Apex Dual-Fuel HVAC Systems

A dual-fuel system pairs an electric heat pump with a gas furnace. The heat pump heats and cools most of the year; when outdoor temperatures drop below a set balance point, the furnace takes over. In the Triangle's mild climate, the heat pump handles the bulk of heating hours, and the furnace covers the coldest mornings.

This guide explains how dual-fuel works, when it makes sense in Apex, and what it costs.

How it works

A dual-fuel thermostat or control board decides which heat source to run based on outdoor temperature, and sometimes on energy prices. Above the balance point, often set somewhere in the 30s °F, the heat pump runs. Below it, the gas furnace provides heat. The two never run at the same time for heating, which avoids the heat pump's electric backup strips.

When it fits

Dual-fuel makes the most sense for homes that already have natural gas service and a furnace in reasonable condition, or homeowners who want gas heat on the coldest days. Homes without gas service usually compare a heat pump with electric backup instead. Duct condition, furnace age and gas and electric rates all affect the decision.

Costs

Published 2026 national estimates put HVAC system replacement at about $5,000–$12,500, averaging around $7,500, and heat pump replacement at about $4,236–$7,942. Dual-fuel costs depend on whether the furnace is replaced or kept, the efficiency of each component, and duct work. Get quotes for dual-fuel and for a heat pump alone so you can compare total and operating costs.

Duke Energy rebates

Duke Energy's Smart $aver program offers rebates on qualifying heat pump and HVAC upgrades installed by participating contractors, who submit the application. Amounts and eligibility change; confirm current rules on Duke Energy's site before signing. Note that the federal Section 25C credit no longer applies to equipment placed in service after December 31, 2025.

Permits

Installing a dual-fuel system involves both mechanical and gas work. The Town of Apex lists replacing furnaces and modifying HVAC systems as permit work, and residential mechanical permits must be submitted by a licensed contractor through ePermits. Inspections follow the Town's process.

Design details to ask about

Ask how the balance point will be set, whether the furnace will be sized for the full heating load, whether the coil and furnace blower are matched to the heat pump, and how the thermostat will be configured. A Manual J load calculation should drive equipment sizing.

Published HVAC cost estimates

Sources: Angi: HVAC replacement cost (2026); Angi: Heat pump cost (2026); Angi: HVAC repair cost (2026); Angi: Heat pump repair cost (2026). Figures are published national or regional estimates compiled by those sites, labeled as estimates; they are not quotes and not prices from any provider on this site. Town of Apex permit fees are separate and set by the Town.

Local rules and code references

• Town of Apex, When do you need a permit?: lists replacing and reconnecting furnaces and adding to or modifying the heating and air conditioning system as work that requires a permit regardless of cost.
• Town of Apex, Obtaining a Building Permit: residential single-trade mechanical permits must be submitted through ePermits by a licensed contractor.
• N.C. Gen. Stat. §160D-1110: subsection (a)(3) requires permits for the installation, extension, alteration or general repair of any heating or cooling equipment system; the $40,000 exemption in subsection (c) does not apply to the addition, replacement or design change of heating or air-conditioning equipment (c)(3).
• IRS FAQs on the One, Big, Beautiful Bill energy credit changes: the Section 25C energy efficient home improvement credit is not allowed for property placed in service after December 31, 2025.

Code text and department procedures change; confirm current requirements with the jurisdiction before work starts.

Related local guides

• Apex Emergency AC Repair
• Apex Heat Pump vs. Central Air
• Apex HVAC Replacement Cost