New Hampshire HVAC Load Calculation Guide
New Hampshire's -6°F winter design temperature, $0.26/kWh electricity costs, and large rural unserved-by-gas population make cold-climate heat pump selection and backup heat planning the defining HVAC challenge across both the Seacoast and the White Mountains.
Try the New Hampshire HVAC Load Calculator
Get a preliminary estimate using New Hampshire-specific design temperatures. Our heating load calculator uses ASHRAE methodology with the local climate inputs below.
Design Temperatures
| Parameter | Value | Source |
|---|---|---|
| Winter Design Temperature (99%) | -6°F | ASHRAE Handbook 2021 |
| Summer Design Temperature (1%) | 88°F | ASHRAE Handbook 2021 |
| IECC Climate Zone(s) | 6A (Cold - Humid), 7 (Very Cold) | ASHRAE 169-2021 |
| HVAC Load Type | Heating-Dominated | — |
New Hampshire Building Codes & Energy Requirements
| Requirement | Detail |
|---|---|
| Energy Code | New Hampshire Building Code (2018 IBC/IECC with NH amendments) |
| Minimum SEER | 14.0 SEER (federal minimum) |
| HVAC License Required | Yes — New Hampshire Department of Safety, Division of Fire Safety — HVACR technician certification required; HVAC contractor state registration |
| Average Electricity Rate | $26.45/kWh (US average: $0.1701/kWh) |
Major Cities — Design Temperature Reference
| City | Summer Design (1% DB) | Winter Design (99% DB) | Load Type |
|---|---|---|---|
| Manchester | 88°F | -6°F | Heating |
| Nashua | 88°F | -6°F | Heating |
| Concord | 88°F | -6°F | Heating |
| Derry | 87°F | -6°F | Heating |
| Dover | 86°F | -6°F | Heating |
Quick Facts
- State: New Hampshire (NH)
- Climate Zone(s): 6A, 7
- Winter Design: -6°F
- Summer Design: 88°F
- Energy Code: New Hampshire Building Code (2018 IBC/IE...
- Avg. Electric Rate: $26.45/kWh
- License Required: Yes
New Hampshire HVAC Challenges
- White Mountains ski resort HVAC must operate reliably at -20°F+ at higher elevations
- High electricity costs at $0.26/kWh make heat pump efficiency and system sizing accuracy critical
- Rural areas outside natural gas service territory rely on heating oil or propane for primary heat
- Granite bedrock makes ground-source heat pump installation drilling challenging and expensive
- Seacoast communities (Portsmouth, Hampton) face Atlantic salt air accelerating corrosion
- Seasonal vacation and lake cottage economy creates major HVAC demand swings spring-to-winter
Local Utilities & Resources
- Eversource Energy (NH) (investor-owned)
- Liberty Utilities (NH Electric Coop) (cooperative)
- Unitil (investor-owned)
New Hampshire HVAC FAQ
The ASHRAE winter design temperature for New Hampshire is -6°F and the summer design temperature is 88°F. These values are used for heating and cooling load calculations per ACCA Manual J methodology.
New Hampshire spans 6A, 7 per ASHRAE Standard 169-2021. This classification determines minimum insulation requirements, energy code compliance path, and HVAC equipment sizing parameters.
The required HVAC size depends on home square footage, insulation levels, window area, and orientation. For a typical 2,000 sq ft home in New Hampshire, use our heating load calculator with the local design temperature of -6°F (winter) or 88°F (summer) for a preliminary estimate.
New Hampshire Department of Safety, Division of Fire Safety — HVACR technician certification required; HVAC contractor state registration
New Hampshire follows the New Hampshire Building Code (2018 IBC/IECC with NH amendments). This code sets minimum requirements for HVAC equipment efficiency, duct insulation, envelope insulation, and ventilation.
Design Guides & Standards for New Hampshire
Explore related resources for accurate HVAC sizing.