What Even is a Heat Pump?

A Comprehensive Guide to What Heat Pumps Are and What They Can Do for You

Heat pumps are flipping the script on home heating and cooling. Instead of burning fuel like old-school systems, they move heat around like energy-efficient magicians—keeping your home cozy in the winter, cool in the summer, and your utility bills in check. But if phrases like “coefficient of performance” or “variable-speed compressor” make your eyes glaze over, don’t worry—we’ve got you. This guide breaks down the jargon so you can talk (and think) like a heat pump pro.

Heat Pump: A superhero appliance that can heat and cool your home. It transfers heat rather than creating it from fuel combustion, which makes it far more efficient than traditional systems. 

HPWH (Heat Pump Water Heater): A heat pump specifically for hot water. It’s efficient, pulling heat from the air to warm your water instead of generating heat directly. Read more about HPWHs in this interview with Harvest’s Co-Founder Pierre Delforge.

Types of Heat Pumps
Heat pumps come in a variety of flavors to fit different needs. Here’s the scoop:

1. Air-Source Heat Pumps
   These are the most common and accessible heat pumps, transferring heat between your home and the outside air. Today’s air-source heat pumps can slash electricity use for heating by up to 75% compared to electric resistance systems like baseboard heaters. Bonus? They’re dehumidification champs in summer, keeping you cooler and cutting energy use.

2. Ductless Air-Source Heat Pumps: Ideal for homes without existing ductwork, these flexible and efficient systems are ideal for zone heating.
   
   • Minisplit Heat Pumps (Ductless): Minisplits are compact, efficient, and great for zone heating. They’re a standout option for retrofitting older homes, especially in regions like New England and the Mid-Atlantic, or adding heating to specific rooms, offering an efficient alternative to baseboard heating.

3. Geothermal (Ground-Source) Heat Pumps
   Geothermal heat pumps, or GHPs, tap into the steady temperatures underground. They’re incredibly efficient—up to 61% less energy use than standard heating and cooling systems—and durable, with ground loops lasting 50+ years. While they come with a higher upfront cost, energy savings, and incentives can offset the investment within 5–10 years.
   

3. Absorption (Gas-Fired) Heat Pumps
   Absorption heat pumps use heat as their energy source rather than electricity. They can be powered by natural gas, solar-heated water, or even geothermal-heated water. These systems are less common and more complex, but they shine in specific setups where electricity demand needs to be minimized, which is limited to liquid pumping..

Advanced Heat Pump Tech
Heat pumps are constantly evolving, bringing new innovations to the table:

• Staged or Multi-Speed Compressors: These allow heat pumps to adjust their output based on demand, reducing wear and energy use. Inverter-driven systems take this further, offering near-infinite speed adjustments for consistent comfort.
• Variable-Speed or Dual-Speed Motors: These motors control indoor and outdoor fans, maintaining a steady airflow while minimizing energy use, noise, and temperature swings.
• Desuperheaters: Found in some high-efficiency models, desuperheaters capture waste heat from cooling to heat water, making them up to 3 times more efficient than standard water heaters.
• Cold Climate Heat Pumps: Designed for temperatures as low as 5°F, these models are a game-changer for regions with harsh winters. Look for ENERGY STAR Cold Climate certifications for the best options.
• Dual-Fuel or Hybrid Systems: These combine the efficiency of a heat pump with the reliability of a gas furnace and are commonly found in regions like the Mid-Atlantic. The system switches to the furnace during extremely cold weather but uses the heat pump to handle most of the heating needs in milder weather, optimizing energy use and comfort. Shared ductwork makes these systems a straightforward upgrade for some homes.

Seasonal Energy Efficiency Ratio (SEER) & Heating Seasonal Performance Factor (HSPF)

SEER: Indicates the cooling efficiency of air conditioners and heat pumps. A higher SEER rating means better energy efficiency during the cooling season.

HSPF: Measures the heating efficiency of air-source heat pumps. A higher HSPF translates to lower energy costs in colder months.

Air Source Heat Pump (ASHP) vs. Ground Source Heat Pump (GSHP)

Air Source Heat Pump: Gathers heat from the outside air (even in chilly temperatures) to warm your home or water.

Ground Source Heat Pump (a.k.a. Geothermal): Uses the relatively constant temperature underground to provide heating and cooling. Both systems transfer heat rather than burn fuel.

Heat pumps are changing the game—making home heating and cooling smarter, cleaner, and way more efficient. Whether you’re eyeing an all-electric upgrade, a hybrid setup, or just a better way to heat your water, there’s a heat pump out there with your name on it. And with tech getting better by the day (not to mention all the juicy incentives up for grabs), there’s never been a better time to make the switch. Your home, your wallet, and the planet will thank you.