What is HVAC

Well alrighty then, let’s not mince words or beat around the bush and let’s get to what you really need to know about “What is HVAC”. That’s all hand-jive.There’s no jibber jabber when we’re talkin’ comfort and control for your space.

What is HVAC? Your Home’s Unsung Hero (and How It Works)

Ever walk into a beautifully cooled room on a sweltering day, or feel that snug warmth fill your house when it’s bitterly cold? That magic, that feeling of just right, is thanks to HVAC. It’s more than just another clever acronym; it’s the brains and brawn behind your indoor comfort, air quality and, yes, even your good health. So, what is HVAC? — you’re about to get the lowdown.

HVAC is short for Heating, Ventilating, and Air Conditioning.It’s more than just another clever acronym; it’s the brains and brawn behind your indoor comfort, air quality and, yes, even your good health.all hand-jive.There’s no jibber jabber when we’re talkin’ comfort and control for your space.

What is HVAC? Your Home’s Unsung Hero (and How It Works)

Ever walk into a beautifully cooled room on a sweltering day, or feel that snug warmth fill your house when it’s bitterly cold? That magic, that feeling of just right, is thanks to HVAC. It’s more than just another clever acronym; it’s the brains and brawn behind your indoor comfort, air quality and, yes, even your good health. So, what is HVAC? — you’re about to get the lowdown.

HVAC is short for Heating, Ventilating, and Air Conditioning. Consider it the ultimate climate control system for your home, office or even your car. Its main gig? To provide you with thermal comfort and reliable indoor air quality that is acceptable. This is more than just cranking the AC or turning up the heat, it’s an entire system meant to keep things balanced, healthy and just good old fashioned comfy inside. It’s a subdiscipline of mechanical engineering drawing on things like thermodynamics, fluid mechanics and heat transfer. Pretty neat, right?

HVAC The Great Three: Heat, Ventilation, Air Conditioning

So, what is that dissect those three HVACs? It’s not just that they are — it’s how they dance together to keep your space dialed in.

Heating: Turning Up the Heat

As the mercury falls, your heating system takes over. All that does is create heat for a building. The majority of modern installations are based on a central system, which may be installed in a furnace or mechanical room.

This is how that warmth is made and spread:

Heat Source: Typically a boiler, furnace or heat pump. Those can operate on a host of fuels: solids, liquids, gases or electricity. Heat pumps, for instance, have become very popular since the 1950s, especially in countries such as Japan and the U.S.. So don’t decide you’re above these possibilities until you’ve had us investigate ones. Blocking out doors, windows, or furry friends isn’t the best strategy, as some of those locations benefit most from cool weather in the form of plenty of open airflow. VAN hook it up just right, with computerized efficiency and ultimate indoor comfort at the best price. 34 A bird in the rein summary The show that puts you at the centre of the conversation. They can also do that in reverse to provide cooling, which is extra handy.

Heat Distribution:

• Water/Steam (Hydronics) Some homes are heated using hot water or steam created in a boiler and circulated throughout the home to heat in radiators, under-floor heat coils or both. This is called hydronics.
• Air (Forced-Air Systems): You may have forced air systems today, which are very common, especially in churches, schools and high-end homes. Here, heated air is distributed through ductwork — metal or fiberglass pipes — to various rooms. A fan or blower pushes the warm air outward, and cooler air is sucked in through “return ducts” to be reheated. Which in many cases do duty as air conditioning as well. Air filters, that will usually be part of this installation to trap dust and pollen.

The Danger Lurking: If you have furnaces, space heaters, or boilers, you should know about the risk of incomplete combustion. This can expel nasty stuff like carbon monoxide (CO), nitrogen oxides, formaldehyde and all sorts of byproducts. Carbon monoxide is the enemy that you can’t see, smell, or taste – it can be deadly even at very low concentrations. At lower doses, it can still mess you up with headaches, fatigue and nausea. So, correct ventilation and functioning CO detectors? Non-negotiable.

Ventilation: Breathing Easy

Ventilation is all about keeping the air in your space fresh and clean. It’s the all-the-time air exchange that washes away stale air, brings in fresh outside air and pushes out pollutants, moisture, odors, smoke, heat, dust and, knocking on wood and the carbon dioxide that could drop in unexpectedly.

There are a few different ways this occurs.

• Mechanical or Forced Ventilation: This is when an air handler (AHU) or exhaust fans get involved, they take it upon themselves to pull air in and push air out. Think about kitchen and bathroom exhausts — they are there to manage odors and humidity. These systems are important for managing indoor air quality and reducing pollutants.
• Passive or “natural” ventilation: This is the OG, operable windows, louvers, trickle vents etc. It depends on natural forces, like wind pressure (cross ventilation) or the “stack effect,” in which warm air rises and escapes through high openings, pulling cool air into low ones. It’s incredibly energy-efficient, but may not be comfortable enough in places that are very hot or humid.

One important measure here is air change rate (ACH) or air changes per hour. This lets you know how many times an hour the air in a room is completely replaced. For comfort, you’re looking at around four ACH, but for places with lots of people, like bars or commercial kitchens, it can spike to 30 to 50 ACH. For health, especially where airborne diseases such as TB or COVID-19 are concerned, ventilation done right is a formidable shield. The CDC even suggests a minimum of 5 ACH for all spaces, and 12 ACH for hospital rooms of airborne contagions.

Air Conditioning: Keeping Your Cool

Air conditioning is your best friend when the temps climb. It is about cooling your space, and dealing with humidity. A.C. cools not by generating cold, but by removing heat. Heat can be transferred out by radiation, convection or conduction.

The secret sauce? The refrigeration cycle:

• Compressor: Low-pressure, low-temp gas refrigerant enters and is pumped up to high pressure and temperature.
• Condenser: The hot, high-pressure gas next flows through a coil (the condenser), where it gives up its heat to the outside air and condenses into a liquid.
• Metering Device (Expansion Valve): The expansion valve controls the amount of liquid refrigerant entered into the next stage!
• Evaporator: The liquid refrigerant enters yet another coil (the evaporator) and evaporates, drawing the heat out of your indoor air. This is what makes the air in your home cool.

The heat is absorbed by the refrigerant and then travels back to the compressor, where the cycle begins again, moving heat from inside to outside your house. In fact, most current systems can even reverse this cycle to heat your home in the wintertime, which means you have a tremendously flexible solution for heating and cooling.

You will find that some systems come with what they call an “economizer mode” or “free cooling”. When the air outside is cool enough, the system actually fans in that fresh, cool air directly instead of turning on the mechanical cooling system that needs to be working otherwise, and that saves a huge amount of energy. Smart!

And let’s not forget humidity. When the evaporator coil cools the air below its dew point, moisture forms on the coil, and your space is effectively dehumidified. You can have this done by a professional, though dedicated dehumidifiers can manage the problem, particularly in moist environments, such as basements. On the other hand, humidifiers infuse moisture when the air is too dry.

What’s Inside? Essential Parts of Your HVAC System

Your HVAC system is not really one single monster machine; a lot of players must successfully collaborate to give you that perfect indoor vibe. Here, the main players you can expect to encounter:

• Thermostat: The thermostat is the heart of your HVAC system. It’s in your home, so you can tell the system how warm or cool you’d like it to be. Newer models, such as smart thermostats, can even learn your habits, set schedules and allow you control beyond the home through an app.
• Air Conditioning Unit (AC): This outside equipment cools your house by expelling heat and moisture. Instead it takes that heat out of the tent, allowing you to be comfortable even on the sweatiest of summer days.
• Heat Pump: The Champion of the cause, a heat pump can heat AND cool your home. It is based on a refrigerator, but it absorbs, transports and releases heat, running backward when you need heat or cool air. Bonus: they are more sustainable than fossil-fuel burning systems.
• Furnace: It’s your heating workhorse, at least if you don’t have a heat pump. Furnaces combust fuel, such as natural gas or propane to generate heat that is then dispersed throughout your home.
• Air Handler: Usually connected to heat pumps or AC units, your air handler is the fan. It pushes warm and cold air through your home’s ducts so you can kind that magical set temperature in each room.
• Ductwork: Think of it as your home’s respiratory system. A system of metal or flexible tubes, ductwork, is used to move and distribute air from your heating, ventilation and air conditioning (HVAC) units to all the rooms of your home. There’s trouble if it’s not sized right or is leaky.
• Vents/Registers (more correctly called grilles): These are the highly visible openings in your rooms, where the conditioned air is sent out of the duct work and into the room.
• Air Filters & Whole-House Air Cleaners: These are your air quality warriors. Filters trap dust, pollen and other debris before they circulate. Whole-house air cleaners or purifiers do you one better, snatching up allergens, viruses, bacteria and other pollutants to actually help improve your indoor air quality.
• Humidifiers/Dehumidifiers: The name of the game here is moisture manipulation. Humidifiers introduce moisture when the air is dry (hi, winter static!), and dehumidifiers tug it out of the air when it’s too moist (adios, summer stickiness!).
• Boilers: Because they’re found more often in older homes or commercial locations, boilers heat water (or generate steam) that’s then distributed through the pipes and radiators in your space, Kerlin says. This is also included in hydronic systems.
• Geothermal Heat Pump: The so-called super-efficient one! These work unlike air-source heat pumps, which rely on above-ground pipes to tap into the earth’s stable temperatures to heat (or cool) your home. Costs more upfront but saves you a lot in the long run.
• Radiant Heating: This system works by delivering heat directly through your floor or wall panels via tubes or panels. Considering heated floors = total luxury. They work off of electricity or water in a hydronic system.

How it All Comes Together: The Work of HVAC Systems

So, you’ve got these components. But how do they really work their magic? It all comes down to a regulated, synchronized dance.

Your thermostat is the maestro of this orchestra. It communicates the temperature you want to the rest of the system, and tells it to produce warm or cool air. If it’s cold, the furnace or heat pump goes to work generating warmth. If it’s hot outside, an air conditioner or heat pump kicks on, removing heat and humidity from the air.

That newly conditioned air is then delivered to your home. Most often, this occurs through ductwork. Refrigerant lines manage the transport of temperature-controlled air if you have a ductless system. Remember, refrigerant is the secret sauce that absorbs and releases heat in both heat pumps and AC units.

HVAC systems may be gas- or electric-powered. Even as electricity becomes more ubiquitous, furnaces and boilers generally remain stuck with gas or oil. The idea is a simple one, continuous control to give you consistent comfort and optimal quality, no matter what’s happening on the outside.

Choosing Your Powerhouse: The Different Types of HVAC Systems

All HVAC systems are not created equal. Which makes the most sense for you depends on your home’s size, your climate and your existing configuration.

And here are the main types you are likely to encounter:

• Split System: This is a standard kind of central heating and air conditioning system in many houses. It’s “split” because it has an outdoor unit (similar to an AC or heat pump) and another indoor unit (air hander or furnace) as well. They’re preferred worldwide.
• Packaged System: If you’re tight on space, a packaged system (where the A/C and heating components are found in a single outdoor unit that sits on the ground or on your roof) might be your best option. It houses the heating and cooling system in a single cabinet, typically mounted outside or on a roof. Best for: Smaller homes or specific commercial uses.
• Ductless Mini-Split System: No ducts? No problem! These are great for older houses, new additions or particular rooms that just need a little boost of comfort. One exterior unit can be connected to up to five indoor units, each controlling a defined “zone”. That way you can heat or cool specific rooms as opposed to whole areas, which isn’t energy-efficient if they aren’t being used.
• Dual Fuel Heat Pump System (Hybrid): Basically, this kind of system is a combo that switches off between an electric heat pump and a gas furnace. It is a hybrid system that chooses the most cost-effective method of heating your home. When it’s not so cold, and the heat pump does most of the work; when it is really cold, the gas furnace kicks in for maximum warming.
• Individual vs. district networks: While most HVAC is in individual buildings, it sometimes plugs into a larger “district” network for heating or cooling. This allows several buildings to share resources, often relying on renewables such as solar heat or cold drawn from lakes, resulting in significant energy savings.

Choosing the right one? Which is where an HVAC pro comes into the picture. They’ll take into account your house size, the climate, the existing ductwork, and what your own energy efficiency goals are.

Why Bother? The Real Importance of HVAC

You may think of HVAC as discomfort and comfort, and it’s much more than that.

1. Health and Well-Being: This is big. Well-maintained HVAC systems are your first line of protection from:

• Pollutants: High efficiency filters which can capture allergens such as dust, mold and pollen do wonders for the quality of the air in your home.
• Moisture Issues: They key is to monitor moisture levels. Too much humidity? Hi, mold, that allergen trigger. Too little? Dry skin and respiratory irritation. HVAC keeps it balanced.
• Airborne Diseases: Proper ventilation can be a game changer in terms of preventing the spread of airborne diseases such as the common cold, flu, and even COVID-19. Cracking windows is helpful, but mechanical systems are frequently necessary for reliable protection.

2. Safety: More than just comfort, HVAC systems also provide valuable safety elements:

• Carbon Monoxide Detection: CO detectors help protect you and your family from deadly and odorless CO gas.
• Moisture Control: Keeping too much moisture away reduces mould, rot, and other structural problems.

3. Energy Efficiency and Sustainability: Your wallet and the planet will thank you. Manufacturers have been going after more efficient systems since the 1980s. Why? As energy costs rose — and then, an environmental conscience emerged. Better HVAC is cheaper HVAC, and that means lower utility bills, and a smaller carbon footprint. And, a healthier system can even enhance your productivity.

Smart Moves: Energy Efficiency in HVAC

Looking to save some serious money, while also feeling good about your eco-impact? Energy efficiency for HVAC is your cheat code.

When you’re shopping for new units, you’ll notice a lot of acronyms. No worries, I’ll break it down. Higher numbers mean more efficiency.

Here’s the rundown:

• AFUE (Annual Fuel Utilization Efficiency): For furnaces or boilers. It’s a figure on the side of the box that will tell you how much of your fuel turns into heat for your home actually (versus how much just gets wasted). Ninety-seven percent AFUE says 97% of the fuel burned funds zone heating your place. That’s money in your pocket.
• HSPF2 (Heating Seasonal Performance Factor): This is just for heat pumps. It gauges the efficiency at which your heat pump heats your home in the winter. Or if it’s recent enough, look for the “2”.
• SEER2 = (Seasonal Energy Efficiency Ratio): It is a measure of how efficiently an air conditioning system will operate over an entire cooling season based on performance for a range of temperatures (65°F to 104°F). The “2” indicates that it’s the new standard. The larger the SEER2, the more efficient the cooling over an entire season.
• EER2 (Energy Efficiency Ratio): Another cooling unit metric, this one focuses on a specific temperature: 95°F. If you live in an especially hot area of the country, EER2 may end up being more important for you than SEER2.
• BTU (British Thermal Unit): A measure of heat energy. A British Thermal Unit or “BTU” refers to the amount of heat required to raise the temperature of one pound of water one degree Fahrenheit. In general, larger spaces require more BTUs for heating or cooling. Your HVAC pro will help you size it right.
• How about DbA (Decibel, A-weighted): this is not about efficiency but comfort! This lets you know how loud your outdoor H.V.A.C. unit is going to be. This translates to a quieter unit: 57 dBa in the amolient while a continuous run of 50 dB each generated.

Here are some of the seriously cool tech-modern systems are doing to make sure the tools to make you productive are there to help boost your efficiency:

• Ground Source Heat Pumps: We discussed these – they leverage the consistent earth temperature for enormous utility savings, even in the harshest climates.
• Solar Air Conditioning Yes, photovoltaic solar panels can dramatically reduce AC operation costs, particularly with newer DC-motor units that get along well with erratic solar power.
• Energy Recovery Ventilation: Devices such as HRVs and ERVs recover heat from exhausted stale air and transfer it to incoming fresh air. This is smart energy recycling.
• Demand-Controlled Kitchen Ventilation (DCKV): This is a game changer when it comes to commercial kitchen exhaust. Instead of running fans on high all the time, DCKV turns the exhaust and supply air on and off in response to real cooking activity, saving energy and reducing noise in the kitchen.

Cleaner Air, Smarter Systems: Filtration & UVC

Clean air is not a luxury; it is a matter of survival. The HVAC systems are important for that.

• Air Filtration: Filters literally catches particles, pollutants, vapors and gases in the air so it can’t be distributed around the room. The goal? To help you keep those nasty bits out of your breathing space.
• Clean Air Delivery Rate (CADR): This measurement describes how much clean air an air cleaner delivers to a room. A higher CADR equals more clean air.
• UVC (Ultraviolet Germicidal Irradiation): Some newer air conditioning units include UVC lights. As air passes through the system, the UV light dings it, and the airborne viruses, bacteria and fungi are rendered dormant. It’s the bouncer for germs, but for your air.

The Backbone: HVAC Trade & Standards

The world of HVAC is a big, global business. It covers everything from developing systems and building equipment to installing, running and maintaining it. To keep things on the up and up there’s a load of organizations and standards in place.

These are to the rulebooks and referees:

Key Organizations:

• ASHRAE (American Society of Heating, Refrigerating, and Air-Conditioning Engineers): The big one. They issue well known standards for design of HVAC practices for regular revision.
• AHRI (Air Conditioning, Heating and Refrigeration Institute): Offers information on refrigeration technology, and publishes related standards.
• SMACNA (Sheet Metal and Air Conditioning Contractors’ National Association): Has nice resources.
• ACCA (Air Conditioning Contractors of America): Another contractor power player.
• IAPMO (International Association of Plumbing and Mechanical Officials) and ICC (International Code Council) The people in charge of updating and (releasing) codes and such like the Uniform Mechanical Code (UMC), International Mechanical Code (IMC) every three years.

Codes and Regulations: These are the HVAC installation and safety Laws. Standards like the UMC and IMC tell you what kinds of systems must be installed; on the international level, ISO 16813:2006 lays down general principles for design of the built environment, to promote health, sustainability and cooperation.

Licensing: In the United States, you will need E.P.A. certification if you work with refrigerants. Many states have their own boiler-operations licenses as well. And some cities? They may have even more local laws for HVAC pros. It’s a patchwork so the technicians have to keep up with it.”

The Unsung Mechanics: How to Become an HVAC Technician

You may not know that it is professionals like theos who install, repair, and maintain these sophisticated systems. That’d be the HVAC technician. These people are necessary, and their job security is solid — it’s an expanding field, and AI ain’t taking their jobs away any time soon.

What do they do? A lot:

• Installation: They install furnaces, air conditioners, heat pumps and ventilation units, and more, tightly following blueprints and manufacturer’s instructions to ensure everything runs smoothly.
• Repairs and Maintenance: That’s a big chunk. They diagnose problems, devise solutions, replace broken parts and generally keep systems running smoothly. Consider cleaning coils, lubricating parts and checking electrical connections.
• System Testing: They will test airflow, temperature, pressure and coolant levels using special equipment and make any necessary adjustments to improve efficiency.
• Your Customer Service: Yes, they actually speak with you! They tell you what is happening, offer tips to conserve energy, suggest improvements, and guide you through maintenance.
• Safety and Compliance: They’re strict about safety and take responsible charge of refrigerants, and they adhere to the electrical code.
• Documentation: Maintaining records of service, maintenance logs and inventory.

It’s not always glamorous. Where HVAC techs work HVAC techs are found in all sorts of locations – homes, offices, factories. It can also be physically taxing: lifting, climbing, squeezing into tight spaces. They probably spend time outdoors in all sorts of weather. And sometimes they’re working strange hours, responding to emergencies on evenings or during weekends.

So, how do you become one?

• Education: Some learn on the job, but a formal training program is the preferred path. You can earn a certificate (6 to 12 months) or an associate’s degree (approximately 18 months to 2 years) in HVAC technology. These programs provide you with the scientific theory and the hands-on skills.
• Apprenticeships: This is paid training that occurs on the job and typically lasts about 3 to 5 years. You are thrown in with wily veterans, acquiring on-the-job lessons and assembling a real-world network.
• Certifications & Licensing This will be the most important thing. You will need to be certified by the E.P.A. to handle refrigerants safely. NATE (North American Technical Excellence) certification is another huge one that shows your expertise. State licenses also vary, so you’ll have to check on local requirements.

Is it a good career? Definitely some upsides and downsides:

If you’re good with your hands, like solving problems, and don’t mind getting a little dirty, it could be a fulfilling and financially rewarding path.

Money Talks: Everything You Should Know About The Cost, Installation & Maintenance of HVAC Systems

Let’s face it, a new HVAC system is not cheap. But it’s one that will pay off in comfort, health and energy savings.

How Much Does It Cost?

The amount that will be spent can vary greatly based on a few things:

• What you’re replacing: Just an AC? Or an entirely new system with a furnace and something called an air handler?
• Size of unit: Larger spaces require larger units (a 3-ton AC versus a 5-ton).
• Location: HVAC Costs differ by region.
• Add-ons: Do you want an air purifier, humidifier or smart thermostat? That adds to the price.
• Ductwork/Electrical upgrades: If your old ducts leak or you need to have electrical work done, count on an increase in price.
• Brand and Contractor: Not all brands cost the same, and what type of contractor you hire matters.

For exact pricing your best bet is to call local HVAC dealers. And be sure to inquire about ENERGY STAR® certified systems, which may qualify you for federal tax credits or local rebates that could offer relief for that upfront cost.

Installation: Don’t DIY This!

If you haven’t been trained and licensed in the field of HVAC, don’t even think of installing your own HVAC system as a DIY project. Seriously. While you can replace a window unit, a central air system is complicated:

• Sealing or installing new ductwork.
• Properly venting gas furnaces.
• Tying into refrigerant lines (and evacuating and charging the refrigerant which takes a special EPA certification!).
• Electrical work.

Making a mess of this can void your warranty, cause expensive repairs down the line, and even be dangerous. Let the licensed pros do that.

Maintenance: Keep It Running Smoothly

Imagine that your HVAC system is similar to your car; the better you take care of it, the longer it will last and the better it will work!

• Air Filters: This is probably the easiest to maintain but is often ignored. They become clogged with dust, pollen, mold and pet dander, impeding airflow and causing your system to work harder. This is a waste of energy, and can cause premature equipment failure, cause you to freeze your evaporator coils and ice the unit up, or it could also cause the thing to over heat. So, replace or wash them routinely — with even more frequency if you have pets or live in a dust-prone place.
• Coil Clean: Your Evaporator and Condenser coils must be clean. If you have a dirt-encrusted condenser coil, your compressor will have to exert more power to keep up, potentially wearing it out.

By performing regular maintenance, not only will your system run with peak performance and energy efficiency, but it will last longer and help to avoid costly breakdowns.

Finding the Right HVAC Company

The HVAC contractor you select for your equipment is equally as important as the equipment itself. A good system can perform bad with a bad installation.

Here’s how to find a winner:

• Ask about: Seek suggestions from friends and family members and inquire which to steer clear of.
• Do your homework: Investigate companies online. When you find potential movers, read their reviews, visit their Web sites and see what their Better Business Bureau profile looks like. Look at how they’re speaking to negative feedback – a responsive company is a good company.
• Full-service: Choose a company that can provide every service, including installation, repair and ongoing maintenance.
• Quotes: If you’re buying a new system, receive quotes from several installers. And remember, you generally get what you pay for.
• The following services may be available: Emergency Service: If you need someone to come immediately, confirm whether they offer 24-hour service.

Just by knowing “What is HVAC,” what the components are, what it does, and how to take care of it, you are on your way to making the best choices for your home, for your comfort and for your peace of mind. It’s a complicated system, but your comfort doesn’t need to be.

Frequently Asked Questions About HVAC

You have questions, we have answers. Let’s tackle some common ones.

HVAC Vs AC: What’s The Difference? This is a classic. Consider it this way: HVAC is the umbrella term for the overall climate control system — Heating, Ventilation, and (you guessed it) Air Conditioning. AC (Air Conditioning) is a part of that system – cooling and dehumidifying the air. So, all AC is in fact HVAC, but certainly not all HVAC is simply AC.

Does my HVAC system include the furnace? Absolutely, yes!. Your furnace is an integral part of your HVAC system and essentially heats the air in your home. It creates heat and circulates it throughout your house, often through ductwork, in the colder months.

What are some of the common types of HVAC systems? Both accountability is largely inescapable-oriented along two broad dimensions that colour how discussions play out but even if a wildly improbable scenario transpired, the general risk landscape facing Canada wouldn’t change.

• Ducted Systems: They rely on a series of air ducts for air to be carried from the device to all parts of your home. That even applies to old-school central air conditioners and furnaces.
• Ductless Systems (Mini-Splits): These are systems that heat and cool specific rooms without the need for ducts. They excel in houses without existing ductwork, or where you want to set up “zones” of comfortable temperatures. You also have hybrid choices like Dual Fuel systems, which pair a heat pump with a furnace.

How often do I need to change my HVAC filter? Although the sources have no specific schedule, with a time frame, such as “once a month,” they emphasize that the filters should be replaced, or washed regularly, “as needed for conditions. If your environment is high-dust, or if you have furry pets, you will have to change it more often. Neglecting to do so will decrease heat transfer, waste energy, decrease the life of your equipment, and even ice up your coils or overheat. So, check it often!