Steps to adding A/C to an existing HVAC (2023)

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(Video) DIY Air Conditioner Replacement Part 1 -Step By Step Guide-

Steps to adding A/C to an existing HVAC (1)

Got AC? If not, You needn’t be left out in the (Not) cold

According to Boston Globe writer Leon Neyfakh, “Since the technology was invented in 1902, and the first window unit was brought to market in 1939, air conditioners have become ubiquitous in the United States. Today, almost 90 percent of American households have one—as do the vast majority of restaurants, stores, museums, and office buildings.”

That article was written back in 2013, so our guess is the percentage of air-conditioned homes is probably even higher today. Of course, if you’re in that less than 10 percent bracket that still doesn’t have air conditioning you’re no doubt sick of suffering through the summer months.

The good news is you can beat the heat once and for all with your existing HVAC unit. In this post we’ll cover a number of things for you to consider including:

  • Window air conditioners pros and mostly cons
  • Benefits of central AC besides cool air
  • Is adding AC to an existing central heating system practical
  • Extra components to add to your existing heating system
  • Sizing your AC system
  • The importance of energy efficiency

Window air conditioners—Pros, but mostly cons

  • Window units are loud
  • A portion of the window is blocked, which means there is no possibility of letting in outside air when temperatures drop (besides operating the unit’s blower) and you’re also blocking out natural light
  • Expensive to operate over time; even units rated energy efficient cost more to run than central air conditioning
  • Their bulky design doesn’t exactly add to the aesthetics of a room

Most important of all, a single-window air conditioner does not cool your entire home. Nor is installing window air conditioners in all the rooms of your house energy- or cost-efficient.

Not just cool air, But better air

A central air conditioning system attached to your furnace not only keeps you cool, it improves your indoor air quality by filtering out dust, allergens and other airborne particulates that at the very least can irritate household members, and in some cases can even threaten their health. Moreover, the air filtration system doesn’t just work with your air conditioning system. Because it is connected to your furnace or air handler, it keeps air circulating throughout your house clean year-round.

(Video) INSTALLING A CENTRAL AIR CONDITIONER \\ Outdoor Air Conditioner Installation

Is it practical to add AC to your existing central heating system?

Whether it is practical to add air conditioning to your home’s central heating system depends on a number of factors. These include whether:

  • Your house has adequate ductwork
  • Your house is sufficiently insulated
  • You want to pay the price


If you have forced air heat, you have ductwork that distributes heated air throughout your house that might work for cool air as well. The keyword here is “might.” The ductwork must be in good shape without leaks or breaks, which it should be anyway regardless of whether or not you decide to add AC. If you have leaky ductwork, sealing and possibly even cleaning in certain situations may be warranted.

The other issue is whether your current ductwork, as well as your existing furnace blower are sufficiently sized, meaning there is adequate airflow to efficiently distribute cool air throughout your home.

How do you know if your current HVAC and ductwork are sufficient? A professional certified HVAC (Heating Ventilation Air Conditioning) technician can perform the necessary test to confirm if they are adequate.

How old is your house?

Homes over 20 years of age typically were under-insulated. That means circulating air is leaking out through cracks in the walls and ceilings, as well as leaking in. In addition, insulation that is 20 years old or older does not have a sufficient R-Value by today’s energy efficiency standards. Without efficient insulation, it takes more energy, and more money, to condition a house.

(Video) Charging R-410A Refrigerant into an Air Conditioner! Pressures, Temps, Tips!

Chances are if you are reading this, you probably have an older home, as most new constructions include air conditioning. You may want to consider upgrading insulation, at a bare minimum in the roof, if only to improve your heating efficiency, as well as seal any detected leaks.

Is it worth the added expense to add AC?

If you have to repair, or worse, replace ductwork and/or insulation, you may be wary of adding AC because of the cost. Keep in mind that if you intend to stay in the house for any length of time, adding AC to your HVAC unit will improve the efficiency of your existing system and reduce your utility bills.

Also, even if you foresee selling your home in the near future, upgraded insulation and the addition of AC improves your home’s resale value. So in many ways, the cost is an investment.

What components do you need to add?

Assuming your ductwork and insulation is up to the task, the addition of two components to your existing forced-air furnace provide central air conditioning to your home:

  • Indoor air handler. Houses the AC evaporator coil and blower. Mounted in the attic or a dedicated HVAC closet. In some retrofit situations, the evaporator coil can be installed in the furnace itself if the existing furnace blower is considered capable, or the furnace blower is replaced with a model that is capable.
  • Outdoor condenser unit. Comprised of the AC compressor, condenser, coil, and fan. Located behind or to the side of the house. Two insulated lines that circulate refrigerant are connected to the indoor air handler.

Sizing your AC system

This added equipment must be properly sized to effectively cool your house. An undersized unit will have to work too hard to cool your entire house, and may struggle to regulate the right temperature levels in every room, while an oversized unit cycles on and off constantly, which causes temperature swings while failing to extract humidity. In both cases, you are wasting energy and increasing utility costs. Most importantly, you won’t be comfortable.

A certified HVAC technician performs a load calculation that determines the capacity of the AC unit needed to cool the house on a typical hot day. They perform this calculation using BTUS or British Thermal Units (the heat energy extracted from a house every hour). Getting the right unit size is absolutely essential to efficiently add AC to your house.

(Video) How I Add Refrigerant to an Air Conditioner

How much does it cost to run air conditioning?

The final factor in your cost calculation is how much it is going to cost to actually run the air conditioning. AC energy efficiency is determined by its SEER (Seasonal Energy Efficiency Rating). This is a ratio of the amount of electricity required to remove BTUs of heat.

Some states, such as California, mandate a minimum SEER of 14, which you should probably consider the minimum rating for your house. The higher the SEER, the more energy-efficient. As you might expect, higher SEER units cost more. The payback is that more energy-efficient models consume less energy, lowering your utility bills.

Consult the HVAC experts

Ongaro and Sons design AC add-on systems using a diagnostics approach to provide the highest levels of efficiency and comfort. Ongaro and Sons’ technicians are trained for all residential makes and models of forced air and air conditioning installation. Ensuring the efficiency of your entire HVAC system also includes a thorough inspection of your duct system. If needed, we can do a thorough and effective cleaning, repair or even replace leaky ductwork.

Ongaro and Sons put the “V” back in HVAC. Ventilation is the process of bringing fresh air into your home to replace stale air filled with indoor pollutants such as cooking smells, pet odors and/or tobacco. Proper ventilation is not only key to the efficiency of your home heating and cooling system, but to your indoor air quality and your family’s health.

Ongaro and Sons offer a number of solutions to increase the quality of your indoor air, including everything from a filtration system to a complete home purification system and fresh air exchanger system. We’re a family-owned business, so we understand the importance of protecting your health and the health of your family.

Contact us with any questions about how you can add AC to your existing HVAC system. We guarantee 100 percent customer satisfaction with every job you entrust to our expert team.

(Video) New AC Unit Install


Steps to adding A/C to an existing HVAC? ›

If your home has an existing forced-air heat system, you can add a central air conditioner to it. An HVAC technician can retrofit your forced-air heating system by installing an evaporator coil onto the furnace plenum, the box next to the furnace that draws in air.

Can you add air conditioning to HVAC system? ›

If your home has an existing forced-air heat system, you can add a central air conditioner to it. An HVAC technician can retrofit your forced-air heating system by installing an evaporator coil onto the furnace plenum, the box next to the furnace that draws in air.

How hard is it to add air conditioning to a existing furnace? ›

If your home already has a functioning air duct system, adding central air can be fairly easy and less costly. The technicians will inspect the existing ductwork to make sure it's sound and sealed well enough to move the air through your home efficiently. Then, they install a split system.

Is it hard to add central AC? ›

Installing a central AC system is hard work. You'll probably be required to do a lot of manual labour, including lifting heavy equipment, pouring a concrete foundation and even getting under the house. If this is not your idea of fun, you can pass this work over to the professionals.

How much does it cost to add air conditioning to existing furnace? ›

How Much Does it Cost to Install Central Air? When added to an existing forced-air heating system, central air for a 2,000-square-foot home costs $3,500 to $4,000 and can be done by two technicians in two to three days, often with little or no change to the ducting.

How much does it cost to add another AC unit? ›

According to HomeAdvisor, it can cost between $3,882 and $7,905, on average, to replace an AC unit. The work required to remove and dispose of the old system adds to the price, as well as the size of your home, the brand of the AC unit and the ductwork complexity.

Can you add a second HVAC? ›

Deciding Whether or Not an Expansion is Necessary

If your current unit is not large enough to properly cool and heat your new room, you have two options. You may upgrade your existing unit or install a separate HVAC unit for the new space.

Can you use the same ducts for heating and cooling? ›

One of the main ways that homeowners can consolidate ductwork is by switching to a central HVAC system. With a central air conditioner, you get cooling in the summer months, heat in the winter, and all with the same use of your existing ductwork. This reuse is a great way to cut down on installation costs as well.

Can I replace AC without replacing furnace? ›

If your existing furnace and your new air conditioner are compatible, you don't necessarily need to replace both systems. This is usually the case when you replace your air conditioner with a similar model. A new furnace could boost your system's efficiency.

Is it better to buy a furnace and air conditioner at the same time? ›

Lower Energy Bill

If you're looking for a more energy-efficient home, you should do so. Replacing both the AC and furnace at the same time reduces your energy bill. Replacing an old furnace with a new high-efficiency model can save up to 33% on your annual heating bill.

Does adding AC to a house add value? ›

So how much does a new HVAC system add to the value of a house? Installing a new HVAC system could increase your home's value by as much as $2,500-$3,000 or approximately 5-10% of the total value of your home. The typical cost of installing a new heating and cooling system is about $10,000.

Does a new AC increase home value? ›

A new HVAC system is simply new heating, ventilation, and air conditioning system. Does New HVAC Increase Home Value? We often receive the query, 'does new HVAC add value to home', and though there are a few factors to consider, the answer is that yes, generally it does. It can increase your home's value by up to 10%.

Can I install AC unit myself? ›

Simply put, no, you cannot replace your AC unit yourself.

Even if you have the technical know-how to install an AC unit, all of the electrical components add an elevated level of risk to the process. Plus, it takes nuanced HVAC experience to ensure you get the right unit for the size of your house.

How long do AC units last? ›

While every unit is different, and every homeowner has a different understanding of when their central air conditioner is broken beyond repair, it's fair to say that, with proper maintenance and care, you can expect a good 15 to 20 years of cooling from a new high efficiency air conditioning system.

Can a furnace provide air conditioning? ›

A gas furnace with an air conditioning combo is an excellent choice for both cooling and heating your home. Also known as gas-electric systems, these HVAC units use natural or propane gas to heat your home in the winter while relying on electricity to cool it during the summer.

How does add on cooling work? ›

An Add-On Cooling system works by being added onto a Gas Ducted Heating System. Add On Cooling installation involves placing a condensing unit outdoors, which is then connected to the gas ducted heating unit through a coil. This allows cool air to flow through the same ducts used by the ducted heating system.

What is the most expensive part of an AC unit to replace? ›

The most expensive part of an AC unit to replace and repair is the air compressor.

What size air conditioner do I need for 2000 sq ft house? ›

Step 5: Match your square footage to an HVAC size chart
Home Square FootageAir Conditioner Size (Tons)
600-1,000 square feet1.5 tons
1,000-1,500 square feet2 tons
1,500-2,000 square feet3 tons
2,000-2,500 square feet4 tons
1 more row

Should my house have 2 AC units? ›

AC units are recommended for your home based on the square footage of your house and your cooling needs. If you have two units, the size of the units needed will be smaller to cool the same square footage of space, versus one large unit. The savings in energy costs can also help offset the cost of having two units.

Can you run 2 air conditioners on the same breaker? ›

Another however ... you can check the ratings of your AC units; they may both be OK on one breaker if their combined load is less than 30 amps. They may cause lights on the same circuit to dim, especially when they start, and if they both kick on at the same time, they might overload the breaker.

Can you have 2 zones with one AC unit? ›

a Dual-Unit System. With a zoned system, one unit provides heating and cooling to multiple areas of your home. In a dual-unit system, you have two totally separate units that each operate a single zone with separate, unconnected thermostats.

Should a 2 story house have 2 AC units? ›

Not necessarily. It's likely that a 2nd unit won't cost as much as you'd expect. Since this additional unit is not going to be used to cool the entire square footage of your home, you won't need a particularly large second unit. A professional HVAC company will calculate exactly what size of a 2nd unit you will need.

Can I add new AC vent to existing ductwork? ›

You can add a vent to existing ductwork if your AC can handle it. This can provide comfort in rooms not served by your HVAC system. It can even improve indoor air quality and increase your home's resale value.

Which HVAC system can provide both heating and cooling? ›

Heat pumps can both heat and cool because they are made with a component called a reversing valve. This valve allows the heat pump to change the flow of refrigerant in the system, so it can operate in either cooling or heating mode.

What is the difference between central AC and ducted AC? ›

As the name suggests, ducted air conditioning provides heating or cooling through a system of ducts spread out all over your home or commercial space. A central unit, consisting of a condenser, compressor, and an air handling unit, is usually located in the basement, attic, or garage.

Should I replace my 20 year old air conditioner? ›

The average lifespan of an HVAC system is 15 to 20 years, but as these systems age, they tend to get less efficient. If your HVAC is over 10 years old, consider replacing it with a more energy-efficient unit, such as one that has earned the ENERGY STAR label.

Can I just replace my outside AC unit? ›

If your AC is newer, you may be able to replace just the outdoor unit. In many cases, this could lead to decreased energy efficiency or early AC failure. Installing a new AC costs between $3,800 to $7,500. Replacing just the outdoor unit can sometimes void the warranty.

Should I replace my 30 year old air conditioner? ›

Age absolutely matters when it comes to HVAC. According to ENERGY STAR®, if your air conditioning unit is older than 10 years and/or your furnace is older than 15 years, it's time to consider a replacement.

What to do before switching furnace to AC? ›

5 Things to Do Before Switching to AC This Spring
  1. Prep the AC Unit. Get your exterior air conditioning unit ready for summer by removing its cover and clearing any surrounding debris. ...
  2. Change the Air Filters. ...
  3. Clean the Vents. ...
  4. Check the Thermostat. ...
  5. Schedule Your Annual HVAC Service.
Apr 8, 2017

Are HVAC systems cheaper in the winter? ›

Shop for an HVAC System During The Off-Season

The rationale is that air conditioners will sell at a lower price during winter and heating systems will be cheaper during summer.

What is the life expectancy of a furnace and AC? ›

A: On Average, 10-20 Years

Air conditioners and heat pumps: 10 to 15 years. Furnaces and boilers: 15 to 20 years. Geothermal: 30 years.

How long does it take to install central air with existing ductwork? ›

A typical air conditioner installation typically takes between 4 and 8 hours to complete. These times can fluctuate depending on the size of the existing system, weather, and accessibility.

What makes your AC bill high? ›

Air conditioners use a lot of electricity, but a loss in efficiency will cause high electric bills. Dirty filters, duct leaks, failing parts (motors, capacitors, etc.), low refrigerant, lack of maintenance, old system, and a bad install are all reasons your air conditioner itself will cause high electric bills.

Does keeping your AC higher save money? ›

The reason raising the temperature saves money is simple: when the thermostat's setting is higher, the unit itself doesn't have to work as hard to keep the air inside the home close to that setting, resulting in less energy usage.

How often should you replace your home AC? ›

If you kept your air conditioner in good condition over its lifetime, expect to need a replacement in about 10-15 years. Keep in mind that as your A/C grows older, its mechanical parts can become unavailable or obsolete over time. If you aren't able to replace a broken part, you will need to purchase new unit.

What factors affect the price of an AC installation? ›

Six Things That Affect HVAC Installation Costs
  • Type Of AC System. ...
  • Equipment Size & Cooling Capacity. ...
  • SEER Ratings. ...
  • Additional Installations. ...
  • Ductwork, Vents & Returns. ...
  • Zones & Controls.

How much energy will a new AC unit save? ›

The benefits of upgrading your central AC.

The first thing any upgrade will do is lower your energy usage. A 20-year-old air conditioning system might use 6 kWh of electricity to cool an average-sized house. A modern AC system could cool that same house using as little as 1.71 kWh of electricity.

Do you need an AC unit in every room? ›

You don't need a head unit in every room. Provided there is sufficient airflow between spaces, a single unit can control the temperature in multiple rooms within the same zone.

Can I install my own ductwork? ›

Whether you're building a home or replacing bad ductwork, DIY duct installation can be tempting. However, a trustworthy professional contractor with the right tools, training and experience is the best person to install air ducts.

What is the best time of year to replace an AC? ›

There is no doubt that the best time to replace HVAC systems is during the off-season. More than often, the off-season stretches from late September to mid-November and from early March to mid-May is the best time to replace HVAC system for your home or business.

Is it bad to leave AC unit on all night? ›

In short, scientists and experts seem to agree that leaving your AC on during the night is pretty safe. What's more, some actually recommend it since the optimal temperature for sleeping seems to be on the cooler end of the spectrum.

Can HVAC last 30 years? ›

It is highly unlikely that your unit will last 30 years before needing to be replaced, however, if you follow a regular preventative maintenance routine and run it appropriately, your chances of keeping the same unit for around 15 years increases dramatically.

How much is a Trane AC unit? ›

What Is the Typical Cost of a Trane Air Conditioner? On average, most homeowners pay between $2,200 and $3,900 for a Trane AC unit, but with installation, the total AC installation cost often ranges from $4,600 to $12,000.

Do heat pumps work as well as air conditioners? ›

So, from a cooling perspective, minus a few technical details, heat pumps and air conditioners are essentially the same when operating in cooling mode, with no significant difference in operation, efficiency, or energy costs.

Can you add air conditioning to a central heating system? ›

Yes, you can use an add-on refrigerated cooling system as an additional component to your ducted gas heating system, allowing you to run refrigerated air conditioning via the same ducting and outlets in your existing system.

Does it cost more to cool a house or keep it cool? ›

Ultimately, heating your home will cost more than cooling—but there are plenty of actions you can take to keep these expenses low.

Is it better to remove hot air or add cold air? ›

The only thing that really matters is the temperature outside your window versus the temperature outside your door. If it's cooler outside your window, blow air in from the window. If it's cooler outside your door, blow the air out the window.

How to add air conditioning to a house without ductwork? ›

Use a Mini-Split System Instead

One way to avoid installing central air in a house without ducts is by using a mini-split system. The installation process for these systems will be much easier because you don't need bulky and hard-to-install ductwork. A mini-split system is also a great way to save on energy costs.

Can you add AC to existing heat pump? ›

You can add a heat pump to your existing furnace or AC unit for a mild-weather solution or you can install a heat pump to be your primary, standalone HVAC solution. Either way, the idea is simple: the heat pump moves air from one place to another, passing it through a condensing unit along the way.

Can you install air conditioning anywhere? ›

In general, split air conditioning units should be installed in a central location in the room you want to cool or heat to ensure balanced airflow throughout the space. Bedroom: The best position for an air conditioner in a bedroom is where the air does not flow directly over the bed.

How much is a new AC unit without ductwork? ›

Do you want to add air conditioning to your home, but it doesn't have any air ducts? You can either choose to: Install new ductwork and a central AC system (which can cost anywhere from $6,000 to $17,000+ combined) Install a ductless AC system (which can cost from $4,000 to $20,000+)

Can you add to existing ductwork? ›

You can add a vent to existing ductwork if your AC can handle it. This can provide comfort in rooms not served by your HVAC system. It can even improve indoor air quality and increase your home's resale value.

How effective is ductless air conditioning? ›

Energy efficiency: Ductless systems don't lose hot or cold air due to duct leakage. Most mini split systems are approximately 20 to 30 percent more efficient than ducted systems. Multi-purpose: Mini splits also offer dehumidifying and air purifying benefits.

Can a heat pump cool a house as well as an air conditioner? ›

Though the name seems to suggest otherwise, heat pumps don't just heat—they cool too! In fact, a heat pump can cool your home just as well as an air conditioner. A heat pump with a 16 SEER rating works just as efficiently as an air conditioner with a 16 SEER rating.

What location should be avoided in installing an air conditioning unit? ›

Keep Your Indoor Unit Away from Heat Sources

Since the location of your air conditioner has a significant impact on efficiency, you should avoid placing your indoor unit close to heat sources.

Where should you not install an AC unit outside? ›

AC units should not be placed near or behind doors or outdoor furniture. The outdoor ac unit should not be placed inside in places like the garage or attic. They are called outdoor units for a reason. The condenser needs to be elevated enough to not be in pooling water during rain.

Do you need planning permission to install air conditioning? ›

Planning permission for air conditioning installations in homes. Generally, most small air conditioning installations don't need planning permission. This means that you don't need to submit a planning permission application before installing your air conditioning – you can just go ahead and do it.


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