Heat Pump Guide: How They Work & When They're Worth It
Heat pumps deliver 2–4× more heat per unit of electricity than a conventional heater. Here's how they work, what types exist, and how to decide if one is right for your home and climate.
Muhammad founded KilowattKit after spending hours trying to decode confusing electricity bills — and realising there were no simple, jargon-free tools to help ordinary homeowners understand their energy costs. He researches electricity rates, EV charging, solar payback, and heat pump economics across the US, UK, Canada, and Australia.
🌡️ Key Takeaways
- ✓Heat pumps move heat, not create it — achieving 200–400% efficiency
- ✓Modern cold-climate models work efficiently down to -15°C (5°F)
- ✓One system provides both heating in winter and cooling in summer
- ✓US federal tax credit covers 30% of cost (up to $2,000) through 2032
- ✓Payback vs. gas heat: 4–12 years depending on gas/electric price ratio
How a Heat Pump Works
A heat pump works like a refrigerator in reverse. Your fridge extracts heat from inside and dumps it outside (feel the warm coils at the back). A heat pump extracts heat from cold outdoor air (or the ground) and delivers it inside your home.
This sounds counterintuitive — extracting heat from cold air — but even air at -10°C contains substantial thermal energy. The refrigerant cycle compresses and expands a fluid to move this heat across a temperature gradient.
What is COP?
The Coefficient of Performance (COP) is the ratio of heat output to electricity input. A COP of 3 means 3 kWh of heat is delivered for every 1 kWh of electricity consumed — effectively 300% efficiency.
| Heating system | Efficiency | Heat per unit of energy |
|---|---|---|
| Electric resistance heater | 100% (COP 1.0) | 1 unit |
| Gas furnace (modern) | 80–98% | 0.80–0.98 units |
| Air-source heat pump (mild weather) | COP 3–5 | 3–5 units |
| Air-source heat pump (cold weather, -10°C) | COP 1.5–2.5 | 1.5–2.5 units |
| Ground-source heat pump | COP 3–5 (year-round) | 3–5 units (consistent) |
Types of Heat Pumps
Air-Source Heat Pump (ASHP)
Extracts heat from outdoor air. By far the most common type. Available as ducted systems (replaces furnace + AC) or ductless mini-splits (for individual rooms or zone-by-zone).
Ground-Source Heat Pump (GSHP / Geothermal)
Extracts heat from the ground (which stays at ~10–13°C year-round). Very high and consistent COP regardless of outdoor temperature. Higher upfront cost due to drilling or trenching.
Heat Pump Water Heater (HPWH)
A standalone appliance that replaces your electric water heater tank. Uses the same heat pump principle — COP of 3–4. Uses 60–70% less electricity than a standard electric tank. The single most cost-effective heat pump upgrade for most homes.
Calculate heat pump running costs
Compare heat pump vs. gas furnace vs. electric heat — enter your energy prices and see annual savings.
Is a Heat Pump Worth It for Your Home?
Whether a heat pump saves money vs. gas heating depends almost entirely on the ratio of your electricity rate to your gas rate. Here's the break-even rule of thumb:
| Country | Avg electric rate | Verdict vs gas | Incentives |
|---|---|---|---|
| 🇺🇸 US | $0.16/kWh | ✓ Saves vs gas in most areas | 30% federal tax credit (up to $2,000) |
| 🇬🇧 UK | £0.34/kWh | ⚠ Marginal — gas cheaper/kWh but BUS grant helps | Boiler Upgrade Scheme: £7,500 grant |
| 🇨🇦 Canada | $0.13/kWh | ✓ Often saves significantly vs gas | Canada Greener Homes up to $5,000 |
| 🇦🇺 Australia | $0.30/kWh | ✓ Saves vs gas (gas prices rising sharply) | State rebates vary — up to $3,500 in VIC |
Installation: What to Expect
A ducted air-source heat pump installation typically takes 1–3 days. A mini-split system for one zone takes about half a day. Here's what's involved:
Ducted system (whole-home)
- • Outdoor condenser unit installed on pad or wall bracket
- • Air handler replaces existing furnace in air handler/attic/basement
- • Connects to existing ductwork
- • Electrical service to outdoor unit (240V)
- • Total cost: $5,000–$15,000
Mini-split (ductless, per zone)
- • Outdoor compressor unit
- • Indoor wall-mounted air handler per zone
- • Small refrigerant line through wall (~3" hole)
- • No existing ductwork needed
- • Single zone: $1,500–$4,000 / Multi-zone: $5,000–$15,000
What to ask your installer
- →Is your system ENERGY STAR certified? (Required for federal tax credit in US)
- →What HSPF2 / SEER2 ratings does the unit have? (Higher = more efficient)
- →What is the minimum operating temperature? (Want −15°C / 5°F or lower for cold climates)
- →Does my electrical panel need upgrading? (Heat pumps need 240V/30–50A circuit)
- →Will you apply for available rebates on my behalf?
Frequently Asked Questions
Do heat pumps work in cold weather?
Modern cold-climate heat pumps work efficiently down to -15°C (5°F) and continue to operate (at reduced efficiency) down to -25°C (-13°F). Models from Mitsubishi, Bosch, and Carrier are specifically designed for harsh winters. The COP drops as temperatures fall, but still typically exceeds 1.5 even at -10°C, making them more efficient than electric resistance heating.
What is a heat pump's COP and why does it matter?
COP (Coefficient of Performance) is the ratio of heat produced to electricity consumed. A COP of 3 means the heat pump delivers 3 units of heat for every 1 unit of electricity. Traditional electric heaters have a COP of exactly 1.0. Gas furnaces have effective COP around 0.8–0.95. So a heat pump with COP 3 is 3× more efficient than an electric heater and about 3× better than a gas furnace per unit of energy cost.
Can a heat pump both heat and cool?
Yes — this is one of the biggest advantages. Most heat pumps work as air conditioners in summer (running in reverse) and heaters in winter. A single system replaces both your furnace and central AC. Ducted heat pumps replace both entirely; mini-split systems work room-by-room without ducts.
How much does a heat pump cost to install?
A ducted central heat pump (replacing a gas furnace + AC) typically costs $5,000–$15,000 installed in the US. A single-zone mini-split runs $1,500–$4,000 installed. Multi-zone mini-splits are $5,000–$15,000. After US federal tax credits (30%, up to $2,000), Canadian and UK subsidies, the net cost is often 25–45% lower.
Is a heat pump cheaper to run than a gas furnace?
In most cases yes, but it depends on your gas and electricity prices. As a rule of thumb: if your electricity rate ($/kWh) is less than 3.5× your gas rate ($/therm or per equivalent unit), a heat pump with COP 3 will be cheaper to run than a 90%-efficient gas furnace. Use our heat pump running cost calculator to model your specific situation.