The wrong Mitsubishi mini split could lead to improper cooling in your home. Knowing how to size a Mitsubishi ductless air conditioner helps you get the maximum energy efficiency. Even with a high-tech unit, you need the correct one to effectively cool a room. Here is the best way to master Mitsubishi ductless sizing!
How the Unit is Supposed to Work
Mitsubishi ductless systems are known for their energy efficiency. With SEER ratings ranging from 13-22, these units are high performance. Cool air goes into your room through the unit itself rather than ducts. Therefore, it doesn’t have to work as hard to maintain your desired temperature.
However, there are obstacles that can interfere with the way the unit is supposed to work. On top of a system that is too big or small for your space, installation errors can cause more problems down the line. If you have an idea ahead of time of what size your space requires, you’ll be able to prevent errors.
What Happens When Your Mitsubishi Ductless Sizing is Too Big or Small?
When your unit is too small, it will run for too long, constantly trying to cool a space it’s not built to cool. This will cause bigger energy bills and uneven temperatures in your home. You might need a blanket in one corner and need to fan yourself in the other. Because the unit is working extra hard, it’s more likely to break and wear out earlier than usual.
Conversely, an oversized unit has its own problems. Firstly, you’ll end up spending too much on a Mitsubishi mini split that’s too large.
Because the unit will cool the room quickly, it will shut on and off frequently, which is called short-cycling. This short-cycling exhausts your unit, causing it to wear out and eventually fail too early. An oversized unit will not get the chance to control humidity on such short cycles, resulting in a damper room for you.
How to Size a Mitsubishi Ductless Air Conditioner Using the British Thermal Unit
So how do you find out what size unit of Mitsubishi ductless air conditioner is best for you? The British Thermal Unit, or BTU, measures how much heat will make one pound of water one degree Fahrenheit warmer.
The BTU per hour needed will vary depending on how large the room is. This cheat sheet will help you generally determine how many BTUs you need per hour to effectively cool your room. Here’s how to size a Mitsubishi ductless air conditioner:
BTU/Square Footage Cheat Sheet
- 9,000 BTU per hour for 350 square feet
- 12,000 BTU per hour for 500 square feet
- 15-18,000 BTU per hour for 750 square feet
- 18-24,000 BTU per hour for 1,000 square feet
- 23-30,000 BTU per hour for 1,250 square feet
- 24-36,000 BTU per hour for 1,500 square feet
What Makes Your Mitsubishi Mini Split Work Harder?
There are other factors besides room size that can cause a Mitsubishi mini split to work harder. You may need to adjust your BTU expectations if any of the following apply to you:
- Daylight and light fixtures: Daylight and light fixtures generate heat, which could make your AC unit work harder to cool the room. If you don’t want to keep the lights off and the blinds closed, you might need a bigger unit.
- Other sources of heat: Besides light, other appliances can cause your home to heat up. For instance, if the unit is close to the kitchen, the oven can cause it to work overtime.
- Carpet vs. hardwood flooring: Carpet is insulating, and that can affect the temperature of the room, therefore affecting how much air conditioning it needs.
- Number of residents: If the room is usually full of people, that body heat can increase the temperature. Take this into account when considering Mitsubishi ductless sizing.
- Ceiling height: Ceilings over 8 feet require about 20% more BTUs to adequately cool the room.
- Climate and environment: Outside air has a way of creeping into our homes. If you live in a hot climate where temperatures often go over 90 degrees Fahrenheit, you may need to increase BTU by about 30%.
- Age of home: Older homes have more worn insulation. Poorly insulated rooms will require about 30% more BTU.
Get an Expert Opinion
Calculating the BTU by yourself can be challenging. To ensure you get the most accurate Mitsubishi ductless sizing, call your local HVAC contractor. Most offer free estimates (terms apply). A licensed expert will give you a complete assessment, so you can rest easy knowing your AC will run smoothly for years to come.