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Welcome to "Isi Knows" - The Best FAQ for Buying New HVAC Systems in San Antonio!

Welcome to “Isi Knows” . . . . the most comprehensive FAQ for when you’re considering a new air conditioning system, new heat pump system, a new furnace, new heating systems or a new commercial packaged AC-Heating unit.

Knowledge is power. When you’re considering buying a new HVAC system, getting educated before you make a buying decision is very important. Making the right choice can save you money right off the bat and save you headaches in the long-run!

Check in with Isi Knows for the latest blogs and facts about new HVAC systems and recommendations!

Isi Knows

It’s like an online Air Conditioner school for regular people!
Learn before you buy a NEW AC system!

Whether you’re buying your first HVAC system or a seasoned homeowner who’ s had to buy a new Air Conditioning Unit before, there are many important things to know before installing a new HVAC system. When your’e choosing a new heat pump system, mini split AC, or a central air conditioning system, it’s important to hire a professional with years of experience and good reviews to make sure you’re not just getting “sold.”

In addition to new technology in today’s HVAC systems (making them more efficient than ever before), your HVAC contractor will be able to help you select the best system for your home, taking into account the size and characteristic of your home, as well as comfort needs, your family’s habits and budget concerns.

If you are installing a brand-new HVAC system or considering whether it makes more sense to repair instead of replacing, This quick article should help steer you in the right direction.

Ready to learn in plain English? Here we go!

While you shop for a new AC System, you’ll have to consider the following:

Consider Cooling / Heating Size, Capacity, and Type of System
One of the first things you should check is the heating and cooling capacity of your new A/C system. Ask your HVAC technician about the reviews of the system and whether they meet the minimum requirements and are properly sized for your home. These companies that offer a “new system for $xxxx” is just trying to get their foot in your door. The reality is, a new HVAC unit will have to be properly sized for your home. Do you have a one-story or a two-story? Do you have really good insulation or is it an older home? Does your family like it really cold in your home? All of these factors play into how your HVAC system has to be properly sized for your home and for your family needs. How can any company throw out a price for a new AC unit without considering all of that? The answer is…. they can’t.
Heating system capacity is measured by BTU (British Thermal Unit), which is equal to the amount of heat needed to raise a pound (by weight) of water by 1-degree F. While input capacity measures the amount of gas burned (not taking into account losses due to the combustion process), output capacity is how much usable heat is generated. When looking at BTU ratings, make sure you know whether it is input or output. Newer units have smaller input BTU rating since they are more efficient at generating more heat and thus more BTU output. Generally, the higher the BTU rating, the greater the heating capacity.
In addition to that, cubic feet per minute (CFM), how many cubic feet of air can pass by a fixed point per minute, is essential for choosing the right capacity for your HVAC system.
Thankfully, choosing the right size, capacity, and type of HVAC system is the specialty of our HVAC system installers here at Air & Plumbing Today. Complicated measurements are used, such as ACCA’s Manual J requirements for properly sizing an HVAC system. If you buy a system that’s too big and you’ll waste a lot of money and energy; buy too small of an ac unit, and your new Air Conditioning system will be overworked without you or your family ever feeling completely comfortable.
If your HVAC contractor tries to size your new HVAC system based on square footage alone, they are making a mistake that you’ll end up having to pay for. Make sure your HVAC technician fully inspects the home prior to sizing a new system. They should never simply replace the existing system with a similarly sized HVAC system.

Consider Cooling/Heating Size, Capacity, and Type

Check the capacity of your new air conditioner before you buy so that you can choose the best air conditioner for your home. Instead of British Thermal Unit (BTU), air conditioners’ cooling capacity is measured by Ton.
1 Ton is equal to about 12,000 British Thermal Unit Per Hour (BTUh). Learn why air conditioner capacity is measured in tons here.
As with your AC and heating systems, it’s important to choose cooling capacity based on the size and needs of your home. By consulting with one of our licensed and experienced technicians or installers, you can choose an air conditioner to provide the right amount of cooling in all areas of your home.
Each brand of Air Conditioning system has a website with a lot of information and specs about the system – print the information off and discuss it with your HVAC installer. We carry Comfortmaker and Trane brands. Click on either to see all of the different systems and specs for each.

Consider Your New HVAC System Energy Efficiency

Heaters and air conditioners consume a significant amount of energy. In fact, around half of your home’s electric or utility cost goes toward heating and cooling your home (according to the U.S. Dept. of Energy).
Therefore, it’s important to check the energy consumption of your new HVAC system before purchase. This will help you to save energy and money across your home.
A gas furnace’s heating efficiency is measured by its Annual Fuel Utilization Efficiency (AFUE). The higher the AFUE number, the more efficient the furnace.
An air conditioner, on the other hand, uses Seasonal Energy Efficiency Ratio (SEER) to measure its energy efficiency. The higher the SEER rating, the more energy efficient the air conditioner. SEER energy ratings will drastically change in 2023 so this is important to look at with a professional.
Heat pumps use a rating very similar to SEER, called “Heating Seasonal Performance Factor” (HSPF). This number measures the heating portion of the heat pump. Again, the higher the HSPF number, the more efficient the unit is.
For you to get your new HVAC system to reach the optimum efficiency printed on its Energy Guide Label, a professional contractor will need to properly install it. The energy efficiency ratings are meaningless unless the unit is improperly installed.

Consider Your New A/C System Maintenance and Indoor Air Quality

The maintenance of your new HVAC system is very important for them to work properly for a long period of time as well as lasting for many years. Before you install a new HVAC system, keep in mind that you will need to regularly maintain the unit to keep your manufacturer’s warranties in effect. Neglecting regular maintenance will void almost all system warranties. Consider signing up for an HVAC maintenance plan. And don’t forget to change your air filter every 30-60 days – more frequently in the peak summer months!
Additionally, if indoor air quality (IAQ) is a problem in your home, ask your technician about effective ways to improve the air quality. Various IAQ solutions are available, such as thicker air filters, air purification systems, humidification control, and ventilation products. Discuss your IAQ concerns with your contractor before any work begins.

Ask About The Noise Levels on Your New HVAC Unit

Is your neighborhood tightly packed? Is your home very close to your neighbor’s home? Make sure your new HVAC system isn’t going to be too noisy or loud for your neighbors. Although the HVAC industry has made great strides to reduce HVAC operating sound, check the noise levels of the system before you make a decision. Ask the manufacturer and your installer about noise levels, measured in decibels (db). Look for systems that are under 60 db. If you have a difficult neighbor, a new, noisy AC unit may be something that they could complain about to your HOA or even the city you live in. Make sure your new Air Conditioning system is as quiet as your current system.

How Much Does a New HVAC System Cost?

The best way to find out how much a new heating and/or cooling system will cost is to call professional HVAC Installers at Air & Plumbing Today. We can text you an estimate or we can send to send an HVAC installer to your home and provide a quote. Remember, as we mentioned earlier, one price does not fit all. You must get a proper quote to ensure you get the proper system for your home.
Your new HVAC unit requires engineering and working with components of the older system, such as ductwork, wiring, ventilation, and controls. It’s important to hire an experienced HVAC company to make sure everything works in concert.
The price of your new HVAC system is contingent on many factors.
By taking all of this into consideration, we know that if you choose Air & Plumbing Today, you will be extremely happy with your new HVAC system and the comfort it provides for many years. You’ll also be happy when you see your electric bill going down, even in the summer!

How Long Does an AC System Last in Texas?

Read this article to see how long Air Conditioning Systems last in San Antonio.
Need a quote on a new HVAC system? Call us at Air & Plumbing Today! We’ll respond as fast as possible and fix your frozen or burst plumbing at a very affordable rate. Call us at 210-519-5959 or book online on our home page!


Most systems have a lifetime of 10 to 20 years. As your equipment gets older, it’s efficiency can decrease dramatically. You may notice that it gets noisier and needs repairs more often. When a unit begins to show it’s age, you have two choices. You can overhaul the system or replace it. Because heating and cooling technologies improve over time, a new system designed with newer, more energy-efficient equipment makes sense, especially if your system is 10 or more years old. We can estimate the cost of a new system as well as a payback schedule that will show you how newer technology will pay you back in lower energy usage.


No. Replacing only the outdoor unit will lower the efficiency of the unit. In fact, you can lose up to 15% of the unit’s efficiency! Even worse, your system may fail sooner than normal and most manufacturers’ warranties will be voided. You should always replace the indoor cooling coil with the outdoor unit.


No, you don’t want your air conditioner to be too big. Air conditioners control the comfort level in your home by cooling the air and by removing humidity. An oversized air conditioner will cool your home faster, but it will use more energy and will not remove humidity adequately.

A unit that is too big for your home will have short run cycles. It may take only a short time to cool the air, but the unit shuts off before enough air blows across the indoor coil where moisture condenses into water and drains from your system. Too much moisture left in the air can lead to mold and mildew problems.

These short run cycles also mean your system starts and stops more often which uses more energy and causes a lot of wear and tear. An air conditioner operates more efficiently during long run cycles.

The same holds true with heating systems. An oversized furnace will warm the house quicker, but it uses more fuel and causes greater temperature swings in the home.


An air conditioning matched system is important for a variety of reasons. One is comfort. When all your components are properly sized to your home, you can control exactly how much heating or cooling you need so you can relax. Also, a properly sized matched system enables every component to perform as designed, meaning proper cycle times are maintained, humidity is controlled, and system sound is minimized.

Another reason matched systems are important is efficiency. Most systems people buy are too large for their homes, which uses more energy than needed for your home. A matched system outlined by a dealer who has completed a load calculation for your home provides just the right amount of heating and cooling you need so you get the most value for your utility dollar.


At the risk of telling you something you’re tired of hearing, replace the AC air filter in your air conditioner or furnace on a regular basis – ,pre often in the summer than in the winter. Dirty air filters reduce the amount of air flowing through a system and make the furnace work harder to maintain the temperature. How often you change the filter depends on the type of filter you use, if you have pets, and the size of your equipment. Please give us a call and we can give you proper guidance.


Proper air filtration is just as important to the health of your heating and cooling system as it is to the health of your family. Without proper filtration, dust and dirt can build up on your system which impacts operation and efficiency. A high-efficiency filter will remove more dust, dirt, pollen, mold, and other particles from the air. If you suffer from allergies or other respiratory problems, you should strongly consider a high-efficiency filter. No matter what type of filter you have, make sure you change it regularly.


Yes. Keeping your system properly maintained will lower energy and repair costs, prevent breakdowns, and prolong the life of your equipment. Neglecting necessary maintenance ensures a steady decline in air conditioning performance while energy use steadily increases.


Without warranty coverage, a breakdown can mean significant expense in parts, labor, or both. However, with one of our service agreements, you avoid that unexpected significant expense. While no warranty can guard against every possible problem, we can explain the broad range of protection our service agreements afford.


With a high efficiency air cleaner, you can remove up to 99% of the pollen and spores that find their way into the home. There is also a great reduction in household dust, dirt, smoke, and other air pollutants. Your indoor air will become cleaner and fresher while reducing the allergens and dust that circulate throughout the house. With a whole house humidifier, you can relieve the irritating discomfort of dry indoor air. The humidifier reduces itchy skin, scratchy throats, static electricity, and damage to your furnishings and woodwork. Since humid air feels warmer than dry air, you do not have to set the thermostat as high to feel the comfort you want. A lower thermostat setting will reduce the costs of your energy bill.


Molds are part of the natural environment. Outdoors, molds play a part in nature by breaking down dead organic matter such as fallen leaves and dead trees, but indoors, mold growth should be avoided. Molds reproduce by means of tiny spores; the spores are invisible to the naked eye and float through outdoor and indoor air. Mold may begin growing indoors when mold spores land on surfaces that are wet. There are many types of mold, and none of them will grow without water or moisture. Click here to learn more about mold prevention in your home from the EPA.

When humid air passes over chilled cooling coils, water condenses and drips through the coils into a collection pan, from which it continuously drains. Problems with these systems may occur when this water collects and becomes stagnant when it becomes blocked, either on the coils or in the drip pan. The pan will grow mold that can infect your home with dangerous mold spores very quickly. Problems also exist when the HVAC ducting contains microscopic mold spores that stay continually present and blow contaminants around the home or office often caused by mold in other parts of your home.

You can do 3 things to prevent mold growth in your system:

Preventative maintenance will ensure that the collection pan under the indoor coil stays clean and clog free.
Install ultra violet lights next to the cooling coils to kill any mold or bacteria growing on the coils or collection pan.
Keep your ductwork clean and use a high-efficiency filtration system to keep your entire HVAC system clean.


SEER, AFUE and HSPF are all measures of energy efficiency. Air conditioners may look similar, but their Seasonal Energy Efficiency Rating (SEER) can vary widely. Higher SEER numbers save more money spent on electricity. A 13 SEER air conditioner, the EPA “current minimum standard”, uses 23% less energy than a 10 SEER unit (EPA standard up until Jan. 2006). Even though 13 SEER is the minimum efficiency available, we currently offer a line of air conditioners that start at 13 SEER and go all the way up to a 21 SEER . Depending on your average usage, higher SEER air conditioners can significantly reduce your electric bill.

Heat pumps have SEER ratings like air conditioners and Heating Seasonal Performance Factor (HSPF) ratings for measuring heating efficiency. Higher HSPF ratings mean greater energy savings. The HSPF scale range is 7.5 to 13.0.

Today’s new high-efficiency furnaces can save up to 50% in operating costs over a ten-year-old furnace. Many 1990 and earlier model furnaces have Annual Fuel Utilization Efficiency (AFUE) ratings of 65% or less. The minimum AFUE rated furnace that can be sold in the United States as of May 1, 2013 is 80% in southern states and 90% in northern states.

Our current product offering starts at this minimum AFUE rating and goes all the way to a very efficient 98.3% AFUE rating. Depending on your average usage, higher AFUE rated furnaces can significantly reduce your gas bill.



Upgrade to a high-efficiency air conditioner – Swapping your old, inefficient air conditioning system for a high-efficient one can cut electricity bills by one-third. Consult one of our professional technicians to ensure your system is the right size for your home, and you aren’t over- or under-cooling for your space needs.

Turn up the temperature — To save electricity during the summer, set the temperature above 75° as every degree below this will add an extra three to five percent to your energy bill.

Install ceiling fans — Change the direction of airflow on your ceiling fans. In the summer, the blades should operate in a counter-clockwise direction as a way of creating a nice, gentle wind.

Have an annual maintenance performed — Having an annual maintenance performed on your air conditioner by a licensed technician will help ensure it operates at its peak efficiency and catches any potential breakdowns before they occur.

Don’t block vents in well-used rooms — Keep your supply and return air vents free of objects like blinds, carpets or furniture so your air conditioner can operate efficiently and there is even cool air distribution.


Upgrade to a high-efficiency furnace — New high-efficiency furnaces use up to 50% less fuel than an older system. It can save you up to 25 percent of your home-heating costs in one year, and within a few years, you’ll have recovered the initial cost of replacing/upgrading your furnace. Choosing a model with an energy efficient motor can save 20 to 50 percent of the energy needed to continuously operate a fan motor. Let us show you the advantages of replacing your old furnace today.

Have an annual maintenance performed — Having an annual maintenance performed on your furnace by a licensed technician will help ensure it operates at its peak efficiency and catches any potential breakdowns before they occur.

Install a programmable thermostat — A programmable thermostat enables you to control your home’s temperature when you’re away or asleep. For every 1° you lower your thermostat for seven hours per day, you save one percent on your heating bill.
Don’t block vents in well-used rooms — Keep your supply and return air vents free of objects like blinds, carpets or furniture so your furnace can operate efficiently and there is even heat distribution.

Install ceiling fans — Change the direction of airflow on your ceiling fans. In the winter, the blades should operate in a clockwise direction helping to push the warm air from the ceiling down into the room.


The average home spends about $1,900 annually on energy bills. Heating and cooling accounts for as much as half of a home’s energy use. The EPA provides important recommendations for energy-efficient equipment, including proper sizing, quality installation and maintenance, and other home improvement considerations to help you get the most out of the heating and cooling products you purchase, save energy, and save as much as 20% annually on your total energy costs.

ENERGY STAR qualified products prevent greenhouse gas emissions by meeting strict energy efficiency guidelines set by the U.S. Environmental Protection Agency (EPA) and the U.S. Department of Energy (DOE).


Heat pumps are a great solution for your home comfort system because they work to provide both heating and cooling. Heat pumps have SEER ratings like air conditioners and Heating Seasonal Performance Factor (HSPF) ratings for measuring heating efficiency. Higher SEER and HSPF ratings mean greater energy savings.

Heat pumps are a very efficient alternative to electric heat. A heat pump works the same as an air conditioner in the summer, but it runs in reverse in the winter to heat your home. The system will be matched with a backup heating source, most often electric heat for those extremely cold days of winter.  See our heat pump page for even more info!


Variable speed fans operate on a simple principle: they are able to spin at different speeds depending on the heating and cooling needs of your home. Usually, they operate at lower speeds, delivering a steady, reliable stream of warm or cool air to your home. This helps control humidity levels, utility costs and system noise. When conditions become more extreme, the fan speed increases so that the system can meet increased demand, guaranteeing that on even the hottest days or coldest nights, you’re comfort needs will be met.


2-stage cooling is a method of cooling that can better manage the cooling of your home while outdoor temperatures are changing. It can also better maximize indoor comfort and energy efficiency. 2-stage cooling systems are typically the most energy efficient systems out there.

2-stage cooling can be done by having one unit with two compressors, one small and one large. The small one is typically capable of putting out about 50% the capacity of the larger one. The second way to have 2-stage cooling is to have a single scroll unloading compressor. This compressor can unload its capacity down to about 66% of maximum capacity. Both these methods of getting 2-stage cooling allow the unit to run at a lower stage when the high stage is not needed. By doing this, energy is saved.

2-stage heating has the same principle as 2-stage cooling. It allows the unit to adjust itself based on the amount of heating that is necessary. 2-stage heating is a good way to save on heating costs.

A heat pump system would have two different sized compressors, a small and a large one. The compressor that is used at a given time would depend upon the need. If only a small amount of heating is necessary, the smaller compressor would be used to save energy. The large compressor would only be used when a large amount of heating was needed.

A gas furnace that is 2-stage has a modulating gas valve that regulates gas flow depending upon the need.


Normal cooling settings are 75 degrees – 80 degrees. Normal heating settings are 68 degrees – 72 degrees. You should always set your thermostat to the highest possible setting that is comfortable for you in the summer, and the lowest comfortable setting in the winter. Setting your thermostat in this way will maximize your energy savings. On average, every 1 degree of temperature change is equal to about 1% energy savings. For example, changing your thermostat setting from 75 degrees to 76 degrees in the summer could result in savings on your cooling costs.


This can occur for many reasons; uneven solar heat load through windows, an undersized system, improperly balanced or clogged system or a single system serving a two-story home with no zoning control. Each situation is different, usually requiring an onsite analysis with problem specific recommendations. Please call to arrange for us to see your home.


Yes. As of January 2010 the refrigerant R-22 (what consumers call Freon®) is no longer allowed to be used in the manufacturing of new equipment. R-22 has been used as the “standard” refrigerant for many years but has been found to be harmful to our planet by our government. All new air conditioners and heat pumps use R-410A, the more “environmentally sound” refrigerant.

R-22 is still the most commonly used refrigerant in existing air conditioning equipment in residential homes today. However, per the Montreal Protocol, caps have been established to eliminate the production of R-22. In 2004, there was a 35% reduction; in 2010 there was a 65% reduction; in 2015 a 90% reduction; and finally in 2020 a 99.5% reduction in the production of R-22. This means that during the time of these reductions with high demand, the price of each pound of R-22 refrigerant could potentially skyrocket.

If you are considering replacing your existing air conditioning equipment, most higher efficiency products have already made the switch to R-410A, the more “environmentally sound” refrigerant.


A difference of 6 decibels (such as between 72 dB and 78 dB) is technically a four-fold increase in compressor sound when rating air conditioners or heat pump units. However, it takes a difference of 10 decibels to double the loudness. It is also noted that it takes approximately 3 decibels for the average human ear to discern any difference in loudness at all.

Great strides have been made in reducing the operating sound level of equipment. We will be happy to show you the difference in sound ratings with our product line.


Yes. Each year, carbon monoxide kills more than 200 Americans and sends nearly 5,000 more to emergency rooms for treatment, reports the U.S. Consumer Product Safety Commission (CPSC). Where does it come from? When carbon-based fuels such as gas, oil, kerosene or wood burn, they produce gases. When fuel combustion or burning isn’t complete, carbon monoxide enters the air. The CPSC advises that carbon monoxide detectors are the only way to alert yourself to the presence of toxic gas in your home. If you wake in the night with a headache — and especially if another member of the family complains of a headache or is difficult to arouse — get out of the house fast and seek medical help. We recommend carbon monoxide detectors be installed in your home!


Propane (LP) gas: You have this type if your gas comes from a tank located outside close to your house. Propane is stored as a liquid under pressure in tanks and cylinders. In most residential applications, propane is used as a vapor. When liquid propane changes into a gas vapor, it expands in volume. This means that even a small leak of liquid propane can result in a much larger quantity of propane vapor, which can be especially dangerous in a confined space. A chemical odorant has been added to propane to give it a distinct smell. Learn to identify this odor. Propane gas is heavier than air, so it will sink to the floor and spread. To check for the presence of propane, carefully smell all over a room, especially in low spots.

If you smell propane (LP) gas:

Exit your home immediately.

Propane gas can ignite easily. Do not light a match, start an engine, use a cell phone, or do anything that may create a spark.

From a safe area, contact your propane supplier and call 911.

If you are able, shut the propane gas supply off at the tank.

Stay away from your home until you’ve been told that it is safe to return.

Natural gas: You have this type if you have a gas meter and pay a natural gas supplier or utility. A chemical odorant has been added to natural gas to give it a distinct smell. Learn to identify this odor.

If you smell natural gas:

Exit your home immediately.

Do not light a match, start an engine, use a cell phone, or do anything that may create a spark.

From a safe area, contact your gas company or call 911.

If you are able, turn the gas off at the meter.
Stay away from your home until you’ve been told that it is safe to return.

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