What is the Right Furnace Size For My Home?

Homeowner’s Guide to Furnace Sizing


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As homeowners in Kansas, you’re well aware how important a reliable furnace is to keep your home warm during the chilly winters. But have you ever wondered about the right size of furnace for your home? While bigger is better for blankets and hot cocoa mugs, that isn’t always the case for heaters.

PD Plumbing, Heating & Cooling has been providing quality furnace installations in the greater Wichita area for decades. Choosing the correct furnace size is crucial for both comfort and efficiency. Our trained and experienced technicians know exactly how to determine accurate furnace sizing for homes.

If you are looking to replace an aging furnace, you can trust a reputable, licensed local HVAC company like PD to properly install the right furnace for your home. However, it’s helpful to understand some of the factors for furnace sizing. In this guide for homeowners, we’ll break down the factors that contribute to determining the size of furnace you need for your home.


Replacing a Furnace: When a Different Size Is Necessary

If you have had a furnace that’s been working well for many years, you are fortunate. A good furnace that was properly installed has the potential to last decades. But a lot has changed over the past decades regarding energy efficiency and heating technology. When it’s time to replace an old furnace, you want to make sure you are getting the best furnace for your home and your budget.

Do not assume your current furnace is the right size for your home. In fact, if it needs to be replaced well before it’s time, it’s possible that it wasn’t the right one for your house. A system that is too small can’t provide adequate heat. But what may be surprising is that a furnace that is too large to a home can also cause problems.

5 Factors in Getting the Right Furnace Size for your Home

  1. Home Size
  2. Insulation Quality
  3. Climate
  4. Window Efficiency
  5. Ductwork


How Home Size Affects Furnace Size

The size of your home is one of the most significant factors in determining the appropriate furnace size. Larger homes require more heating power to maintain a comfortable temperature and smaller homes need a smaller furnace.

The size of the home is determined by the total living space. You can calculate the square footage of the finished rooms in your home. You would not need to include spaces that are not included in your HVAC’s system ductwork. This total space will serve as a starting point for determining your heating needs.

If you don’t know the square footage of your home, there are a few different ways you can find it. You may be able to search your address on home listing sites like Zillow that list the square footage of homes. Otherwise, you can find the total square footage of your house by adding the square footage of each room in your house.

  • Family room
  • Dining room
  • Kitchen
  • All bedrooms
  • Finished basement
  • All bathrooms
  • Laundry room or other room receiving heating and cooling from your HVAC system


Insulation Factors

The quality of insulation in your home plays a big role in determining the right furnace size. Well-insulated homes retain heat better, which means they require less heating power. On the other hand, poorly insulated homes may need a larger furnace to compensate for heat loss.

Homeowners replacing their furnace may want to consider improving their home’s insulation first. This improvement may allow you to choose a smaller furnace as well as help to reduce your energy bills.


Our Kansas Climate

As all of us here in the Wichita are know, we get our fair share of cold winters. But as you can imagine, it gets worse in more northern states. The types of heating needs for Kansas homeowners is different than those in other states.

HVAC industry calculations factor in the specific climate region for the home when determining the right furnace size. For example, an Oklahoma home the same size as yours would probably need a smaller furnace. To calculate the right heating system for your home, be sure you are using information specific to our midwest region.

Window Efficiency

A lot of homes, especially older ones, can suffer a lot of heat loss through our windows. How modern are your windows? Do you feel cold drafts near any of them?

Energy-efficient windows can reduce heat loss, which may allow you to need a smaller furnace. If you have a number of windows are old or poorly insulated, consider upgrading them to improve energy efficiency and reduce the heating load on your furnace.


Ductwork Quality

Your furnace’s efficiency also depends on the quality of your ductwork. Leaky or inefficient ducts can lead to heat loss, which may make it necessary to choose a larger furnace to compensate. You can inspect your ducts and seal any leaks to maximize your heating system’s efficiency.


Furnace Size Factors: BTU & Energy Efficiency

Part of furnace calculation is to determine the unit’s BTU. BTU is a measurement of the energy expended to make the system work. You need to take the total square footage of your home and multiply it with the BTU requirements for your Climate Zone.

Here in the Wichita area, we are in Climate Zone 3. The proper BTU range for zone 3 is 40-45 BTUs per square foot. So if you have a 2500 square foot house here in southcentral Kansas, you will need a furnace with at least a 100,000 BTU rating.

Square footage x BTU = BTU requirement

2500 x 40 = 100,000 required BTU output

This BTU requirement is a great starting point. Then you can work in the various other factors to help determine how much more BTU may be best for your home. Add more for a home that is poorly insulated or drafty.

Now that you have a good BTU number, it’s time to factor in energy efficiency. A furnace with a BTU of 100,000 that only has a 75% energy efficiency rating is only generating a total BTU output of 75,000. Meanwhile, a 90,000 BTU furnace with 92% efficiency has a total BTU output of 82,500.

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Professional Furnace Sizing

Choosing the right furnace size is essential for maintaining a comfortable home while minimizing energy consumption. Factors such as home size, insulation quality, climate, window efficiency, and ductwork all contribute to determining the appropriate furnace size for your Kansas home.

Ultimately, the most accurate way to determine the right furnace size for your home is to consult a professional HVAC technician. They can perform a load calculation, which takes into account all the factors mentioned above, to determine the precise heating needs of your home. This ensures that you select a furnace that is neither too big nor too small, optimizing both comfort and efficiency.

PD Plumbing, Heating & Cooling is here to help you make the right choice and ensure your home stays warm and cozy throughout the winter. We provide free quotes on new installations. We have the team of experienced and licensed furnace install technicians who will ensure you have exactly the right sized furnace for your home.

Contact us today for expert advice and installation services tailored to your specific needs.You can send us a message online for more information or call us at (316) 871-5499.

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