HVAC Questions | Heating & Cooling Advice

Change Dirty AC Filters

Airflow is critical. Air can’t flow properly through air filters when they get clogged with dust. This means your Air Conditioner has to work harder to cool the same space. An Air Conditioner that is working harder draws more electricity, which means higher energy bills. Believe-it-or-not, not changing your air filters can also lead to expensive repairs, and eventually require replacement. Replacing dirty air filters is a critical part of maintaining your Air Conditioner.

Your MD Air Conditioning pro will check your Air Conditioning and Heating unit twice per year as weather changes because any machine with moving parts requires maintenance to keep it from breaking down. It’s important that belts are not cracked and dry, ventilation ductwork is not gapped, cracked or rusted, and components, such as coils and fans, are clog-free and adequately lubricated for unimpeded operation. But it’s up to you to keep your filters changed!

How often should one change the air filter on their air conditioning unit?

How often you need to change your filter will vary depending on your make and model, the presence of pets in the house, and how often the doors are opened and closed. As a rule, most air filters should be changed once per month. The air filter is especially important if the HVAC unit is going to be on the clock year-round.

Check your filter’s condition and change it once a month if:

You run your unit six months a year to year-round.
You have pets. Pet dander can become airborne and circulate through the home’s ventilation system just as typical household dust does.
You have a large family. More activity means more household dust, dirt and debris.
You smoke indoors.
You or someone in your household suffers from allergies or a respiratory condition.
You live in a particularly windy area or experience high winds for extended periods, especially if there are no nearby shrubs or trees to provide a natural windbreak.
You live in an area prone to or having recently experienced any wildfires. Airborne ash outdoors will eventually find its way indoors.
You have a fireplace that you occasionally use.
You live on a working farm or ranch. Dust and dirt that gets kicked up by outdoor work activity and/or large animals can be pulled into the home’s ventilation system, especially through open windows.
You have a large garden. Depending on its size and how often you work it, tilling the soil, planting, pulling weeds, using herbicides and pesticides, and even watering mean that dirt, chemicals and condensation can be pulled into your home’s ventilation system.
There is construction taking place around or near the home. You may be installing a new roof or a pool, or perhaps a neighbor is building a home or addition. Even if the activity is only temporary, dust and debris from worksites adjacent to or near the home can be sucked into the home’s ventilation system, and this increased activity can tax your HVAC system.

Change the filter immediately if:

The filter is damaged. Whether it happened inside the packaging or while being installed, a damaged filter that has bent fins and collapsed cells or holes will not work as well as an undamaged filter, so treat it like precious cargo when taking it home from the local hardware store.
The filter is damp. A filter affected by moisture intrusion, system condensation, or even high indoor humidity can quickly become moldy and spread airborne mold spores throughout the home via the ventilation system. Not to mention leaving an unwanted odor.
There is mold on the filter. Mold spores already infiltrating the home via the HVAC system are not only bad for the unit itself, but they can pose a health hazard for the family, ranging from an irritated respiratory system to a serious allergic reaction. The musty smell produced by a moldy HVAC filter is also unpleasant and may take a while to completely eradicate from inside the home. If you discover that you have a moldy air filter, it’s important to have the cause investigated further by an MD Air Conditioning pro.

Have more questions? Call MD Air Conditioning and Heating at (210) 569-0928 for fast and friendly answers to your questions.

Cooling BTUs

Cooling BTUs What Size Unit Works Best for YOU!

A well-designed home includes a “Manual J” calculation, often called “Heat Load Calculation” or “Cooling Load Calculation” which indicates how much cooling and heating a home needs to stay cool and dry in the summer and warm in the winter. Unfortunately, sometimes Manual J is neglected in the design of a home, especially an older home. Room additions can also complicate the cooling and heating loads in your home. If you are too warm in some areas of your home, and too cold in others, it may be time for another look at your Manual J calculation.

Manual J was developed by heating and air conditioning engineers and has been used for decades to accurately size heating and air-conditioning equipment. After completing load calculations, your MD Air Conditioning and Heating technician can help you select the proper Central Air Conditioning Unit to satisfy the load.

What does a Manual-J Load Calculation report actually provide?

Heating Load – Heating Load is the amount of heat your home requires on the coldest day of the year, in the middle of the night (when there’s no heat from the sun). This is the number, or load, used to choose your Heating Unit.

Sensible Cooling Load – This is the sensible heat (the amount you can feel or measure with a thermometer) that your system needs to be able to remove on the warmest day of the year, during the day (when that San Antonio sun is heating the building). This is used with the Latent Cooling Load to choose your A/C system.

Latent Cooling Load – This describes the volume of moisture your system should be able to pull out of the air under “worst-case” conditions. The worst-case scenario for latent loads is when it’s hot and wet outside, or the Springs-like-Summers we get in San Antonio.

The two cooling loads are used to choose Air Conditioning Units and Heat Pumps. When it comes to a Furnace or HVAC Unit, all three loads come into play. Your system should be able to supply the proper amount of latent and sensible cooling and be less than 15% over-sized. This way your system is capable of proper dehumidification, the removal of water from the air.

Ready to learn more? Call MD Air Conditioning and Heating at (210) 569-0928 today to schedule your appointment.

Duct Static Pressure

Understanding Duct Static Pressure

Why is Duct Static Pressure important? Simply put, we all want to keep our electricity bill as low as possible. Poor installation, duct air loss, and poor seasonal Air Conditioning maintenance can lead to inefficiencies in your Air Conditioner which translates to more work for your A/C System and higher electrical bills for you.

What is Duct Static Pressure? Think of blood pressure checks. When you visit a doctor for a checkup, the first thing they check is blood pressure. It’s the same with Static Duct Pressure. If the pressure is too high or too low, it is an indication of the failing health of your HVAC system and various treatments are in order. Your MD Air Conditioning and Heating technician is trained in tuning your system to make sure you get the optimal airflow delivered to every room of your home, year-in, and year-out.

An ideal duct system has an air register blowing air into every room. Most homes, however, have only one or two return registers for the entire house. Air from other rooms must find its way back to these registers to be cooled or heated, depending on the season. Closed rooms without a register are a common air circulation problem because air has no place to go in order to get reheated or re-cooled.

Blockage of supply or return air ducts and registers can increase or decrease pressure in a single room, which means poor performance and more air leakage through the building envelope. Airflow restrictions are hard on the return-air side of the system, so repairs should start with return ducts if necessary.

Finally, air from every supply register must have an unobstructed path back to a return register. An MD Air Conditioning and Heating technician can install louvered grilles in walls and doors, between-room ducts, and additional return ducts and registers to improve air circulation.

MD Air Conditioning Technicians may also increase airflow by cleaning the evaporator coil, increasing fan speed, or enlarging or adding ducts—especially return ducts. While it might seem drastic, sometimes enlarging ducts may be the only way to fix poor comfort or high energy costs.

Remember, every home is different. Call MD Air Conditioning and Heating today at (210) 569-0928 so you can start feeling the right pressure for your comfort and cost savings.

Is Your Air Conditioner Obsolete?

For Years, Air Conditioners were Part of the Problem

Modern Air Conditioners follow strict guidelines that help protect the environment while protecting you, the consumer.

The government is phasing out Freon 22 as a refrigerant by 2020, because it has been identified as an environmental hazard that causes ozone depletion.
Environmentally-friendly refrigerants like R-410A do not contribute to ozone depletion, but operate at higher pressures which means technicians must have R-410A Certification.
Out-dated Air Conditioners are the biggest energy consumers in our homes.
Modern Air Conditioners use multiple-speed motors so you only use the electricity you need.

What is NATE Certification?

Without oversight and certification, anyone could show up at your door with a set of gauges, a bottle of Freon and a roll of duct tape and call himself a technician. In serving San Antonio home owners for a minimum of sixteen years each, MD Air Conditioning and Heating technicians have seen all manner of Wild-West repairs and installations by fly-by-night operators. NATE stands for North American Technician Excellence. It was founded by like-minded experts in the industry who wanted to see more accountability for our customers.

There are over 32,000 NATE-certified HVACR technicians providing world-class service and installations throughout North America and MD Air Conditioning has answered the call in San Antonio. The new 2013 American Home Comfort Survey found that roughly 30 percent of homeowners who recently had new HVACR equipment installed had to have a technician come back to solve a problem. MD Air Conditioning and Heating strives to fix it right the first time, and help you to keep it properly maintained for the future.

NATE is an independent organization that certifies the installation of services technicians with a knowledge-based test. From the perspective of manufacturing, distribution, and contracting, there were concerns that many individuals involved in servicing and installing systems and equipment lacked the proper knowledge and experience.

And as a result, consumers and contractors were unhappy with recurring callbacks and added costs; manufacturers were receiving unnecessary and costly returns of equipment that were not defective, and technical advisers were plagued with repeated calls on service and installation questions that should have been common knowledge. NATE was founded in 1997 and is the nation’s largest non-profit certification organization for heating, ventilation, air conditioning, and refrigeration technicians. The NATE organization is owned, supervised, operated, supported, and developed by the entire HVACR industry.

But what does it mean to be NATE certified in HVAC? NATE certification tests represent real-world working knowledge of HVACR systems. Developed by a committee of industry experts nationwide, the NATE exams represent HVACR topics pertinent to contractors, educators, manufacturers and utilities alike. All of the NATE tests are rigorous, multiple-choice, knowledge-based tests and validate a technician’s knowledge. NATE candidates may earn Installation and/or Service certification in one or more specialty areas.

What Does NCI Certification Do For You?

When learning stops, you’re walking backwards. Your MD Air Conditioning and Heating technicians put the latest continuing education programs to work for you. The National Comfort Institute Inc. (NCI) provides training, test instruments and consultation to HVAC contractors worldwide so they can provide home owners and business owners safer, more comfortable, and more energy-efficient homes and offices.

National Comfort Institute trains heating and air conditioning professionals to test systems just like yours to determine existing efficiency and delivered comfortable air. NCI Certified Professionals that complete NCI’s System Performance and Air Balancing courses are certified to test your heating and cooling equipment and make the necessary recommendations and repairs to maximize the results in your home. NCI also trains them to pinpoint troubles in your system and fix these problems.

How does the proper training translate to value for the consumer? The Air Force entrusted MD Air Conditioning with a major contract at Lackland Air Force Base to install and balance all the air conditioning for their newest subdivision, including nearly fifty, two-story homes.
What is air balancing? Air balancing is about delivering the right volume of air to every room in your home or office. Factors that affect air balancing include the capacity of your system, size of your plenum, duct size and length, door and hallway placement, and more.
Why inspect your air conditioning ducts? Ducts have to be sealed and unrestricted to function properly. A 30% return duct link can cut cooling capacity by 50%. Your MD Air Conditioning expert knows where to look for weak spots and other possible problem areas.

What Are The Benefits to an HVAC Technician Who is NCI Certified?

Certification by the National Comfort Institute means your technician has been trained to deliver top-notch customer service. Each NCI recipient brings with them international credibility, status, and legitimacy throughout their HVAC career.

MD Air Conditioning & Heating works with only the Best.

We want to provide you, the customer, with the best customer experience when providing HVAC services. That is why we only work with the best-trained technicians who have the credentials to prove it… because in order to be the best you have to work with the best.

Troubleshooting Tips for Your AC System

trane rep talking to homeowners in their kitchen

The first thing to do in a cooling emergency is call MD Air Conditioning and Heating at (210) 569-0928! When your central air conditioning isn’t working like it should, we want to help you get it going again just as soon as we can…and we will.

Before we arrive, here are techniques you can use to help keep your family cool:

Turn off any un-necessary sources of heat within your home, such as lights, TVs, or other appliances…all these contribute heat to your home’s interior air. If you have a microwave oven, use it to prepare meals rather than your stove-top or regular oven.
If you have ceiling fans, turn each on to its highest speed in whatever rooms your family is occupying – rapid air movement will help you feel about 10° cooler than the actual air temperature.
If you don’t have ceiling fans, but you do have portable fans, place them so each blows constantly on each family member. Be sure to keep each out of the reach of any small children in your home.
If fans alone do not seem to keep you comfortably cool, then in addition to the fans, drape your head with a damp washcloth, or place a wet washcloth on the back of your neck, or sprinkle water on your shirt. As much as you can, let the fans blow across these wet cloths. Even though our air usually contains quite a bit of moisture, the evaporative cooling effect of air across wet will add some additional cooling.
Crack some ice cubes and let every family member suck on the pieces…this will help cool you from the inside out. Also, be sure everyone is drinking cool water at least every 15 minutes.
If you still feel uncomfortably hot, or if anyone in your family seems to be getting red-faced, drowsy, or short of breath, take a cool-water shower or soak in a bath with tepid water. Cool water will draw a substantial amount of heat from your body.
If it’s going to be more than a few hours before our service technician is scheduled to arrive, you may want to consider taking your family to an air-conditioned public space such as a shopping mall, especially if the outside air temperatures are above 95 degrees.

These are just a few ideas to help you stay comfortable until your system’s normal cooling can be restored. You may have other ideas yourself. The important idea is to keep you and your family safe from heat-related illness until your air conditioning system can be brought back to life.

Troubleshooting Tips for Your Heating System

trane tech showing homeowner how to us thermostat

Obviously, the first thing to do when your heat is out is call MD Air Conditioning and Heating at (210) 569-0928! When your central heating system isn’t working like it should, we want to help you get it going again just as soon as we can…and we will.

Before we arrive, here are tips you can use to help keep your family warmer in the meantime:

Turn on any low-wattage sources of heat within your home, such as lights and TVs…all these contribute heat to your home’s interior air. Prepare your meals using your stove-top or regular oven rather than using the microwave oven.
If you have ceiling fans that allow you to reverse their direction of rotation, reverse each fan so its blades are pushing air UP toward the ceiling rather than blowing downward. Turn each ceiling fan to its low or medium speed setting. The objective here is to keep MIXING the warmest air near the ceiling with the cooler air from lower in the room, without creating much of a breeze. Since warm air rises, you’ll find the air temperature near the ceiling toastier, but that doesn’t help you unless you can get it moved back down to the level where you are.
If you have ceiling fans, but can’t reverse their rotation, just turn them to the lowest speed setting to let them push the warm air near the ceiling back down into the room.
If you don’t have ceiling fans, but you do have portable fans, angle them as best you can to move air up toward the ceiling. Again, the object here is to mix cooler, lower air with the warm air near the ceiling. Be sure to keep fans out of the reach of any small children in your home.
Adjust your family’s clothing – dress in multiple layers. Each additional layer of material helps trap some body heat we each naturally generate. Three layers, such as a long-sleeved shirt worn over a short-sleeved shirt worn over a T-shirt can provide substantial comfort inside in cool weather. A fourth layer, if desired, could be a light windbreaker or hoodie.
If it’s going to be more than a few hours before our service technician is scheduled to arrive, or even overnight, you may want to consider purchasing an oil-filled electric room heater for each of your bedrooms. These are shaped much like an old-time steam-heat radiator, with vertical fins. In addition to being more efficient at keeping the chill off a room than direct-radiant type portable heaters (because they circulate warm air by convection across the fins), they also are less likely to be a fire hazard because their surfaces do not get red-hot.

These are just a few ideas to help you stay comfortable until your system’s normal heating can be restored. You may have other ideas yourself. The important idea is to keep you and your family safe from cold-related medical problems until your central heating system can be brought back to life.

If you have babies, any other children not yet school-age, anyone with heart or circulatory problems, or any elderly in your home, it’s particularly important to protect them from temperatures below 70°. If the measures listed above don’t succeed in keeping the air temperature at bed-height at least 70°, then be sure the susceptible age groups are dressed in multiple layers, even for sleeping.

(210) 569-0928

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What Are The Benefits to an HVAC Technician Who is NCI Certified?

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Frequently Asked Questions

What Are The Benefits to an HVAC Technician Who is NCI Certified?

Areas We Serve

Call us at (210) 569-0928