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Mini-split BTU planner

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People sizing a ductless head. The decision this page isolates is narrow on purpose: translate room square feet into a mini-split btu class. Fit and capacity are the expensive mistakes. Settle those before you commit to a finish or a brand.

This page produces an explainable category or size so options can be compared without a product ranking. The calculator does not rank MRCOOL and LG. It produces an explainable class so MRCOOL 12k DIY class, MRCOOL 18k DIY class, and LG Dual Cool 12k class can be compared as examples of that class.

The working method is: Convert the inputs into a published planning class using the method on this page, then compare official product pages that match that class. Planning notes are grounded in ENERGY STAR. This page does not quote a price or rank a brand.

How to use this calculator

People sizing a ductless head. Translate room square feet into a mini-split BTU class. If you can answer room square feet, this page can produce a class you can shop against.

What this page will not do

  1. Enter the planning inputs

    Estimate a ductless head by recording room square feet. Use real measurements or counts, not a rounded marketing number.

  2. Keep optional extras off until they are real

    This tool has no optional add-ons. If a number is uncertain, calculate a range and keep the more conservative class.

  3. Read the btu class

    Calculate class and treat the headline as a class, not a product name. Matching examples below follow 9–12k, 15–18k, and 21k+.

  4. Compare official pages, then verify

    Open the official page for each example in that class. Confirm current specifications, dimensions, and terms. Decision Lantern does not quote a live price or complete an install review.

Planning classes on this page

9–12k
Example: MRCOOL 12k DIY class, LG Dual Cool 12k class
15–18k
Example: MRCOOL 18k DIY class
21k+
Example: MRCOOL 18k DIY class

Estimate a ductless head

BTU class

9–12k BTU

Compare options with at least:

  • 350 sq ft
  • Climate and insulation change the class

Example products for Mini-split BTU planner

Real products that fit this planning category. Specs come from the manufacturer’s product page. These are examples, not rankings. The links are official product pages—not affiliate links yet.

Compare the official examples

The table below is a side-by-side of the official examples on this page. Columns are published facts—maker, planning class, and notes taken from the official page—not scores. MRCOOL 12k DIY class, MRCOOL 18k DIY class, and LG Dual Cool 12k class are included so you can see how classes differ, then open the official page for the current specification.

Published facts for the example products on this page. Not a ranking.
ExampleMakerPlanning classesPublished notesOfficial page
MRCOOL 12k DIY classMRCOOL9–12k12000 BTU class; Single zoneMRCOOL 12k DIY class official page
MRCOOL 18k DIY classMRCOOL15–18k, 21k+18000 BTU class; Larger roomsMRCOOL 18k DIY class official page
LG Dual Cool 12k classLG9–12kInverter head; Energy Star modelsLG Dual Cool 12k class official page

Which example fits which class

MRCOOL 12k DIY class

MRCOOL

MRCOOL 12k DIY class from MRCOOL is an example in the 9–12k class. Published notes on the official page include 12000 BTU class and Single zone. Keep it in the shortlist when your result lands in that class, then confirm the current specification before you buy.

MRCOOL 18k DIY class

MRCOOL

MRCOOL 18k DIY class from MRCOOL is an example in the 15–18k and 21k+ class. Published notes on the official page include 18000 BTU class and Larger rooms. Keep it in the shortlist when your result lands in that class, then confirm the current specification before you buy.

LG Dual Cool 12k class

LG

LG Dual Cool 12k class from LG is an example in the 9–12k class. Published notes on the official page include Inverter head and Energy Star models. Keep it in the shortlist when your result lands in that class, then confirm the current specification before you buy.

What to verify before you buy

How this estimate works

Convert the inputs into a published planning class using the method on this page, then compare official product pages that match that class.

Know the limits

  • This page does not quote a price or rank a brand.
  • Manufacturer specifications and program terms can change and must be verified on official pages.
  • The result is a planning category, not a safety, medical, legal, or install guarantee.

Frequently asked questions

How does the mini-split btu planner work?

It converts room square feet into a planning class using a published rule. Convert the inputs into a published planning class using the method on this page, then compare official product pages that match that class. The headline is a class such as 9–12k, 15–18k, and 21k+, not a vendor ranking.

Is MRCOOL 12k DIY class better than MRCOOL 18k DIY class?

This page does not rank MRCOOL 12k DIY class, MRCOOL 18k DIY class, and LG Dual Cool 12k class. MRCOOL 12k DIY class and MRCOOL 18k DIY class are listed because they are real products with official pages that map to different or overlapping classes. The useful question is which class matches your inputs.

Can I treat the result as a buying recommendation?

This page does not quote a price or rank a brand. Use the class to decide what to read next, then verify fit, terms, and installation requirements on the official page and with a qualified installer when the product needs one.

Do the product links earn Decision Lantern a commission?

Not on the current preview. Links go to official manufacturer or service pages. If compensated links are added later, the disclosure on this page will say so in plain language.

What should I verify after I get a class?

Confirm the current specification, dimensions or plan limits, and any program terms on the official page. Manufacturer specifications and program terms can change and must be verified on official pages. The next editorial review for this page is due 2026-11-14.

Why these 3 examples?

They are real home and office options with an affiliate program on file and an official product page. MRCOOL and LG appear because each one can represent at least one planning class on this page, not because Decision Lantern tested or endorsed them.

Sources

  1. ENERGY STAR ductless heating and cooling, ENERGY STAR. Retrieved .

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