Buying guides
Straight answers to the AC questions people ask
Every guide gives a direct recommendation, computed from the same live catalog and sizing rules as our comparison tool, so the answer is real, current and never paid for. Pick the question closest to yours.
Prices last refreshed Sep 24, 2026
Not sure what size you need?
Enter your room and get a straight BTU target, climate-adjusted, plus the in-stock units that fit.
By room size
How many BTU your room needs, and the real units sized to match.
By cooling power (BTU)
The best unit at each standard BTU size, from real in-stock picks.
By system type
The best of each kind: portable, window and mini-split.
By price
The cheapest to buy and the cheapest to run, from real in-stock prices.
By what matters to you
Quietest, most efficient, heats too, and best for renters.
In-depth articles
What It Costs to Run an Air Conditioner in 2026
The sticker is the smallest part of what an AC costs you. Using live prices and ENERGY STAR data on 459 units, here is what a year of cooling really costs.
What Size Air Conditioner Do I Need? BTU Guide 2026
How many BTU do you need to cool your room? The real BTU-per-square-foot math, the adjustments that matter, and why a bigger AC is usually worse.
Most 'Air Conditioners' Online Are Not Air Conditioners. Here Is How to Tell
Search a marketplace for 'air conditioner' and the first page is full of fans, evaporative coolers, and 'mini AC' gadgets that cannot cool a closed room. Here is how to spot a real one, decode the specs, and avoid the rules that catch buyers out.
