DIY heat pumps are efficient and cost-saving solutions for many homeowners. But here’s the catch: when temperatures drop below freezing, heat pumps may struggle to keep up on their own. That’s where a backup heat source comes in.
Whether you live in a climate that dips below zero or just want peace of mind during winter storms, pairing your heat pump with a secondary system ensures comfort, safety, and energy savings. Let’s break down the best backup heating options, their pros and cons, and how to choose the right fit for your home.
Why Backup Heat Matters for DIY Heat Pumps
Efficiency Drops in Extreme Cold
Heat pumps work by moving heat from outside air into your home. But the colder it gets outside, the harder the system works. According to the U.S. Department of Energy, efficiency can drop significantly in subfreezing temperatures.
Safety and Comfort
A reliable backup system prevents frozen pipes, keeps indoor temperatures stable, and avoids relying on space heaters during outages.
Code and Warranty Requirements
In some regions, building codes require a backup heat source. Many manufacturers also recommend or mandate it for warranty compliance.
Electric Resistance Heaters
What They Are
Electric resistance heaters include baseboard units, wall-mounted heaters, or electric furnaces. They generate heat directly by running electricity through coils.
Pros
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Simple to install—many are DIY-friendly
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No fuel storage or venting required
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Quick, direct heat
Cons
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High operating costs (electric resistance heat is less efficient than heat pumps)
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Not ideal as a primary source in cold climates
Best For
Mild climates where backup is rarely needed, or homeowners who want a low-cost, emergency-only option.
The ENERGY STAR program recommends choosing high-efficiency models where possible to reduce electricity costs.
Gas Furnaces (Dual-Fuel Systems)
What They Are
Dual-fuel systems combine a heat pump with a natural gas furnace. The heat pump runs until temperatures dip below a set point, then the furnace takes over.
Pros
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Reliable, powerful heat even in sub-zero conditions
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Seamless automatic switch between systems
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Long lifespan if maintained properly
Cons
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Higher upfront cost
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Requires a gas line and proper venting
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Installation usually requires a professional
Best For
Homeowners in colder climates with access to natural gas.
The ASHRAE highlights dual-fuel setups as one of the most effective strategies for cold-climate heating.
Propane or Kerosene Heaters
What They Are
Portable combustion heaters fueled by propane or kerosene, often used in emergencies.
Pros
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Affordable upfront
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Independent of grid power (ideal for outages)
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Portable and versatile
Cons
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Ventilation and carbon monoxide risks if used indoors
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Ongoing fuel costs
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Less efficient for long-term use
Best For
Rural areas or households that want a backup option during extended power outages.
The New York State Division of Homeland Security and Emergency Services stresses safety when using portable heaters: never leave them unattended, always ventilate properly, and keep them away from flammable items.
Pellet and Wood Stoves
What They Are
Stoves that burn compressed pellets or logs to generate heat.
Pros
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Renewable fuel option
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Can be cost-effective if wood or pellets are readily available
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Operates independently of the electric grid
Cons
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Requires manual loading and fuel storage space
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Regular maintenance and chimney cleaning
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Slower to heat compared to forced-air systems
Best For
Homeowners in colder regions with access to wood or pellets who want an eco-friendly, off-grid capable backup.
The EPA regulates emissions from wood and pellet stoves—look for EPA-certified models to reduce pollution and maximize efficiency.
Ductless Mini-Split Backup Units
What They Are
A secondary ductless mini-split or small heat pump installed alongside the main system.
Pros
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High efficiency, especially in shoulder seasons
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Provides redundancy if the main unit fails
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Easy to zone rooms for extra comfort
Cons
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May not provide enough heat in extreme cold
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Adds upfront cost
Best For
Homes in moderate climates or households that want backup and supplemental heating without switching fuels.
How to Choose the Right Backup Heat Source
Consider Climate Zone
The colder your winters, the stronger your backup needs to be. Gas furnaces or pellet stoves are best for extreme cold, while electric heaters may suffice in milder regions.
Factor in Costs
Compare upfront installation costs with long-term operating expenses. For example, while electric resistance heaters are cheap upfront, they’re costly to run over time.
Safety and Code Compliance
Follow the International Code Council’s HVAC guidelines and local codes for safe installation. Always prioritize systems that meet safety standards and certification requirements.
Efficiency and Sustainability
Think long-term: ENERGY STAR-certified equipment and EPA-approved wood stoves not only reduce bills but also minimize environmental impact.
Final Thoughts: Always Plan for Backup Heat
Even the best DIY heat pump can use some backup support in winter. Whether you go with a simple electric heater, a powerful dual-fuel system, or a renewable pellet stove, the right secondary heat source ensures you stay safe, warm, and efficient.
Backup isn’t just about emergencies—it’s about peace of mind and protecting your investment.
👉 Want the full picture on planning and installing your own system? Check out our Complete Guide to DIY Heat Pump Installation
👉 Next in this series: How to Ground and Bond Your DIY Heat Pump Safely
