The plan: heat your house smarter in real winter
You’re not chasing fancy features you just want steady, affordable heat that still works when it’s freezing. Modern cold-climate heat pumps (ccASHPs) are built for exactly that. Many keep full rated heat down to 5°F (-15°C) and continue running to -22°F (-30°C). In this guide, we’ll walk the same path we use on real installs: choose the right unit, size it correctly, place it where it won’t ice up, wire it safely, and keep it humming all winter. We’ll flag the spots where DIY is smart and where it’s time to call a tech. When you’re ready to compare systems or parts, keep these handy: our Sizing Guide, R-32 heat pump systems lineup, and line sets & accessories.
Is a cold-climate heat pump a fit for your home?
If your winters regularly dip near -15°C (5°F) or below, you want a ccASHP rated to keep ≥80% of its 47°F capacity at 5°F and to continue operating down to -22°F (-30°C). Also look for a turn-down ratio ≥4:1 so the unit can throttle low on mild days and ramp up when the wind howls. Homes with air sealing, attic insulation, and newer windows get the most out of heat pumps, but even drafty homes can benefit with the right sizing and backup plan. If you’re moving from oil/propane, the operating cost and safety wins are noticeable.
Great fit: tight or recently weatherized homes, open floorplans, hydronic/boiler homes adding air handlers.
Needs planning: very leaky homes, rooms cut off by closed doors, heavy electric baseboard usage.
Browse our R-32 heat pump systems to see cold-climate options built for 2025 codes.
2025 models & refrigerants: what to choose (R-32 vs R-454B)
With the phase-out of R-410A, you’ll see R-32 and R-454B leading residential systems. Both deliver strong performance; R-32 often adds up to ~12% efficiency gains, while R-454B has a lower GWP (~466). Major brands now ship one or both. On the performance side, look for SEER up to ~33 and HSPF up to ~12.5 in premium lines. Installed price ranges vary widely (~$5k–$18k) depending on tonnage, ductwork, and controls.
Neighbor take: Pick the refrigerant that matches the models you can actually service locally. Availability, parts, and trained techs beat a spec sheet every time.
Need a ductless approach? Compare DIY ductless mini-splits.
Sizing skip the square-foot shortcut (here’s what actually works)
A 2,000-sq-ft home can need anywhere from 20,000 to 120,000 BTU/h depending on insulation, air leakage, window area, and design temperature. Rules of thumb miss badly in real cold. For tough climates, we often see 35–40 BTU/sq-ft as a ballpark, but that’s only a starting point. Your real number comes from a heat-loss calculation that considers R-values, infiltration, and window U-factors.
There are four practical strategies:
Size for cooling (requires more backup heat in deep winter).
Size for cooling, maximize heat (tight balance).
Cover most heating loads (common sweet spot).
Cover 100% heating load (largest unit, highest upfront).
Use manufacturer performance tables at your design temp (say -25°C). Want a hand? Our Design Center can review your numbers.
Aim for a balance point a few degrees below your typical winter day. That’s where comfort and cost meet.
Ducted, ductless, or mixed: mapping your system like a pro
Your house layout decides a lot:
Ducted: great if you’ve got decent ducts; use a matched air handler and verify static pressure.
Ductless: ideal for additions, finished basements, and rooms that are always colder.
Mixed: a ducted main floor plus a ductless head for that stubborn bonus room.
Keep zones simple over-zoning can confuse controls on weather-compensated systems. For space-by-space solutions, explore wall-mounted units.
Outdoor unit placement that wins in February, not just June
Winter placement makes or breaks performance. Follow these habits:
Avoid roof driplines and spots where meltwater can re-freeze on coils.
Keep ~24 inches (60 cm) clearance on all sides.
Elevate 4–8 inches on a pad or stand so that the water drains and doesn’t ice the feet.
Keep it out of dominant winds (they can spin the fan backward and stress the motor).
Don’t place it where defrost steam crosses a walkway and turns the path into an ice rink.
Grab covers or line-hide kits in Accessories to protect insulation from UV and critters.
Line sets: short, straight, fully insulated (DIY-friendly details)
Performance in the cold loves short, tidy line sets. Keep them as short and straight as possible every extra foot adds friction and capacity loss. Follow the brand’s minimum/maximum lengths and height change rules. Insulate both suction and liquid lines and protect outdoor insulation with UV-resistant wrap or rigid line-hide. Seal wall penetrations with foam and make them rodent-resistant (PVC sleeve + steel wool works).
Browse matching accessories.
Power, disconnects, and controls: safe, code-clean installs
Most outdoor units need a dedicated 240V circuit (commonly ~40A), and many air handlers need 240V ~20A. Install a service disconnect within sight of the condenser. Follow the nameplate MCA/MOP and local code. Use the manufacturer’s control wiring—skip third-party “smart” thermostats that aren’t heat-pump-aware; they can hurt performance and confuse defrost/aux logic.
Do this right:
Torque lugs to spec.
Use anti-short bushings on whips.
Keep low-voltage separate from line voltage.
If you’re unsure on electrical work, bring in a licensed electrician. It's not the place to experiment. For model-specific guidance or a quick double-check, tap our Help Center.
Backup heat: set it and save (strips or dual-fuel)
In a real cold, auxiliary heat keeps you comfortable when the heat pump nears its limit. Common options:
Electric heat strips in the air handler simple, reliable.
Dual-fuel: pair the heat pump with a gas furnace; heat pump runs most of the season, furnace covers the deep freeze.
For efficiency, set the backup’s thermostat 5–10°F lower than the main heat pump setting so the pump stays primary. Many systems auto-engage aux when outdoor temps drop, but control settings matter.
Considering packaged gear? See R-32 packaged heat pumps.
Daily operation: thermostat settings that actually save
Keep it simple: set 68°F (20°C) when you’re home. Heat pumps like steady targets—stop fiddling every hour. You can drop 7–10°F overnight (about 8 hours) to trim up to ~10% on heating costs, but avoid aggressive day-to-day swings. In winter, use “Heat” mode, not “Auto,” so the system doesn’t bounce between heating and cooling. For best results, don’t set heat below 65°F for long stretches. Ensure supply registers aren’t blocked by rugs or furniture.
Quick wins:
Use a MERV-8+ filter and change it regularly.
Keep doors open where you want heat to move.
Verify fan settings; “Auto” is usually best for heat.
Winter maintenance & defrost what’s normal, what’s not
Seasonal:
Book pro maintenance twice a year (heat pumps run all year).
Trim vegetation 18 inches from the unit.
Replace worn pipe insulation.
Defrost basics: After startup, a defrost may occur within ~45 minutes and lasts 5–10 minutes. You’ll notice steam, the outdoor fan slowing or stopping, and temporary loss of indoor heat. Defrosts shouldn’t happen more often than every 30–40 minutes. Blocks of ice, constant defrosting, or defrosts that never finish? Call a tech could be sensors, reversing valve, charge, or airflow.
Mistakes to avoid, when to call for help, and your next steps
Skip these headaches:
Third-party thermostats that don’t speak heat-pump logic.
Over-zoning weather-compensated systems.
Crushed line-set insulation (zip ties) causing sweat and heat loss.
Obstructed registers and high aux setpoints that burn energy.
Ignoring odd noises, heavy ice, or performance dips.
DIY is perfect for filters, snow clearing, and basic inspection. Call a pro for refrigerant issues, electrical faults, persistent defrost problems, or when ice won’t clear after a normal cycle.
Need tailored help? read our HVAC Tips blog, or Contact Us.
