Whether you are talking about an air conditioner or a heating device, you will often also see a mention of BTUs per hour which directly correlates to a kilowatt-hour in terms of energy usage. More BTUs produced per hour will generally cost more in terms of electricity usage compared to a device with a lower BTU output.
A Higher BTU Number Doesn't Always Indicate a Better Product
On the other hand, AC units with too few BTUs will need to run constantly to reach the target temperature, which may add strain to the system. Therefore, it is crucial to choose the appropriate BTU based on the size of the space.
BTU is a climate capacity unit. The abbreviation means “British thermal units.” It is estimated that an air conditioner with a capacity of 9000 BTU is sufficient for a room of 20 to 35 square meters. For a room of 35-60 square meters – you need air conditioning capacity of 12000 BTU.
Does a higher BTU use more electricity? Choosing a unit with higher BTUs can use more electricity if the BTUs are more than what's necessary for your room size. However, choosing an AC with BTUs that match the size of your room or house, your unit will cool your space efficiently.
A undersized system will run more and remove more humidity in cooling, but you give up being able to keep your home at, or near, setpoint on the really hot days. A oversized system in a humid area will not run enough to remove enough moisture from the home and it could cause issues with mold and mildew.
Installing an air conditioner with too many BTUs for the size of your home will cause it to run for shorter periods of time, thereby causing less-than-ideal temperatures and humidity within your home, more wear and tear on your HVAC system, and higher utility costs.
Larger units provide more cooling power, but they also consume more energy. In addition, big cooling systems are expensive and run in short cycles.
Whether you are talking about an air conditioner or a heating device, you will often also see a mention of BTUs per hour which directly correlates to a kilowatt-hour in terms of energy usage. More BTUs produced per hour will generally cost more in terms of electricity usage compared to a device with a lower BTU output.
You also don't want to buy a model that's too powerful for a room. Sure, a 12,000-BTU air conditioner will cool a small space (150 square feet or less) quickly. But it might cool it too quickly, preventing it from removing some of the ambient humidity from the room and leaving the room damp.
An efficient 12,000 BTU model consumes about 300 watts per hour, while a less efficient one can consume over 1,000 watts per hour.
As a general rule, the recommendation for an average double bedroom is a 9,000BTU air conditioning unit. 'BTU' stands for British Thermal Unit and is a unit most commonly used to measure energy when they're discussing machines that heat or cool air – such as air conditioning units and heaters.
Portable air conditioners are generally the worst choice for your energy consumption. For example, a portable air conditioner with a power of 2.5kW (or 9000 BTU) consumes about 2 kWh per hour.
If you choose a BTU that is too high - the moisture extraction can not keep up and this can cause a humid atmosphere. This can also put a strain on the system which reduces the lifespan of it as it is having to stop the cooling cycle too frequently.
If your room is 10'x 20' (200 square feet), you'd need to look at a 6,000 BTU unit. Once you get into 340 and 400 square feet per room, you'd need an 8,000 or 9,000 BTU air conditioner, respectively. Kitchens need more cooling power, since you'll be operating the oven, which adds heat to the room.
Their sizing is much simpler compared to whole-home systems: 5,000 - 8,000 BTUs - Cools spaces up to 350 sq ft. 8,000 - 12,000 BTUs - Cools 350 to 550 sq ft. 12,000 - 18,500 BTUs - Cools 550 to 1,000 sq ft.
Many AC units come with a sleep mode or timer feature, allowing you to set a specific duration for the AC to run before shutting off automatically. According to the International Energy Agency, using these features can save up to 30% of the energy consumed by an air conditioner .
Your AC system uses more electricity if some parts, like the capacitors, motor and condenser, fail. Further, your air conditioner will be less efficient due to too much strain on the functioning parts. If you don't address the issue, your system might experience a total breakdown.
More is not better. A unit with too many BTU's, will cool the room fast, but leave the room humid. Too few BTU's will never cool the room down and the unit will run incessantly. To be sure you're making the right decision, call us to get answers about air conditioner sizes and efficiency.
How much does air-conditioning cost to use? On average, an air conditioner costs between $0.06 and $0.88 per hour to use. Let's see how much air-conditioning costs every month (assuming it runs for 8 hours per day). The cheapest option is $14.40 per month and $211.20 per month on the high end.
Higher Utility Bills
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.
Neither oversizing nor undersizing your AC unit is ideal. Both scenarios can lead to issues with efficiency, comfort, and longevity of the system. Oversizing: If your AC unit is too large for your home, it will cycle on and off frequently, leading to inefficient operation and increased energy bills.
Running the AC unit full-time in our big house example would cost $7.39 per day for the efficient unit, or about $222 per month. For the less efficient unit, you're looking at $10.56 per day or about $317 per month. Not only that, but running all day is hard on your air conditioner.
On average, you can only expect about 15 years of reliable service from a central AC system. And that's only if you maintain your system well. So, if your home has an AC that's 20 years old or older, it's likely living on borrowed time. Here are all the reasons to replace your home's 20-year-old air conditioner.