Best way to cool attic

Do you have a hot attic?

Are you looking for the best way to cool an attic so it’s more energy efficient?

Or how about making better use of that space in your home?

If so, this article is for you.

Below, you’ll find the top 7 best ways to cool your attic down.

We’ll start with the easiest methods that most homeowners can do and work our way up to the more time-consuming DIY projects.

If you’re serious about finding the best way to keep an attic cool, this guide has the answers you need.

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Best Way to Cool an Attic

1. Indoor Air Conditioning Unit

All of the other tips listed below are good for cooling down an attic so that the rest of your house doesn’t get too hot.

If you’re using your attic as a functional space, like a bedroom or workroom, then you’ll want to consider adding an indoor air conditioning unit.

An AC unit will keep the temperature much more pleasant and comfortable for you to be in your attic for long periods of time.

As for attic air conditioners, you have two best options without a window:

  • Portable air conditioner
  • Mini split ductless air conditioner

A portable air conditioner is the easiest solution for cooling your attic.

It’s a standalone unit that’s about two feet tall and 18 inches wide and has wheels for mobility. 

Portable air conditioners do need to be vented to pump the hot air outside. Most come with a window kit for this purpose that attaches to a hose on the back of the unit. However, you may not have a window in your attic.

If that’s the case, then you’ll need to cut a hole somewhere that leads to the outside for proper ventilation. A good place is down through a soffit since this won’t allow rain to get in.

You can view our best stand up air conditioner list to find a model that works best for your budget.

Also, check out our portable air conditioner venting options to get some more ideas on the setup.

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Another option is to go with a mini split ductless air conditioner.

These systems can mounted on a wall, ceiling, or floor depending on the type that you get.

Mini split AC units don’t require a big hole for ventilation like a portable unit.

Instead, there’s a small line set that comes out the back of the system and can be run anywhere you’d like. This line set attaches to an outdoor compressor unit that powers the indoor evaporator cooler.

All that’s required to get the line set from the indoors to the outside is a 3-inch hole. And that can be through the roof, a soffit, brick, or siding.

Check out our best mini split AC unit list if this seems like a better solution for cooling your attic.

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2. Seal Cracks and Gaps

When it comes to the best way to cool attic with or without an air conditioner, you need to ensure that any cracks, gaps, or holes are taken care of.

As you can imagine, leaving any open areas will allow warm air to seep into your attic during the summer.

In addition, allowing cracks, gaps, and holes to remain open throughout the space increases the chances of water getting into your attic—and this can cause water damage and rot.

If the holes, cracks, or gaps in your attic are less than one-quarter of an inch, you can use a weatherproof caulk to seal them.

If you have a chimney and notice issues around this structure, make sure to use a heat-resistant caulk to seal these holes.

For holes that are larger than one-quarter of an inch, you’ll want to use an expandable foam spray.

This plugs the hole more efficiently to ensure that your attic isn’t leaking air from the inside of your home or letting in air from the outside.

Best way to keep attic cool insulation

3. Upgrade the Insulation

If you’ve ever wondered why your attic has insulation, it’s because it acts as a barrier against temperature extremes.

Having insulation in your attic can help you save up to 20% in heating and cooling costs.

And, having insulation in your attic keeps the area at a consistent temperature.

You want high-quality insulation in your attic, as it will ensure that the cool air from your air conditioner can’t escape your home.

During the winter, insulation also keeps the hot air trapped inside your home to keep you warm.

When it comes to finding the right insulation for your attic, you want to look at the R-Value.

This number shows the insulation’s ability to resist the transfer of heat. The R-Value is determined by the following factors:

  • The material it’s made from
  • How thick it is
  • Its density
  • How and where the insulation is installed

If the insulation has a high R-Value number, that means it’s better at trapping heat. In general, the R-Values you should be looking for are the following:

  • R30 is best for hot climates, such as those found in California
  • R38 works well in temperate climates
  • R49 works well in cold climates—particularly areas where it’s common for businesses and schools to be shut down due to extremely cold temperatures

The recommended level for most attics is to insulate to R38 or about 10 to 14 inches depending on the insulation type, according to Energy Star.

Some of the different materials you might choose for your attic insulation include the following:

  • Fiberglass
  • Cellulose
  • Mineral wool
  • Cotton
  • Foam

Knowing which material is the best option for your attic will depend on your budget and where you live.

You may also need to check state laws, as some places have specific requirements for what type and the R-Value your insulation should be.

4. Add Ventilation for Improved Circulation

Having a properly vented attic is the best way to keep attic cool because it allows the hot air to escape during the summer.

If hot air is allowed to sit in your attic, it could overheat the shingles on your roof and cause damage.

In addition, hot air in your attic could increase moisture levels, which could result in wood rot and mold growth.

There are a variety of different ways to add ventilation to your attic for improved circulation, including the following listed below.

Knowing which vent type will work best depends on the type of roof you have, where you live, and your airflow needs.

Working with a professional roofer is your best option, as they’ll be able to let you know exactly how to ventilate your attic to keep it cool.

Soffits

These are the most popular intake vents to add to your home.

They’re often installed under your roof’s overhang, which means they are hidden from sight and protected from dirt and debris, pests, and adverse weather.

The narrow soffit slits allow air to flow freely into your attic. The airflow pushes the hot air out, which is exactly what you need to keep your attic cool during the summer.

Ridge Vent

These are exhaust vents that are installed on the ridge of your roof (i.e. the peak).

Ridge vents are available in a series of pieces or as one long piece.

Because of their size and positioning at the peak of your roof, ridge vents allow the warm air to escape your attic efficiently.

However, not all roofers recommend adding this type of vent to your roof in wet climates.

In addition to the openings that allow hot air to escape, ridge vents could potentially let moisture, rain, or snow into the attic.

Gable Vent

The area on your roof where two sides meet and form a triangle is called a gable.

Adding a slotted piece of wood or siding to this area allows air to flow in and out of your attic.

Since gable vents rely on strong winds to make them effective, gable vents are often used in addition to other attic vents, including soffit vents.

Most roofers do not recommend installing gable vents on houses that are exposed to driving rain, as they may allow excess moisture into your attic.

5. Install Radiant Barriers

Radiant barriers are made from highly reflective material, and they work to keep an attic cool by preventing the electromagnetic transfer of heat.

In essence, they reflect the light back from where it came, keeping it out of your attic.

The most common material used for radiant barriers is aluminum foil.

Adding a radiant barrier prevents the sun from beating down onto your attic and heating it up, which means this option can help keep your attic cool in the summer.

When installing a foil-type barrier, the U.S. Department of Energy recommends that you allow the material to droop between the attachment points to make at least a 1.0 inch (2.5 cm) air space between it and the bottom of the roof.

Foil-faced plywood or oriented strand board sheathing is also available if you want a more solid fix.

6. Install an Attic Fan

Adding an attic fan can improve the airflow in your attic to keep it cool.

Attic fans push out the hot air and pull in the cool air from the vents installed on your roof.

To ensure that the attic fan is working properly, you need to make sure that your attic is sealed up tight where it touches the ceiling of the top floor.

Be sure that the access door is well fitted and doesn’t let air escape around the edges.

Otherwise, the fan could pull the cool air from inside your home upward, which will cause your house air conditioner to run longer—and that could increase your electricity bill.

7. Add Reflective Roofing

Adding reflective roofing is another option you might consider when it comes to the best way to cool your attic.

Reflective materials keep things cooler.

As the sun shines on the top of your house, the heat is absorbed by your roof. This will then make the attic hot.

If you add a reflective roof, the rays will be deflected away from your roof, which means they won’t be brought into your house where they can heat up your attic.

For this solution, you’ll want to hire a professional roofer, unless you’re very handy at heavy-duty DIY projects.

Best Way to Keep Attic Cool Summary

We hope you enjoyed this article on the best way to cool an attic. 

You now have at least 7 ways to keep an attic cool that can work for any home.

If you like DIY projects, then you can try some of these tips on your own.

If not, you at least have the expert knowledge to talk with and hire a technician that can implement the fix you want to cool down your attic.

As a reminder, if you’re trying to use your attic as a functional space, like a bedroom or workroom, then you’ll want to make sure that it’s cool enough for you to be in for extended periods of time.

In addition to adding any one of the best ways to keep an attic cool mentioned above, you’ll want to install an air conditioner of some sort to regulate the temperature.

Check out our top portable air conditioner list and best mini split AC unit list to find the system that’s right for you.

Cooling down an attic is not as hard as it may seem and a good solution exists for every homeowner.

Avatar for Katherine Dyson

About Katherine Dyson

Katherine is the lead Staff Writer. She conducts in-depth research and interviews with industry experts in order to produce a wide range of content for the site. Her main role is to write helpful articles that aid people who are seeking to improve their indoor air quality and comfort. (See Full Bio)