West Virginia Heating Degree Days Calculator
Estimate seasonal Heating Degree Days (HDD) for your WV region to forecast heating energy demand. Select your region, base temperature, and heating season to get started.
Typical residential base: 65°F. Commercial buildings may use 60–68°F.
Formulas Used
Monthly Heating Degree Days (HDD):
HDDmonth = max(0, Tbase − Tmean) × Days
When the mean temperature is within the daily amplitude range (±15°F), a sinusoidal correction is applied:
HDDcorrected = Days × [Δ·f + (A/π)·sin(π·f)]
where f = 0.5 + Δ/(2A), Δ = Tbase − Tmean, A = 15°F (daily amplitude)
Seasonal Heat Load:
Qseason = UA × HDDtotal × 24 hr/day
where UA = ufactor × Area (BTU/hr·°F)
Fuel Consumption:
Fuel = Qseason ÷ (BTUper unit × η)
where η is system efficiency (0.80 for gas/propane, 0.82 for oil, 1.0 for electric, 2.5 COP for heat pump)
Assumptions & References
- Monthly mean temperatures from NOAA Climate Normals 1991–2020 for WV stations (NWS Charleston, Huntington, Morgantown, Elkins, etc.)
- Standard base temperature of 65°F per ASHRAE and U.S. EIA convention; adjustable for building-specific balance points
- Daily temperature variation modeled as sinusoidal with ±15°F amplitude (typical WV diurnal range)
- UA (heat loss coefficient) values derived from IECC 2021 envelope requirements and DOE Building America benchmarks
- Fuel prices: WV average retail — Natural Gas $1.18/therm, Propane $2.45/gal, Heating Oil $3.60/gal, Electricity $0.115/kWh (EIA 2023)
- Heat pump COP of 2.5 represents average seasonal performance for WV climate (HSPF ≈ 8.5)
- IECC Climate Zones: Eastern Panhandle = 4A; Southern/Mountain WV = 5B; remainder = 5A
- Annual HDD65 normals: Charleston 4,476 | Huntington 4,280 | Elkins 5,980 | Beckley 5,620 (NOAA)
- Model does not account for solar gain, internal loads, infiltration, or thermostat setback schedules
- For utility billing reconciliation, contact WV American Water / Mountaineer Gas or the WV State Climatologist Office