Winter Sustainability Spotlight: Heat Pumps
- Published on Monday November 11th, 2024
Author: Steve O.
When we purchased our 30-year-old home in 1993, it still had the original HVAC equipment, including foam ductwork with deteriorating foil exterior and tape. When the air conditioner first failed on a hot summer day in the mid ‘90s, we replaced the failed part, and also installed new ductwork once the weather cooled down. When the AC failed a second time a few years later, again on one of the hottest days of the year, we ended up paying a premium to get the unit replaced because we didn’t have time to shop or schedule the work. We ended up buying the most affordable unit that would service our home, and certainly not the most efficient.
In the mid-aughts, I started learning more about energy efficiency, and in 2007 we had our first energy audit done. Somewhere along the line I learned that a heat pump is simply an air conditioner working in reverse; instead of extracting heat from the interior and exhausting it outside, the heat pump extracts heat from the outdoors to warm the interior. 
Most people aren’t aware that, in order to make your freezer cold, refrigerant is simply compressed and expanded to remove heat from the subfreezing temperature. The most impressive thing is that heat pumps work at a fraction of the cost of electric or fossil fueled furnaces, though lower natural gas prices have reduced the savings.
After the Great Recession, financial incentives were offered to make investments in high-efficiency HVAC equipment more affordable. We used the St. Louis County SAVES program to get a low-interest loan to make it easy to pay off over a 10-year period. A combination of lighting; HVAC; plug loads (ie. power going to appliances that are plugged in but not turned on); and insulation projects, (along with some behavior modification!) enabled us to cut our energy usage in half.
Buildings are the largest source of greenhouse gas (GHG) emissions in the St. Louis region, and almost half of a household’s energy bill goes to heating and cooling. So heat pumps offer an opportunity to reduce GHG emissions significantly. According to the International Energy Agency, the number of heat pumps will have to triple by 2030 to stay on track with climate goals. In the Midwest, replacing a gas furnace with an air-source heat pump can reduce carbon dioxide emissions by 13-31%. As Ameren adds more renewable energy in Missouri and Illinois (or if you install rooftop solar!), emissions will shrink even more. Heat Pumps are one of six high-impact, energy efficiency improvements recommended by ENERGY STAR’s Home Upgrade that are designed to work together to deliver significant energy and cost savings. (Pro tip: If you are interested in getting a smart thermostat - one of the other six improvements - keep in mind that a heat pump might come with its own unique smart thermostat.) You can read more about how the energy efficiency improvements I made and solar all work together to lower my utility bills in my blog post here.
In addition to reducing greenhouse gas emissions, heat pumps have many other benefits. They can both heat and cool your home, eliminating the need to have both a furnace and an AC unit. They also dehumidify indoor air, resulting in less energy usage and more cooling comfort in summer months. According to ENERGY STAR, no indoor combustion means better indoor air quality because there are no direct emissions such as NOx, carbon dioxide, or carbon monoxide. It was previously thought that air-source heat pumps can’t work as well in cold climates, but today’s heat pumps, when properly installed, offer models that heat effectively at low temperatures.
To make heat pumps cheaper, tax credits are available through 2032, and rebates are available for a limited time from Ameren Illinois and Ameren Missouri. It’s important to note that not all heat pumps qualify for the tax credit, so be sure to confirm yours does. You can start by checking out ENERGY STAR’s information about the credit. In order to get the best heat pump system for your home, it’s important that you hire a reputable contractor with experience installing heat pumps who will pick the right equipment for your home and climate, and that you make any recommended weather-sealing improvements and/or insulation upgrades. Also, given the wide array in HVAC pricing, it’s recommended to get multiple quotes in order to make sure you’re getting the best deal. Rewiring America offers a search tool to find contractors through networks that qualify their members.
It’s probably best for the environment and your wallet to wait to replace your furnace with a heat pump until it breaks. But now is the time to make a plan to use incentives and line up possible contractors to make your home more efficient - not when your furnace breaks on the coldest day of the year!
