How to choose the right aircon HP for your room size | NoypiGeeks (2023)

With the heat becoming more unbearable each day, air conditioning in our homes increasingly feels like a necessity. But when looking for the perfect aircon for your room, the decision should not be made based on price or brand alone.

There are other factors that you need to consider when shopping for your next unit, particularly horsepower, or the aircon’s HP. Let’s discuss some of the important factors when choosing the correct aircon for your room.

Table of Contents

  • What is aircon HP?
  • Why should I consider HP when choosing a unit?
  • How do I compute the right aircon HP for my room size?
  • What type of aircon should I get?
    • Window type vs split-typeairconditioner
    • Inverter vs non-inverter
  • What other factors should I consider when picking an airconditioner horsepower?

What is aircon HP?

Horsepower, or HP, simply refers to how much work your aircon unit’s motor can sustain. For air conditioners, this translates to the unit’s cooling capacity, or how well and how quickly it can cool a room.

Why should I consider HP when choosing a unit?

It’s crucial that you choose the correct aircon HP for your room size. Higher HP doesn’t always mean better. In fact, if you have an AC unit that has too high HP for your room, then you likely experience that uncomfortable clammy feeling.

This is because the oversized unit has reached the thermostat temperature too quickly without sufficient dehumidification, which leaves the air feeling wet and heavy. The unit also has to turn and off more frequently, consuming more energy.

On the other hand, an AC unit with too low HP will take much longer to reach the desired temperature. It will also have a hard time maintaining that temperature, leaving it constantly running and consuming more energy.

(Video) Air Conditioner - How To Select The Proper Size Unit

Having an aircon with the right HP for your room size not only leads to a more pleasant experience, but it’s also energy-saving and cost-efficient.

How to choose the right aircon HP for your room size | NoypiGeeks (1)

How do I compute the right aircon HP for my room size?

Most aircon brands and suppliers provide a guide for selecting which of their units is suitable for your room size. These guides may slightly differ depending on the aircon brand. Based on recommendations from Meralco, here’s a general HP to room size guide that you can follow:

Room Size (sq. m.)Aircon HP
< 110.5
12 to 170.75
18 to 221.0
23 to 271.5
28 to 402.0
41 to 542.5

What type of aircon should I get?

Once you have decided what aircon size you should get based on HP, you should next consider what type of aircon works best for your room. Choosing the right aircon type matters just as much as choosing the right HP if you’re looking to get the most value out of your AC unit.

Window type vs split-type airconditioner

Window type and split type AC units are the two most common aircon types for home use, and both come with their own sets of pros and cons.

The window type aircon is the cubic, compact unit that is installed through a window or a hollow area in a wall. Because of its simple and compact structure, it’s easy to install even without professional assistance. They are also the most affordable aircon types available on the market. However, window type ACs are notoriously noisy, and because they require a hole in the wall for installation, some may consider them to be quite awkward and unappealing.

(Video) How to calculate room air conditioner size | AC calculation | Earthbondhon

How to choose the right aircon HP for your room size | NoypiGeeks (2)

On the other hand, a split type aircon is divided into two units: an indoor unit and an outdoor unit. This split design keeps the noisy compressor unit outside and away from your room, leading to a much quieter experience.

A split type AC can be hung from a wall and only requires a small hole to connect the two units. The flip side is that a professional is required to have a split type AC seamlessly installed. They are also more expensive than the standard window-type with the same HP.

Choosing between these two aircon types is a matter of budget and aesthetic preference. Both window type and split type AC units have different HP capacities available which you can choose from depending on your room size.

Inverter vs non-inverter

If you’re looking to lower your monthly electricity bill, an important question you should ask is whether to buy an inverter or a non-inverter aircon. The main difference between the two lies within the compressor.

In a traditional non-inverter aircon, the compressor always operates at its maximum capacity. On the other hand, an inverter aircon has a smart compressor that automatically adjusts to maintain the set temperature. Because it’s not always running at maximum capacity, an inverter AC unit is energy-saving and more cost-efficient.

(Video) How to compute your Air Condition's HP based on your room size

The catch is that inverter aircons are more expensive than their non-inverter counterparts. An inverter aircon is a great investment to make if the higher upfront costs are within your budget. Choosing an inverter aircon with the right HP for your room size is the best way to cut down on your energy bill in the long run.

How to choose the right aircon HP for your room size | NoypiGeeks (3)

What other factors should I consider when picking an airconditioner horsepower?

The aircon HP recommendations provided above are only based on the average room size. When looking for the right aircon size and HP for your room, there are other factors that come into play, which may require you to get an air conditioner with higher HP.


Direct sunlight is one of the primary sources of heat in your room. If the room has little shade and receives direct sunlight throughout the day, you may want to consider getting an aircon unit with one HP capacity higher.

The number of occupants

(Video) How to choose the right Horsepower?

Most people forget that humans also emit body heat, which must be considered when computing aircon HP. If more than three people frequently occupy the room, most aircon brands recommend getting a unit with higher HP.

Room layout

If your room has large windows, this means that it receives more direct sunlight which heats up the room, especially if the windows don’t have anything to protect against the sun’s rays, such as curtains, blinds, or tinting. The position of the windows also matters. If the room has west-facing windows, this means that it gets especially hot when it receives the afternoon sun, which is hotter compared to the morning sun.

Another thing to consider is whether the room has any insulation installed. If the walls and roofs are properly insulated, they keep the heat out while also trapping the cool air from the aircon so it stays inside the room.

See also: Cheap 32-inch TVs under Php5,000

Lighting and other sources of heat

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Another factor to add to the equation is the heat that is emitted from the different appliances inside the room such as televisions and refrigerators, as well as light sources such as light bulbs and lamps. Stove ranges are also a major source of heat, which are common in studio-type condo units. Although their individual heat emissions may be minimal, the cumulative emissions of multiple appliances may be significant, especially if several of these are frequently in use.

Before looking for your next AC unit, do a quick survey of the room and check for these factors. If your room has one or more factor that increases the heat load inside the room, you may opt for getting an aircon unit with at most one HP capacity higher than recommended.

When purchasing a new air conditioner, make sure to consider the unit’s HP so that you get the best cooling experience, without shooting up your electricity bill. Even on the hottest days, having a good aircon unit for your room will help you keep your cool.


How do I calculate aircon HP for room size? ›

Multiply the size of your room by 500 to obtain a rough estimate. In the case of a 10 square meter room, a cooling capacity of 5,000kJ/hr is required, which most 0.5HP window air conditioners have.

How do I choose the right HP aircon for a room? ›

If your room is heavily shaded, get an aircon with a lower HP. If your room gets too much direct sunlight, consider getting an aircon with a higher horsepower so that it can cool your room efficiently.

How do I choose AC by room size? ›

To calculate the size, simply multiply the length times the width of the room or area to be cooled. Then, as a practical number, multiply that total times 25 BTU. This allows ample cooling, whether it is a rainy, moist day or a hot, sunny, humid day. Let's say the room is 12 feet wide by 15 feet long.

What size AC do I need for a 12x12 room? ›

Obviously, the problem arises when you have a tiny 12×12 room, for example. According to the US Department of Energy directive, an air conditioner's most appropriate size would be 2,880 BTU unit.

What HP aircon do I need calculator? ›

How to Calculate HP for an Air Conditioning Unit
  1. Multiply the air conditioner's size in tons by 12,000 to convert its cooling capacity to British Thermal Units per hour. ...
  2. Divide this answer by 3.412 to convert it to watts: 18,000 / 3.412 = 5,275 watts.
Apr 18, 2018

How much AC HP do I need? ›

A small room of about 12 square meters (130 square feet) or less requires about 1 HP. A medium-sized room of about 18 square meters (200 square feet) or less will require about 1.5 HP. A large room of about 30 square meters (325 square feet) or less will require 2 HP.

What is the rule of thumb for aircon sizing? ›

Air conditioning capacity is measured in British Thermal Units, or BTUs. A good rule of thumb to follow is that you'll need approximately 20 BTU for every square foot of floor area.

How do I choose the right air conditioner? ›

  1. Find the right fit. Decide on the type of HVAC system that is right for your home and get the correct size. ...
  2. Consider the SEER rating. Weigh how much the energy savings will offset the cost of a higher-efficiency unit.
  3. Check on the warranty. ...
  4. Know your installer.
Mar 18, 2019

How do I choose the most energy efficient air conditioner? ›

A room air conditioner's efficiency is measured by the energy efficiency ratio (EER). The EER is the ratio of the cooling capacity (in British thermal units (Btu) per hour) to the power input (in watts). The higher the EER rating, the more efficient the air conditioner.

What if air conditioner is too big for room? ›

An oversized HVAC unit can make your home's inside temperature uncomfortable. An HVAC system with excess capacity can heat or cool your home faster, but that speed often results in a couple of other issues. First, your home won't benefit from gradual, even heating and cooling.

What happens if room is too big for AC? ›

It Won't Cool Your Home

Too big: An AC that is too big will only run for a short period of time, shutting on and off quickly as the temperature fluctuates.

Can an AC be too big for a room? ›

And when it comes to air conditioners, bigger isn't always better. In fact, having a unit that's too big for your home could end up causing you costly problems. Air conditioners that are too big consume more energy, endure more wear and tear, and simply don't work as well or as long as an appropriately sized unit.

What size AC do I need for a 150 square foot room? ›

150 – 250 sq. feet: 6,000 BTUs. 250 – 300 sq. feet: 7,000 BTUs.

Which AC is best for bedroom? ›

Best Small Room AC in India
  1. Carrier 1 Ton 3 Star Split AC. ...
  2. Panasonic 1 Ton 5 Star Split Inverter AC (CS/CU-NU12XKYWA) ...
  3. LG 1.5 Ton 5 Star Window AC (JW-Q18WUZA) ...
  4. Hitachi 1.5 Ton 3 Star Window AC (RAW318HFDO) ...
  5. Symphony 30 L Tower Air Cooler.
7 days ago

What size AC do I need for 1500 square feet? ›

What size air conditioner do I need for a 1,500 square foot house? A 2.5 ton air conditioner is best because about 30,000 BTU is needed for a house that's 1,500 square feet.

How much power does a 1.5 HP air conditioner use? ›

That means that such AC units have a wattage of 2,000W when running at 100% cooling output. A more efficient 5-star 1.5 ton AC have an EER rating of about 11. At 100% output, it will run on about 1,6000 watts. Cost Of Electricity (Per kWh).

How do I calculate room size? ›

To calculate feet squared (or sq. ft. for short), determine the length and width of the area you are working with, measured in feet. Multiply the length by the width and you'll have the square feet. Here's a basic formula you can follow: Length (in feet) x width (in feet) = area in sq. ft.

How long does an HP AC system 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.

How much cooling capacity does a 1 HP air conditioner have? ›

Usually, a 1HP air conditioner can remove 9,000 BTU/hour of heat. With better technology, some air conditioners can remove up to 10,000 BTU/hour of heat with the same capacity (for calculation purpose, 1 HP ≡ 9,500 BTU/hour).

What is the capacity of 1HP air conditioner? ›

Air Circulation (m³/h)550
Capacity (W) | Cooling2640
Capacity (W) | Heating/
COP (W/W)/
EER (W/W)3.25
9 more rows

How do I know if my AC is big enough? ›

You need approximately 6,000 BTUs to cool an area under 300 square feet, 10,000 BTUs for 301 to 549 sqft., 16,000 BTUs for 550 to 999 sqft., 22,000 BTUs for 1,000 to 1,199 sqft., 30,000 BTUs for 1,500 to 1,999 sqft. and 34,000 BTUs for 2000 to 2,499 square feet. 5. If necessary, adjust the BTU rating.

How do I know if my AC is too small? ›

5 Signs of an Undersized Air Conditioner
  1. Your AC Never Stops Running. ...
  2. Low Airflow. ...
  3. Your Home Is Never Cool Enough. ...
  4. Your Home Has Temperature Inconsistencies Throughout. ...
  5. High Energy Bills.
Nov 9, 2018

How do I know if my air conditioner is too big for my house? ›

4 Signs Your AC System Is Too Big for Your Home
  1. High Humidity. Oversized units don't run long enough to dehumidify indoor air. ...
  2. Short Cycling. Because it's so large, an oversized AC meets your home's cooling load in ten minutes or less and then cycles off. ...
  3. Hot and Cold Spots. ...
  4. Shorter Lifespan and Higher Utility Bills.
Apr 18, 2018

Is it better to oversize or undersize AC? ›

Better to oversize or undersize ac

However, in general, it is better to slightly undersize your AC unit than to slightly oversize it. If your AC unit is too small, it will have to work harder to cool your home, which can lead to increased energy costs and a shorter lifespan for the unit.

Should I get a bigger AC than I need? ›

Simply put, bigger is not always better when buying a new air conditioner. In fact, bigger than big a mistake that costs you a lot of money upfront as well as in the future. There is no denying the fact that a bigger AC unit with more power has a greater ability to keep a space cool.

Is it better to have a bigger air conditioner? ›

A bigger unit simply gobbles more power than a smaller one. To make matters worse, your oversized air conditioner will likely never reach its promised level of energy efficiency. Just as it is cycling up to its most efficient level, the thermostat will tell it to shut off again.

Is higher or lower BTU better for air conditioner? ›

BTUs are the energy used to remove heat from a room. Therefore, the more BTUs an air conditioner unit has, the better equipped it is to cool a larger space.

What is the most efficient type of air conditioner? ›

If you're looking for whole-house cooling, and you already have ductwork in place, this is the most popular option. Central air conditioning is the most efficient way to keep your whole house cool. You can expect lower energy bills alongside better indoor comfort, cooler temperatures and lower humidity.

What is the most efficient home air conditioner? ›

For an ultra-efficient central air conditioning unit, it's difficult to top the Lennox XC25. Rated most efficient by EnergyStar for 2022, this air conditioner has an outstanding SEER rating of 26 thanks to its advanced technology.

How big of an AC unit do I need calculator? ›

Size and Ceiling Height
Area To Be Cooled (square feet)Capacity Needed (BTUs per hour)
100 to 1505,000
150 to 2506,000
250 to 3007,000
300 to 3508,000
10 more rows

What is the HP of 1.5 ton AC? ›

If the air conditioner has a 1.5 ton capacity: 1.5 x 12,000 = 18,000 BTUs per hour.

How much power does aircon use vs room size? ›

Generally, you will have to use about 0.142 kilowatts for every square metre of your room. Let us have some examples: If you have a small room, which is about 18 square metres, your AC wattage should be around 2.5kW to provide you with a cool and comfortable space.

What is the capacity of 1 HP aircon? ›

Usually, a 1HP air conditioner can remove 9,000 BTU/hour of heat. With better technology, some air conditioners can remove up to 10,000 BTU/hour of heat with the same capacity (for calculation purpose, 1 HP ≡ 9,500 BTU/hour).


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