What size heat pump or AC do I need for 3,500 Sq Ft in Washington?

A 3,500 Sq Ft home in Washington (4950 HDD / 380 CDD) typically requires 5.0 Tons (60,000 BTU) of heating and cooling capacity, depending on insulation quality and ceiling height.

What is the average monthly heating and cooling bill for 3,500 Sq Ft in Washington?

At Washington's utility rate of 14¢/kWh, a 3,500 Sq Ft home averages $84/month ($1,002/yr) with a heat pump, $95/month ($1,139/yr) with natural gas, and $255/month ($3,056/yr) with electric baseboards.

Cost to Heat & Cool a 3,500 Sq Ft Home in Washington (2026 Bill & BTU Size)

2026 Monthly & Annual Utility Breakdown (3,500 Sq Ft in Washington)

Recommended Equipment Size:5.0 Tons (60,000 BTU)

Washington Residential Electricity / Gas Rate:14¢/kWh | $1.38/therm

Cold-Climate Heat Pump (15-Yr Lifespan):$1,002/yr ($84/mo)

Winter Heating vs. Summer Cooling Split (Heat Pump):$963/yr Heat | $39/yr AC

Natural Gas Furnace + Central AC (18-Yr Lifespan):$1,139/yr ($95/mo)

Electric Baseboard + Window AC (25-Yr Lifespan):$3,056/yr ($255/mo)

15-Year Heat Pump Lifespan Net Savings vs. Baseboard:+$27,210

Customize Insulation, Solar & View 20-Year Lifespan Graph →

💰 Up to $2,600 Rebate

Compare 3 Local Washington HVAC Installer Quotes

Verify 2026 Federal 25C Tax Credit & Puget Sound Energy / Seattle City Light rebate eligibility and compare turnkey contractor pricing for a 5.0-Ton system (3,500 sq ft).

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🛠️ Save 45% on Install

DIY Pre-Charged Ductless Mini-Split Kits

Avoid $3,500+ in ductwork labor. Calculate exact multi-zone mini-split BTU capacity for your 3,500 sq ft Washington home.

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☀️ Offset 14¢/kWh

Washington Solar + Heat Pump Net-Zero Calculator

See how an 80%–100% rooftop solar net-metering array eliminates annual electric heating and cooling bills in Washington.

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Compare Other Home Sizes in Washington

800 Sq Ft 1,000 Sq Ft 1,200 Sq Ft 1,500 Sq Ft 1,800 Sq Ft 2,000 Sq Ft 2,200 Sq Ft 2,500 Sq Ft 2,800 Sq Ft 3,000 Sq Ft 3,500 Sq Ft 4,000 Sq Ft