What Size Furnace Do You Need

WhatSizeFurnaceDoYouNeed AirAceHeating&Cooling

There are many different reasons why you may require a new furnace. Perhaps your current one has broken? Maybe you are moving into a new property? Or, are you looking to lock in improved levels of energy efficiency? 

No matter what applies, you need to make sure the furnace you select is right for your property. From the brand to the different features that come with the furnace, there is a lot to take into account. One of the most important things you need to consider is what size furnace is going to be right for you. So, let’s take a look at this in further detail so you can get a better understanding. 


What Size Furnace Do You Need - Air Ace Heating & Cooling


Understanding why size matters when buying a furnace for your property

Whether you are looking for a furnace for your home or business premises, it is important to get the size right. Both undersized and oversize heaters can cause problems. We will take a look at both below so you can understand why this is so vital. 

The problems of a furnace that is too small for your home

First, let’s take a look at the issues that can arise if the furnace you select is not big enough for your home. There are several issues that you can run into if this is the case, including the following:

  • Your home will not heat evenly – As the furnace is not adequate, you will find parts of your home that are cold and other areas that are warm.
  • Your furnace will have a shorter lifespan – You are going to need to run your furnace more often (perhaps all of the time during the winter), and this will cause your furnace to wear out a lot quicker than it should.
  • You will find that your energy bills become considerably more expensive – This leads on from the former point about needing to run your furnace all of the time to keep your home warm. This can end up with you receiving very high energy bills every month, which is the last thing that anyone wants!
  • You won’t be able to get comfortable in your own home – Last but not least, if your home cannot keep up with the declining weather during the winter months, you may find that the furnace is unable to provide you with the level of warmth that is required to stay comfortable. 

The problems of a furnace that is too big for your home


What Size Furnace Do You Need - AirAce Heating & Cooling


Not only is an undersized furnace an issue, but if your furnace is too big, there are also some problems that can arise. A lot of people assume that going for something bigger than required won’t cause any issues and will make sure that their home is warm enough. However, some of the following problems can arise:

  • You will have to repair your furnace more often than you should – You are going to likely find yourself needing to dig into your back pocket to fund repairs that are likely to be more frequent because the furnace you have selected is not right for your home.
  • Your furnace will have a shorter lifespan – The system will wear as a consequence of the continual cycling on and off of the heater. This can result in your furnace failing before it should. 
  • You will be using more energy than required – Having a furnace that is too big for your home is not good for the environment nor is it good for your bank balance. This is because you will be using more energy than you actually need, as you will find yourself turning the furnace on and off regularly. 
  • You won’t feel comfortable if your furnace is too big – Oversized heaters have a tendency to work in rapid bursts. When the weather is cold outside, they will often heat up parts of the house too quickly, causing it to get too warm. You then will need to turn the heater off. Yet some parts of your property may still feel too cold. It can almost feel impossible to get your property to a suitable temperature. 


What size furnace do you need?


What Size Furnace Do You Need - AirAce Heating & Cooling


When you purchase a furnace, size is most definitely important. When looking at the different heating and cooling equipment that is available, they may all look similar upon your first glance. However, systems do differ considerably, and one of the main differences is capacity. 

To ensure that you end up with the perfect furnace for your home, which delivers the ideal living conditions, it is vital to purchase the correct size. 

How the size of a furnace is measured

Before we can figure out what size is going to be right for you, we first need to understand how a furnace is measured. 

The furnace size is based on how much heat can be produced per hour. This is measured in British thermal units, which tends to be shortened to BTUs. A BTU is the energy that is needed for a pound of water to be heated by one degree Fahrenheit. 

The higher the furnace’s BTU rating, the more warmth it is able to supply. 

So, what is going to be the right furnace size for your home?


What Size Furnace Do You Need - AirAce Heating & Cooling


Now that you understand how furnace size is measured, let’s figure out what size furnace you actually need. 

The first factor that needs to be considered is the square footage of your property. Bigger properties, generally speaking, will need more BTUs to heat. However, this is only the beginning, so do keep that in mind. 

To get you started, though, let’s take a look at the furnace BTUs that are needed for properties of a specific size:


Size of property BTUs needed
2,400 square-foot house 72,000 to 144,000 BTUs
2,100 square-foot house 63,000 to 126,000 BTUs
1,800 square-foot house 54,000 to 108,000 BTUs
1,500 square-foot house 45,000 to 90,000 BTUs
1,200 square-foot house 36,000 to 72,000 BTUs


You can see that a broad range is provided when it comes to the BTUs required based on the size of the property. 

To get a more accurate understanding of the precise BTU that is going to be right for your home, there are a number of other factors to take into account, which we will explain for you.

A three-part calculation for determining the right furnace size

  • Your home’s square footage – We recommend determining the square footage for all of the rooms in your home you want to heat as a starting point. 
  • Determine what Climate Zone you are in – There are five Climate Zones in the USA, and you need to understand your climate zone, as it will have a recommended heating factor. For example, New York and Chicago are in Zone 4. Zone 4 has a recommended heating factor of 45 to 50 BTUs. 
  • Multiply your square footage by the lower number recommended for the climate zone – A good way of determining your ideal BTU is by then taking your home’s square footage and multiplying it by the lower number recommended for your climate zone. This should give you a good calculation of the BTUs required to keep your home warm.

What are some of the other factors you should consider when selecting the right size furnace for your home?


What Size Furnace Do You Need - AirAce Heating & Cooling


There are many other factors that come into play when getting the furnace size right for your property. This includes the following:

  • Ceiling fans
  • Ceiling height
  • Desired temperature
  • Age
  • The number of floors
  • The number of dwellers
  • Exposure to the sun
  • Windows
  • The shape of your house
  • The color of your roof
  • Ductwork

As you can see, there are a number of other factors that can have an impact. So, if you are struggling to find the best furnace for your home, it definitely makes sense to consult with professionals who will be able to work all of this out for you.


Check out our range of furnaces or contact us today if you have any questions

If you browse our website, you will see that we have a range of different furnaces for sale, ensuring that there is something for all requirements. If you have any questions about any of the furnaces we have for sale, or you would like our advice regarding the best furnace for your property, please do not hesitate to get in touch with us today for more information. 

We provide our heating service across Peoria, Farmington, Brimfield, Pekin, Morton, Washington, East Peoria, and all of the other towns that make up Central Illinois. You can fill in the contact form on our website and we will get back to you as soon as possible. Alternatively, you can call our friendly and professional team on 1-309-678-9577, and we will be more than happy to assist you in any way possible. 


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