HVAC Load Calculator for
Seattle Homes
Local Climate Analysis for Seattle
Seattle typically experiences summer highs reaching design temperatures of 82°F. With moderate humidity, standard sizing rules apply, but insulation quality remains critical.
📊 Energy Usage Profile
Days you need AC
Days you need Heat
⚙️ Technical Factors
Standard humidity management sufficient.
No derating needed.
Manual J Tip for WA
Because the design temperature difference (Delta T) in Seattle is approximately 7°F (Summer) and 36°F (Winter), your system may need to be sized primarily for one extreme season over the other.
Installation Cost in Seattle
Local labor rates and equipment standards in WA influence the final quote. For a standard 3-ton system changeout in Seattle, calculate roughly $1,800 - $2,200 per toninstalled, depending on whether you choose a single-stage or variable-speed inverter unit.
Understanding HVAC for Seattle's Climate
What is a Manual J Calculation?
The industry standard that powers our calculator
The FundamentalsUnderstanding Delta T
The primary driver of Seattle's load
Myth BustingThe 500 Sq Ft per Ton Rule
Why this outdated method fails
Critical WarningOversized vs. Undersized AC
Get the right size for Seattle