Do Shutters Keep Heat Out? Best Types & How They Improve Energy Efficiency

TLDR;

Yes, shutters do keep heat out. They work as thermal barriers that reflect sunlight, reduce heat transfer through windows, and help maintain cooler indoor temperatures—especially when the right types are used.

How Heat Moves Through Your Windows (And Why It Matters)

Heat enters your home through windows in three main ways:

• Radiant heat: Solar rays directly heat surfaces inside your home
  
• Conductive heat: Heat transfers through the window glass itself
  
• Convection: Warm air leaks in around window frames and gaps
  
  

Even the most modern double-pane windows can let in a surprising amount of heat. That’s where shutters come into play, acting as an additional layer of insulation and reflection.



Windows are among the weakest points in your home’s insulation. In summer, they act like magnifying glasses for solar heat. Without barriers like shutters, your HVAC system works overtime trying to keep things cool.

How Shutters Help Keep Heat Out (Science + Real-World Use)

Shutters don’t just look good—they’re functional heat blockers. Here's how they work:

• Conduction: Shutters reduce heat transferred through the window glass by creating a physical barrier
  
• Radiation: Reflective shutter materials bounce sunlight away before it heats your space
  
• Convection: A tight seal reduces warm air leaks
  
  

In the real world, well-fitted shutters can reduce solar heat gain by up to 60%, depending on the materials and placement. This benefit becomes even more obvious in rooms with lots of sun exposure.

Day vs. Night Effectiveness:

• Daytime: Exterior shutters block direct sunlight before it hits the window
  
• Nighttime: Interior shutters trap cooler air inside and keep warm air out



The result? Lower cooling costs and a more comfortable home.

Top 3 Types of Shutters for Insulation & Heat Control

Let’s explore the most effective types of shutters to block heat:

1. Aluminum Shutters

• Highly reflective—great for sun-facing exteriors
  
• Durable and weather-resistant
  
• Often used in tropical or desert climates
  
• Typically mounted outside to block radiant heat before it enters
  
  

Best For: Homeowners in hot, dry climates or commercial buildings needing maximum heat reflection

2. Composite Shutters

• Made from engineered materials like MDF, polymers, and resins
  
• Offer superior thermal insulation compared to traditional wood
  
• Resist moisture—ideal for humid environments
  
• Available for both interior and exterior mounting
  
  

Best For: Versatility in both function and style with strong insulation properties

3. Wooden Shutters

• Naturally insulative due to the density of wood
  
• Provides both aesthetic warmth and functional cooling
  
• Can be painted or stained to match decor
  
• Works best when tightly sealed to minimize air gaps
  
  

Best For: Homes seeking a classic look while improving energy efficiency

Want to upgrade your patio or sliding glass door? Consider Plantation Shutters for Sliding Doors to combine elegance, insulation, and light control in one stylish solution.

Exterior vs. Interior Shutters – Which Blocks More Heat?

Exterior shutters typically perform better at keeping heat out because they intercept sunlight before it hits the glass.

Interior shutters, while still useful, allow some heat to pass through the window first. However, when combined:

• They form a double barrier, which is significantly more effective
  
• Ideal for climates with extreme heat and sun exposure
  
  

Exterior Advantages:

• Blocks radiant heat early
  
• Can include reflective finishes
  
• Adds weather protection
  
  

Interior Advantages:

• Easier to operate and adjust
  
• Still reduces conductive and convective heat
  
• Visually appealing with better control of privacy and light

Choosing the Right Shutters for Your Region’s Climate

The effectiveness of shutters often depends on your climate:

In Hot, Arid Regions (e.g., Arizona, Southern California)

• Go for aluminum exterior shutters
  
• Add reflective coatings to bounce sunlight
  
  

In Humid Climates (e.g., Florida, Coastal North Carolina)

• Choose composite materials that resist moisture damage
  
• Consider interior + exterior combo for ultimate control
  
  

In Temperate Zones (e.g., North Carolina Piedmont)

• Use wooden or composite shutters with tight interior seals
  
• Focus on multi-season performance—cool in summer, warm in winter
  
  

Shutters should not only reflect heat but also fit your home’s weather patterns. At Love Is Blinds NC, we often recommend materials based on long-term weather forecasts and energy efficiency goals.

Shutter Installation & Placement Tips for Maximum Thermal Performance

Proper installation is just as important as choosing the right material.

Key Tips:

• Ensure a tight fit with no gaps around the frame
  
• For exterior shutters, mount close to the wall/window to minimize air passage
  
• Install radiant barriers or foil backing for additional reflection
  
• For windows facing south or west, prioritize exterior reflective shutters
  
• Use louvered shutters for adjustable ventilation
  
  

The more airtight the installation, the better the thermal barrier effect.

Do Shutters Also Keep Heat IN During Winter? (Year-Round Benefits)

Absolutely. The same features that keep summer heat out also keep winter heat in.

• Shutters reduce heat loss through windows by slowing air and temperature exchange
  
• Interior wooden and composite shutters are especially effective in preventing drafts
  
• This translates into lower heating bills during colder months
  
  

In North Carolina, where seasonal temperatures vary significantly, year-round thermal shutters are a smart investment for consistent energy savings.

What the Experts Say: R-Values & Energy Star Guidelines

The R-value measures how well a material resists heat flow. The higher the R-value, the better the insulation.

• Aluminum Shutters: Low R-value alone, but high reflective capability
  
• Composite Shutters: R-values between 3.5 to 6, depending on thickness and build
  
• Wooden Shutters: Natural R-value around 3.0 to 4.0
  
  

According to Energy.gov, window treatments like shutters can reduce heat gain by 45–60% when properly used.

While Energy Star doesn’t certify shutters directly, their guides recommend combining thermal window treatments with air-sealing strategies for best results.

Are Shutters a Good Investment for Energy Savings?

Yes—especially when installed strategically and used consistently.

Why They're Worth It:

• Lower electricity bills from reduced AC and heater use
  
• Increase your home’s resale value with a stylish, functional upgrade
  
• Improve interior comfort and climate control
  
• Extend the lifespan of furnishings by reducing sun exposure
  
  

At Love Is Blinds NC, we’ve helped hundreds of homeowners choose shutters that match both their design goals and energy efficiency needs.



Bonus: Shutters are low maintenance and last for years, making them a strong ROI for your home.

FAQs – Shutters & Heat Management