How To Size A Mini Split Heat Pump

How to choose a ductless mini split system - BTU calculator

A ductless mini split system is an ideal manner to oestrus and cool several areas of your home in i convenient and free energy-efficient package. All the same, the arrangement is but every bit good as the size — too large and you risk wasting power and utility bills; as well small and it might non do the job sufficiently. And then how practice you size a mini split?

Hither we'll help y'all find the ideal mini split size based on the specific dimensions of the rooms that demand cooling.

The Importance of Proper Mini-Split Sizing

When it comes to mini splits, bigger isn't always better. There are several reasons why the arrangement should be proportionate to the room size:

Comfort – An underpowered unit might not be enough for the space, or may struggle if there are boosted occupants in the room

Utility – An oversized unit may non be efficient in terms of free energy, initial and operating price, infinite occupied, and ability consumed from the total organisation load. Similarly, an undersized unit of measurement tin also crusade bigger bills, since they will need to run for longer periods and on higher settings just to cool the room.

Short cycling – Considering they are designed for bigger cooling requirements, oversized units can struggle to maintain temperature in smaller spaces. In such cases, they tend to speedily bike on and off, resulting in more habiliment and wasted energy.

What Size Mini Carve up Do I Need?

Once you know the number of rooms that need cooling, the next question is "What size of mini split do I need?"

First y'all need to know how many square anxiety a ductless air conditioner can absurd. This capacity is measured in British thermal units, or BTUs. A BTU is the heat needed to heighten the temperature of one pound of water by one degree Fahrenheit. The larger the space, the more BTUs are needed.

For air conditioners, there is a BTU-to-room sizing rule of thumb. This can provide a crude estimate of the mini split BTU per foursquare foot you demand to efficiently service the room. 1 major reward of mini splits over portable air conditioners with the same BTU rating is that they can absurd a larger area.

Space in square ft.	BTUs per hour needed
0-150	v,000
150-250	half dozen,000
250-300	7,000
300-350	8,000
350-400	ix,000
400-450	10,000
450-500	12,000
550-700	fourteen,000
700-1,000	18,000
1,000-1,200	21,000
i,200-1,400	23,000
1,400-1,500	24,000
1,500-two,000	thirty,000
2,000-2,500	34,000

Getting the Square Footage

We've tackled sizing a mini split. Now information technology's time to size up the space. While BTU ratings are straightforward, computing the room size is more complicated. Since rooms come up in all shapes and sizes, hither'due south how to determine the square footage:

Square and rectangular spaces:

Multiple the length by the width

Triangular spaces:

Multiply the length by the width, then divide past two

Non-standard linear spaces:

Split up the room into squares, rectangles or triangles as applicable
Make up one's mind the size of each subplot, and so add everything together

Round spaces:

If yous happen to have an oval office, don't worry – there'due south a formula for that too.

Mensurate the diameter (the largest width of the room)
Divide information technology by two
Square it
Multiply the effect by π (3.14159265)

Other Room Factors to Consider

Notation that Square-human foot-to-BTU is but one part of the cooling equation. Another gene to consider is the rut load, which is the oestrus gained past the room from dissimilar sources. These include the insulation, windows, floors, ceiling, and even the room'southward specific location and direction with respect to the dominicus.

Ceiling height – if it's higher than viii ft., you will to need multiply by the difference. For example, x human foot loftier ceilings are 25% taller then you will demand to increase your BTU total by 25%.

Sunlight – if the room gets lots of dominicus, add x%. Conversely, reduce the BTU by 10% if the room is heavily shaded.

Room type – If information technology's a kitchen, add 4,000 BTUs to compensate for kitchen appliances that emit heat like the fridge, cooktop and oven. If you're looking for a mini split for your garage , you'll also accept to consider the level of insulation and weather. Add 20% for old or drafty garages, or for hot seasons like summer.

Capacity – If more than than two people occupy the room regularly or for long periods (such as a family den), add 600 BTUs for each additional person.

Insulation – If the room is poorly insulated, add 20% to compensate for heat loss.

Location – If you live in the south or in climates that feel seasonal temperatures over 90 degrees Fahrenheit, consider adding 30% BTU.

For more than information on estrus gain and how to calculate the oestrus load of a room, refer to our check out our Rut Load BTU Reckoner.

Indoor-to-outdoor Unit Ratio

Multi-zone units allow you to connect multiple indoor units provided that their total BTU load falls within the outdoor condenser'southward capacity. Depending on the model, it is often acceptable for the total load of the indoor units to exceed the outdoor rating by up to xxx%.

For example, an outdoor condenser rated for 36,000 BTUs may be packaged with four 12,000 BTU indoor units, for a combined load of 48,000 BTUs. Each outdoor unit volition listing its maximum connection chapters. This will vary by brand and model then be sure to check the documentation when planning out your system.

This is because each indoor unit functions independently, so they tin can adjust according to free energy need. Unless all rooms are fully occupied in the middle of a rut moving ridge, it's rare that all units will operate at total capacity simultaneously. So getting a bigger condenser may just be overkill and wasted money.

What Nigh Mini Split Heat Pumps?

Nosotros've tackled cooling. What nigh heating? The practiced news is that when on heating mode, mini splits are much more than free energy-efficient than traditional electric heaters. This is because they move heat from the outside condenser instead of generating it.

In fact, their heating mode is and then efficient that mini splits actually consume less power than when on cooling way. So if y'all're looking for a mini split heat pump sizing nautical chart, simply use the above sq human foot-to-BTU table or mini split calculator, and decrease 1,000 BTUs when on heating mode.

Since mini splits concluding for a very long time, getting the right BTU capacity for the room size is essential. This will ensure many years of condolement, savings and efficiency. When it comes to mini splits, the right size matters to become the best satisfaction.

Observe Your Mini Split – Next Steps

Be sure to cheque out our Multi-Zone Mini Split up Buying Guide for a thorough explanation of how to find the correct mini divide for your needs. And then, hop on over to TotalHomeSupply.com to scan our drove of ductless mini splits.

If you lot have whatever other questions or concerns regarding BTU ratings and choosing the best ductless mini-split for you lot, please do non hesitate to contact us and speak with one of our qualified sales representatives.