Heat Pumps Demystified – Energy-Efficient Heating and Cooling

The problem is that heat pumps don’t have the sleekness of solar panels or the awesome power of electric cars to stoke public enthusiasm. Plus, they cost more upfront.

A heat pump system can produce two to three times more heating energy than the electricity it consumes. But this is not magic. It’s physics: you can’t create or destroy energy, only move it.

What is a Heat Pump?

A heat pump is a system that moves heat from the air or ground to your home, rather than burning fuels like propane or heating oil. The system is powered by electricity, which reduces its environmental impact over a traditional fossil fuel furnace.

The system works much like an AC in cooling mode, and is even more efficient for heating. It is possible to replace a furnace with a heat pump, depending on the size of the house and how it’s insulated and hermetic.

The key components of a heat pump are an outdoor unit, which rejects or absorbs the heat by way of aluminum fins and coils, and an indoor unit, which hooks up to ducts in your home and blowers that circulate the heated or cooled air throughout the house. The system is connected to both units by a refrigerant line that contains the thermal energy-transferring refrigerant. The indoor unit is available in a variety of configurations, including ductless mini-splits and models that can be added to a forced-air furnace (called a split system). All use the same technology.

How Does a Heat Pump Work?

Heat pumps are becoming increasingly popular, thanks to their lower carbon footprint and cost savings over fossil-fuel furnaces. In heating mode, the system uses metal coils, a fan, and refrigerant to absorb ambient air outside and transfer it inside your home—or pump warm air out in cooling mode.

The coils in the indoor unit, commonly called an air handler, act as the evaporator or condenser depending on the season, and the fan blows air across them to circulate it throughout your house through ducts. The compressor compresses the refrigerant between the outdoor and indoor units, and a reversing valve reverses the flow of heat to switch modes.

The reversing valve also preheats the super-hot refrigerant so that it can absorb more warmth from your home’s air, or move heat out to cool it down. Heat pumps maintain a continuous cycle in this way, delivering two to three times more energy in heat output than they use in electricity input, and providing even better efficiency when powered by renewable sources of electricity like solar or wind.

How Can a Heat Pump Save You Money?

A heat pump system can save you money on your energy costs. It’s also one of the best ways to reduce your carbon footprint. In fact, if you swap an electric heat pump for your oil-based heating system, you can cut your annual emissions by about 1 metric ton. That’s more than you can save by going vegan or skipping an international trip!

That’s because heat pumps extract free heat from the air, water, and soil. They use about 3 times less primary electricity than a gas furnace to generate the same amount of heat. That means you’re saving more than just fossil fuels — because it takes a lot of energy to produce electricity.

What are the Benefits of a Heat Pump?

Heat pumps are much better for the environment than traditional gas furnaces. They don’t use combustion, so there’s no carbon monoxide leaking into your home. They also maintain healthy moisture levels in the air year-round, raising humidity in winter and dehumidifying in summer, improving indoor air quality.

They’re even better for the environment when the electricity used to run them is from low-carbon sources like solar and wind power. Current models have a coefficient of performance (COP) figure of four or more, meaning they generate heating energy that is several times greater than the amount of electricity they consume.

Modern heat pumps are most efficient when they’re left to run at a constant temperature, so you can actually save energy by leaving your thermostat set at one temperature, including overnight (which goes against all the eco-friendly advice we’ve internalized). They also produce far fewer noises than furnaces. There’s also a wide range of options, from ducted to ductless, so you can find the right fit for your home or business.