mother and daughter cooling off when AC is broken

Any homeowner who doesn’t want to suffer in the sweltering heat during the hottest summer months (particularly in the South), would do well to ensure their heating, ventilation, and air conditioning (HVAC) system is working effectively.

First and foremost, what should you do if you find there’s a problem with your system? Secondly, how do you decide if the system needs repair or complete replacement?

If you discover that your system is having trouble circulating cold air, and is essentially just blowing air around the home instead of cooling it, your first step should be to try to figure out the problem for yourself. The filter might need replaced, or there could be a clog. If you don’t want to tempt fate by checking the system yourself, consult an HVAC technician.

After this step, it’s relatively easy to decide between replacement and repair if you use the ‘5,000 rule’. The 5,000 rule means that you multiply the age of the system by the quoted repair costs. If it’s under 5,000, repair is a sensible choice. If it’s over 5,000, replacement is recommended.

So, now that you know what to do in the event of finding a problem with your HVAC system, how much does new air conditioning cost? The average air conditioner costs $4,000 to $5,000 with installation. Let’s examine a few factors that affect the overall price of a new system:

British Thermal Units

If you are replacing window air conditioners, or just don’t want to spend the money to replace a more extensive system, it’s helpful to find out the size of the window air conditioner that you need. Learn more about how much a window air conditioner costs.

You do this by measuring the room you intend to put it in. Multiply the length by the width of the room, and from these measurements, you can find out the recommended energy requirements for a room of that size.

For window air conditioners, you will encounter a measurement called ‘BTU,’ which stands for ‘British Thermal Unit’ and is the international measure of energy. One BTU is the amount of energy needed to increase the temperature of one pound of water by one degree Fahrenheit.

To put things in perspective, a 10 foot wide by 10-foot long room needs a window air conditioner capable of reaching 5000 BTUs.

Climate Zones

A useful way of figuring out how much energy it takes to heat your home is to examine a heating climate zone map. On such a map, America is divided into a number of zones according to how mild or extreme the cold temperatures are.

There are five different zones, all of which have different requirements for effective home heating. Zone 1 is the warmest and Zone 5 is the coldest. Zone 1 represents many Southern states including Florida and Texas. Zone 5 represents many of the states that border with Canada including Montana, North Dakota, and Minnesota.

In general, homes in Zone 1 require the least amount of energy per square foot, and those in Zone 5 require the most. The overall numbers range from 30 to 60 BTUs per square foot. Here are two examples to illuminate the difference using the median BTUs for their designated zone:

A 2000 square foot home in Montana requires 110,000 BTUs of energy to heat.

A 2000 square foot home in Texas requires 65,000 BTUs of energy.

Finding out how many BTUs you need to heat your home will help you to decide on a new HVAC system because the heating and cooling capacities work hand in hand to maintain a comfortable environment during different seasons.

In other words, an HVAC system that is purchased in Montana with enough output to heat a home during the winter will be calibrated to provide sufficient cooling power in the summer.

The Cost of a New HVAC System for an Average-Sized American Home

When you take the average amount of BTUs per square foot from the heating climate zones measurements and multiply this by the number of square foot in an average sized home, this gives a reasonable ballpark estimate of how much new air conditioning cost. Below is the relevant calculation to show you the process:

The average size of an American home built in 1983: 1,725 square feet

The average size of an American home built in 2013: 2,598 square feet

Thus, let’s assume an average size of 2,000 square feet for the sake of simplicity.

The climate zone BTU range is from 30 to 60 BTUs per square feet, so let’s use the middle figure of 45 BTUs per square foot for the calculation.

The required BTU of an average house, then, is 90,000 BTUs.

When you get this figure, you divide it by 12,000 to find the appropriate air conditioning tonnage. 90,000 divided by 12,000 equals 7.5 tons.

A 7.5 ton HVAC unit costs an average of $3,000 but can be more or less depending on the brand and special features.

Thus, the average cost of having a good quality, good brand HVAC system installed in an average house in America will cost you around $4,000 to $5,000 including labor and any extras.