Does a Heat Pump Replace a Furnace?
Yes, a heat pump can replace a furnace as a home's primary heat source. But for most southern New Hampshire homes the most economical setup is not a full replacement. It is a dual-fuel system: the heat pump handles most of the heating season at high efficiency, and a furnace covers the coldest days as backup. The thermostat switches between them automatically.
At A.J. LeBlanc Heating we install both full heat pump conversions and dual-fuel systems across NH. Here is how each option works and how to choose.
Full heat pump replacement
The heat pump replaces the furnace entirely. The home runs on electricity for heating and cooling year-round, with electric resistance backup ("emergency heat" or "aux strips") in the air handler for the coldest stretches.
Pros:
- Eliminates fossil fuel use for heating
- Simpler system (one heat source instead of two)
- Eligible for NHSaves rebates
- Same equipment provides AC in summer
Cons:
- Aux heat is expensive to run, so the heat pump must be sized to handle most NH winter days on its own
- Needs a well-insulated, air-sealed home; a leaky home loses heat faster than the heat pump can replace it at low temperatures, driving up electric bills
Best fit: well-insulated or newer NH homes, projects that include air sealing and attic insulation, and owners committed to electrification.
Dual-fuel: heat pump + furnace backup
This is the most common heat pump setup in NH. A cold-climate heat pump pairs with the existing gas, propane, or oil furnace, and a smart thermostat switches between them by outdoor temperature: above the balance point the heat pump runs, below it the furnace runs.
Pros:
- Lowest year-round operating cost in most NH homes
- Reliable backup heat on the coldest nights
- Heat pump can be sized to the common heating load rather than peak load (smaller unit, lower upfront cost)
- Reuses the existing furnace, avoiding removal and disposal cost
- Same equipment provides AC in summer; NHSaves rebates apply to the heat pump portion
Cons:
- Two systems to maintain (annual heat pump service plus annual furnace service)
- Continues fossil fuel use, though dramatically reduced
- More electronics and controls than a single-source system
Best fit: most NH homes considering a heat pump for the first time, especially when the existing furnace is still functional or relatively new.
How the balance point works
The balance point is the outdoor temperature at which the heat pump and furnace cost the same per BTU of delivered heat. Above it the heat pump is cheaper; below it the furnace is cheaper. It depends on your electricity rate, your fuel rate, the heat pump's COP at various outdoor temperatures, and the furnace's AFUE rating. For NH homes at current rates:
- Heat pump + natural gas furnace: typically 25 to 35°F
- Heat pump + propane furnace: typically 15 to 25°F (propane is pricier, so the heat pump wins down to lower temps)
- Heat pump + oil furnace: typically 15 to 25°F (oil tracks propane in NH economics)
Smart thermostats from ecobee, Nest, and Honeywell Home are programmed with the balance point during commissioning.
NH homes converting from a straight oil or propane furnace to dual-fuel typically cut fossil fuel use 50 to 80 percent and total heating cost 20 to 40 percent, plus lower summer cooling cost since the heat pump is also the AC. Exact savings depend on local rates and how well the balance point matches your fuel pricing.
Rebates and tax credits
The federal 25C Energy Efficient Home Improvement Credit ended for installations placed in service after December 31, 2025, and is not available for new installations in 2026. NHSaves utility rebates remain the live lever: amounts vary by program, and income-eligible households may qualify for substantially higher incentives. See nhsaves.com or ask us for current amounts.
Schedule a consultation
If you are weighing a heat pump or dual-fuel system for your NH home, contact A.J. LeBlanc Heating or call 603-623-0412. We will run the numbers for your specific home, current fuel rates, and the equipment options that fit. Every heat pump install starts with a Manual J load calculation to size the system correctly. Learn more about heat pumps. Serving New Hampshire families since 1928.
Frequently Asked Questions
Can a heat pump fully replace my furnace?
Yes, in well-insulated homes with adequate envelope performance. For most NH homes, dual-fuel (heat pump + furnace backup) delivers lower operating cost and more reliable performance on the coldest days.
What is the balance point on a dual-fuel system?
The outdoor temperature at which the heat pump and furnace cost roughly the same per BTU. Above it the heat pump runs; below it the furnace runs. Typically 15 to 35°F in NH depending on rates and fuel type.
Do I have to remove my existing furnace?
Not in a dual-fuel install. The existing furnace stays in place as backup. In a full electrification conversion, yes.
Will my heating bill go up or down with a heat pump?
For most NH homes converting from oil or propane, total heating cost drops up to 20 to 40 percent with a dual-fuel system. Specific savings depend on rates.
How do I know what size heat pump I need?
A Manual J load calculation determines the home's actual heat loss at design temperature. We perform this for every heat pump install. Sizing correctly is the single most important factor in long-term satisfaction.