The Ultimate Guide to Buying a Restaurant Hood

Fire safety and legal compliance are two of the biggest responsibilities for any restaurant owner. In a busy kitchen, the greatest risks often come from the very equipment you rely on. Airborne grease particles can build up in your ventilation system, creating a serious fire hazard. That’s why a high-quality restaurant hood isn't just a piece of equipment—it's your first line of defense. It’s also a non-negotiable requirement to meet local fire and health codes. This article breaks down the essential safety standards, explains how to choose a compliant system, and covers the features that will protect your staff, your property, and your investment.

Key Takeaways

• View Your Hood as a Safety System First: Its primary job is to prevent fires and ensure you meet legal codes; think of it as a critical safety investment, not just another appliance.
• Match the Hood to Your Kitchen's Specific Needs: The right choice depends on your kitchen's layout (wall-mounted vs. island) and must be sized to overhang all cooking equipment by at least six inches for effective ventilation.
• Budget Beyond the Sticker Price: The true cost of a hood includes the unit, professional installation to meet code, and a consistent maintenance schedule to ensure it runs safely and efficiently for years.

What is a Restaurant Hood? (And Why You Absolutely Need One)

Think of a restaurant hood as the unsung hero of your commercial kitchen. It’s the large, canopy-like appliance installed directly above your cooking equipment—like your ranges, grills, and deep fryers—and it does a whole lot more than just hang there. Its main job is to act as a powerful ventilation system, pulling heat, smoke, steam, grease, and cooking odors out of the air. By capturing these elements at the source, the hood prevents them from spreading throughout your kitchen and into your dining area. This process keeps your kitchen air cleaner, cooler, and safer for everyone working in it.

A proper hood system is not just a recommendation; it's a fundamental piece of equipment for any professional foodservice operation. It plays a critical role in fire safety, employee health, and meeting legal requirements. Without one, you risk creating a dangerous and unpleasant work environment, not to mention facing potential fines or shutdowns. It's an investment in the safety of your property, the well-being of your staff, and the longevity of your business. Let’s break down exactly why this piece of equipment is so essential.

Stay Safe and Compliant

First and foremost, a restaurant hood is a critical safety device. As you cook, tiny particles of grease become airborne and can build up on your walls, ceilings, and other equipment, creating a serious fire hazard. A hood is specifically designed to capture these flammable materials before they can settle. It effectively removes the grease-laden vapor, heat, and smoke from the air, drastically reducing the risk of a fire.

Beyond safety, installing the right hood is a matter of legal compliance. Local health and fire departments have strict commercial kitchen hood code requirements that dictate the size, placement, and power of your ventilation system. These regulations are in place to ensure your kitchen operates safely. Failing to meet them can result in failed inspections, hefty fines, or even a forced closure of your business.

Protect Your Team's Health

A busy kitchen produces a lot of airborne particles that can make the air difficult and unhealthy to breathe. A quality hood system is essential for maintaining good air quality, which directly impacts the health and comfort of your kitchen staff. By constantly removing smoke, steam, and strong odors, the hood creates a much more pleasant and safer working environment. This helps prevent respiratory irritation and keeps your team feeling more comfortable during long, demanding shifts.

Neglecting your hood system can lead to more than just poor air quality; it can create genuinely unsafe working conditions. A system clogged with grease doesn't just become a fire risk—it also stops working efficiently, leaving the air thick and hot. Regular cleaning and maintenance are key to ensuring your hood is always protecting your team and keeping your kitchen a healthy place to work.

Find the Right Hood for Your Kitchen

Choosing the right restaurant hood isn't just about picking a piece of equipment; it's about matching the ventilation system to your kitchen's unique layout and workflow. The arrangement of your cooking appliances is the single most important factor in determining which type of hood you need. A hood that’s a perfect fit for a long line of fryers against a wall will be completely wrong for a central cooking island. Getting this choice right from the start ensures your kitchen stays clear of smoke, grease, and excess heat, creating a safer and more comfortable environment for your staff.

Think of it as the lungs of your kitchen—it needs to be the right size and shape to breathe properly. A well-chosen hood improves air quality, reduces fire risk, and helps you stay compliant with health and safety codes, which is a non-negotiable part of running a successful foodservice business. As you explore your options, you'll find that different designs are built to handle specific spatial challenges, from tight corners to open-concept spaces. Let's walk through the most common types so you can find the perfect match for your restaurant equipment setup.

Wall-Mounted Hoods

If your ranges, griddles, and fryers are lined up against a wall, a wall-mounted hood is your go-to solution. This is one of the most common and effective designs for commercial kitchens. Installed directly on the wall above your cooking line, it creates a canopy that efficiently captures heat, smoke, and grease-laden vapors right at the source. Because they are flush against a wall, they are excellent for maximizing your kitchen's floor space, leaving more room for prep areas and foot traffic. Their straightforward design makes them a reliable and cost-effective choice for many restaurant layouts, from bustling diners to cozy cafes. They are built to handle the high-volume output from heavy-duty appliances like commercial deep fryers.

Island Hoods

For kitchens with a central cooking station or an open-concept design, an island hood is essential. Unlike wall-mounted versions, these hoods are suspended from the ceiling directly over a cooking island. They are larger and more powerful because they need to capture air from all directions, providing 360-degree coverage. This makes them incredibly effective at preventing smoke and odors from spreading throughout an open kitchen or into the dining area. Island hoods often become a visual centerpiece, so they come in a variety of styles to match your restaurant's aesthetic. If your kitchen layout is built around a central hub of activity, an island hood is the only option that will provide the comprehensive ventilation you need.

Under-Cabinet Hoods

When space is at a premium, an under-cabinet hood can be a smart solution. These compact units are designed to fit neatly beneath a cabinet or a low ceiling, making them ideal for smaller kitchens, food trucks, or specific, smaller-scale cooking stations within a larger kitchen. They are perfect for placement over countertop equipment or a small range that doesn't require a full-sized canopy hood. Under-cabinet hoods can be designed to vent air outside or, in some cases, to filter and recirculate it back into the room. This flexibility makes them a practical choice for areas where extensive ductwork isn't feasible, providing targeted ventilation right where you need it.

Custom Hoods

Sometimes, a standard hood just won't cut it. If your kitchen has an unusual layout, architectural challenges like low or sloped ceilings, or a unique arrangement of cooking equipment, a custom hood is the answer. These are tailor-made to your exact specifications, ensuring a perfect fit and optimal performance for your space. A custom hood allows you to address both functional and aesthetic needs, whether that means building a system that wraps around a corner or designing a statement piece for an exhibition kitchen. While they typically require a larger investment and more planning, they provide a bespoke solution that guarantees your ventilation system works flawlessly with your kitchen's specific design.

Key Features to Look For in a Restaurant Hood

Once you know which type of hood fits your kitchen's layout, it's time to get into the details. The specific features of a restaurant hood are what determine its performance, longevity, and overall value. Paying close attention to these key elements will help you choose a system that works efficiently, keeps your kitchen safe, and saves you money in the long run. Think of it as choosing the engine for your car—the right one makes all the difference.

Get the Right Airflow (CFM)

The single most important job of your hood is to pull smoke, heat, and grease out of the air. Its power to do this is measured in cubic feet per minute, or CFM. A higher CFM means more air is moved every minute. The right CFM for your kitchen depends entirely on the heat and fumes your cooking equipment produces. A lineup of high-output deep fryers and charbroilers will require a much more powerful fan than a small oven. Matching the hood’s CFM to your appliances ensures it can effectively capture everything, keeping your kitchen air clean and comfortable.

Find the Perfect Size and Fit

For a hood to work properly, it needs to be the right size and in the right place. As a rule of thumb, your hood should extend beyond your cooking equipment on all open sides. This overhang creates a capture zone that prevents smoke and grease from escaping into the kitchen. Local fire and safety regulations often have strict requirements for hood size and placement, so this isn’t just a suggestion—it’s a matter of compliance. An undersized or poorly placed hood is inefficient and can lead to safety violations, so measure your space carefully and always check your local codes.

Consider Materials and Grease Filters

A commercial kitchen is a tough environment, so your hood needs to be built to last. Most commercial hoods are made from stainless steel because it’s durable, heat-resistant, and easy to clean. The thickness of the steel used for the hood and its ducts is also a critical factor for safety and code compliance. Just as important are the grease filters. These metal baffles are your first line of defense, trapping airborne grease before it can build up in your ductwork and become a fire hazard. High-quality filters are essential for maintaining good air quality and protecting your entire ventilation system.

Look for Energy-Saving Features

While it might not be the first thing you think of, a hood’s energy consumption can have a real impact on your utility bills. Modern hoods are often designed with energy efficiency in mind. Look for models with high-efficiency motors, like DC or electronically controlled motors (ECMs), which use significantly less power to operate. Some advanced systems even include variable speed controls that automatically adjust fan power based on how much cooking is happening. Investing in these energy-saving features can lead to substantial cost savings over the life of the hood, making it a smart choice for your budget and the environment.

How to Size Your Restaurant Hood Correctly

Getting the size of your restaurant hood right is one of the most important decisions you'll make for your kitchen. It’s not just about fitting it into the available space; it’s about ensuring it can effectively do its job of capturing heat, smoke, and grease. A hood that’s too small will leave your kitchen hazy and can even become a safety hazard. On the other hand, an oversized hood can be an unnecessary expense. Think of it like buying a pair of shoes—the right fit makes all the difference for performance and comfort. Let's walk through the two key factors you need to get right: coverage and make-up air.

Cover Your Cooking Equipment

Your restaurant hood should act like a giant umbrella, catching everything that rises from your cooking surfaces. To do this effectively, it needs to be larger than your cooking area. The standard rule is to have the hood overhang all your cooking appliances by at least six inches on each side. This overhang creates a buffer zone, ensuring that any smoke or grease-laden vapor that drifts sideways is still captured before it can escape into your kitchen. Sizing your hood correctly is essential for maintaining air quality, preventing grease buildup on your walls and ceilings, and creating a safer, more comfortable environment for your team.

Calculate Your Make-Up Air Needs

For every bit of air your exhaust hood pulls out of the kitchen, you need to bring an equal amount of fresh air back in. This is called make-up air, and it's critical for a balanced and safe kitchen environment. Without a proper make-up air system, your kitchen can develop negative air pressure. This can cause all sorts of problems, from pilot lights blowing out to doors becoming difficult to open and even exhaust fumes being pulled back into the building. Calculating your make-up air needs depends on your hood's exhaust volume (CFM), your kitchen's size, and the type of cooking you do. Properly investing in a complete system that includes make-up air is non-negotiable for a functional commercial kitchen.

What's the Real Cost of a Restaurant Hood?

When you start shopping for a restaurant hood, it’s easy to get fixated on the sticker price. But the real cost of ownership goes far beyond that initial number. To budget accurately, you need to think about three key areas: the price of the unit itself, the cost of professional installation, and the ongoing expenses for maintenance and operation. It’s a significant investment, but it’s one of the most critical pieces of equipment for keeping your kitchen safe, clean, and compliant with health codes. A properly functioning hood protects your staff from harmful grease-laden vapors and reduces the risk of a kitchen fire, making it a non-negotiable part of your setup.

Understanding the full financial picture from the start helps you make a smart decision for your restaurant's future. It prevents sticker shock when the installation quote comes in and ensures you're prepared for the long-term upkeep. If the total investment feels like a stretch for your current budget, remember that options like restaurant equipment financing can help you get the high-quality system you need without a massive upfront cash outlay. By planning for all these costs, you can avoid surprises and ensure your kitchen ventilation system is an asset, not a financial drain.

Upfront Purchase Price

Let's talk numbers. You can expect to spend anywhere from $1,000 to $10,000 for a basic commercial kitchen hood. This wide range exists because the price depends heavily on the hood’s type, size, and features. A simple wall-mounted canopy hood for a small cafe will be on the lower end of that spectrum, while a large, custom-designed island hood for a high-volume kitchen will be at the top. Factors like the brand, the type of filtration system, and whether it includes a built-in fire suppression system will also influence the final cost. When you shop for restaurant equipment, be sure to compare models that fit your specific cooking line and kitchen layout to find the best value.

Factoring in Installation Costs

The price of the hood itself is just one part of the equation. Installation is a separate and substantial cost that you must factor into your budget. This isn't just about paying someone to hang the hood on the wall. Professional installation includes the cost of labor, all the necessary ductwork to carry air outside, the ventilation fans that power the system, and the required permits and inspections to ensure everything is up to code. This is definitely not a DIY project. A professional installer will make sure your system is safe, efficient, and compliant with local regulations, saving you from major headaches and potential fines down the road.

Planning for Maintenance and Running Costs

Once your hood is up and running, you’ll have ongoing costs to keep it in top shape. Regular maintenance is essential for performance and safety, and you should budget around $200 to $500 per year for professional cleaning and inspections. Neglecting this can lead to serious problems. As cleaning professionals point out, skipping maintenance can cause costly repairs and create unsafe working conditions for your team. Beyond professional servicing, you'll also need to account for the cost of replacing filters and the energy your ventilation system uses daily. Planning for these recurring expenses ensures your hood operates efficiently for years to come and protects your initial investment.

A Look at Top Restaurant Hood Brands

Once you know what type of hood you need, it’s time to look at brands. The right brand can make all the difference in performance, reliability, and long-term value. There are several key players in the commercial kitchen ventilation space, each with its own strengths. Let's walk through a few of the top names you’ll encounter so you can feel confident in your choice.

The Restaurant Warehouse Selection

Here at The Restaurant Warehouse, we know that every kitchen has unique demands. That’s why we offer a wide variety of commercial kitchen equipment, including high-quality restaurant hoods. We focus on helping you find the perfect solution, whether you need a standard size or a custom build. Our team can help you consider all the important factors, from the type of cooking you do to your local building codes, ensuring you get a hood that fits your space and your budget perfectly. We believe in providing affordable, quality equipment to help your business thrive.

Captive-Aire Systems

You can’t talk about kitchen ventilation without mentioning Captive-Aire. They have earned a reputation as a leader in the industry, known for their innovative and energy-efficient designs. They offer complete ventilation systems, which include not just the exhaust hood but also make-up air units and fire suppression. Restaurant owners often choose Captive-Aire because their products are built to meet the highest standards for both performance and safety, giving you peace of mind that your kitchen is well-protected and running efficiently.

Greenheck Ventilation

Greenheck is another top-tier brand that specializes in all things air movement. Their hoods are engineered for high efficiency, packed with advanced features like superior grease extraction to keep your ductwork cleaner. Greenheck really focuses on how proper ventilation creates a safer and more comfortable kitchen for your staff. Their kitchen ventilation products are a popular choice in commercial kitchens everywhere because they are reliable, powerful, and designed to handle the demands of a busy restaurant environment.

Halton Commercial Hoods

If energy efficiency and sustainability are high on your priority list, Halton is a brand you’ll want to check out. They are known for their high-quality ventilation solutions that incorporate advanced technology to reduce energy use without sacrificing performance. This can lead to significant savings on your utility bills over time. Halton’s commercial kitchen ventilation systems are versatile and can be found in all types of settings, from casual diners to upscale restaurants, making them a smart choice for the modern, eco-conscious kitchen.

Stay Compliant: Regulations and Safety Standards to Know

Buying the right hood is only half the battle; installing it correctly is the other. The world of codes and regulations can feel overwhelming, but it’s a non-negotiable step for keeping your kitchen safe, your staff protected, and your business open. Think of these rules not as hurdles, but as a clear roadmap to a safe and efficient kitchen. Getting compliance right from the start saves you from costly fines, failed inspections, and the major headache of having to redo your installation. It all comes down to understanding a few key sets of standards from national organizations and your local authorities. Before you finalize any purchase, make sure you know exactly what your kitchen needs to pass inspection with flying colors. This knowledge will help you and your installer choose and set up the perfect system.

Meet NFPA 96 Requirements

If there’s one code to know, it’s NFPA 96. The National Fire Protection Association sets the standard for ventilation control and fire protection in commercial cooking operations. This guide is the foundation for most local fire codes, so understanding its basics is essential. NFPA 96 covers everything from the design of your hood and grease removal devices to the construction of your ducts and the placement of your exhaust fan. Its primary goal is to mitigate fire hazards by ensuring every part of your exhaust system works together to effectively and safely remove grease-laden vapors. Adhering to these requirements is your first line of defense against a kitchen fire.

Check Local Fire Codes and Get Permits

While NFPA 96 provides the national framework, your local fire marshal and building department have the final say. Local fire and safety regulations are often based on NFPA standards but may include additional rules specific to your city or county. These codes will dictate the minimum size and placement of your hood, ensuring it’s installed correctly to meet safety standards. Before you even think about installation, you’ll need to secure the proper permits. This process usually involves submitting your plans for review. Contacting your local officials early is one of the smartest moves you can make. They can provide a checklist of requirements, saving you time and preventing costly mistakes.

Follow Rules for Placement and Materials

The specific details of your installation matter—a lot. Codes are very clear about how your hood should be positioned and what it should be made of. For instance, a critical rule is that the inner edge of your commercial hood must extend at least six inches beyond your cooking equipment on all open sides. This overhang is crucial for capturing heat, smoke, and grease effectively. The materials used are just as important. Ducts connected to a Type I hood, which handles grease, must be made from durable materials like steel or stainless steel of a specific thickness to withstand high temperatures and prevent fire from spreading. Following these placement and material rules is essential for a safe and compliant kitchen.

Common Challenges of Restaurant Hood Installation

Installing a restaurant hood is a bit more involved than just hanging it on the wall. It’s a major project that comes with its own unique set of hurdles. From navigating tight spaces to dealing with strict safety codes, being aware of these common challenges will help you plan a smoother, more successful installation.

Dealing with Space and Ductwork

One of the biggest headaches during installation is simply finding the space. Kitchens are often cramped, and you’ll need to fit the hood and its extensive ductwork around existing equipment, pipes, and structural elements. A poor layout can lead to inefficient airflow and create serious safety hazards. For example, ducts installed without proper access doors are difficult to clean, while those placed too close to heat sources can become a fire risk. It’s crucial to plan a path for your ductwork that is both efficient and safe, ensuring it properly vents smoke and grease out of your kitchen.

Why You Need a Professional Installer

While a DIY approach can be tempting for some projects, restaurant hood installation isn’t one of them. This is a job for a certified professional, period. Common mistakes like choosing the wrong size hood or miscalculating airflow can render your entire system ineffective, leaving your kitchen full of smoke and grease. An improperly installed hood not only fails to do its job but also poses a significant fire risk. A professional installer ensures your system is sized correctly, has adequate airflow, and captures contaminants effectively, protecting your staff, your customers, and your investment.

Getting Through Permits and Inspections

Before you can even begin installation, you’ll need to work through local permits and regulations. Every jurisdiction has its own set of strict fire and safety codes that dictate everything from the hood’s minimum size and placement to the exact type of steel required for the ductwork. These rules can be complex and vary significantly from one city to the next. A professional installer will be familiar with the local code requirements in your area, helping you avoid costly mistakes and ensuring your kitchen passes inspection without any delays.

Your Guide to Restaurant Hood Maintenance

Once your new restaurant hood is installed, the work isn’t over. Proper maintenance is the single most important thing you can do to protect your investment, ensure your kitchen is safe, and keep your system running efficiently for years. A neglected hood isn’t just a performance issue; it’s a major fire hazard and can lead to health code violations. Creating a simple maintenance schedule—and sticking to it—will save you from costly repairs and keep your team safe. Think of it as a crucial part of your kitchen’s overall health and safety plan.

Daily Cleaning vs. Professional Service

Your maintenance plan should have two key parts: daily tasks for your staff and periodic deep cleans from a professional service. Your team should handle the daily upkeep, which includes wiping down the hood's interior and exterior surfaces to remove any fresh grease splatters and emptying the grease traps. This simple routine prevents heavy buildup and keeps the visible parts of your kitchen looking clean.

However, this daily wipe-down doesn't replace the need for a certified technician. Professional hood cleaners tackle the parts you can't see, like the exhaust fan, ductwork, and rooftop components. They use specialized tools and chemicals to remove the hardened, flammable grease that accumulates deep within the system. This service is essential for fire prevention and is required by law to keep your restaurant compliant with safety regulations.

When to Replace Your Filters

Your hood’s grease filters are the first line of defense, trapping airborne grease before it can enter your ductwork. Most modern kitchens use stainless steel baffle filters, which are durable and designed to be cleaned regularly. You should get your staff into the habit of running them through the dishwasher at the end of every day.

While these filters are built to last, they don’t last forever. It’s time for a replacement if you notice they are bent, warped, or have holes. Damaged filters create gaps that allow grease to bypass them and build up in the ducts, increasing your fire risk. If a filter is so clogged with baked-on grease that even a deep soak won't clear it, it’s time for a new one. You can find replacement filters and other essential restaurant equipment to keep your kitchen running smoothly.

Common Maintenance Myths, Busted

There are a few persistent myths about hood maintenance that can put your kitchen at risk. The most common one is that you only need to clean the system when you can see grease buildup. This is completely false. The most dangerous grease deposits are the ones you can’t see, hidden deep inside the ductwork.

Another misconception is that a quick cleaning once in a while is sufficient. In reality, the National Fire Protection Association (NFPA) has specific guidelines for cleaning frequency based on the type and volume of cooking. A restaurant that does a lot of high-heat cooking or uses solid fuel like a wood-fired oven will need professional cleaning far more often than a small café. Don’t guess—stick to a professional schedule to ensure you’re always safe and compliant.

Avoid These Common Mistakes When Buying a Hood

Choosing a restaurant hood is a major decision, and a few common missteps can lead to big headaches down the road. Getting it right from the start not only ensures your kitchen is safe and compliant but also saves you from costly fixes and operational disruptions. Let’s walk through the top three mistakes to avoid so you can invest with confidence.

Undersizing Your System

It can be tempting to choose a smaller, less expensive hood, but this is one of the most critical errors you can make. An undersized hood simply won’t do its job. As experts note, improper hood sizing directly affects the capture of smoke, heat, and grease-laden air from your cooking appliances. This failure leads to poor air quality, a greasy film covering every surface in your kitchen, and a serious fire hazard. To avoid this, make sure your hood extends at least six inches beyond your cooking equipment on all sides. This creates an effective capture zone, pulling contaminants up and out before they can escape into your kitchen.

Skipping Professional Installation

While a DIY approach might seem like a way to cut costs, installing a commercial kitchen hood is a complex job best left to the pros. One of the most common obstacles is dealing with limited space and intricate ductwork. A professional installer has the experience to handle these challenges and ensure your system is set up for optimal performance. They are also experts on local fire codes and permit requirements, which can save you from failed inspections and fines. Think of professional installation not as an expense, but as an investment in your restaurant’s safety and long-term compliance.

Forgetting About Long-Term Costs

The sticker price is only one part of the equation. The total cost of a restaurant hood includes the initial purchase, installation, and ongoing operational expenses. A cheaper unit might save you money upfront, but it could cost you more in the long run through higher energy bills and frequent repairs. Investing in an energy-efficient system can reduce your energy bills by up to 30% and extend the equipment's lifespan. When you're browsing for restaurant equipment, look for features like variable-speed fans and LED lighting. Planning for these long-term costs helps you make a smarter, more sustainable choice for your business.

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Frequently Asked Questions

What's the single most important thing to consider when choosing a hood? It all comes down to what you're cooking. The type and power of your cooking equipment dictate everything else—the hood's size, its airflow power (CFM), and the kind of filters you'll need. Before you even start looking at models, make a complete list of every appliance that will sit under the hood. That list is the foundation for every other decision you'll make.

What's the difference between a Type I and a Type II hood? The distinction is simple: Type I hoods handle grease, while Type II hoods handle heat and steam. If your equipment produces smoke and grease—like a fryer, grill, or range—you are required to have a Type I hood, which includes grease filters and is built for fire safety. Type II hoods are used over appliances like ovens or dishwashers that only release moisture and heat, not flammable grease.

How often do I really need to get my hood professionally cleaned? This isn't a one-size-fits-all answer, as the required frequency depends entirely on your cooking volume and style. A restaurant that does a lot of high-heat frying or charbroiling might need monthly service, while a small cafe might only need it quarterly. The National Fire Protection Association (NFPA) sets the standards, and your local fire department has the final say. A certified cleaning service can help you determine the right schedule to stay safe and compliant.

Can I save money by buying a used restaurant hood? While it might seem like a good way to cut costs, buying a used hood is a significant risk. You could be inheriting hidden problems like a damaged fan motor or internal grease buildup that's impossible to fully remove. More importantly, a used hood might not meet current local fire and health codes, which could prevent you from passing your inspection. If you do consider it, have a certified professional inspect the unit thoroughly before you commit.

Do I always need a make-up air unit with my hood? For nearly every commercial kitchen, the answer is a definite yes. Your hood is a powerful exhaust fan pulling huge volumes of air out of the building. A make-up air unit's job is to bring in fresh air to replace what's being removed, keeping the air pressure balanced. Without it, you can create a negative pressure environment that causes everything from doors that are hard to open to dangerous backdrafts from your gas appliances. It's a critical component of a safe and functional ventilation system.