How we evaluate mini splits

Straight answer: we read manufacturer spec sheets, AHRI certification filings, and real-world owner reports. We don't take money to rank units. Here's the longer version.

What goes into a ranking

Efficiency (SEER2 / HSPF2 / EER2). Pulled from AHRI's public directory and cross-checked with the manufacturer's latest submittal sheet. We weight SEER2 heavier for warm-climate picks and HSPF2 heavier for cold-climate picks.
Cold-climate rating. Specifically, capacity retained at 5 °F and the manufacturer-stated minimum operating temperature. Units that maintain ≥100% rated capacity at 5 °F get a cold-climate badge; everything else doesn't.
DIY install-ability. Is the lineset pre-charged with refrigerant? Does the outdoor unit ship with Quick Connect flares, or does it require a vacuum pump and EPA 608 certification? This is the single biggest split in our recommendations — it determines whether a unit qualifies for our "Complete DIY" tier or gets routed to the "Pro install required" tier.
Warranty. We look at both the compressor warranty (the expensive part) and the parts warranty. Longer is better, but we flag brands where warranty service is a documented pain in the neck (owner-reported).
Sound levels. Manufacturer dB ratings on low-fan indoor mode, verified against third-party reviews when available.
Real-world reliability. We comb through owner forums (Reddit r/HVAC, HVAC-talk, Garage Journal), one-star reviews on Amazon and Home Depot, and HVAC tech commentary on YouTube. We're looking for patterns — is one brand's compressor dying at year four, is another's PCB prone to lightning damage?
Price per BTU. Not raw price — price divided by capacity, which makes it fair to compare a 12k unit against an 18k unit.
Parts availability. For a unit that needs repair in year 8, can you get a replacement board without waiting six weeks? MrCool scores well here; some obscure import brands score poorly.

Data sources

AHRI Directory of Certified Product Performance — the authoritative source for SEER2 / HSPF2 / EER2 on any unit sold in the US.
Manufacturer submittal sheets — detailed specs, sound levels, dimensions, operating ranges.
DOE Energy Star Cold Climate database — for identifying truly cold-climate-rated heat pumps.
CEE / ENERGY STAR tier lists — for confirming which models qualify for state and utility rebate programs. (The federal 25C tax credit expired December 31, 2025.)
Homeowner forums and review aggregators — for reliability signals that don't show up in spec sheets.

What we don't do

We don't run our own thermal chamber. Any site that claims to is probably lying. Real thermal testing requires an AHRI-certified facility that costs hundreds of thousands of dollars per year to operate.
We don't accept payment for inclusion, placement, or ranking. No brand has ever bought a slot on this site, and no brand ever will.
We don't run "best of" lists shaped by business relationships. If a unit is the right answer, we recommend it even if we can't earn a commission on it.
We don't manufacture fake user reviews or testimonials.

Affiliate relationships — disclosed

We currently have no affiliate relationships. No link on this site earns us a commission, and no brand pays for placement or clicks.

The takeaway: no financial relationship decides our recommendations. We point readers wherever the specs and the price actually lead.

Update cadence

We review every guide at least twice a year — once before peak cooling season (late spring), once before peak heating season (late fall). Model years, efficiency ratings, and pricing shift enough that stale guides become actively misleading. Every page has a "Last updated" date in the header; if that date is more than six months old, let us know and we'll audit the page.

Corrections

We make mistakes. When we do, we fix them fast and we note the correction at the bottom of the page. If you spot one, email hello@bestdiyminisplits.com.