How Much Would It Cost to Replace My Furnace and AC at the Same Time?

April 05, 2018

AC condenser

If you’re planning to replace both your furnace and your air conditioner at the same time, you can expect to pay anywhere from $8,000 to $15,000+.

While that price can seem steep for some Colorado homeowners, the actual price you pay depends on:

  • The efficiency levels of the units
  • The size of the units
  • The features/technology you choose
  • The contractor you choose

We’ll cover those 4 factors in more detail below.

But first, let’s make sure you absolutely need to replace both your furnace and your air conditioner…

First, determine whether you really need to replace both

We won’t lie—some HVAC companies will push homeowners to replace their AC and furnace in the same project when it’s not necessarily needed.

Their motive for this is clear: More money.

To save you from that trap, we’ll explain the 3 instances when it’s best to replace both your AC and furnace:

1. When the AC is over 10 and the furnace is over 15.

A furnace typically lasts much longer than an AC. Which means, if you initially had the two units installed at the same time and the AC is aging, it’s very likely that you don’t really need to replace your furnace for another 5 or so years.

Related: How Often Should I Replace My Air Conditioner?

2. If you’re upgrading your AC efficiency.

Your furnace and AC are like conjoined twins; they each have their own separate compartments but share the indoor unit (the blower motor).

So, if you spend extra money to upgrade your AC but leave the furnace and blower motor as is, you’re basically wasting money since the AC is really only half upgraded and won’t work as efficiently as it’s designed to.

If you’re upgrading to an AC with a SEER over 16, you should consider upgrading the furnace as well.

3. If you know you won’t be able to afford an installation later on.

Planning to retire soon or have other big investments coming up? If you know you won’t be able to handle a furnace installation in the next 5 or so years, it’s best to go ahead and replace both units now. That way, you can relax knowing that your new HVAC system will be solid for the next 10+ years.

Are you absolutely sure that you need to replace both your AC and furnace together?

If so, your biggest question is most likely about cost. To help you budget appropriately, let’s look at 3 factors that will affect your installation price.

If you believe that you meet any of the above three criteria, we recommend contacting a Denver metro HVAC expert to help you further. 


Factors that affect the cost of an AC + furnace installation

1. The efficiency level of the units

The bottom line:The higher the SEER and AFUE of the units, the more the installation will cost.

An AC SEER label (left) and a furnace AFUE label (right).

What they mean…

  • SEER(Seasonal Energy Efficiency Rating): A number from 13 to 21+ that measures how efficient an AC unit is. The higher the number, the more efficiently the AC can cool your home (i.e. lower energy bills)
  • AFUE (Annual Fuel Utilization Efficiency): A percentage from 80% to 100% that measures the efficiency of a furnace. The higher the percentage, the more efficiently the furnace can heat your home (i.e. lower energy bills).

When it comes to choosing your SEER/AFUE, it’s important that the AC efficiency not greatly exceed the furnace’s (or vice versa). Remember, your AC and furnace work like conjoined twins since they share an indoor unit. So, if one system is much less efficient than the other, it decreases the other system’s efficiency.

Ask your contractor for SEER and AFUE ratings that will complement each other and save you the most money in the long run.

Want more information on SEER and AFUE? Check out our blogs:

2. The size of the units

The bottom line: The higher the tonnage and BTU output, the more the installation will cost.

Not sure what “tonnage” and “BTU output” mean? We’ll explain...

  • ACs are sized in “tonnage”, which measures the amount of cooling the unit can provide in an hour. Typically, residential ACs range from 1-ton units to 5-ton units (half sizes included, i.e. 2.5 tons).
  • Furnaces are sized by “BTU output”, which measures the amount of heating a furnace provides in a given time. For reference, one BTU is equal to the heat output of lighting one match. Typical residential furnaces range from 35,000–100,000 BTUs.

So what size do you need? Well it all depends on your home’s heating/cooling load, which should be calculated by a professional.

Related: How to Estimate AC Size For Your Denver Home

But beware of techs who only use rule-of-thumbs to size your HVAC system (i.e. only looking at square footage of your home).

This “shortcut” often leaves homeowners with furnaces/ACs that are either too big or too small for their home, which can result in:

  • Higher-than-necessary energy bills
  • Shortened unit lifespans
  • Frequent repairs

3. The features/technology you choose

The bottom line:The more “comfort” features you choose for your furnace and/or AC, the higher the installation cost.

Optional comfort features include:

  • Variable-speed technology. This technology means that the shared blower motor and/or the AC compressor is able to continually adjust its speed to provide the precise amount of heat/cold air needed at any time. This provides lower energy bills and higher comfort. Related: “Single-stage vs Two-Stage vs Variable Speed ACs for Denver Homes”.
  • Noise reduction technology. Some examples of this include dampening strips, compressor insulation/mounts, and insulated furnace cabinet or noise-reducing fan blades.
  • Smart thermostat. These thermostats can automatically adjust your home’s temperature to lower/raise according to your schedule (whether you’re at home or out) for lower energy use.

4. The contractor you choose

The bottom line:The higher the quality of your contractor, the more they will charge to install your HVAC system.

When choosing a company to install your furnace and AC, be wary of contractors who charge much lower prices than others. This usually means that the quality of the installation will be low—which can result in improper installation, frequent repairs and high energy bills.

Instead, assume that slightly higher prices means a quality installation backed by a professional company who will provide excellent service.

To help you choose a quality professional, follow these tips:

  • Make sure the company is licensed and insured in the state of Colorado
  • Check that the company is experienced in combo AC/furnace installations
  • Ask the company to provide 2–3 referrals from past customers
  • Make sure the company has been in business for at least 10 years
  • Check reviews on sites such as Google+, Yelp and BBB to make sure they have positive reviews

Related: "7 Things to Look For in the Best HVAC Contractor in Denver, CO"

Need a quote on your furnace + AC combo installation?

Just contact us. We’ll send over a tech who can help you choose the system that’s best for you.

Then, we’ll complete the project quickly and correctly—on your schedule.

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