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HVAC Sizes: How do I know what size HVAC I need?

June 11, 2019

When you are thinking about buying a new HVAC system, an important consideration is the sizes of available equipment. Just think: this new cooling and heating system will be serving your home for ten years or longer. It’s important to get this right!

For cooling and heating systems, it’s important to get the right size of equipment.

  • Bigger is not better – Rounding up might seem like a good idea, but over-sizing HVAC equipment can lead to lots of operational problems. An HVAC system that is sized too large will turn on and off regularly. That’s not only annoying for the people in the space, but the incessant startups will wreak havoc on your energy bills. And, it can lead to a shorter equipment lifespan.
  • Less is not more – It goes without saying that you don’t want to undersize your equipment. An under-sized HVAC will not be able to keep up with demand. Even if you think you’re not using very much of your HVAC system, consider the days where your home gets the heaviest use. For example, friendly gatherings or bake-offs in the kitchen. You want your system to be able to keep up in those scenarios!

Now you know the importance of investigating sizes of HVAC equipment. So how do you get to a number?

The Trouble with Using the Same HVAC Size

A lot of homeowners think that if they are replacing an HVAC system, they don’t need to worry about sizes. Just use the same size as the existing HVAC. Right?

The truth is that this approach can be problematic.

So before you get too far down the path in ordering a new heating and cooling system, consider if you’re experiencing any of these issues with your current setup:

  • Does your HVAC seem to be running constantly, or only turning off very briefly?
  • Conversely, does your HVAC system kick on and off, rarely staying on for more than a few minutes?
  • Are there areas of your home that aren’t being cooled or heated to your comfort levels?

If you are having any of these troubles with your cooling and heating system, you will be better off looking at different sizes of HVAC equipment. Our highly-trained technicians at Brody Pennell can help you choose the appropriate size system for your home.

Special Considerations for HVAC Sizes when Replacing

Homeowners that are replacing their HVAC should consider improvements that have been made to the home. Changing physical features of the home, adding energy-saving improvements, or remodeling spaces can impact the size of an HVAC system.

When you meet with a licensed contractor at your Los Angeles home, be sure to tell him or her about any changes you’ve made to the home since your current HVAC system was installed. Some of these items include:

  • New windows
  • Improved roof insulation
  • Additions of new spaces
  • Remodeled areas like kitchens, laundry rooms, bathrooms, or home gyms
  • Finished out spaces like attics, basements, or garages

Determining the Right Size of HVAC Equipment

So, what size does your air conditioner or furnace actually need to be?

If you’re building a brand new home, adding a new space, or you have done many renovations to your home, a load calculation needs to be performed.

load calculation takes into account a number of variables. For example, how many windows you have, the orientation of your home in comparison to the sun, and insulation in your walls and roof. A load calculation will also include the heat generated by the people, lights, and electronic devices in your home, just to name a few. An industry standard for load calculation is the Air Conditioning Contractors of America (ACCA) Manual J method.

When you have a final load value from the calculation, you’ll know what size your HVAC needs to be.

Isn’t there a simple rule of thumb?

If you’re doing research about HVAC sizes, you might find simplified methods for determining the load. For example, a certain number of tons per hundred square feet. Simple online tools will also spit out numbers for you. Homeowners should use caution when using these tools. These tools make sweeping generalizations about your home, and may not be able to produce accurate numbers.

Work with the best… and save money, too

The team at Brody Pennell has been in the heating and air conditioning business for more than 70 years. We understand how to size equipment correctly the first time by doing industry-standard heat load calculations.

Right now we are offering great specials on HVAC systems of all sizes. With the Carrier Cool Cash program, you can get up to $1,650 off a new HVAC system. You can combine this deal with other incentives, like utility rebates and financing. Now is a great time to buy if you are on budget – this is the best deal of the year.

Between our long history in LA, and our partnership with the best equipment manufacturers, our team can then provide a range of solutions that will best meet your needs. Give us a call to schedule an appointment today!

About The Author

Brody Pennell

Since 1945, Brody Pennell Heating & Air Conditioning is the committed to helping homeowners in the greater Los Angeles area experience total home comfort. In 2021, the readers of the Los Angeles Times voted Brody Pennell the Best HVAC Company in the area.

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