The Keystone 10,000 BTU Through-the-Wall Air Conditioner w/ Heat and the Perfect Aire 10,000 BTU Casement Window Air Conditioner (4PASC10000) side by side on one honest scale: cooling, room coverage, noise, energy rating and live price, with which one actually fits your room. Every number is the manufacturer's own or a live retailer price. We never invent a spec.
The verdict
The Keystone 10,000 BTU Through-the-Wall Air Conditioner w/ Heat and the Perfect Aire 10,000 BTU Casement Window Air Conditioner (4PASC10000) are close alternatives: the Keystone 10,000 BTU Through-the-Wall Air Conditioner w/ Heat is both quieter (54 dB(A)) and cheaper ($569.99), so it is the stronger pick of the two. Set your room size to see which one fits it better.
![]() Keystone 10,000 BTU Through-the-Wall Air Conditioner w/ HeatWindow In stock $569.99 Buy at Sylvane | ![]() Perfect Aire 10,000 BTU Casement Window Air Conditioner (4PASC10000)Window In stock $649 Buy at Sylvane | |
|---|---|---|
| Cooling & fit | ||
| Cooling power | 10,000 BTU · 2.9 kW | 10,000 BTU · 2.9 kW |
| Covers | up to 450 sq ft | up to 450 sq ft |
| Comfort | ||
| Indoor noise | 54 dB(A)about as loud as a dishwasherBest | 56 dB(A)about as loud as a dishwasher |
| Indoor unit size | Average | |
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Both units are scored on the exact same scale, from the manufacturer's own published specs and the live retailer price where we have one. Room fit uses the official ENERGY STAR sizing chart, or an estimate from cooling power when a maker publishes no coverage. Where the two efficiency scales are not comparable, we never crown a winner. Nobody can pay for placement.
Read our full methodologyThe bigger questions behind this comparison, answered from live prices and real specs.
| Practicalities | ||
| Heats too | Yes | No |
|---|---|---|
| Install | Plug and play | Plug and play |
| Outdoor unit | No | No |
| Price | ||
| Price | $569.99Best | $649 |
|---|---|---|