Does AC need a furnace?

Author: Eugenia Hessel  |  Last update: Friday, November 7, 2025

Your furnace and air conditioner are stand-alone components of your HVAC system. Both your furnace and your AC use ducts and vents to circulate air throughout your home. These systems are tied together because they use the same infrastructure. However, they still operate independently of each other.

Can you install an air conditioner without a furnace?

Yes, you can replace just the air conditioner without replacing the furnace, but it's important to consider the compatibility and efficiency of both units. If your furnace is relatively new and in good working condition, it might make sense to replace only the air conditioner.

Does my furnace have anything to do with my AC?

Your furnace and your air conditioning system are two central components of your HVAC system, connected and controlled for greater efficiency. During warmer weather, you'll need to turn off your furnace and use your air conditioner instead. Your central air conditioning system is independent of your furnace.

Can you replace AC and not furnace?

Yes, You Can!

Keep rebates and efficiency in mind when making any decisions on replacing just the AC unit.

Will a furnace work if the AC is broken?

Yes... your gas furnace will work just fine without the condenser. Insulate the wiring with tape. If you plan to reuse those copper lines... plug them as best you can.

What size of furnace do I need? Shanklin Heating and Air Conditioning

Can AC run without furnace?

However, they still operate independently of each other. Does the furnace need to be on for the AC to work? No!

How much does it cost to replace a furnace and AC together?

The cost of replacing both your air conditioner and furnace at the same time is around $6,500 – $12,500. You will save about $750 – $1,000 by replacing them both together, rather than doing them separately.

How much does a new furnace cost?

You should expect to spend between $3,800 and $12,00 on a new furnace, including both the unit and installation costs. Factors influencing the price include the type of furnace (gas, electric, or oil), the unit's efficiency rating, and the complexity of the installation.

Do you need a furnace if you have HVAC?

In a nutshell, a furnace heats your home. An HVAC system combines a furnace, air conditioner, and ventilation system (more on that below). So, if you need HVAC service, it may or may not include the furnace.

Does each AC unit have its own furnace?

each AC system also probably has an integrated heating system in line with the AC system in the air handling system. Usually the heater is placed before the AC heat exchanger.

Why is AC not blowing cold air?

First, check your filters and coils for dirt and debris that may be impeding airflow. Once you've cleaned the filters and coils, run the air conditioner with just the fan so that the ice accumulation can melt off. If the AC still doesn't blow cold air, it could be that refrigerant levels are too low.

Do you have to buy the furnace and AC at same time?

If your air conditioner has quit, but the furnace still works (or vice versa), it's tempting to just replace the appliance that's broken. However, getting AC and furnace replacement at one time—even if one is still working—can save energy and money over the long term.

Are AC and furnace on the same breaker?

If the home includes an electric furnace, that unit will also have its own dedicated breaker. Issues such as low airflow due to a clogged air filter, obstructed air vents in rooms, a failing blower motor, or internal electrical defects inside the unit may be the cause of breaker trips.

Can I just replace my outside AC unit?

Your Warranty Might Be Voided

This could mean the difference of your manufacturer covering the cost of replacement or repair down the road versus you footing the entire bill. To summarize so far, the answer to “can you replace just the outside AC unit” is: not unless you want major issues.

Does the furnace have anything to do with the AC unit?

Air conditioners and furnaces work together to keep the air in your home at a manageable temperature. In the winter, your furnace heats the air in your home, while the AC blower circulates works to circulate that air throughout the home.

How much does a new HVAC system cost?

An HVAC replacement cost is $7,500 on average. This range could be as low as $5,000 or as high as $12,500, depending on the type and size of your unit, the brand, and labor costs. Your overall cost for a new HVAC unit could reach $22,000 if you add new ductwork and additional features like a HEPA filtration system.

Is there a furnace and air conditioner combo?

Air conditioner + furnace matched systems

An air conditioner and furnace is a popular matched system throughout the United States, because it can be paired with a high efficiency air conditioner, and provides significantly warmer air to the home.

What if my house doesn't have a furnace?

Fireplaces: The oldest solution for heating your home is starting a fire in your fireplace, if you're lucky enough to have one. Get some fire logs or gather your own tinder to make a cozy fire in your living room.

Is a furnace only for heat?

On the other hand, furnaces only provide heat, so a separate air conditioning unit is required to cool your home in warmer months. While both products have different purposes, some climates allow for a furnace to be installed with a heat pump, known as a dual fuel system for heating and cooling.

Does homeowners insurance pay for new furnace?

A standard policy typically won't cover the cost to replace your furnace if there was a mechanical problem, but you may be able to add an equipment breakdown endorsement for an additional cost that may provide coverage.

What time of year is cheapest to replace furnace?

For people taking a proactive approach, doing a furnace replacement during the “shoulder seasons” of spring and autumn may offer lower prices, shorter lead times, and a better selection of products and service appointment availability.

Does Home Depot install furnaces?

Yes, our service providers will install to local code and follow required permitting procedures. Permit requirements vary by location, and some municipalities do require a permit. Your Home Depot authorized service provider will obtain a permit if it's required.

Can you have an air conditioner without a furnace?

Since a ductless unit doesn't require a forced-air furnace or ductwork, you can install one indoors or outdoors. Consequently, a ductless conditioner is able to adapt to whatever zoning system you prefer.

How much is a furnace for a 1500 square foot house?

Understanding Total Costs

Gas Furnace: $3,000 – $6,000. Electric Furnace: $2,500 – $5,000. Oil Furnace: $4,000 – $8,000.

Is it cheaper to install furnace and AC at same time?

If you are replacing your AC unit​, it's worth your time to look into how your new unit will work with your existing furnace. Installation costs and complications - having both your AC and furnace replaced at the same time can save money on the combined cost by not having to pay for two separate installation fees.

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