Our HVAC systems are an appliance that we normally don’t think about until we have to. Studies show that HVAC makes up 31% of energy usage in California, and 47% of energy usage in the US.  With installation costs for new HVAC systems in the thousands of dollars, it’s in your best interest to know the truth about what you are investing in.

Here are some common misconceptions about HVAC systems, and the truth you need to know.


MYTH #1: Bigger is Better

It can be enticing to look for the best deal on a new HVAC system and find a bigger system for a lower price. It is often believed that a bigger system can cool your home faster.  Cooling your home faster means it’s more efficient, with this logic. It’s easy to think that because you are getting more tonnage for your money, this would be an upgrade.  However, this is far from true!

FACT: Properly Sized is Best

Going for a bigger unit means you are risking getting an oversized system. An oversized HVAC system is like wearing oversized shoes: it won’t do what you need it to do, and will leave you uncomfortable.

Having an oversized system will actually make your system work less efficiently. It will also cause more wear and tear on your system, shortening its lifespan. An oversized system will also cycle on and off more often.  This will not give your system enough time to remove the proper amount of moisture in the air, which is essential to making a room feel comfortable.  It also wastes much more energy.  This means if you have a high efficiency system that is oversized, you are not getting the SEER rating you paid for.

The best way to ensure your new system is properly sized is to make sure your contractor performs a load calculation on your home.  A load calculation will, in a sense, figure out how much air conditioner is needed to specifically keep your home comfortable.

MYTH #2: “Not cooling? It just needs a little Freon.”

Another common misconception is that your system should need to be “topped off” with refrigerant every or every other summer.  Unfortunately this myth is reinforced by companies who are willing to gas and go–add some refrigerant to your system, turn it on, collect their fee and go.  Even if this gets your system to blow cool air again, there are several reasons to be weary of this.

FACT: Your system should almost never need refrigerant, unless there is a leak.

The refrigerant in your HVAC system is in a closed system of pipes.  It circulates through your system similar to the way blood circulates in your body.  It is not fuel for your air conditioner, so it doesn’t burn off as you use it.  The purpose of the refrigerant is to move heat energy from either inside your home to the outside, or from the outside of your home to the inside.  Just like needing blood added to your body is a red flag that something bigger is wrong, needing refrigerant added to your HVAC system is a potential red flag to something bigger.

In situations where refrigerant needs to be added, especially if your system is less than 10 years old, it is likely that there is a refrigerant leak. This leak should be addressed with a leak check and repair before refrigerant is added to the system.

Tip: It is impossible to get accurate refrigerant readings without getting air pressure readings inside your home. Make sure your technician checks this before you agree to adding refrigerant to your system.

MYTH #3: You will save more energy if you only run your air conditioner when you feel hot in your home.

This seems like common sense: if you turn on your system only when you can’t take the heat anymore, you will use less energy. Using less energy means you will spend less money on your utility bills. Leaving your system on all day sounds like it would eat up your energy and your wallet.

FACT: You will save more energy if you run your air conditioner on a schedule.

The harshest act your equipment performs is starting up.  Starting up multiple times wears on your equipment and its components.  Also, the bigger the difference between your set temperature and the current temperature, the harder your system has to work.  Waiting until the last possible minute to turn on your air conditioner is like trying to hit the gas to merge on the freeway from a complete stop. It causes unnecessary stress on your system, and it wasn’t designed to work this way!

Your HVAC equipment was built to run on a schedule.  Programming your air conditioner to keep your home at a constant temperature is key to its efficiency.  It will start up less often and have smaller temperature differences between the set temperature and the current temperature. It will be able to remove moisture, pollutants, and dust from the air more efficiently. Since setting a schedule is like setting it on cruise control, it puts less stress on the system components and uses less energy. So you stay more comfortable, and your system can live longer and healthier.

MYTH #4: Turning the temperature down really low will cool your home faster.

This is a common occurrence especially when there are more people in a room than usual.  It still feels warm or uncomfortable in the room, so someone goes to set the thermostat to a lower temperature. If the temperature in the room has not reached the original set temperature, then setting it lower will not do you any good.

FACT: Setting your thermostat to a constant temperature throughout the day will keep you most comfortable.

Similar to the previous myth, programming your thermostat to run on a schedule is the best and most efficient way to keep your home comfortable. This is especially important in situations where there are a larger number of people in a room than usual. 

More people in a room increases the heat load of the room.  This means your air conditioner will have to work a little harder to keep the room comfortable. The more people in the room, the higher the heat load, and the longer it will take to remove moisture and lower the temperature. Leaving your air conditioner on for the day set to the same desired temperature will reduce the amount of work your system will need to do when the heat load increases.  So this will make it easier for your system to keep the room comfortable when more people are in it.  

MYTH #5: The UV light in my air purifier will kill viruses inside my home.

It’s true that UV lights have proven to be effective in neutralizing certain viruses and killing certain bacteria. They can be a great tool for decontamination, and do have a place in your HVAC system. However, there are some technicalities with how and where these UV lights can be effective in relation to your home.

FACT: The UV light in your air purifier will kill viruses inside your coil (or any surface the light touches).

UV lights work by disinfecting the surfaces they touch.  Usually in terms of air purification, your UV light is installed inside your evaporator coil.  The idea is that they will disinfect the air as it passes through the coil.  However, the air passes through your coil too quickly for the UV light to kill any viruses, bacteria, or mold.  Also, the UV lights in your air purifier do not touch any surfaces in your home.  This means any contaminants already on these surfaces will not be affected by the air purifier. Overall, UV lights are not the best option for decontaminating the air and surfaces in your home.

UV lights can be a great tool to keep your coil clean and prevent contaminants like mold from growing in your HVAC system.  Since they decontaminate surfaces they touch, they can effectively sterilize the inside of your coil.  Keeping your coil clean is necessary to keep your system in peak condition.

More Information

Have questions about your HVAC system? Unsure about what to do? We’re here to help at Castillo Heating & Air Conditioning, Inc. Call our office at (951) 301-4452, or book an appointment on our website with our new online booking system!