A close-up of an air conditioner's outdoor unit.

What Size AC Unit Do I Need?

Choosing the right size AC unit for your home is an important endeavor. If your air conditioner is too small, it won’t adequately cool your home, leading to higher energy bills and discomfort. Conversely, an oversized unit will cycle on and off frequently, wasting energy and causing wear and tear on the system. So, how do you determine what size AC unit you need?

In this blog, we’ll guide you through the factors that influence AC unit sizing and help you make an informed decision.

Understanding AC Unit Sizes

AC unit sizes are typically measured in tons or British Thermal Units (BTUs). One ton equals 12,000 BTUs. The size you need depends on the cooling capacity required for your home, which is influenced by several factors, including the square footage, ceiling height, insulation, and sun exposure of your living space.

Factors Influencing AC Unit Sizes

A properly sized air conditioner system boasts many benefits; for starters, it will operate more efficiently, use less energy, and potentially help save you money on your utility bills. So, you’re probably asking, “What size air conditioner do I need?” Several variables can affect the size of the air conditioner you need:

Square Footage

The total square footage of your home is the primary factor in determining the size of the AC unit. Generally, you need about 20 BTUs per square foot. For instance:

  • What size AC unit for 1400 square feet? A home of this size typically requires an AC unit with a capacity of around 28,000 BTUs (2.5 tons).
  • What size AC unit for 1000 square feet? This size of the home usually needs an AC unit with a capacity of 20,000 BTUs (1.5 tons).

Ceiling Height

Higher ceilings mean more space to cool. If your home has high ceilings, you’ll need a larger AC unit compared to a home with standard eight-foot ceilings.


A well-insulated house retains cool air more effectively, reducing the demand on your AC unit. Homes with poor insulation may require a larger unit to maintain a comfortable temperature.

Sun Exposure

Homes with large windows or significant sun exposure, especially in warmer climates, will require a more powerful AC unit to offset the extra heat.

Number of Occupants

The number of people living in your home also affects the cooling load. People generate heat, so more occupants mean more cooling is needed.


Always assess your ductwork capacity when sizing a new AC unit. For example, installing a larger AC unit than your ductwork can support will reduce airflow, causing the system to freeze. So, it’s important that your existing ductwork can support the airflow produced by your new AC unit.

The Importance of Energy Efficiency

When considering what size air conditioner you need, it’s essential to think about energy efficiency. Look for units with a high Seasonal Energy Efficiency Ratio (SEER). A higher SEER rating means the unit is more efficient, which can save you money on energy bills over time.

Energy Star Label

Air conditioners with the Energy Star label meet strict energy efficiency guidelines set by the EPA and the Department of Energy. These units are specially designed to use less energy, reduce greenhouse gas emissions, and lower your utility bills.

Calculating the Right Size AC Unit

So, what size air conditioner do you need? To properly determine the answer to this question, you can use a Manual J calculation. This involves measuring the various factors that affect your home’s cooling load, such as square footage, insulation, windows, and more. While this method provides a precise calculation, it can be complex. Hiring a professional HVAC contractor to perform this calculation can guarantee you get the right size unit for your home.

Why AC Unit Sizes Matter

Choosing the right size AC unit is critical for several reasons:

Energy Efficiency

As we already mentioned, an appropriately sized unit runs more efficiently, using less energy to cool your home. This can result in lower energy bills and a reduced carbon footprint.


A properly sized AC unit will maintain a consistent, comfortable temperature throughout your home. An undersized unit may struggle to keep up on hot days, while an oversized unit can cause uneven cooling and humidity issues.


AC units that are the correct size will operate within their optimal range, reducing wear and tear and extending the system’s lifespan. Overworking a small unit or constantly cycling a large unit can lead to more frequent repairs and a shorter lifespan.

Cost Savings

While a larger unit may seem like a better option, it will cost more to purchase and operate. An oversized unit can also lead to higher energy bills due to frequent cycling. By choosing the right size air conditioner, you can save money upfront and in the long run.

Tips for Maintaining Your AC Unit

Once you’ve chosen the right size AC unit, regular maintenance is essential to keep it running efficiently:

  • Change Air Filters: Replace or clean the air filters every one to three months to confirm good airflow and reduce strain on your system.
  • Schedule Regular Inspections: Have a professional inspect and service your AC unit on an annual basis to identify and address any issues before they become major problems.
  • Keep the Outdoor Unit Clean: Check that the outdoor unit is clean and free of debris, leaves, and dirt. This simple task can help maintain optimal airflow and efficiency.
  • Use a Programmable Thermostat: A programmable thermostat can help you control your home’s temperature more efficiently, reducing energy usage and costs.

What Size AC Unit Do You Need If Your Home Has High Ceilings?

If your home has high ceilings, you’ll need a larger AC unit to cool the additional space. Add approximately 10% more capacity for ceilings higher than 8 feet.

What Size Air Conditioner Do You Need for Multiple Rooms?

If you have multiple rooms or zones, consider a central AC system with a zoning feature. This allows you to control the temperature in different areas independently, improving comfort and efficiency.

Install a New Air Conditioning Unit With JJ&A Mechanical!

So, what size AC unit do you need? As you can see, answering this question involves considering several factors, including your home’s square footage, ceiling height, insulation, sun exposure, and number of occupants. By understanding these factors and calculating the appropriate cooling capacity, you can choose an efficient, effective air conditioning system that keeps your home comfortable while minimizing energy costs.

Ready to upgrade your cooling system or need help figuring out what size air conditioner you need? JJ&A Mechanical is here to assist. Our expert team can perform a comprehensive assessment of your home’s cooling needs and recommend the perfect AC unit size for maximum efficiency and comfort.

Contact JJ&A Mechanical today to schedule your appointment in Vancouver! We’re here to make sure your home stays cool and comfortable all summer long with a reliable air conditioner.

A man wiping sweat off his forehead as he adjusts a thermostat.

Top 10 Common Air Conditioner Problems and Solutions

We rely on our air conditioners to keep us cool and comfortable, so it’s important to understand what can go wrong with them and how to fix these issues. In this blog, we’ll cover the top ten common air conditioner problems and their solutions. Whether you’re dealing with minor AC issues or more significant air conditioning problems, having the right knowledge can help you manage them effectively.

Refrigerant Leaks

Refrigerant leaks are one of the more common air conditioner problems. When your AC system is low on refrigerant, it can’t cool your home properly. Signs of a refrigerant leak include ice buildup on the evaporator coils, reduced cooling efficiency, and higher energy bills.

How to Identify and Fix a Refrigerant Leak

To identify a refrigerant leak, look for ice on the coils, listen for a hissing sound, or check for reduced cooling output. Because handling refrigerants requires special training and certification, it’s crucial to call a professional for repair. A technician will fix the leak and recharge the refrigerant to the proper levels.

One of the most frustrating air conditioner issues is when it blows warm air instead of cool air. This can make your home uncomfortable, especially during the summer. If you think a refrigerant leak is to blame, don’t hesitate to turn to an expert for help.

Dirty or Clogged Filters

Dirty or clogged air filters are a frequent cause of air conditioner issues. When air filters are clogged, they reduce airflow, causing the AC unit to work harder and less efficiently. This can lead to higher energy consumption and even system failure.

Steps for Replacing or Cleaning a Dirty Air Filter

To keep your AC running efficiently, replace or clean the filters regularly. Here’s how:

  1. Turn off the AC unit.
  2. Locate the filter (usually found behind the return air grille, inside the blower compartment, or in a slot on the side of the unit).
  3. Remove the old filter.
  4. If it’s a reusable filter, clean it with water and let it dry completely before reinstalling. If it’s disposable, replace it with a new one.
  5. Insert the clean or new filter back into the unit, following the arrows for proper airflow direction.

Thermostat Issues

Thermostat problems can lead to improper temperature readings and cause your AC to cycle on and off incorrectly. This is one of the common AC problems that can be frustrating and lead to discomfort in your home.

Troubleshooting Thermostat Problems

Do you think thermostat troubles could be at the root of your air conditioner issues? First, check that the thermostat is set to the correct temperature. If the problem persists, try recalibrating or resetting it according to the manufacturer’s instructions. If the thermostat is old or malfunctioning, consider replacing it with a newer, programmable model for better accuracy and energy efficiency.

Electrical Control Failures

Electrical control failures are common air conditioner problems that manifest as frequent cycling or the system not turning on at all. These issues are often due to wear and tear on electrical connections and contacts within the unit.

How to Address Electrical Issues Safely

It’s best to call an HVAC professional to handle electrical control failures. They can safely inspect and repair electrical components, guaranteeing your system operates correctly. Regular maintenance can also help prevent these problems by catching issues early.

Drainage Problems

Proper drainage is essential for air conditioning units to function correctly. When the condensate drain line is clogged, it can cause water leaks and damage to the system.

Clearing Clogged Condensate Lines

Are you concerned about your air conditioner leaking water? To prevent drainage problems:

  1. Turn off the AC unit.
  2. Locate the condensate drain line (a PVC pipe usually connected to the indoor unit).
  3. Use a wet/dry vacuum to clear any blockages in the line.
  4. Flush the drain with a mixture of water and vinegar to remove any remaining debris. Regularly checking and cleaning the condensate drain can prevent clogs and water damage.

Capacitor Problems

Capacitors are vital components in your air conditioning unit, providing the necessary energy to start the motor and keep it running. When capacitors fail, it can cause hard starting, frequent system shutdowns, or even total system failure.

Diagnosing and Replacing Capacitors

Is your AC not turning on? Check your electrical panel for a tripped circuit breaker. If that’s not the problem, the issue could be with the thermostat or the power supply.

If you suspect a capacitor problem, listen for clicking sounds from the unit. Because capacitors store electrical energy, handling them can be dangerous. It’s best to call a professional to diagnose and replace a faulty capacitor.

Compressor Troubles

The compressor is the heart of your AC system, responsible for circulating refrigerant and maintaining pressure. Compressor problems can lead to warm air blowing from your vents or unusual noises from the outdoor unit.

Repairing or Replacing a Malfunctioning Compressor

If you suspect compressor issues, it’s essential to call a technician immediately. They can determine whether the compressor can be repaired or if it needs replacement. Regular maintenance can help prevent compressor failure by keeping the system clean and properly charged with refrigerant.

Fan Malfunctions

Fans in your AC system are responsible for moving air over the evaporator coils and blowing it into your home. When fans malfunction, it can reduce air circulation and cooling efficiency.

Inspecting and Repairing Fan Issues

To inspect a fan problem:

  1. Turn off the AC unit.
  2. Remove the access panel to locate the fan.
  3. Check for loose or damaged blades and listen for unusual noises.
  4. Tighten any loose screws or replace damaged blades. If the motor is the issue, contact an HVAC professional to replace it.

Coil Blockages

Coils in your AC system can become blocked with dirt and debris, reducing efficiency and causing the system to overheat. This is one of the common air conditioner problems that can be easily avoided with regular maintenance.

Cleaning Coils to Restore Efficiency

To clean the coils:

  1. Turn off the AC unit.
  2. Remove the access panel to locate the evaporator and condenser coils.
  3. Use a soft brush or vacuum to remove dust and debris.
  4. For deeper cleaning, use a coil cleaner spray, following the manufacturer’s instructions. Regularly cleaning the coils can prevent blockages and keep your system running efficiently.

General Wear and Tear

Over time, wear and tear on your AC system can lead to various issues, from reduced efficiency to component failure. Regular maintenance is key to preventing these problems and extending the life of your system.

Benefits of Professional HVAC Inspections and Tune-Ups

Having your AC system professionally maintained at least once a year can help catch potential issues before they become major problems. A professional can inspect, clean, and tune up your system, making sure it operates at peak efficiency and reduces the risk of unexpected breakdowns.

Schedule Your AC Services With JJ&A Mechanical!

Understanding common air conditioner problems and their solutions can help you keep your home cool and comfortable all summer long. Regular maintenance, timely repairs, and professional inspections are crucial to extending the life of your AC system and avoiding inconvenient breakdowns.

If you’re experiencing any of these air conditioning problems or need a professional to inspect your system, don’t hesitate to schedule your HVAC repair with JJ&A Mechanical. Our experienced technicians can diagnose and repair any air conditioner issues, keeping your home cool and comfortable when you need it most.

Now that you know the most common AC problems and solutions, why wait to get the assistance you need? Contact us today to book your air conditioner repair service and keep your system running smoothly all season long!