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18 guides

HVAC Sizing Guides

The reasoning behind the calculators — written for homeowners who want the honest tradeoffs, not a sales pitch.

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Oversized AC

Why an oversized air conditioner short-cycles, leaves rooms clammy, wears the compressor and raises bills — an…

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Manual J Explained

What ACCA Manual J actually calculates, why code requires it, and what online AC calculators can and cannot re…

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SEER vs SEER2 vs EER

The difference between SEER, SEER2 and EER air conditioner efficiency ratings, the 2023 SEER2 test change, and…

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ISEER & BEE Star Ratings Explained (India)

How India's BEE star labels and ISEER ratings work for split ACs, why labels are revised, and how many units a…

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Top Floor Under the Roof

How roof heat gain affects AC sizing for top-floor rooms — RCC slabs, tin roofs, and the 10–15% tonnage adjust…

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Window vs Split vs Portable AC

Honest comparison of window, split and portable air conditioners — efficiency, the portable SACC derating, noi…

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3 Ways to Find Your Existing AC's Tonnage

How to find your current air conditioner's tonnage: model number decoding, data plate reading, and the RLA est…

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AC Wiring Basics

How many amps your AC draws, choosing the right MCB or breaker size, and why every air conditioner needs a ded…

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US Climate Zones for AC Sizing

US climate zones for air conditioner sizing — BTU per square foot by zone, with state-by-state placement from …

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Hot-Dry vs Hot-Humid

How AC sizing differs across India's climate groups — hot-dry (Delhi, Jaipur), hot-humid (Mumbai, Chennai), co…

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How Many BTU per Square Foot? (And When the 20 BTU Rule Breaks)

The 20 BTU per square foot rule explained — where it comes from, when it works, and the climates and rooms whe…

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Ceiling Height and AC Sizing

How ceiling height affects air conditioner sizing — the 10% per foot adjustment above 8 feet, and what to do w…

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1.5 Ton vs 2 Ton AC

1.5 ton vs 2 ton AC compared for Indian rooms — coverage, electricity cost difference, and the room conditions…

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Heat Pump Sizing Basics

Introduction to heat pump sizing — why cooling load anchors the size, what HSPF2 and the balance point mean, a…

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Server Room Cooling

How to size air conditioning for server rooms and IT closets — converting equipment watts to BTU, redundancy, …

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Inverter vs Non-Inverter AC

Inverter vs fixed-speed air conditioners — how compressor modulation saves energy, improves comfort, and when …

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Is Your Electrical Panel Big Enough for a New AC or Heat Pump?

Can a 100 amp panel handle a new AC or heat pump? How to read your main breaker, what an NEC load calc is, and…

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Humidity, Latent Load and Why 24°C Can Still Feel Sticky

How air conditioners handle humidity — sensible vs latent load, why oversized units leave rooms clammy, and dr…