Kara Zorn on May 1, 2014 31 Comments When shopping for a portable air conditioner, you may have come across the foreign acronym “BTU.” It appears not only in every product description but also in many product names. It is obvious that this is important to understanding portable air conditioners, but it is not clear why that is and why it should matter to you. B-T-U The acronym stands for British Thermal Unit, which is the unit used to measure thermal (heat) energy. Specifically, it is the amount of energy needed to raise 1 pound of water 1°F at sea level. When used in relation to air conditioning systems or heaters, the measurement is expressed in terms of how many BTUs per hour the product can add or remove from the air. With that said, unless you are involved in the manufacturing or retailing of cooling and heating supplies, this may not mean anything to you. But it should, and here’s why: Too Much of a Good Thing A higher number of BTUs isn’t always the answer. Using a portable air conditioner with a BTU level higher than needed can cause the unit to cool quickly, cycle off and then, to maintain your desired temperature, have to cycle on again soon after. By cycling on and off in such fitful spurts of time, your portable air conditioner’s compressor will quickly over-work itself. If done excessively and frequently, you will likely shorten your unit’s lifespan. This is not exclusive to portable AC units, either. The same goes for all AC units, including the popular window and central air conditioners as well. Too Little, Too Late Using a portable air conditioner with not enough recommended BTUs will keep you from reaching your desired comfort level. The heat load will be too much for your unit to handle. This will cause your AC unit to run continuously and never reach your set temperature level. Not to mention shorten its lifespan. This is why it is important to pay attention to square footage recommendations per the each air conditioner you considering of buying. As well as have a pretty good idea of the square footage of the space you are intending to use the AC unit in. BTU Recommendations Based on Square Footage: We would recommend using our BTU cooling calculator to determine the specific amount of BTUs you will need from your air conditioner in order to properly cool your space. However, below we have listed some general BTU recommendations that will help get you started. BTU Chart Based on Room Size Room Size BTU’s Needed Room Size BTU’s Needed 150 sq. ft. 5,000 BTU’s 700 sq. ft. 14,000 BTU’s 250 sq. ft. 6,000 BTU’s 1,000 sq. ft. 18,000 BTU’s 300 sq. ft. 7,000 BTU’s 1,200 sq. ft. 21,000 BTU’s 350 sq. ft. 8,000 BTU’s 1,400 sq. ft. 23,000 BTU’s 400 sq. ft. 9,000 BTU’s 1,600 sq. ft. 25,000 BTU’s 450 sq. ft. 10,000 BTU’s 1,900 sq. ft. 28,000 BTU’s 550 sq. ft. 12,000 BTU’s 2,700 sq. ft. 36,000 BTU’s Other Important Factors to Consider: Although square footage recommendations are typically correct, there are some other confounding variables that you should pay attention to when looking at the BTU’s of your air conditioner. If you are attempting to cool a second story that is typically warmer than the ground floor or a space that gets a lot of direct sunlight (for example, a room with a large west-facing window), you want to add 10% of the recommended BTUs. After adding 10%, you will have a better estimate of the cooling power you will need for this space. This is due to the added ambient heat added due to the environment. This may mean going up to the next available cooling power. On the other hand, if the area you are going to be cooling has lots of shade and very little sunlight exposure, you may want to consider subtracting 10% of the recommended BTU. This is not always recommended, as it is better to have too many BTU’s than not enough. If there is going to be more than two people in the area at a time, you should add approximately 600 BTUs per additional person. If you plan on using your air conditioner in your kitchen, or any area of your home where your appliances will likely generate higher levels of heat, you will need to add 4,000 BTUs to the recommended cooling power. Lastly, you want to consider whether or not your space is open or confined. Our square footage recommendations are meant for confined areas, so if your room open ups into another space without the option of closing a door, you will want to add in that other space. For example, if you want to cool a kitchen that opens into a living room, you will want to combine the size of those two rooms as if they were one space and use that as your determinate square footage. For help calculating the right BTU for your needs, feel free to give our portable air conditioner experts a call at 1.800.297.6076. Recommended Reading: FAQs: Portable Air Conditioners 5 Benefits of Portable Air Conditioners 5 Ways a Portable Air Conditioner Can Save You Money Cooling Capacity Calculator: How to Find the Right BTU for You
jane says May 4, 2016 at 12:03 pm How big of an air conditioner would I need to cool a house with 5 bedrooms a kitchen and dining room and how can you tell if its a 110 or a 220 unit Reply
L. Weerakkodey says July 6, 2016 at 3:54 am use the BTU chart Ex: if your room is floor area is 250 sqf you can use 7000- 8000 BTU AC likewise use that cart accordance with the floor area Reply
Logan says August 3, 2019 at 1:05 pm It’s more about the square footage of your whole house since it will be dispersed evenly. A 2000 sqft house is usually good with a 5 ton ac. It also depends on the geographic area you’re in because the max temp outside can add or shave a ton off. If your in the desert, for instance, you wouldn’t even use an AC, and instead would go for a swamp cooler. Reply
Sharon Alston says May 22, 2016 at 10:58 pm My apartment faces the sun and it stays hot even during the winter if the sun is out. I can enter my living rm into my kitchen it’s wide open. I also have a foyer as soon as you walk into my apt and my bedroom ( which has a fire escape) is more between my kitchen & bathroom. I hardly get any air in my bedrm. I previously had a 12,000 btu which just gave out after 10yrs. Would a 14 or 15,000 btu work better. In need of a new one.Please help. Thank you in advance. Reply
Bill Layton says July 11, 2016 at 3:48 pm I’m confused! I know that the BTU is a unit of energy and that even if a candle is left on long enough, it can deliver any amount of BTUs. Shouldn’t the unit for Heaters and Air Conditioners be a unit of power, or perhaps BTU per (some unit of time)? Perhaps everyone (but me) understands what the implied unit of time is. Reply
MAA says July 13, 2016 at 9:49 am The article actually covers this at the beginning. It can be easy to gloss over if you already know what a BTU is before reading. “When used in relation to air conditioning systems, the measurement is expressed in terms of how many BTUs per hour the product can remove from the air.” Reply
t.morix@yahoo.com says November 16, 2016 at 5:16 am i think they must have forgotten to include the power… it actually in BTU/h Reply
Douglas Carter says May 18, 2019 at 7:27 pm It says above, “When used in relation to air conditioning systems or heaters, the measurement is expressed in terms of how many BTUs PER HOUR the product can add or remove from the air.” Hope this helps! Reply
a late reply says April 21, 2020 at 11:40 am 1 BTU is the amount of energy it takes to raise the temperature of 1 pound of water, 1 degree Fahrenheit at sea level. A candle will not raise the temperature of 1 pound of water, 1 degree Fahrenheit at sea level because the heat from the candle will dissipate out of the water faster than it will raise the temp Reply
Karen says December 1, 2016 at 9:54 pm How important is it that a portable aircon. unit states a dehumidifier function included please? Reply
Ahmad says May 24, 2017 at 6:55 am Hi dear, I need to know I pick 8000 BTU/hr conditioner, how much of amperage I need at the beginning(inrush current) and at static state knowing that my voltage is around 220V? please I need the answer as soon as possible. Reply
Lynn says June 28, 2017 at 12:57 pm So 5 bedrooms kitchen n dining are ..sounds like aprox 250 per room ..so I am guessing aprox 2800. To 3200 BTU’s When considering how hot rooms and they come in to consideration as extra BTU’s counted in Reply
Ahmed says July 7, 2017 at 11:09 am Hi, need your help regarding below. Kindly let me know how much is the cooling efficiency difference is between below figures of two different AC units. Is it big or marginal. BTU/H Capacity (H/S/L*) 19100/17750/5118 BTU/H Capacity (H/S/L*) 22550/19600/4260 thanks Reply
Ruben says July 21, 2017 at 1:23 pm Hi, if the home has a 4 ton unit, with 1900 sq ft. what if we replace with a 5 ton unit will i have any problems?thanks.. Reply
Frank says July 18, 2019 at 2:11 pm Dunno are you trying to assets cooling or the weight? If you put a larger unit are you sure it will run ok or short cycle. Reply
Frank says July 18, 2019 at 2:05 pm 5.27 kWh now 1 hp is 746 watts 5270 div 746 is 7,5 times approximately 7,5 horse power Reply
kadali rama krishna says April 15, 2018 at 9:00 pm i con’t understand about BTU “the amount of energy needed to raise 1 pound of water 1°F at sea level” in this why temperature raise in A.C actually we need cooling. “the amount of energy needed to ( cool) 1 pound of water 1°F at sea level” please explain any one Reply
ILYAS says November 13, 2019 at 2:15 am if you convert 1F to celceous means to centigrade, actually this is the energy required to reduced the temp of one pond water ,at the level of sea , Reply
Brian says May 20, 2018 at 9:05 am Will a 10000 btu unit use more power then a 6000 btu unit even though my 10000 btu unit rates 115 volts Reply
Dan English says June 19, 2018 at 3:04 pm Is a Trane 48,000 BTU the same as a Lennox 37,200 BTU? Reply
Elvia Heredia says July 25, 2019 at 4:13 pm What a great article. You have provided such useful and important information. Thank you. I now know what type of air conditioner I need and will that work appropriately and efficiently. You have done a good job. I like your throughness. Reply
serge says July 11, 2020 at 6:43 am does a space colled by 12000 btu portable air conditioner same with12000 btu fixed air conditioner ? Reply
CompactAppliance.com says July 17, 2020 at 7:58 pm A fixed wall or window air conditioner is going to be much more efficient than a portable unit, meaning you’ll be able to cover much more space with the same BTU output. Reply
Terry says July 19, 2020 at 9:53 pm I share an upstairs apt with a roommate and his bedroom is very small, but he insists on using his 10,000 BTU portable ac. I have 2 window AC units that are 5,000 BTUs, but I don’t use both at the same time (one in the bedroom, one in the living room). Our electric bill for next month is $117 for one month. How do I know how much of that $117 is due to his 10,000 BTU ac? (Last month our bill was only $79.00). Reply
