Thermal Vs Blackout Curtains: Which Insulates Better?

Suppose you are a homeowner wondering which type of curtains are the best to purchase for insulation? Or are blackout or thermal curtains similar? These are excellent questions. We've done the research and found definitive answers to your questions.

Blackout curtains will block the sunlight and are not insulated. Please make sure you buy thermal or insulated curtains to insulate your windows during the coldest or hottest months to reduce energy use in your home. 

We know you are interested in learning more about the differences between blackout and thermal curtains? Or, how to wash curtains correctly? We've researched these topics and have gathered quality research results to share with you!

modern room with curtains interior design, Thermal Vs Blackout Curtains: Which Insulates Better?

Thermal Vs. Blackout Curtains: Which Insulates Better?

Whether you are selecting curtains to keep the sunlight out or are interested in reducing drafts from your windows, both blackout and thermal curtains have pros and cons to consider. 

Details of white fabric roller blinds on the plastic window in the living room

Blackout curtains

The primary purpose of blackout curtains is to block out natural sunlight by 100% via tightly woven black fibers in the back layer of the curtain. Blackout curtains are made from synthetics, felts, suedes, or velvets, because those materials are great for blocking out stubborn sunlight.

These curtains are available in a wide variety of colors and sizes that will fit any home decor style. Please note that the blackout curtains must fit the windows' dimensions to block light.

Failure to purchase or install blackout curtains correctly will cause light to shine in areas where the curtain doesn't fit the window frame correctly.

Thermal curtains 

Thermal curtains are manufactured from double or triple-layered heavyweight fabrics, and are paired with an insulating backing, and a polyester-film vapor barrier. Usually, thermal curtains are made from cotton, polyester, or wool, because natural fibers are excellent for insulation.

Owing to the thickness of thermal curtains, they will omit 90% of natural light and keep your home at are comfortable temperature. Also, you can purchase thermal curtains with blackout and noise-reducing properties online or at brick-and-mortar stores. 


Click here to view the BGment blackout, thermal, and noise-reducing curtains at Amazon.

How Much Energy Do Thermal Curtains Save?

According to, the average home will lose roughly 30% of the heat via the windows. The good news is that traditional curtains and draperies can reduce lost energy by 10 percent. Also, depending on the brand, color, and material, thermal curtains will reduce energy loss by up to 25%.

Please note that several variables will impact how much energy your thermal curtains will save on your energy bill. For example, the climate where you live, and the size and age of your home will affect how well the thermal curtains will reduce your home's energy use.

What Curtains Are Best for Insulation?

Suppose you are mainly interested in selecting the best curtains for insulation. Your best option will be to buy thermal curtains because they have a design that optimizes insulation. The added layers of fabrics will serve as a barrier that will insulate your windows. 

Do Blackout or Thermal Curtains Reduce Cold?

According to Martha Stewart, using thermal curtains will help reduce the cold temperatures indoors by preventing heat loss. However, blackout curtains that are not insulated will not reduce the cold from the window frames. Instead, these blackout curtains will only block sunlight from entering the room. 

Are you wondering how to get more fresh air into your home without letting too much cold air inside? Click here to read How To Get Fresh Air From Outside Without Letting Cold Air In

Do Blackout Curtains Keep Heat in During the Winter?

Great question. Blackout curtains are designed to block out the light. This will help you and your loved ones sleep more soundly and prevent damage from sunlight in your home.

Moreover, it depends on which brand and type of blackout curtains you intend to purchase. Note there are insulated blackout curtains on the marketplace that will serve both purposes. 

Always read the product description before clicking 'add to cart' to ensure you choose the best curtains to keep your house warm. 

Do Blackout Curtains Help Drafty Windows?

Blackout curtains will block sunlight and keep the room dark. Please note that blackout curtains will not prevent draftiness, nor will they offer a solution to a window that needs repairs. 

For the best results, get your drafty windows repaired before the winter. Or, cover and seal the perimeter of the window with plastic to reduce the amount of heat escaping, which wastes valuable energy. 


Click here to view the Frost King window insulation kit at Amazon.

table and chairs in the meeting room in the office, in the classroom or in the library hall White, black and gray pa

Is Thermal Lining Also Blackout?

The curtain's thermal lining will depend on the manufacturer's brand and the type of materials used. Usually, the thickness of the thermal lining will be thick enough to block 90% of sunlight while it helps keep the room at a comfortable temperature. 

However, you can purchase thermal curtains with blackout lining to serve dual purposes in your home. 

Click here to view the Wontex thermal with blackout lining curtains at Amazon.

Are Thermal Curtains the Same as Insulated Curtains?

No. The thermal curtains retain heat during winter and reduce solar heat over warmer months. Insulated curtains simply have an added layer of insulation or fabric. And this will keep heat indoors during the winter. But it will not help reduce heat from the sun during the spring and summer months.

blackout curtains the curtains are drawn and block out the daylight

Do Thermal Curtains Help in the Winter?

Yes, thermal curtains are excellent for reducing heat from escaping via windows . They create a barrier around the window that will prevent the cold air from entering the room. 

Thermal curtains aren't only excellent for the winter months. You can use them in the summer months too because they will block heat generated by sunlight from entering your home. 

Motorized roller shades in the interior automatic roller blinds beige color on big glass windows

How to Wash Blackout Curtains? 

Please do not put your blackout curtains into the washing machine or dryer. It will damage or melt the synthetic materials.

  1. Vacuum the front and back of the curtains with a dusting attachment. 
  2. Remove the curtains from the rods.
  3. Use gentle soap or laundry soap to spot clean any dirt or stains. 
  4. Hang the curtains back on the rods to dry.

For the best results, read and follow the washing instructions from the manufacturer. 

How to Wash Thermal Curtains?

  1. Vacuum the front and back of the curtains and use a soft brush or dusting attachment. 
  2. Remove the curtains from the rods.
  3. Spot test a small corner with water and your chosen laundry soap. 
  4. Fill the tub with warm water and soap. 
  5. Submerge the curtains. 
  6. Gently wash and use a small brush to scrub dirty patches.
  7. Rinse with clean, warm water. 
  8. Wring the excess water out. 
  9. Air dry on the rods or outside on the clothesline.

For the best results, read and follow the washing instructions from the manufacturer. They are usually on the curtains tag. No-tag, no problem. Google the company's name and search their website for washing instructions. 

In Closing 

modern room with curtains interior design

Thank you for reading our article! Today we discussed the difference between blackout and thermal curtains, and how selecting the best option for your home will help you reduce your energy bills and keep your home at a comfortable temperature. 

All of us at HVAC Seer hope this has been a helpful blog post for you and that you are more prepared to select the best curtains for your home. 

Please be sure to check out some of our other posts before you go to further your knowledge about window treatments!

Should I Leave My Curtains Open At Night?

How To Weatherproof Windows With Plastic Wrap [A Step-By-Step Guide]

How Cold Will An Unheated House Get?

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