What Size Furnace Do I Need?

Choosing the right gas furnace is important for where you live and how large your home is.

When it comes to picking a gas furnace, it’s possible to have too much of a good thing.

A heating system that’s too big can be a waste of energy, and might require extra-large duct work, further hurting your energy savings. On the other end of the spectrum, a furnace that’s too small won’t be able to keep your home warm.

So how do you choose the right gas furnace? It starts by looking at these factors:

Look at the size of your home and how it's built to help decide what size furnace to buy.1. Your home

The size of your house is a key consideration when figuring out what size furnace you need, but you’ll want to look at other factors as well. Does your home have a lot of individual rooms, or a more open floor plan? How is your house oriented? If your living areas face south, you’ll get more sun – and more heat – in the winter.

The construction of your home makes a difference as well. If you built your house out of brick, you’ll have more natural insulation than a home with wood siding.

Even factors like trees or shrubs surrounding your home can affect the size of your furnace. If your house is protected from frigid air by your landscaping, you’ll need less heat.

iStock-163985482-1-RT.jpg2. Your climate

The part of the country where you live makes a difference when choosing a gas furnace. If you live in New England, you’ll want a bigger, more powerful furnace. If you live in northern California, you’ll typically have mild winters and therefore need less heat.

3. Efficiency

Our country has required furnace makers to be more efficient over the past few decades. In 1992, the Department of Energy established new manufacturing standards for furnaces, mandating that they have at least 78 percent efficiency. That number rose to 80 percent in 2013, although most high-quality units hit 98 percent efficiency.

That means you could have two furnaces of the same size, but dramatically different efficiency levels. A high-efficiency furnace that gives off 100,000 British Thermal Units (BTU) and a 98 percent rating will give you substantially more warmth than a same-sized furnace with an 85 percent rating.

Therefore, you could buy a furnace with a high efficiency rating, but still use a smaller unit and get the same amount of heat at home.

Many heating and cooling companies estimate their clients’ heating needs with this standard: 25 to 30 BTUs for every square foot of space in the home.

Infographic-Furnace-La-BTUs.pngThat means if your house was 2,000 square feet, you’d need a furnace that gave off 50,000 to 60,000 BTUs to get sufficient heating. The less efficient the furnace, the more BTUs you’d need.

But this really isn’t a calculation you should do on your own. Choosing a gas furnace is a job best left to a qualified HVAC contractor, who will be able to look at all the factors we’ve listed and find the unit that’s right for you and your family.

If you’re ready to install a new gas furnace in your home, turn to All Seasons Comfort Control. For more than 15 winters, we’ve helped Bucks and Montgomery County-area homeowners keep their homes warm and comfortable. Contact us today to learn more.

Right now we’re offering up to $1,000 Instant Rebate or Special Financing for 60 Months** on new systems.