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What Size HVAC Unit Is Right for Me?

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Before purchasing an HVAC system, it is important to know right size air conditioner or heating system for your house. A common mistake homeowners make is to purchase the wrong air conditioner size, sometimes too large of a unit for their home. This results in the homeowner spending more money on energy and operating costs than necessary.

The most efficient way to determine HVAC system capacity will depend upon what type of heating or cooling you prefer.

When it comes to HVAC equipment, bigger isn't always better. You’ll see the best results, longest life and most energy efficiency from a system that's selected based off the proper air conditioner sizing for the square footage you want to cool and heat.

To help you identify the best fit for your home and budget, here are just a few of the factors you must consider when an HVAC replacement decision.

So What Size HVAC Unit Does a Building or Home Need?

To determine what size HVAC unit works best for your home, it's important to know what type of heating or cooling system you currently have installed. If you are unable to identify what your current HVAC system is, then here are some general guidelines on what size unit is most often used for what type of heating or cooling.

  • For homes with forced air heat, most often a 5 ton unit will be sufficient.
  • Homes with gas heat will require what is referred to as a "heat pump" which can heat and cool, so what size unit you need will be determined by what type of heating or cooling system you prefer.
  • Most homes with electric heat will require what is known as a 3 ton unit.
  • If your home does not have forced air for your heating needs, what size unit is needed will be determined by what the highest BTU (British Thermal Unit) heating load is for your home.
  • If you do not have any type of cooling system in place, what size AC unit should I install will depend upon what type or rooms need cooled. A general rule of thumb is what size unit to install will be what is recommended by the manufacturer of your existing system if you are unable to identify what type or cooling system you currently have in place.

Often, there will be a sticker on the outdoor compressor with information about what size unit it is. This sticker has all of the necessary information needed to determine what size system is currently in place.

If you are unable to locate this, then you can check what type of controls are being used for cooling or heating your home by checking what type of thermostat is being used as this will indicate what type of electrical system is currently in place.

Alternatively, you can also check what size system your home builder installed. Simply call your builder and ask what size cooling or heating systems were used for your new construction. Another option would be to contact a local HVAC contractor and have them inspect your home and what type of cooling or heating system is currently installed.

Calculating the Right-Size Central Air Conditioner

Once you have determined what size HVAC unit is currently in place, it will be easier to determine what size system you should install so as not to purchase too large a unit and lose out on energy savings.

Keep in mind that if your existing HVAC system is larger than what is needed, what size system you should install will be what is recommended by the manufacturer of your existing unit. It would not make sense to purchase an outdoor unit that is too small for what you currently have in place.

Different Home Sizes Require Different BTUs

When shopping what size HVAC unit you should buy, what matters the most is what size house you have and what your desired temperature range is that you want to maintain throughout. Knowing how many BTUs are required for your home will allow you to make the best decision what size HVAC system you should purchase.

BTU stands for British Thermal Units. A BTU is what's required to heat or cool one pound of water by 1 degree Fahrenheit.

For example, your home's square footage total, including all floors and ceilings, is what determines what size what size HVAC unit you need. For every 500 BTUs required for your home, you will need approximately one ton of air conditioning or heating capacity (1 ton = 12,000 BTUs). Every degree above or below what the desired temperature is set at requires another 500 BTUs to increase or decrease.

Size Matters

There are two types of what size HVAC systems, single stage and two-stage. Single stage units are what you want for you home if your desired temperature does not go above what the normal setting is set at during summer or winter times.

Two-stage units are what you should get if there are times where temperatures get either hotter or colder than what the what size HVAC system you have will allow. If you live in an area where temperatures reach far extremes you need to add this into your residential load calculation.

Manual J Calculation

The Manual J calculation is what HVAC professionals in the industry use to calculate what size unit you need. The Manual J sizing method includes measuring the cubic feet in your home, finding out what kind of attic insulation you have inside (R-11, R-13 etc.) and what your specific climate is like where you live. Here are the steps you should take to figure what Manual J sizing is perfect for your home:

1. Measure the outside air temperature of where you live and what the inside temperature averages during the winter.

2. Your manual J calculation requires knowing what your insulation is, what's included in your insulation and what climate zone you live in (hot or cold).

3. Look for what your insulation is and what the inside temperature averages on the Manual J calculation chart, and follow those steps to find what size unit you need.

4. Remember what features come with different sized units, so you can choose the perfect one that will fit all your needs.

Using Square Footage to Determine What Size HVAC System is Necessary

When determining what size HVAC system is necessary for your home, it's important to get an accurate reading of what the square footage of your house will be. A square foot heating guide will make sure you're purchasing a unit that is big enough.

House Square Footage BTUs Needed
100 – 150 5,000
150 – 250 6,000
250 – 300 7,000
300 – 350 8,000
350 – 400 9,000
400 – 450 10,000
450 – 500 12,000
500 – 700 14,000
700 – 1,000 18,000
1,000 – 1,200 21,000
1,200 – 1,400 23,000
1,400 – 1,500 24,000
1,500 – 2,000 30,000
2,000 – 2,500 34,000

There are online calculators that can help you determine what size HVAC system you need based on what you input into them as well.

Buying an HVAC System Too Big or Too Small for Your Home

One of the most important things to consider is what size HVAC system your home uses now . It is generally most economical to replace an existing system, especially if it is old and inefficient. If you have a new home, however, it may be most cost-effective to install a much larger system.

What size HVAC unit you need for your home also depends on what climate zone it is in . The closer you are to the equator, the warmer it will be year-round. If your area has mostly mild temperatures, you do not need an incredibly powerful unit to cool your home. However, if there are frequent heat-waves and you live in an area near the equator, your unit is going to have to be able to keep up.

What size HVAC unit you need for your home is also based on what season it is . If it is winter and you live in a cold climate zone, choose a system that will easily heat your home without constantly turning on and off. Try to make sure it will be powerful enough to heat your house during what is expected to be the coldest day of the year. On hot days, however, you do not want a system that can cool your entire home all at once.

There are many other factors that affect what size HVAC unit you should purchase for your home. Before deciding what system to buy, calculate what size HVAC unit you need based on what season it is and what climate zone your house is in. Also consider what size system it currently has so that you do not waste money or energy trying to cool or heat the entire home at once.

What Size HVAC System Should You Get?

So what size HVAC unit should you get for your home size? For a single what size HVAC unit, what matters the most is what area of your home to run it in and what temperature range you desire throughout.

For average sized homes between 1,500 to 3,000 square feet, what size HVAC system you should purchase is what's called a three-ton unit. Depending on what your desired temperature range is will depend what size what size HVAC system you decide to get.

For every degree above or below what the desired temperature is set at will require what size HVAC system you should purchase to be an additional 500 BTUs.

For example, if your desired temperature is set at 71 degrees and what size what size HVAC unit you should get for your home size is a three-ton air conditioning or heating capacity system, then this what size what size HVAC unit should get what size HVAC system your home requires for that temperature range is 6,000 BTUs.

Call 1-800-277-9400 today to make an appointment with an HVAC pro! We can recommend and install a right-sized system for your home.

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