How do I calculate what size heat pump I need?

A general rule is 20–25 BTU per square foot for average homes. Climate zone and insulation quality significantly affect this. Cold climates may need 30+ BTU/sq ft, while well-insulated homes in mild climates may need only 15–18 BTU/sq ft.

What does "tons" mean for a heat pump?

One ton of heating/cooling capacity equals 12,000 BTU per hour. A typical 2,000 sq ft home needs a 3–4 ton (36,000–48,000 BTU) heat pump.

Can a heat pump replace a furnace?

Yes, modern cold-climate heat pumps can efficiently heat homes down to -15°F (-26°C). They are 2–4x more efficient than electric furnaces and can save 30–50% compared to gas heating in moderate climates.

What SEER rating should I look for?

Minimum efficiency is SEER 15–16 in most areas. High-efficiency models are SEER 20+ and HSPF 10+. Higher ratings cost more upfront but save significantly on energy bills.

Heat Pump Size Calculator

Calculate the right heat pump size in BTUs and tons for your home based on square footage, climate zone, and insulation quality.

Home Square Footage

ft²

Climate Zone (1–7)

Insulation Quality

Recommended Tons

—

Recommended BTU/hr —

Est. Annual Savings vs Electric Furnace —

Extended More scenarios, charts & detailed breakdown ▾

Home Square Footage

ft²

Climate Zone

Insulation

Heating BTU/hr

—

Tons Required —

Common Unit Size —

Professional Full parameters & maximum detail ▾

Conditioned Area (ft²)

ft²

Climate Zone

Insulation Quality

HSPF Rating ?

SEER Rating ?

Heating Design Temp (°F) ?

°F

Backup Electric Strip (kW) ?

Number of Zones

Ductwork Condition

Available Rebates/ITC ($)

Install Cost Estimate ($)

Sizing

Required Capacity —

Tons Required —

Est. COP at Design Temp —

System Design

Backup Heat Assessment —

Zoning Recommendation —

Economics

Net Cost (after rebates) —

Est. Payback vs Furnace —

How to Use This Calculator

Enter your home square footage.
Select your climate zone (1 = warmest, 7 = coldest).
Select your insulation quality.
Results show recommended BTU, tons, and estimated savings vs. electric furnace.

Formula

Base BTU = sq ft × BTU factor (15–30 based on climate & insulation)

Tons = BTU ÷ 12,000

Example

Example: 2,000 sq ft home in Climate Zone 4 with average insulation → 20 BTU/ft² → 40,000 BTU (3.5 tons).

Frequently Asked Questions

A general rule is 20–25 BTU per square foot for average homes. Climate zone and insulation quality significantly affect this. Cold climates may need 30+ BTU/sq ft, while well-insulated homes in mild climates may need only 15–18 BTU/sq ft.
One ton of heating/cooling capacity equals 12,000 BTU per hour. A typical 2,000 sq ft home needs a 3–4 ton (36,000–48,000 BTU) heat pump.
Yes, modern cold-climate heat pumps can efficiently heat homes down to -15°F (-26°C). They are 2–4x more efficient than electric furnaces and can save 30–50% compared to gas heating in moderate climates.
Minimum efficiency is SEER 15–16 in most areas. High-efficiency models are SEER 20+ and HSPF 10+. Higher ratings cost more upfront but save significantly on energy bills.