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Heat Pump FAQ
Quick answer: Most heat pump questions come down to size, cold-weather performance, running cost and installation. In short: size from a load calculation, check output at your design low, compare costs with your own energy rates, and use licensed trades for refrigerant and electrical work. The answers below cover the common details homeowners ask about.
Guides
Sizing questions
How do I know what size heat pump I need?
Start with the heat pump size calculator for a rough range, then ask a contractor for a room-by-room calculation (ACCA Manual J in the US, CSA F280 in Canada). The calculation looks at insulation, windows, air leakage, orientation and ducts. It often lands well below rules of thumb based on floor area.
Should I size for heating or cooling?
In cold climates the heating load is usually larger, so contractors often size for heating while making sure the unit can still manage humidity in summer. Variable-speed units help by running at low speed when the cooling load is small. In hot climates, cooling often governs.
What is a design temperature?
It is a cold outdoor temperature that your area exceeds most of the time, published for each location in sizing standards. Equipment is matched to deliver enough heat at that temperature. Colder snaps are rare and short; backup heat or stored warmth in the house covers them.
What is a balance point?
The outdoor temperature at which the heat pump's output exactly matches the home's heat loss. Below it, supplemental heat runs. Cold-climate models push the balance point lower.
Is it bad to oversize?
Moderately oversized variable-speed units are usually fine, but large oversizing raises cost and can cause short cycling, poor humidity control in summer and uneven comfort.
Cold weather questions
How cold can a heat pump work?
It depends on the model. Many standard units work well to around 20°F, while cold-climate units are rated to keep providing heat at 5°F and some well below that. Check the extended performance table, not just a marketing claim. See cold-climate heat pumps.
Why is there steam coming off my outdoor unit?
That is usually the defrost cycle melting frost from the coil. It is normal, and the unit should return to heating within a few minutes.
Why does the air from the vents feel cooler than with my furnace?
A heat pump delivers air at a lower temperature, often around 90 to 105°F, compared with 120°F or more from a gas furnace. It runs longer to deliver the same heat. That is normal if the house holds temperature.
Do I need backup heat?
Depends on your climate, the unit and the house. Many homes use electric backup heat strips or keep a furnace in a dual-fuel setup.
Cost questions
Is a heat pump cheaper to run than gas?
It depends on local electricity and gas prices, the unit's efficiency and your climate. Use the operating cost calculator with your own rates. In many places heat pumps beat oil, propane and resistance heat; against natural gas the answer varies.
What affects installation cost?
System type, capacity, ductwork changes, electrical panel capacity, line set length and local labour. See heat pump installation cost.
Are there rebates?
Often, but programs change and vary by location and income. We do not quote amounts. Check Canada or US guidance, then confirm with official sources before signing.
Equipment questions
What is the difference between HSPF2 and SEER2?
HSPF2 rates seasonal heating efficiency and SEER2 rates seasonal cooling efficiency, both under updated test procedures. Higher is better. See HSPF and SEER explained.
Ducted or ductless?
If you have good ducts, a ducted system is often simplest. Without ducts, ductless mini-splits avoid major construction. See ducted vs ductless.
Are geothermal heat pumps better?
They are very efficient and steady but cost much more to install because of ground loops. See geothermal vs air source.
How long do heat pumps last?
Often 12 to 20 years with good maintenance; see heat pump lifespan.
Installation and safety questions
Can I install a mini-split myself?
Some kits are marketed as DIY, but electrical connections need a licensed electrician and most jurisdictions require a licensed technician for refrigerant work. Read the DIY mini-split guide before buying.
Do I need a permit?
Most areas require permits for new HVAC equipment and electrical circuits. Your contractor usually pulls them.
Does a heat pump need a new electrical panel?
Not always. An electrician does a load calculation on your service to check capacity. Some homes need an upgrade, especially with electric backup heat.
Operation questions
Should I set back the thermostat at night?
Small setbacks are fine. Large ones can trigger backup heat during recovery and cost more. See thermostat settings.
My heat pump is running constantly. Is that a problem?
Variable-speed units are designed to run long, low cycles. It is a concern only if the house will not hold temperature. See heat pump not heating.
What is emergency heat?
A thermostat mode that runs only the backup heat source, used if the heat pump fails. It is usually expensive to run for long.
Worked example
Figures below are illustrative examples (2026-10-29), not quotes or guarantees.
A homeowner pays $0.14/kWh and $1.40/therm and wants to compare a heat pump with HSPF2 8 against a 96 percent furnace. The calculator's season estimate for their house is 60 million BTU. Heat pump: 60,000,000 ÷ 8,000 = 7,500 kWh ≈ $1,050. Furnace: 60,000,000 ÷ 0.96 ÷ 100,000 = 625 therms ≈ $875. With these rates gas comes out lower; at $0.10/kWh the heat pump would cost about $750 and win.
Still have questions?
Write to hello@charlandandco.com. We answer general questions about using the calculators but cannot size equipment for a specific house or recommend contractors.