What’s the Difference Between a Window Unit and a Central Air Conditioner?

What’s the Difference Between a Window Unit and a Central Air Conditioner?

Choosing the right air conditioner for your home boils down to understanding your specific needs. Central air conditioners are best for cooling larger areas uniformly but come with higher installation and maintenance costs. Window units, more affordable and easier to install, are ideal for cooling smaller, individual rooms but have a limited cooling range.

Let’s explore more.

Table of Contents

Understanding Central Air Conditioners

Central air conditioners are sophisticated systems designed to cool your entire home. Unlike portable units that cool a single room, central air conditioning integrates into your home’s HVAC system, providing consistent and efficient cooling throughout.

The central air conditioning system is made up of two primary components:

Indoor Evaporator Coil: Typically located inside an air handler or attached to the furnace, this coil plays a crucial role in absorbing heat from your home’s air.

Outdoor Condenser Unit: Situated outside your home, the condenser expels the heat absorbed from your indoor air to the outside environment.

These components work together, connected by a series of refrigeration lines, to maintain a comfortable temperature in your home.

How They Work

The process begins inside the home, where warm air is drawn into the system through return ducts and passes over the cold evaporator coil. Here, the heat from the air is absorbed by the refrigerant in the coil, cooling the air, which is then circulated back into the house.

Outside, the refrigerant, now carrying the absorbed heat, moves to the condenser unit. In the condenser, the heat is released into the outside air, and the refrigerant is cooled and sent back indoors to continue the cycle.

A thermostat located in your home allows you to control the temperature, maintaining a comfortable environment by regulating the operation of your central air conditioner.

Installation Process

Installing a central air conditioning system is a complex process that requires professional expertise. Unlike window units, central air conditioners are not a DIY project. Key considerations during installation include:

  • Dedicated Electrical Outlet: Central air systems often require a specific electrical setup, ranging from 15 to 60 amps, depending on their capacity.
  • Ductwork: If your home doesn’t already have ducts, installing a central air conditioner will include the additional task of ductwork installation. This process involves creating a network of ducts that allows cool air to travel throughout your home.
  • Time and Space: The installation can take several days and may involve significant modifications to your home’s infrastructure, especially if new ductwork is needed.

Understanding Window Units

Window air conditioners are compact, self-contained cooling systems designed to fit snugly into a window sill. They are a popular choice for cooling individual rooms or small spaces. Unlike central air conditioners that require extensive installation, window units are an all-in-one solution, housing all necessary components within a single casing.

The design of a window air conditioner is straightforward: it comprises a double shaft motor, an evaporator, and a condenser, all enclosed within a box-like structure. This design makes it an efficient and space-saving option for targeted cooling.


The functionality of window air conditioners centers around their internal components:

  • Double Shaft Motor: This motor drives two fans – one located near the condenser and the other by the evaporator.
  • Evaporator: Located on the side of the unit facing indoors, the evaporator plays a key role in cooling the air. As warm air from the room passes over the evaporator coil, the refrigerant within the coil absorbs the heat, effectively lowering the room’s temperature.
  • Condenser: Positioned on the exterior side, the condenser expels the heat absorbed from the indoor air to the outside. This process is vital for the cooling cycle, ensuring that the air conditioner maintains efficient cooling.

Installation and Portability

One of the significant advantages of window air conditioners is their ease of installation. Most homeowners can install these units without professional help. The basic installation process involves:

  • Opening the window.
  • Placing the unit on the sill.
  • Closing the window onto the top of the unit.
  • Securing the unit with provided brackets and side panels to ensure stability and reduce air leakage.

Window units are also semi-portable. While they are designed to be installed in a window, they can be relatively easily removed and relocated to another window, making them a convenient option for renters or those who move frequently. However, their weight and size mean they’re not as portable as smaller, personal cooling units.

Central Air Conditioning vs Window Units: Pros and Cons

Central Air Conditioning Pros

  • Whole-Home Cooling: Central air conditioning systems are ideal for efficiently cooling an entire home. Unlike window units that cool a single room, central systems distribute cool air evenly throughout the house, eliminating hot spots.
  • Improved Air Quality: Central air conditioners often come with filters that purify the air, removing dust, allergens, and other pollutants, which is particularly beneficial for individuals with allergies or respiratory issues.
  • Noise Reduction: The bulk of a central air conditioning system is located outside the living space, leading to quieter operation compared to window units, which can be noisy.
  • Increased Home Value: Central air conditioning is a significant home upgrade. It not only enhances the comfort of your living space but can also increase the resale value of your property.

Central Air Conditioning Cons

  • Higher Costs: Both the initial installation and ongoing maintenance of central air conditioning systems can be more costly compared to window units. This includes expenses for professional installation and regular service checks.
  • Space Requirements: Central systems require space for installation, including an outdoor unit and ductwork. Homes without existing ductwork will need substantial modifications to accommodate these systems.
  • Complex Installation: The installation of a central air conditioning system is not a DIY project; it requires professional HVAC technicians and can take several days to complete.

Window Unit Pros

  • Energy Efficiency: Window units can be more energy-efficient for cooling small spaces. They use less electricity compared to central systems, which can lead to lower energy bills, especially if you’re only cooling a few rooms.
  • Easy Installation: These units are designed for DIY installation. You can easily install or remove a window air conditioner without specialized tools or skills.
  • Affordability: Window units are generally less expensive than central air conditioning systems, both in terms of initial purchase and installation costs.
  • Suitability for Non-Permanent Residences: For renters or individuals living in temporary housing, window units offer a practical cooling solution that can be taken along when moving.

Window Unit Cons

  • Limited Cooling Area: Window air conditioners are designed to cool single rooms or small areas, making them less effective for larger homes or spaces.
  • Noise: Some window units can be quite loud during operation, which might be disruptive in quieter environments.
  • Obstruction of Views and Natural Light: These units can block natural light and views when installed in a window.
  • Potential Restrictions: In some apartments, dormitories, or neighborhoods with homeowners’ associations (HOAs), the use of window units might be restricted due to aesthetic or safety concerns.

Energy Efficiency and Cost Considerations

When choosing between central air conditioning and window units, understanding their energy efficiency and cost implications is crucial. Let’s delve into the specifics:

Energy Efficiency

Window Units: Typically, window AC units use between 500 and 1,440 watts of electricity​​. Their energy efficiency is especially noticeable when cooling single rooms or small spaces. They are ideal for targeted cooling without the energy expenditure of larger systems.

Central Air Conditioning: In contrast, a central air conditioner for an average-sized home uses about 3,500 watts​​. However, when cooling an entire home, central air can be more efficient overall. It eliminates the need for multiple window units, which, when added together, could surpass the energy usage of a single central system.

Long-Term Costs

  • Operating Costs: For central air conditioners, the higher initial investment is coupled with higher long-term operating costs. This includes energy consumption and maintenance. Regular professional maintenance is recommended to keep the system running efficiently.
  • Maintenance and Repair: Window units, while lower in maintenance needs, might require more frequent replacements than a well-maintained central system. If a window unit fails, replacing it is often more cost-effective than repairing it.
  • Energy Bills: The impact on energy bills will depend on usage. For large homes or those requiring consistent cooling in multiple rooms, central air can be more economical in the long run. For small apartments or homes where only one or two rooms need cooling, window units are typically more cost-effective.

Ideal Situations for Each System

When it comes to cooling your home, the choice between a central air conditioning system and window units depends largely on your specific situation. Here are some scenarios where each option might be more appropriate:

Central Air Conditioning: Best for Larger Homes and Permanent Residences

  • Whole-Home Cooling: Central air is ideal for homes with multiple rooms that need consistent cooling. It’s especially beneficial in larger homes where window units would struggle to maintain a uniform temperature throughout.
  • Permanent Residences: For homeowners, investing in a central air conditioning system can be a wise long-term decision. Not only does it improve living comfort, but it also adds value to the property.
  • Homes with Existing Ductwork: If your home already has ductwork due to a forced-air heating system, installing central air conditioning becomes more straightforward and cost-effective.
  • Concerns about Aesthetics and Noise: Central air conditioners are less obtrusive and quieter compared to window units, making them a good choice for those concerned about the appearance and noise level in their living space.

Window Units: Ideal for Smaller Spaces, Rentals, and Specific Cooling Needs

  • Small Apartments and Spaces: In smaller apartments or individual rooms where installing central air is impractical, a window unit can effectively cool the space needed.
  • Rentals and Temporary Residences: For renters or those in temporary housing, window units offer flexibility. They can be installed and removed easily, making them a practical choice for non-permanent living situations.
  • Targeted Cooling Needs: If you only need to cool a specific area of your home, like a bedroom or home office, a window unit can be an efficient and economical choice.
  • Budget Constraints: When the budget is a primary concern, window units provide a cost-effective solution. They offer cooling relief without the significant investment required for central air conditioning.

Each air conditioning system has its unique advantages, and the best choice depends on factors like the size of your home, your lifestyle, and your cooling needs. Consider these scenarios to determine which system aligns best with your specific situation.

Maintenance and Lifespan

Proper maintenance is key to maximizing the lifespan and efficiency of both central air conditioners and window units. Here’s what you need to know about maintaining these systems:

Central Air Conditioning Maintenance

  • Regular Check-Ups: Central air conditioning systems should be professionally inspected at least once a year. These check-ups involve examining the system’s components, including the condenser unit, evaporator coil, and thermostat, to ensure everything is functioning correctly.
  • Cleaning and Replacing Filters: One of the most crucial maintenance tasks is regularly cleaning or replacing the air filters. This should be done every 1-3 months, depending on usage and environment, as dirty filters can reduce system efficiency and air quality.
  • Duct cleaning: Although not needed as frequently, duct cleaning is important to maintain air quality and system efficiency. Ducts should be inspected and cleaned as needed to remove dust, debris, and potential obstructions.
  • Professional Servicing: Beyond DIY maintenance, annual or bi-annual servicing by a professional is recommended to handle more complex aspects like refrigerant levels and electrical connections.

Window Unit Maintenance

  • Regular Cleaning: Window units need regular cleaning to ensure efficient operation. This includes cleaning the air filter monthly and the condenser coils and evaporator annually.
  • Winter Storage: If applicable, window units should be removed and stored during the winter to protect them from harsh weather conditions.
  • Check for Seals and Damage: Regularly check the seals between the air conditioner and the window frame to ensure there are no air leaks. Also, inspect for any signs of damage or wear that could impact performance.

Lifespan Considerations

  • Central Air Conditioning: With proper maintenance, central air conditioning systems can last 15-20 years. However, their efficiency can diminish over time, which might warrant a replacement even if the system is still functional.
  • Window Units: Window air conditioners typically have a shorter lifespan, ranging from 10-15 years. Their longevity can be influenced by how well they are maintained and the environment in which they are used.

Regular maintenance is essential for both types of air conditioning systems to ensure they operate efficiently and have a long service life. By adhering to a routine maintenance schedule, you can prevent common issues and extend the lifespan of your air conditioning unit, whether it’s a central system or a window unit.

Central Air vs. Window Units: Comparison Overview


Central Air Conditioning

Window Units

  • Whole-home cooling
  • Improved air quality
  • Noise reduction
  • Adds value to home
  • Energy efficiency
  • Easy installation
  • Affordability
  • Suitable for non-permanent residences
  • Higher installation and maintenance costs
  • Space requirements for installation
  • Complex installation process
  • Limited to cooling small spaces
  • Potential noise issues
  • Blocks natural light
  • May face restrictions in certain living situations
Energy Efficiency and Cost While central systems have higher energy consumption, they are more efficient for cooling an entire home. Window units use less energy individually, but multiple units may be required to cool several rooms.
Ideal Situations Best for larger homes or permanent residences where whole-home cooling is needed. Suited for smaller spaces, individual rooms, or rentals where temporary or localized cooling is sufficient.
Maintenance and Lifespan Requires regular professional check-ups and cleaning. Generally lower maintenance, but annual cleaning of filters and coils is recommended.

Choosing the Right Air Conditioning System and Next Steps

When selecting between central air conditioning and window units, consider your space size, cooling requirements, and budget. Central air is ideal for comprehensive, whole-home cooling, especially in larger spaces, while window units offer flexibility and cost-effectiveness for smaller areas or specific cooling needs.

For expert guidance on making the best choice and ensuring professional installation, LEGACY is your go-to resource. With their experience and knowledge, we can help you navigate these options and find the perfect solution for your home’s unique needs.

Ready to make your home more comfortable? Contact LEGACY for personalized advice and top-quality air conditioning solutions.

Share this post