Retrofit Relay
Heating & cooling

Heat pumps: the complete guide.

How they work, what they cost, which rebates apply, and how to size one for your climate. Written by contractors who install them.

01 · Overview

What to know about heat pumps

A heat pump moves heat instead of generating it, making it 2-4x more efficient than a furnace or boiler. In heating mode it extracts heat from outdoor air (even at sub-zero temperatures with cold-climate models) and delivers it inside. In cooling mode it reverses, functioning as an air conditioner. Modern cold-climate heat pumps maintain full heating capacity below -15°F, making them viable as the sole heating source in every US climate zone when paired with adequate insulation and air sealing.

02 · Costs

What does it cost?

Typical installed costs before rebates. Your actual cost depends on home size, accessibility, and local labor rates.

Type Low High Notes
Ductless mini-split (single zone) $3,500 $6,000 Installed. Most common residential upgrade.
Multi-zone ductless (3-4 heads) $10,000 $18,000 Whole-home coverage without ductwork.
Ducted central heat pump $12,000 $25,000 Replaces existing furnace + AC. Requires ductwork.
Ground-source (geothermal) $25,000 $50,000 Highest efficiency, highest upfront cost. 3-5x COP.
05 · FAQ

Common questions

Do heat pumps work in cold climates?

Yes. Modern cold-climate heat pumps (Mitsubishi Hyper-Heating, Fujitsu XLTH, LG Arctic) maintain full capacity at -15°F and continue operating to -22°F. Field data from Maine and Vermont shows they can serve as the sole heating source in Climate Zones 5-7 when the building envelope is properly insulated.

How much does a heat pump cost to install?

A single-zone ductless mini-split costs $3,500-$6,000 installed. A whole-home multi-zone system runs $10,000-$18,000. After federal and state rebates, net cost is typically 30-60% lower. Operating cost savings of $500-$1,500/year further reduce the payback period.

What rebates are available for heat pumps?

State programs vary widely. Efficiency Maine offers $1,000-$3,000 per unit depending on income. Mass Save provides $1,125-$2,650 per ton. NYSERDA's EmPower+ covers up to $24,000 for income-eligible households. Use our Rebate Matcher to see every program you qualify for.

Can a heat pump replace my furnace?

In most cases, yes. A properly sized cold-climate heat pump can be your only heating source if your home is well-insulated and air-sealed. The key is sizing: the system must cover at least 80% of your peak heating load. An energy assessment will determine if your envelope is ready.

Heat Pumps rebates by state

See what's available where you live.