11 of the Most Frequently Asked HVAC Questions

To most people, how air conditioners work is a matter of magic. They don’t know how HVAC systems make temperatures bearable in their homes and offices, but they’re awfully glad they do.

According to the U.S. Department of Energy, 75 percent of all homes in the U.S. have air conditioners. These devices use about 6 percent of all the energy produced in America. U.S. homeowners spend about $29 billion on energy costs each year related to controlling the temperature inside their homes.

Air conditioners work by applying the principles of refrigeration. They remove heat from an area of the home to the outside, and the cold air created by this process is distributed by a fan through ducts throughout the home.

Heating and cooling units are very durable devices. Most run several hours per day and have a useful life of 15 years or more. Considering their workload and the fact that the units are exposed to wind and rain and hot and cold temperatures outside, that’s pretty impressive.

When homeowners’ air conditioners aren’t working properly, they get curious about how these devices that they often take for granted work. Here are some of the most commonly asked questions about heating and cooling units:

How often do I need to change my air filters? 

Once a month is a pretty good rule of thumb for most people. Depending on where you live and how much dirt, pet dander, and other contaminants are present, the answer could be more or less. Check your filter frequently to determine if it’s dirty. If it is, change it.

What size unit do I need? 

There’s no easy answer for this one. A lot of factors will go into what size heating and cooling unit you’ll need. The type of house you own, its walls, insulation, attic space, and more can go into determining what size unit is required. A system that is too large could result in a home that’s too humid, causing problems with moisture and mold. A system that is too small will run constantly, running up your energy bill. Only a qualified heating and cooling technician can determine what size unit is best for your home.

If I replace my outdoor unit, do I need to also replace my indoor unit? 

In most cases, the answer is yes. There are a variety of reasons why you should replace both the outdoor and indoor units simultaneously. For starters, air conditioner and heat pump outdoor units are manufactured to work with a matched indoor unit. When you mix and match units, it can result in reduced efficiency and performance.

Also, if you bought your indoor and outdoor units at the same time, your indoor unit will probably be approaching the end of its useful life at about the same time as the outdoor unit. By not replacing the indoor unit too, all you’re doing is delaying the inevitable and likely paying higher energy bills at the same time.

By purchasing indoor and outdoor units simultaneously, you’ll get a warranty covering the whole system, meaning that you won’t have to cover the full cost of any needed repairs to your unit during the warranty period.

Should I cover my unit in the fall and winter? 

While covering your unit can prevent unwanted debris from accumulating on the unit, it can also cause problems if you try to operate it with the covering in place. If you’re going on a long trip and plan to turn the unit off while you’re gone, feel free to cover it up. Just make sure you disconnect the power source before leaving.

Why should I replace my R-22 outdoor unit with an R410A? 

R-22 refrigerant and equipment are being phased out as Montreal Protocol regulations intended to reduce the impact on ozone take hold. As time passes, replacement parts and refrigerants for old R-22 units will become harder to find and more expensive, so replacing your unit now can save you some headaches in the future.

What causes AC units to freeze up? 

There are a lot of reasons why your air conditioning system might freeze up, and all of them require help from a professional technician to resolve, as only they have the training and correct tools to fix the problem.

Ironically, low refrigerant can cause your system to freeze up. Over time, wear and tear to your system can result in leaks that cause the system to lose refrigerant. When your unit loses refrigerant, it causes the system to freeze up because of low pressure inside the system.

When freon levels are low, the refrigerant still is forced to expand to the same amount. The more that expansion occurs, the cooler the temperature is produced. The colder temperature will cause moisture in the air around your unit’s evaporator coil to freeze, eventually icing up the coil and impeding its function.

Dirty evaporator coils can cause units to lose airflow and, eventually, cause the system to freeze up. Defective blower motors can also cause freezing.

How often should I have my unit serviced? 

Heating and cooling units need to have scheduled check-ups to make sure everything is operating properly. HVAC experts recommend an annual inspection and service call by your heating and cooling company. Technicians should inspect your system, lubricate components, and repair or replace any malfunctioning components.

Why are my ducts making a popping sound when the furnace starts or stops? 

Popping noises are usually indicative of ducts that are too small to manage the airflow your system is generating. Qualified air conditioner repair specialists can evaluate your ductwork and make necessary adjustments.

What is a zoning system? 

Zoning Systems separate your air conditioning system’s ductwork into different segments, allowing you to exercise temperature control in each segment, thus allowing for more targeted and efficient air conditioning.

For example, you may have a room with many windows that gets hot in the summer and which may need more air to cool down, while you may also have a rarely occupied guest room on the other end of the house. With a zoned air conditioning system, you can direct more cold air to the many-windowed room and less air to the unoccupied room. This allows for more efficient use of your AC system and more comfortable home.

What can I do about indoor air quality? 

Indoor air quality is a major concern, as many studies show that air pollution is much worse indoors than outdoors. You can improve your indoor air quality with frequent dusting and vacuuming, and you can also have a qualified technician install devices such as UV light units, special air filters, and electronic air cleaners to improve indoor air quality. Poor indoor air quality has been linked to many illnesses, so improving your home’s air quality is an investment worth making.

How do I find out if my unit is under warranty? 

Check the label on the outer surface of your equipment to determine its manufacture date. If it’s less than five years old, there’s a good chance that your equipment is covered by a warranty. Contact the manufacturer for more details.

What’s the best way to extend the life of my unit? 

Heating and cooling units are a big investment, so it’s understandable that you’d want them to last as long as possible. Reducing usage is always helpful, so turn the thermostat up or down, as needed, to reduce use when you’re not at home. Changing air filters will prevent clogs. Regular check-ups can also help you ward off any potential trouble spots.

These are just a few of the questions air conditioning and heating specialists answer every day. When you have questions about your heating and cooling system, it pays to get help from experienced professionals.

Barstow & Sons is a family-owned HVAC installation, repair, and maintenance service helping customers in the greater Annapolis area. Available 24 hours a day, seven days a week, Barstow & Sons services all makes and models of HVAC equipment, as well as water heaters. For answers to your heating and cooling problems, contact Barstow & Sons today at (410) 777.9185.

There’s nothing like walking into a cool home or business on a hot summer’s day! Cooling systems, such as air conditioners, make that comfort possible. Many homeowners aren’t particularly familiar with these systems, so the pros at HVAC.com are here to answer your most common AC & air conditioning questions!

Air conditioning questions: how does my AC work?

Air conditioners work to cool a home using refrigerant that absorbs and discharges heat. Here are the steps an AC takes to cool your home.

• Warm air from your home moves across the air conditioner’s evaporator coils. The refrigerant within the coils absorbs the air’s heat. Refrigerant converts from cool liquid to hot vapor, cooling the air.
• The vapor travels to the compressor located in the outdoor air conditioner unit. The refrigerant vapor is compressed here, raising temperature and pressure.
• Refrigerant travels to the condenser where it is condensed into a liquid form again. This causes heat to release, and heat dissipates to the outdoors through the exterior unit’s fins.
• The refrigerant is now cooled and in a liquid state. It cycles back to the indoor unit, regulated by the expansion device, so the cooling process can continue.

AC questions: what are the different types of air conditioners?

When most people think of air conditioners, systems with a condenser outdoors and an air handler indoors are what they visualize. In reality, there are many different types of air conditioners that can be used to cool a home.

• Central air conditioners utilize an outdoor condenser and an indoor air hander (that also works with the furnace or heat pump) to deliver cool air indoors.
• Heat pumps can operate for both heating and cooling, and are an option for central air conditioning.
• Ductless mini-split air conditioners utilize individual air handlers installed throughout the home, connected to an outdoor heat pump, to provide zoned cooling in the specific areas that need it.
• Portable and window air conditioners are additional options for space cooling – they are not a whole-home cooling solution.

Air conditioning questions: common AC repairs

Air conditioners are complicated mechanical systems with many working parts. Good maintenance will help prevent AC problems, but a system may still malfunction over the course of a cooling season. Below are some common AC repair issues and their fixes:

• Refrigerant leaks. The lines transporting refrigerant through the system can leak, causing refrigerant to spill out and less pressure to complete the cooling process. To solve the issue, your air conditioner repair technician will diagnose the source of the leak and fix it to prevent further issues. Your AC system will be recharged so the appropriate amount of refrigerant is added to the system.
• Drainage problems. The cooling process produces condensation that needs to exit the system. Your air conditioner is equipped with a condensate drain line and drip plan to handle the flow of moisture. If these components become clogged with algae or obstructions, or are damaged, moisture can back up into the system, causing humidity problems within your home and damage to your air conditioner. Your technician will clear the clog or repair components so moisture properly exits your air conditioning system.
• Frozen condenser coils. The air conditioner’s condenser coils can freeze up, preventing your system from cooling. This typically happens when there is poor airflow through the unit, caused by obstructions such as dirty filters or debris surrounding the outdoor unit. Low refrigerant levels may also be the cause. Your technician will diagnose the cause and correct it, deicing your coils so the cooling process can flow smoothly again.

AC questions: measuring air conditioner efficiency

An air conditioner’s efficiency is measured in SEER. SEER stands for Seasonal Energy Efficiency Ratio. A unit’s SEER is calculated by dividing the unit’s cooling output over an average cooling season by the amount of electric energy input over the same period.

The higher the SEER rating, the more efficient the air conditioner. The minimum SEER allowed by law for newly manufactured air conditioner is 13 or 14, depending on where in the country you live. The most efficient air conditioners on the market have SEER ratings of around 22.

Find local help for AC repair

HVAC.com is home to a comprehensive Contractor Directory that connects you to local HVAC contractors who can answer all the AC questions specific to your home. Enter your ZIP code to find professionals in your area who can come take a look at your cooling system and give answers to the air conditioning questions that are standing in the way of your home comfort.