routers, and entertainment systems are commonly placed in attics for installation convenience but also emit heat during use.

Provide adequate ventilation and cooling attics and electronics or consider relocating them to a lower level of the home.

Keeping your attic cool starts with controlling heat sources.

Proper exhaust vents, insulating or relocating appliances and electronics can help lower attic temperatures and make your whole home more comfortable and energy efficient.

Addressing these hidden heat sources, along with improving attic insulation and ventilation, can help you cool your attic for good.

Conclusion

Now you know why attics are scorching hot attics in the summer. The heat gain from the rooms below, the roofing materials, and the lack of ventilation are the main culprits.

The good news is there are some easy fixes you can put in place to significantly lower the temperature up there.

Adding insulation, air sealing, and weatherstripping the attic access door or hatch, installing attic fans or vents, and choosing a lighter-colored roofing material can all help.

FAQ