Introduction: Your Home’s HVAC System 101Admin
Your home’s HVAC system is one of the most critical components of your household. It keeps you warm in the winter and cool in the summer, and maintains your indoor air quality all year round. So as you might imagine, maintaining it and choosing the right HVAC options for your situation is important. In this guide, we’ll discuss a few of the most common HVAC elements, and what you should know about the care and upkeep of each.
Let’s dive in.
Note: HVAC is an acronym for heating, ventilation and air conditioning but also includes indoor air quality.
Central Heating Versus Central Cooling
Central heating warms the whole interior of a home, moving warm air from one point, out through venting, and eventually into multiple rooms. Typically, central heating systems are used in conjunction with other systems, like HVAC, humidification, or vent fan systems, to build and maintain the interior climate. The heating system works in tandem with a cooling system and together are typically called a split system. We cover central cooling here in more detail.
So What Type of Heating Does My Home Have?
Traditional central heating systems use a primary appliance, such as a furnace, to heat the home. Typically, this appliance is located in the attic, basement or garage of a home. All central heating systems have four main components:
- Burners. The burners combust and deliver fuel, which creates heat.
- Heat exchangers. Heat exchangers convert the heat into a usable form for the indoor space.
- A blower. Blowers move warm air out of the furnace and through the home’s vents.
- A flue. The flue serves as an exhaust system to move gaseous by-products out of the home.
One of the things that make central heating systems so popular is their flexibility. Depending on your needs, you can select a heating system that runs on gas or oil, or choose a hybrid system that uses both kinds of fuel.
In this section we focus on gas furnaces because they have been the standard in American homes for half a century. There are however newer, safer and more efficient systems called heat pumps that can save you money over time. Before you can decide which option is right for you, it’s essential to understand traditional central heating systems.
Gas furnaces are used in about 57% of American homes, gas furnaces are the most common central heating system. Today gas furnaces come in AFUE ratings of 80-98% and multiple stages of heat. (Insert details about how AFUE and stages alter cost to use and overall comfort). A forced-air gas furnace is an efficient heating option and uses the following heating cycle to provide warmth:
- The burner ignites natural gas or propane.
- Flames in the furnace heat up a metal exchanger, which then pushes exhaust and fumes out the flue.
- The incoming air moves across the heat exchanger and picks up the heat.
- The blower within the furnace forces the heated air out into the ductwork and through the home.
- As the warm air moves through the home, cold, dense air comes back through the return ducts to repeat the furnace’s process.
Visit our pricing page for a more comprehensive list of common HVAC repairs.
Understanding How Your Furnace Works
You’ve probably had your furnace stop working at some point and when it does again, we recommend you read our blog Things to Check Before Calling for AC Services). But in case changing the filter or resetting the breaker doesn’t get your heat working-it’s important to understand how your heating system actually works. Here’s a brief breakdown of your furnace system components:
- Thermostat. The thermostat is a temperature-activated switch that detects dips in indoor temperature and tells the furnace’s control board to activate the heating cycle.
- Draft Hood/Fan. When air moves into the burners, it mixes with the gas and creates combustion. The draft-induced fan makes combustion more efficient and directs gases outside the structure.
- Burners. Furnace burners are tubes that direct gas through the system to be burned.
- Heat exchanger. The heat exchanger is a complex network of metal tubes heated by the burners to warm the indoor air. When gasses combust inside the heat exchanger, the system transfers its radiant heat into the passing air.
- Blower. The blower fan directs air in the central heating system – moving air from return ducts into the heat exchanger and forcing warm air out through the home’s ductwork.
- Flue. A flue vent collects combustion gases used to create heat and carries them outside the home.
Potential Gas Furnace Repairs
While gas furnaces are durable and long-lasting, they will eventually require repairs. Common causes of repairs include the following:
- Dirty filters
- Wear and tear
- Problems with the electric ignition or pilot control
- Thermostats that break or stop working
- Lack of maintenance
- Improper heating levels
- Frequent cycling
- Continuous blower operation
- Excessive operation noise
The easiest way to maintain your furnace and make it last-is regular maintenance. Our Secure Comfort Club residential maintenance membership includes an annual furnace maintenance. To learn more about our step-by-step cleaning process and benefits visit our Secure Comfort Club page.
Repair or Replace?
Furnaces have a lifespan of 20+ years and are easy to maintain and clean. The main concern with furnaces is cracking in the heat exchanger as this can emit toxic gas that can lead to death. A furnace should be serviced and maintained regularly to keep the air in your home safe.
If you do decide to replace your existing furnace, there are many common brands including:
- Rheem or RUUD
- American Standard
Speak to a qualified gas furnace installer to learn which brand is ideal for your home and your specific preference. A heat pump might also be a good alternative if your goal is to save money – especially if your local municipality offers rebate incentives. There may also be other federal cash incentives, checkout our blog HVAC System Tax Credits Extended Thru 2021 to see if this is an option for you.
New Alternatives to Central Heating Systems
Reliable heat doesn’t have to come from a central heating system. Heat pumps are a popular alternative to gas-fueled heating systems. While heat pumps are technically a type of furnace, they don’t work like a typical forced-air furnace. In fact, they resemble a central air conditioner in reverse. The exact mechanics of their function depends on which type of heat pump you install. According to the U.S. Department of Energy:
Like your refrigerator, heat pumps use electricity to move heat from a cool space to a warm space, making the cool space cooler and the warm space warmer. During the heating season, heat pumps move heat from the cool outdoors into your warm house and during the cooling season, heat pumps move heat from your cool house into the warm outdoors. Because they move heat rather than generate heat, heat pumps can provide equivalent space conditioning at as little as one-quarter of the cost of operating conventional heating or cooling appliances.
For homes in moderate climates, heat pumps can be an energy-efficient alternative to an air conditioner or furnace.
Today, there are three types of heat pumps: air-to-air, water source, and geothermal. Each kind of heat pump, respectively, draws heat from the air, water, or ground around a home and concentrates and transforms it for indoor use. As it stands now, air-source heat pumps are the most common type. These heat pumps use the outside air to condense heat before transferring it into the home, which transfers heat between your house and the outside air.
Modern, efficient heat pumps can reduce a home’s electricity need and heating requirements by approximately 50% compared to electric resistance heating like furnaces and baseboard heaters. Additionally, high-efficiency heat pumps also pull moisture out of the air better than air conditioners, which means more efficient cooling during the hot summer months.
Popular throughout the United States, air-source heat pumps have recently become a viable heating alternative for colder regions.
Heat Pump Energy Transfer Source
A heat pump has two main components: an outdoor unit and an indoor air handler. The outdoor unit looks like an air conditioner but is actually a heat pump. It contains a compressor unit, which works to circulate refrigerant throughout the system. The refrigerant absorbs and releases heat as it moves between outdoor and indoor units.
Heat exchange in a heat pump can draw from three different sources:
- Ground Source. Ground-source heat pumps have a complex network of pipes set into the ground. These pipes absorb heat and send it inside to the house.
- Air-Source. On the other hand, air-source heat pumps use an outdoor compressor unit that looks like a central air unit. This unit draws air in, pulls the heat out, and sends it to the indoor portion of the home’s heat pump, which then disperses the heat through the house via a heat pump.
- Water-Source. Typically uses a water heater as source of heat exchange.
Air source is the most common heat pump-generally it consists of one indoor air handler and outside heat pump condenser-referred to collectively as “heat pump split system”. But in recent years ductless mini splits have become increasingly popular offering a variety of space options in homes. For older homes or non-traditional work or living spaces-mini splits may provide temperature zoning without ductwork or controls.
Common Heat Pump Repairs
The most common heat pump repair requirements include the following:
- Refrigerant Leaks
- Frozen Outdoor Units
- Broken Reversing Valves
- Electrical Failures
Replacing Your Existing Central Heat With a Heat Pump
If you’ve determined that you would like to replace your existing hvac system, starting fresh with a heat pump is a good option. You’ll have plenty of variety to choose from as this is the direction that most heating and cooling is going in temperate climates. All the major HVAC brands manufacture heat pumps, including
- Rheem or RUUD
- American Standard
Maintenance of Central Heating Systems
Even high-quality central heating systems need maintenance and repair. Here are a few maintenance duties to be aware of:
To keep your system running strong, have it tuned up at least once a year. Most common tune-ups include condenser coil cleaning, thermostat calibration, refrigerant evaluation and leak inspection, examination and tightening of electrical parts, and assessment of the motor and blower belt. Every heating maintenance should include some variation of the following:
- Clean and/or check the gas burners
- Check and/or clean the pilot tube
- Check the igniter for proper resistance and function
- Clean the flame sensor
- Check the blower motor amps and speed
- Evaluate the temperature rise
- Inspect the heat exchangers
- Check for proper combustion
- Clean out and inspect the pressure switch tubing
- Evaluate the pressure switch operations
- Make sure that the flue gases are venting properly
- Test all of the limit and roll out switches
- Inspect the gas pipe plumbing
- Set manifold gas pressures
- Check the gas input rate
- Light the pilot and check the thermocouple
- Inspect all of the wiring
- Set the heat anticipator on the thermostat
- Check the pilot safety thermocouple (electronic ignition)
- Make sure that there are no code violations
- Check the safety interlock switch
- Test the combustion fan motor and check amps
- Make sure that there is proper combustion air
- Inspect the duct system
- Perform a carbon monoxide test
Since your central heating system moves air throughout the home, maintaining the air filtration mechanism is critical. The Department of Energy recommends routinely replacing or cleaning filters. We’ll cover air filtration in greater detail, but for now it’s important to understand that clean air filters make a difference:
Clogged, dirty filters block normal airflow and reduce a system’s efficiency significantly. With normal airflow obstructed, the air that bypasses the filter may carry dirt directly into the evaporator coil and impair the coil’s heat-absorbing capacity. Replacing a dirty, clogged filter with a clean one can lower your air conditioner’s energy consumption by 5% to 15%.
Central cooling is one of the most common ways people keep their homes cool. Efficient, effective, and relatively simple to maintain, this cooling mechanism exists in about 100 million US homes.
Air Conditioners-the Gold Standard
Air conditioners are the most traditional central cooling system. Designed to disperse cool air throughout a home, air conditioners use an indoor evaporator coil that utilizes refrigerant to cool the air. An air conditioning system generally consists of five distinct components:
- Compressor. The compressor is the “engine” of the AC unit. It works to convert low-pressure gas to high-pressure gas, which begins the cooling process.
- Fan. The fan works to disperse the cool air throughout the home and to maintain a consistent indoor temperature.
- Condenser Coil. The condenser coil uses a fan to cool high-pressure gas and revert it into a liquid, before moving it into the evaporator.
- Evaporator Coil. The evaporator turns liquid into gas once more, using refrigerant to remove the heat and cool the substance.
- Thermostat. The thermostat senses and helps maintain the home’s temperature, regulating air flow both inside and outside the unit.
What Are Some Common Air Conditioning Repairs?
At some point every air conditioner is going to stop working and need a repair. It could be something minor like a capacitor or fuse, these are normal areas of maintenance-related repairs. But sometimes a capacitor going out could be an indication of a deeper issue. An HVAC service technician can diagnose your air conditioner and determine the cause and recommend a series of repairs. Here are some common repairs:
- Low Refrigerant. AC units use refrigerants to remove heat and create cool air. If the refrigerant system develops a leak, it will not be able to complete the cooling process. In this case, a repair tech will need to examine the lines for leaks and cracks and replace any worn parts.
- Frozen Evaporator Coils. The evaporator coils are filled with refrigerant, which is responsible for absorbing heat from the air. To continue working correctly, these coils need airflow. If the airflow stops, the coils get too cold and stop working.
- Dirty Condenser Coils. AC condenser coils are part of the outdoor segment of the unit. When the coils get dirty, they struggle to remove heat from the air and can result in an AC system that works much harder than it needs to. In some cases, dirty condenser coils can even cause a system failure.
- Fan Problems. The AC has two fans: one that blows indoor air over the evaporator coil to cool the air, and another that blows air over the outdoor unit’s condenser to get rid of heat outside the building. When those fans break down and stop working, it creates airflow and air conditioning problems.
- Leaking Ducts. Ductwork is central to an AC unit. When it develops leaks, cracks, or holes, the conditioned air winds up poorly routed through the house, where it can’t help anyone.
- Thermostat Problems. Thermostats must be correctly calibrated to work correctly. When they aren’t, they can result in increased energy bills and improper indoor temperature.
- Clogged Drains. AC units create moisture, which has to go somewhere. Ideally, it runs out of the space through a drain line. If the drain gets clogged, though, waste backups can occur. These damage floors and can cause expensive repairs.
Maintenance of Cooling Systems
Cooling systems require maintenance. To keep your unit running strong, we recommend maintaining it at least once a year – once in the spring for the cooling side. Your system should have at least one annual cooling tune-up. This tune-up should include:
- Check the refrigerant charge including suction line pressure and liquid Line pressure
- Take the TD across the coil including return air temp and supply air temp
- Look for signs of a refrigerant leak
- Inspect the suction line insulation
- Test the capacitors
- Look at the contactor
- Test the incoming line voltage
- Inspect the wiring
- Treat the electrical parts for ants
- Test the relays and switches
- Test the pressure switches
- Blow out the drain line
- Check all motor amperes
- Look at the circuit breaker specs
- Inspect the equipment disconnect
- Remove leaves and debris
- Rinse the condenser coils
- Check the drain for proper fall
- Proper float switch operation
- Check the secondary drain pan
- Inspect the evaporator coil
- Look at the return air filter
- Calibrate the thermostat
- Inspect the duct system
- Insure there are no code violations
Upton Air has a monthly and annual HVAC maintenance program – which includes your choice of 1, 2, 3 or 4 seasonal tune-ups. Members get 15% off routine repairs and never pay dispatch fees on approved repairs. We’ve found that homeowners that regularly maintain their system (just like your car needs an oil change) and do routine repairs – have systems that last longer.
Don’t Forget Air Filtration!!
Your AC unit’s system filters should be cleaned or replaced every month to two months during the cooling season. If the conditions where you live are dusty or you have pets in the house, you may need to change the filters more frequently. We cover air filtration in a bit, but for now it’s important to note that filters need to be managed (cleaned or replaced).
How Air Distributes Throughout a House
We’ll briefly touch on ductwork (indoor air distribution). As not to leave it out. There are two types: flexible ducting and hard pipe ducting. Approximately two-thirds of homes in the U.S. use forced-air systems. These forced-air systems serve the vital purpose of moving conditioned air out from a central air conditioner, furnace, or heat pump and through the home’s vent system to its various rooms. While they serve similar purposes, indoor air distribution systems and ventilation systems are not the same things. While a forced-air system controls air distribution throughout the home, ventilation systems control how air enters and exits the house.
Most air distribution systems are installed behind drop ceilings or in similar structures. These overhead systems disperse conditioned air into living space via a series of vents and diffusers in the ceiling or along the room’s top walls. Other air distribution systems are installed beneath the floor of a building. In these systems, air travels through ductwork and emerges through vents built into the floor. In general, under-floor air distribution systems are more expensive yet more efficient than their overhead structure.
How Air Enters and Exits a House
Ventilation. These systems serve an important role – they keep your home’s indoor air clean, comfortable, and safe to breathe. Additionally, ventilation systems depressurize a home’s interior, making it a more enjoyable place to spend time.
According to the Department of Energy, “energy-efficient homes — both new and existing — require mechanical ventilation to maintain indoor air quality.” Today, there are four basic types of ventilation systems: attic fans, exhaust fans, ceiling fans and whole house fans.
Attic fans are a relatively simple, affordable fan option. They operate on a simple principle: they push the attic’s hot air outside the home and replace it with cool air from outside. Attic fans can help decrease your energy costs and cool your home efficiently. We like the QuietCool Smart Cable Attic Fan.
Most attic fans have two primary components: a series of small vents in the gables and soffit of the home to draw in the cool air, and a primary, powerful fan that pushes hot air outside.
What If I Need An Attic Fan Repair?
Since attic fans are a relatively simple system, the repair process generally is, as well. Here are the top attic fan repair needs you may encounter:
- Electrical Supply Issues. When the attic fan doesn’t turn on, it could result from a tripped circuit breaker, bad connection, or blown fuse. Alternately, it could be the result of a faulty thermostat or fan motor.
- Fan Blades Not Moving. Sometimes, the fan’s motor will run, but the blades won’t move. This is usually due to a faulty belt. A repair person will evaluate the fan’s outer casing and identify any problem areas where the belt is cracked, sagging, or worn.
- Decreased Air Flow. Intake or exhaust problems can cause a decrease in airflow. There may be debris in the vents or a problem with the positioning of the fan.
- Weird Noises. If the attic fan is making a humming or a loud noise, it is likely the result of an airflow problem. Have it inspected immediately.
Exhaust ventilation systems work to depressurize the home. These systems work by moving hot, humid air out of a small area, allowing fresh air to come into the house from a doorway or vent. They’re best suited to cold climates since they can draw moist air into wall cavities and building gaps in hot, humid climates. This is typically a more custom option. We recommend you get in touch with an HVAC specialist to determine your specific needs.
Exhaust fan systems can be either simple and straightforward or surprisingly complex. The simplest systems use an automatic timer, which connects to a bathroom or laundry room fan in a central location in the home. The fan will cycle on or off a few times per hour or every 12 hours, depending on the settings. Typically, these air exchange cycles happen during the times of the day when people are home – such as mornings and evenings.
Exhaust fans are simple systems, but they can run into a variety of repair needs. The most common include the following:
- Motor issues
- Power failure
- Moisture buildup
- Faulty wiring
Ceiling fans cool a room by using rotating blades in a reverse counter-clockwise motion to produce a breeze. While they don’t cool the room’s temperature, they do make it more comfortable to be in. The ceiling fan movement pushes air up and pulls warm, trapped air down the sides of the room to improve heat distribution.
Ceiling fans are pretty basic and contain typically contain the following:
- An electric motor
- Blade irons, which connect the blades to the motor at their base
- A flywheel, which attaches the blade irons to the motor shaft
- A rotor
- A mounting mechanism
Ceiling fans are convenient and cost-effective and can be a great way to keep a home without AC cool, or to make AC units more effective. They may, however, run into the following problems:
- Flickering lights
- Wobbling fan
An electrical technician can always troubleshoot these types of issues and get them resolved quickly. Also, due to the inexpensive nature and availability of ceiling fans, if yours isn’t working-it may just make sense to replace.
Whole House Fans
Whole house fans pull air from open windows and exhaust it through the attic or roof. These fans provide unmatched ventilation while also moving hot air out and replacing it with cool air. Most whole-house fans provide about 3-6 air changes each hour.
The two most common forms of ventilation are whole house fans and as previously mentioned attic fans. For both we recommend QuietCool because of their 15 year manufacturer warranty, ratings and solid consumer reviews.
If you already have a whole house fan, it may not be working anymore or have mechanical issues if it is older. Common components include: plate assembly, motor, wall switch, pulley and motor and fan blades. Repairs could include blades that don’t spin anymore, intermittent operation, humming or making noise.
It’s easy enough to repair the motor on a whole house fan, the older versions often require an OEM or aftermarket part. But sourcing the part will require research and with fees could be more trouble than it is actually worth. If you are mechanically-minded a DIY route may be an option.
Indoor Air Quality
Indoor air quality matters. Unfortunately, it’s not something homeowners tend to think about very much. Right now, the average American spends 90% of their time indoors, where, according to the EPA, the concentration of certain pollutants can be 2-5x higher than they are outdoors.
To make matters worse, at-risk individuals like people with cardiovascular and respiratory diseases tend to spend even more time inside.
Indoor concentrations of some pollutants have increased in recent decades due to such factors as energy-efficient building construction (when it lacks sufficient mechanical ventilation to ensure adequate air exchange) and increased use of synthetic building materials, furnishings, personal care products, pesticides, and household cleaners.
While that statistic seems frightening, there are ways to improve indoor air quality. The best of which is through advanced, modern indoor air quality, or IAQ, systems.
Thanks to various elements of our modern lives, our indoor environments often contain high quantities of pollutants, toxins, and pesticides. IAQ systems, however, target these components to make indoor air safer and healthier. Specifically, IAQ systems seek to eliminate the following:
- Particles. Particles in a home include pollen, pet dander, hair, and dust. These particles are irritating to people and pets and are also bad for a home’s HVAC system. While many people think indoor air filters catch these things, the reality is that disposable air filters capture less than 5% of particles in a home, meaning the other 95% are free to drift around and wind up in your respiratory tract.
- Biological. Most of us try to avoid germs, especially in the post-COVID-19 world. Unfortunately, heating and cooling systems can aid the growth and spread of viruses, bacteria, and other nasty biological substances. Fortunately, certain types of IAQ systems target these elements for healthier air.
- Gases & Odors. Chemical gasses and odors are common in the standard home. Fortunately, IAQ systems can target these chemicals and remove them from the air – for a cleaner,r crisper breathing experience.
5 Types of IAQ Systems
Today, there are five common types of IAQ systems. They are as follows:
- UV Lights. UV lights can be installed within your residential or commercial duct system. These lights work to provide additional purification layers for your indoor air. As your HVAC system runs, the ventilated air passes beneath the UV lights, which destroy microorganisms before they enter your home and affect your family.
- Electrostatic Air Filters. Electrostatic Air Filters are an affordable, accessible form of IAQ. The word “Electrostatic ” means that the filters are made of a media that undergoes a process that charges the material, creating an “Attractive” quality. As air pulls through the filter, the particles are attracted to the filter fibers. These filters are a great way to save money and improve your home’s air filtration systems’ functionality. If you have asthma or severe respiratory disabilities, though, you may prefer a HEPA filter.
- Washable Air Filters. Washable air filters and electrostatic air filters have a lot in common. Both can be cleaned and refused for several years before they need to be replaced. Washable filters, however, tend to be a bit more affordable and can be reused for a longer period. They are also, as the name indicates, fully washable.
- Low Maintenance Air Purification. Low Maintenance Air Purification systems, such as the iWave system. are available at virtually every retailer out there right now. These freestanding ventilation units offer a certain number of air exchanges per hour, or minute, and feature HEPA filters for maximum air scrubbing.
- Humidifiers. Humidifiers improve indoor air quality by actually conditioning the air. They emit water vapor or steam to boost the moisture levels indoors. While they condition the air, humidifiers don’t actually clean it. While humidifiers add moisture to the indoor environment, air purifiers filter the air of pollutants.
Controls are a critical part of any electric HVAC system. Essentially, controls act as the “brain” of the HVAC system, governing various equipment functions, and ensuring correct system operation. In most homes, the thermostat is the HVAC system control. But larger homes with more complex heating and cooling requirements may also need zoning controls to dictate temperature in different parts of the house.
Regardless, the thermostat manages the operation of the home’s air conditioner and furnace, as well as the blower responsible for pushing all that conditioned air out through the home.
In years past, thermostats were basic, manual devices that simply started and stopped equipment and designated temperature set points. Today, thermostats are much more advanced, efficient, and effective. Things like digital programmable thermostats, smart thermostats, and zoning systems allow for unparalleled control of the indoor environment and greater unification of all indoor systems.
Some Final Thoughts
Whether or not you are looking to repair your hvac system or replace it – we recommend you work with a reputable company to perform the work. Upton Air has been providing hvac system repair, replacement and maintenance for almost forty years. Give us a call today for repair services or a free quote!