HVAC Blog | National Air Warehouse

When looking for a new furnace, you’ll probably notice different options have different AFUE ratings. AFUE (which may be pronounced as “A-Few” or “A-F-U-E”) stands for Annual Fuel Utilization Efficiency. Essentially, it is a measure of the efficiency with which the furnace operates. Therefore, it essential to consider the AFUE rating when you purchase a new furnace.

Calculating the AFUE Rating

The Federal Trade Commission requires all new furnaces and boilers in the United States to display their AFUE rating to consumers. Like SEER ratings for air conditioning systems, the AFUE rating indicates the level of efficiency with which your system operates. However, unlike the SEER rating system, which utilizes an arbitrary rating scale, the AFUE rating coincides with the direct calculation of the ratio of the annual heat output of the furnace to the total amount of energy consumed by the furnace. Put more simply, it is the amount of heat produced per unit of energy consumed.

AFUE = (Total heat output) / (Total energy consumed)

When you perform this calculation, you will come up with a percentage -- which is your AFUE rating. If your AFUE rating is 85%, then 85% of the fuel you put in your furnace will be converted into usable heat. The other 15% will be lost to air leaks, burners, and other sources of inefficiency. However, it is important to note that heat losses in the duct system and piping are not included in the AFUE rating. According the the U.S. Department of Energy, additional energy losses can be as high as 35% if your ducts are located in an attic, garage, or other unconditioned area.

What to Expect from an AFUE Rating

For old, low efficiency heating systems, the AFUE is usually between 56% and 70%. A heating system is considered to have medium-level efficiency if the AFUE rating is between 80% and 83%. To be considered a high efficiency heating system, a furnace must have an AFUE rating that is between 90% and 98.5%. Choosing a higher efficiency system with a higher AFUE rating will help you save both energy and money.

An Important Caveat: AFUE Ratings and Fuel Type

When it comes to energy cost comparisons, AFUE ratings can only be directly compared if you are looking at systems that utilize the same fuel type. For example, natural gas furnaces can vary widely in AFUE rating, while all electric furnaces have AFUE ratings between 95% and 100%, since there are basically no sources of energy loss -- but that doesn’t mean that choosing the electric furnace will yield lower energy costs. Electricity costs more than natural gas in most parts of the country, so a gas furnace with a slightly lower AFUE rating will probably save you money in the long run.

National Air Warehouse offers a wide range of medium- and high-efficiency gas furnaces. Contact us today to find the right system for your home or business!

Evaporator coils are essential to the proper functioning of your air conditioning unit, ensuring an optimal climate in your home or business. Just as the electrical coils that comprise heat strips warm the air that comes out of your heater, evaporator coils cool and condition the air that is released from your air conditioner. Your air conditioner works by drawing in surrounding air from your home. When the air passes over the evaporator coils, the heat is removed. The evaporator coils also work in conjunction with the condenser unit to condense the water in the air, thereby reducing the humidity. That way, the air that is released into your home or business is cool and dry, optimizing the climate during the dog days of summer.

There are several types of evaporator coils on the market today. Cased evaporator coils are the most common, with several different subtypes available, but you can also find uncased coils that can meet your unique needs.

Cased Evaporator Coils

The air conditioning units in most homes and businesses are equipped with cased evaporator coils. Cased evaporator coils are particularly popular because they are highly durable and because they are relatively easy to install. Within this category of evaporator coils, there are three common subtypes:

• A Coils. A Coils are named for the shape that they take within the case, which resembles a capital letter “A.” They are most commonly used in vertical air conditioners, in which the air flows either up or down as it pases through the coils. A Coils can accommodate enough refrigerant to operate at a relatively high efficiency.

• N Coils. Like A Coils, N Coils get their name from the shape of the coils within the case, which resembles a capital letter “N.” They can work for either vertical air conditioners or for horizontal air conditioners, in which the air flows in one side of the unit and out the other. It is important to note that N coils are growing in popularity because they are smaller than the other options and because they operate at a higher level of energy efficiency.

• Slab Coils. Slab coils are the least common type of coils on the market. They are usually used for horizontal air conditioning units.

Uncased Evaporator Coils

Uncased evaporator coils can work for either vertical or horizontal air conditioning units. They are ideal for systems that require customization because their is no outer casing. As a result, the shape of the coils can be easily maneuvered in an ideal position. However, it is important to note that after you purchase an uncased evaporator coil, you may need an expert technician to help you customize the shape to fit your unit.

National Air Warehouse offers a variety of cased evaporator coils, and we can also help you find uncased options that can be customized to your individual needs. Contact us today for more information about our products!

If you are thinking about installing a heat pump system in your home or business, you might be considering a gas split system -- the most common type of heat pump system on the market today. A gas split system consists of an outdoor heat pump condenser and an indoor handler that is usually stored in your basement or attic. While there are a variety of decisions you will have to make when choosing a gas split system, one important question is whether or not you want to include optional heat strips in your system.

How Heat Strips Work

Heat strips provide supplemental heat during unexpectedly cold periods, when your regular heat pump system cannot adequately warm your home or office. To understand how heat strips work, it can be helpful to know how the heat pump operates under normal conditions. The heat pump pulls in air from the surroundings, and the liquid refrigerant captures the heat in the air. This causes the refrigerant to be converted into a warm vapor, making it possible for the heat to be dispersed throughout the building.

However, when the outside temperature drops below 40 degrees, there is very little heat for your heat pump to use, and the heat pump system is unable to draw in enough warm air to sufficiently heat the building. That’s where heat strips come in. Heat strips are strips of electric heating coils, consisting of wire elements that can be heated using electricity. When air flows over the heat strips, it is warmed before being distributed throughout your home or business.

Choosing a Gas Split System with Heat Strips

When choosing a gas split system, you will have to decide whether you want to buy a traditional system or a complete system that includes supplemental heating via heat strips. It might be a good idea to choose a gas split system that includes heat strips if you live in a location that is prone to low temperatures and sudden cold snaps in the winter.

Some buyers shy away from heat strips because the heat pump system operates less efficiently when they are in use. You might worry that heat strips will start working when supplemental heat isn’t actually needed, unnecessarily driving up your energy bill. However, there are certain things you can do to prevent this from happening -- like keeping your thermostat set at a constant temperature, gradually increasing the temperature on your thermostat when it does need to be raised, and avoiding the emergency heat setting. If you follow those procedures, you can avoid unnecessary energy expense, but still have optional heat strips available to provide supplemental heat when you need it.

National Air Warehouse offers a wide variety of gas split systems, including our featured Rheem Gas Split Systems, some of which include optional supplemental heating via heat strips. Contact us today for more help choosing the gas split system that is best for you!

When you look for a new thermostat for your home or business, you are often faced with a dizzying array of choices. The many thermostats on the market today have a wide range of capabilities, so it can be challenging to figure out which one best meets your needs. The first decision that you need to make in the thermostat purchasing process is whether you want a programmable thermostat or a non-programmable thermostat.

Programmable Thermostats

Programmable thermostats are becoming increasingly popular for controlling the heating and cooling systems in homes and businesses. With a programmable thermostat, you can set the temperature in advance. That way, you can coordinate your heating and cooling needs with your schedule. For instance, if you work a 9-to-5 job in the summer , you might set the thermostat so that the air conditioner doesn’t waste energy running all day long, but it turns on just soon enough that you come home to a cool kitchen. Similarly, in a small business, you can set your heating and cooling system so that it ensures a comfortable environment during working hours, but doesn’t cut into your budget by running at night.

A programmable thermostat can be especially helpful if you live in a place where there is a large temperature swing at night. You don’t want your air conditioner running when the temperature drops to 55 degrees in the early morning, but if you know that it will be 85 degrees by 3pm, you can set the thermostat to keep the building cool in the afternoon.

In fact, according to Energy Star, you shouldn't set your thermostat to one temperature and just leave it there. By setting your thermostat to different temperatures according to the time of day or season, you will maintain home comfort, save energy, and also save on air conditioning and heating costs. The infographic below shows different programmable thermostat settings you should definitely know.

Thank you actionac.net for sharing this infographic. Please include attribution to actionac.net with this graphic if you would like to use it on your site.

Non-programmable Thermostats

Non-programmable thermostats, sometimes called manual thermostats, provide a more traditional way to control the heating and cooling system in your home or business. You’re probably familiar with these thermostats, which allow you to manually choose the temperature of the building at any given time. Some people prefer non-programmable thermostats because they make it easier to change the climate of your home in response to changing weather conditions -- with programmable thermostats, it can be harder to alter the program when a heat wave or a cold front comes in unexpectedly. In addition, manual thermostats usually cost less upfront.

If you are retired, work at home, or spend all day in the house caring for kids, you might always be around to change the thermostat, so a non-programmable thermostat may be just as good as programmable one. Also, if you live in a place where the outside temperature doesn’t vary much, leaving a non-programmable thermostat at a single temperature level can ensure that your building maintains a consistent temperature too.

To meet the specific needs of your home or business, National Air Warehouse carries both programmable and non-programmable thermostats. Contact us today to find out more about what we offer!

Copper refrigerant lines play an essential role in air conditioning systems: They are responsible for carrying the refrigerant between the condensing unit and the evaporator coil. There are two copper lines that run between the condenser and the evaporator coil. The larger line is known as the suction line, return line, or vapor line. It carries cool gas, so it must be insulated with tubing. The second copper line is small and bare, and it is commonly known as the liquid line. Because the liquid line carries warm liquid, no insulation is needed.

When to Change Out Copper Refrigerant Lines

As you might expect, copper refrigerant lines need to be changed out whenever you are replacing an air conditioning or installing a new one. However, it is also important to note that copper refrigerant lines are also recommended to be changed out when upgrading your air conditioning system. It can be tempting to reuse old copper refrigerant lines after a system upgrade, but it is never a good idea. In order for a copper line to work properly, it needs to be fully dehydrated. An old copper refrigerant line may not be adequately sealed from moisture. As a result, any moisture in the line will combine with the refrigerant to form an acid, which can damage the compressor motor.

You might also need to replace your copper refrigerant line in case of leaking. A sure sign of a refrigerant line leak is an oil stain, because oil travels through the air conditioning system alongside the refrigerant, and it remains visible even after the refrigerant has boiled off. Some of the most common causes of leaks include:

• Mechanical damage. When outdoor copper refrigerant lines get bumped by lawnmowers, exposed to harsh weather, or stepped on by kids or workers, it can cause a leak.

• Corrosion. If the copper refrigerant line is exposed to contaminants, it can lead to corrosion and subsequent leaks. This could occur through direct contact with ductwork or other dissimilar metals, or it could result from exposure to a corrosive atmosphere from chemical storage or furniture refinishing

• Settlement. When the building or the condenser settles, it puts stress on the copper refrigerant lines, making leaks more likely.

Ultimately, a leaky line can reduce the quality of the performance of your air conditioning system, so it is critical to resolve the problem as quickly as possible.

Changing Out Your Copper Refrigerant Lines

When changing out copper refrigerant lines, you need to make sure that the length and the diameter of the new line fit with your air conditioning system. National Air Warehouse offers a wide variety of copper refrigerant line options, and we can help you figure out which one is right for your project. Contact us today for help!

For home builders and remodelers, summer is a peak time for business. With good weather and lots of light, you can really make progress on major construction projects. At this time of year, most people aren’t worried about indoor heating, but for all of your home building projects, you need to think about the best way to make sure the house stays warm during the cold, dark days of winter. That means choosing the ideal furnace for the building.

One of the factors to consider when choosing between furnaces is indoor airflow -- that is, the way that warm air flows out of the furnace. You can choose between an upflow furnace (with top discharge), a downflow furnace (with bottom discharge), and a horizontal furnace (with side discharge). As a home builder or remodeler, there are important things you need to know about each time of system in order to find the best one for your project and install it in an appropriate location.

Upflow Furnace (Top Discharge)

An upflow furnace draws air in from the bottom of the unit. The air is warmed in the heat exchanger, and then it is discharged from the top of the furnace into the ductwork of the house. Because heat rises, it is best to place an upflow furnace in a basement or crawlspace. If the building you are working on has a basement with a low ceiling, you need to make sure that the furnace fits in the space. That often means choosing a “lowboy” furnace (which is typically about 4 feet in height), rather than a “highboy” furnace (which is usually about 6 feet in height).

Downflow Furnace (Bottom Discharge)

Just as you would assume, the air travels through a downflow furnace in the opposite direction as it does through an upflow furnace. The air enters at the top, is warmed in the exchanger, and then is released from the bottom of the furnace into the ductwork of the home. Often, a downflow furnace is placed in the attic, but it can also be installed in the garage or some other location on the main level. A downflow furnace can be a good choice for a home that does not have a basement or a crawl space.

Horizontal Furnace (Side Discharge)

A horizontal furnace takes air in from one side, warms it in the exchanger, and then pushes it out into the ductwork from the opposite side. Horizontal furnaces, like “lowboy” upflow furnaces, usually have a relatively low vertical clearance, so they can be installed in basements and crawlspaces. When choosing between different horizontal furnaces for a home with highly specific space constraints, you may want to check to see if the furnace discharges the air to the left or to the right, in order to ensure that it will work for your project.

National Air Warehouse offers a wide range of upflow furnaces, downflow furnaces, and horizontal furnaces. If you are building or remodeling a home this summer and need help finding the right one for your project, contact us today!

This summer, you’ll be relying on your home air conditioner to keep your house cool. Memorial Day is only a week away, which means that for the next few months, your air conditioner will probably be running most of the time. Before the dog days of summer hit, it is critical to make sure your air conditioner is working properly, but you also need to think about indoor air quality. Even a well-functioning air conditioner can’t prevent the circulation of environmental pollutants without an air filtration system.

In recent years, better home construction and insulation methods have made buildings air-tight and easier to cool, which has improved energy efficiency. At the same time, however, these improvements make it harder for pollutants to escape from your home and be replaced by fresh air. As a result, the Environmental Protection Agency (EPA) now ranks indoor air pollutants among the top five environmental health risks. Your family may be exposed to a wide range of damaging particles in the air, including contaminants that can trigger allergies and cause breathing problems. Dust, pollen, pet dander, smoke, and even mold spores are all commonly found in the air in people’s homes.

Home Air Filtration System Options

One way to improve the air quality in your home is to install a home air filtration system. When choosing between filters, one of the most important factors to consider is the minimum efficiency reporting value (MERV) rating, which ranks home air filtration systems on a scale of 1 to 20, based on the following three categories:

• The filter’s ability to remove particles from the air.
• The filter’s ability to resist air flow.
• The expected operating lifetime of the filtration system.

Some of the most common types of systems you’ll find on the market today include pleated media air filters and washable/reusable air filters. There are benefits and drawbacks to each type, so you must consider your individual situation when choosing between them.

The main benefit of pleated media air filters is that they are particularly efficient for catching both small and large particles in the air, compared to some of the other types of filters that are available. They also operate relatively quietly, and they have relatively low airflow resistance. The MERV rating for pleated media air filters typically ranges between 5 and 13.

The best thing about washable/reusable air filters is their durability. They are designed to last a long time, and the washable filters are easy to clean and reuse. It is important to note that the MERV rating can vary widely. For traditional models, the rating is usually between 2 and 8, but for high efficiency models, it can be as high as 14 or even 16, depending on the airflow.
National Air Warehouse offers both pleated media air filters and washable/reusable air filters. With hot temperatures right around the corner, now is the time to add one to your home air conditioning system in order to ensure that you stay cool and healthy all summer long! If you need more help determining which air filtration system is right for your home, contact us today!

Over the last few weeks, we’ve been talking about getting your air conditioning system up and running for summer. That means you need to make sure that all components of your AC system are in top shape. If they’re not, you may need to repair or replace individual parts or the whole system. For owners of split systems, it is not uncommon to find that the condenser -- also known as the outside system or the outdoor unit -- has been damaged by inclement winter or spring weather. If you need to replace your condenser to get ready for summer, there are a few important things to know.

Condenser Basics

The condenser is an essential part of a split system air conditioner, which is why it is necessary to have it replaced if it is not working. After the refrigerant is heated in the compressor, it is transferred to the condenser, where it passes through a series of coils. As it passes through these coils, the heat from the refrigerant escapes through the fins of the condenser, and by the time it reaches the end of the coils, it is much cooler. Ultimately, the refrigerant leaves the condenser as a mist, which is turned into a gas and cooled in the evaporator coil before being blown out as cool air by the fan.

Today, most condensers come pre-charged with a refrigerant. R-410A is the newest type of refrigerant and the one to look for when you are buying a condenser. In contrast to alkyl halide refrigerants that contain bromine or chlorine, like R-22, R-410A does not contribute to the depletion of the ozone layer. It also allows for higher seasonal energy efficiency (SEER) ratings than R-22.

Understanding SEER Ratings

When choosing between condensers, you are likely to encounter models that have different SEER ratings. Most commonly, you can find 14 SEER and 16 SEER models, but 18 SEER condensers are also available. The SEER rating indicates the energy efficiency of the condenser model, with a higher number indicating a higher level of efficiency. Although it may cost more upfront, choosing a system with a higher SEER rating can save you money in the long-run and reduce the degree to which the refrigerant contributes to climate change.

Understanding Cooling Capacities

If you are replacing your condenser, it is essential that you choose a model with a cooling capacity (tonnage) that is consistent with your indoor system. If you are unsure about what size to buy for your split system, it can be helpful to contact your retailer.

National Air Warehouse provides a wide selection of condensers at multiple sizes, and we can help you figure out which size you need. All of our condensers come pre-charged with R-410A, and we ship to your home or office for free. Contact us today to replace your condenser before summer heats up!

As temperatures heat up and spring turns to summer, you have to make sure that your air conditioner is ready for the hottest months of the year. Last week, we went through the basic steps you should take at the beginning of the season to figure out whether you need to replace your air conditioner. Another issue to consider when planning for summer is whether or not you need a new evaporator coil. There are a few reasons why you might want to replace this essential part of your unit, including malfunction and inefficiency.

Malfunctioning Evaporator Coil

When going through the steps to check whether your air conditioner is ready for summer, you may find that your evaporator coil isn’t working. Here are some of the scenarios that suggest malfunction:

• When you flip the switch, the air conditioner will not turn on.
• You feel warm air coming through the vents instead of cool air.
• You hear unusual noises, like hissing and banging, when your air conditioner is running.
• There are air leaks around the indoor unit.
• The air conditioner turns itself on and off randomly.

If you find yourself in any of these situations, it may be unsafe to run the unit, and you should turn it off until the problem has been diagnosed. A new evaporator coil may be able to resolve the issue.

Inefficient Evaporator Coil

Older models of evaporator coils can prevent an air conditioning unit from running with maximum energy efficiency, so investing in a replacement could pay off in energy savings in the long run. Plus, most evaporator coils are only built to last for seven to ten years, so if you’ve been using your evaporator coil for almost a decade, there is a much greater risk that your evaporator coil will malfunction at the peak of summer, when it will be much worse to have no air conditioning while you get a replacement installed. If you’re looking to improve energy efficiency anyway, spring is the ideal time to replace the evaporator coil.

When looking for a more efficient evaporator coil, you can choose between models with different Seasonal Energy Efficiency (SEER) ratings. The most common options are SEER 14 and SEER 16 rated products. While SEER 16 rated evaporator coils provide slightly higher cooling efficiency, both can provide greater cooling efficiency than legacy models. However, when choosing a new evaporator coil, it is critical to make sure that it is the same size as your original model, or your  cooling efficiency could take a hit regardless of the SEER rating.
If you need to replace your evaporator coil before the summer starts, National Air Warehouse offers a wide selection of models at affordable prices, entirely online. Explore our offerings to find solutions for all of your HVAC needs.

It’s finally May, which means that summer is just around the corner. That means you can start looking forward to all the things you love about summer -- backyard barbecues, garden-fresh vegetables, beach days, baseball games on TV, ice cream... But it also means that temperatures are going to start creeping up, and you need to make sure that your air conditioning system is ready for the warm weather. Spring is the best time to determine whether your air conditioner will make it through another long, hot summer, or if it is time to replace it.

Checking Your Air Conditioner

It is critical to check your air conditioner in the spring to make sure it is working. That way, if you need to get a replacement, you will have ample time to look into the options and find one that works for your building and your budget. When getting your air conditioner ready for its first test after winter, there are a few things to check for before turning it on. Some of these can serve as red flags, indicating that it may be time to find a replacement.

• Outdoor unit panels. Sometimes, in the winter, the panels covering the electrical connections in the outdoor unit get misaligned or blown away by heavy winds. Severe damage or missing panels could be a sign that it’s time for a replacement. It is not safe to start the system until all panels are in place.

• Suction line insulation. The insulation of the suction line, which is the large pipe on the outdoor unit, may also be have been damaged, by ice or small animals. It’s usually not very hard to find replacement insulation before testing the unit, but if the suction line itself is damaged, you will likely need to replace your system.

• Debris in the outdoor coil and surrounding area. For the air conditioner to run efficiently, it is critical to remove debris from the outdoor coil, and also to clear the area around it of leaves and mulch that may have accumulated during the winter months.

• Dust in the supply vents and return air grills. Inside the building, it is common for dust to accumulate in the supply vents and return air grills. You can usually clear away the dust with a vacuum cleaner.

After all that is done, and it looks like everything is in place, it’s time to turn the air conditioner on. Within a few minutes, cool air should start to come out of the registers. If the air is warm, or if there is no air at all, you should turn off the unit immediately and start looking for causes of malfunction.

If it turns out that your air conditioner isn’t ready to handle the summer season, you’re in great shape, because you still have time to replace it before the temperatures get too high. Learn more about some of the best-priced replacement options offered by Air National Warehouse.