Ottawa homeowners seeking energy-efficient heating and cooling often consider two main options: air-source heat pumps (ASHPs) and ground-source heat pumps (GSHPs), also called geothermal systems. Both can significantly lower utility bills and reduce greenhouse gas emissions, but their performance, installation requirements, and costs differ greatly.
Ottawa’s winters bring average lows near -14°C and occasional cold snaps to -30°C. The city also experiences humid summers, making a year-round heating and cooling solution especially valuable. Choosing between ASHP and GSHP means balancing upfront cost, long-term savings, installation complexity, and property suitability.
How Air-Source Heat Pumps Work
Air-source heat pumps extract heat from outdoor air in winter and move it indoors, reversing the process in summer for cooling. Modern cold-climate ASHPs use advanced compressors and refrigerants to perform reliably even when outdoor temperatures drop to -25°C or below.
Key Benefits:
- Lower upfront cost than GSHPs
- Easier, faster installation (no excavation required)
- Effective in most Ottawa homes with proper sizing and backup heat
Considerations:
- Efficiency drops during extreme cold
- May require supplemental heating in prolonged sub-zero conditions
Extra Ottawa Insight: Because Hydro Ottawa’s electricity comes primarily from low-carbon hydro power, running an ASHP produces far fewer emissions than natural gas heating.
How Ground-Source Heat Pumps Work
Ground-source heat pumps transfer heat from the ground, where temperatures remain stable year-round (around 8-10°C in Ottawa). This stability allows GSHPs to maintain high efficiency regardless of air temperature.
Key Benefits:
- Extremely high year-round efficiency
- Lower operating costs over time
- Long equipment lifespan (20-25 years for indoor unit, 50+ years for ground loop)
Considerations:
- Higher upfront installation cost
- Requires space for horizontal loops or drilling for vertical loops
- Best suited for new builds or major renovations
Extra Ottawa Insight: GSHPs are often favored in rural areas or large suburban lots where there’s space for trenching or drilling without disrupting neighboring properties.
Performance in Ottawa’s Climate
- Ottawa’s climate challenges any heating system. Air-source heat pumps have improved dramatically, with variable-speed compressors and advanced refrigerants allowing operation in temperatures well below freezing. However, during prolonged periods near -30°C, they may require supplemental heating to maintain full comfort.
- Ground-source heat pumps bypass this issue entirely by drawing energy from the stable ground temperature, ensuring consistent performance and avoiding efficiency drops. This makes them particularly appealing for rural Ottawa properties where installing backup heating can be more challenging or costly. Their reliability during cold snaps is one reason many rural homeowners consider the higher initial investment worthwhile.
Graph: Efficiency comparison (HSPF2 ranges)
The above graph shows Cold-climate ASHP ~8.5-10 vs GSHP ~10-12 (midpoint bars with error bars).
Cost Comparison
| Feature | Air-Source Heat Pump | Ground-Source Heat Pump |
| Typical Installed Cost | $8,000-$14,000 | $20,000-$35,000 |
| Efficiency (HSPF2) | 8.5-10 | 10-12 |
| Lifespan | 15-20 years | 20-25 years (indoor) |
| Backup Heat Needed | Often, during extreme cold | Rarely |
| Installation Time | 1-3 days | 1-3 weeks |
| Rebate Eligibility | Yes | Yes |
Graph: Installed cost ranges (ASHP vs GSHP)
The above graph shows ASHP ~$8-14k vs GSHP ~$20-35k (midpoint bars with error bars from your ranges).
Choosing the Right System for Ottawa
- Air-Source Heat Pumps are ideal for those wanting a lower upfront cost, quicker installation, and strong cold-climate performance. They suit most urban properties and can integrate with existing ductwork.
- Ground-Source Heat Pumps are a better match for homeowners with higher budgets, larger properties, and long-term plans to stay put, where maximum efficiency and durability outweigh initial expenses.
Frequently Asked Questions
- Which is more efficient in Ottawa’s climate?
Ground-source systems offer higher year-round efficiency due to stable ground temperatures. However, modern cold-climate air-source units also perform efficiently in Ottawa winters, especially with proper sizing and backup heat. - Are ground-source heat pumps worth the high installation cost?
They can be, especially for large homes or long-term owners. Lower operating costs over decades often offset higher initial expenses, making them cost-effective for committed homeowners. - Can air-source heat pumps handle extreme Ottawa winters?
Yes. Cold-climate models can efficiently operate at temperatures as low as -25°C to -30°C, though a supplemental heating source is recommended during prolonged severe cold periods. - Which type has lower upfront installation costs?
Air-source heat pumps are significantly cheaper to install, averaging $8,000-$14,000. Ground-source systems typically cost $20,000-$35,000 due to excavation and loop installation requirements. - Do both systems qualify for rebates?
Yes. Both air-source and ground-source systems qualify for federal and provincial incentives in Ottawa if installed by certified contractors and meeting program efficiency standards. - How long do these systems last?
Air-source units typically last 15–20 years. Ground-source indoor units last 20-25 years, with buried loop systems often exceeding 50 years with minimal maintenance. - Which system is quieter in operation?
Ground-source systems are generally quieter since most components are indoors or underground. Air-source units produce some outdoor noise from the external fan and compressor. - Which requires more property space?
Ground-source systems often need substantial yard space for horizontal loops or drilling access. Air-source units require less space, making them better for smaller urban lots. - Do ground-source systems need backup heat?
Rarely. Because they draw from stable ground temperatures, GSHPs maintain output in any weather. Air-source units may need backup heat during extreme cold spells. - Which heats and cools faster?
Ground-source systems maintain consistent performance in any temperature. Air-source models may slow slightly in extreme cold but still provide rapid heating in most winter conditions.
Conclusion
In Ottawa, both air-source and ground-source heat pumps can be excellent choices for energy-efficient, year-round comfort. Air-source systems win on affordability and ease of installation, while ground-source systems excel in efficiency, stability, and long-term savings. Your choice will depend on your budget, property layout, and long-term plans.
If your home is well-insulated and you want the most efficient option for decades to come, GSHPs may be worth the investment. For a faster, more budget-friendly upgrade with excellent performance, a cold-climate ASHP is a smart, practical choice.
Contact details
Heat Pump Ottawa Pros
Address: 150 Elgin St, Suite 807, Ottawa, ON K2P 1L4
Phone Number: 613-706-0838
Email: heatpumpottawapros@gmail.com
Office Hours
Monday – Sunday: 9:00 AM – 5:00 PM
