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Bigger Furnace

December 29, 2025
bigger furnace

Why A Bigger Furnace Is Not Always Better

Bigger is not always better when it comes to furnaces. Furnaces come in a variety of sizes and there are various reasons to not go bigger. If you are looking to purchase a new furnace for your home you may be tempted to look for a larger furnace thinking it will heat your home more efficiently and quickly. Unfortunately, that is not the case. Unless your previous furnace was undersized for your home, the truth is your home can suffer from many different issues if your furnace is too large for your home. Below we will discuss why a bigger furnace is not always better and the common issues that come with an oversized furnace.

Uncomfortable Home

A furnace that is too big will produce too much conditioned air at once into your home and lead to major temperature swings. A bigger furnace can lead to some areas of your home heating up more quickly than others and make some rooms feel too warm. Furthermore, it is possible that rooms further away from your furnace will not warm up. This can happen if the thermostat is located in an area of the home that heats up first and then the furnace shuts down before every room is properly heated. An oversized furnace can also lead to humidity issues in your home.

To maintain indoor comfort, the humidity levels in a home should also be consistent throughout. A too big of a furnace could cause the humidity levels in your home to fluctuate constantly which results in the humidity issues. Humidity issues in the home can lead to mold growth, uncomfortable indoor environment, and trigger respiratory issues.

Less Efficient

An oversized furnace will also be less efficient which can lead to higher electricity bills. Your furnace consumes the most energy at start up and does not reach peak efficiency until it has gone through the warmup phase. An oversized furnace will quickly reach a level that will satisfy the thermostat and then shut off. When the temperature drops again, it will kick on and quickly shut off again. It will not spend much time at peak efficiency because it will constantly run in the warmup phase.

Shorter Lifespan

An oversized furnace will not last as long as a properly sized furnace. The life of the furnace will dramatically decrease due to excess wear and tear or overheating of the system components. The constant cycling can also cause your heat exchanger to fail due to the metal heating and cooling repeatedly.

Short Cycling

Oversized furnaces are known for an issue called short cycling. Short cycling occurs when the furnace overheats and shuts off too quickly before the whole home has reached the proper temperature. Since the furnace is too large for your home it will generate more heat than can be used and the safety sensors will shut the unit off. If a modern furnace, goes through this cycle it will go into shut down mode to help prevent further damage. Simply put, short cycling will increase wear and tear and increase the likelihood of frequent or complete breakdowns.

Contact LA Heating & Air

To avoid these issues it is important to work with an experienced HVAC professional  who is qualified to help you find a perfectly sized furnace for your home. Give us a call today at 818-341-3406 or contact us online to schedule a furnace service call, routine furnace maintenance or a free replacement estimate. We can help you find a furnace that meets your needs to help you enjoy a more comfortable home with are liable heating system.

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