There are two things most people associate with Wisconsin: cheese and frigid winters. The latter of those two things means homeowners here depend heavily on their residential heating systems. It also means they have to accommodate some hefty heating bills each year. To help with that, installing the most efficient heating system possible is advisable. For a long time, the best option was a high-efficiency gas furnace. However, dual-fuel heating systems are now more than giving them a run for their money. Here’s what dual-fuel HVAC systems are and why they’re a perfect fit for Wisconsin homes.

What’s a Dual-Fuel HVAC System?

A dual-fuel HVAC system is a packaged system containing an electric heat pump and a high-efficiency gas furnace. They’re a best-of-both-worlds approach that finally makes it practical to install a heat pump in a cold climate like ours. They also have the advantage of offering cooling in the summer, which traditional heating systems don’t do.

How Do Dual-Fuel HVAC Systems Work?

When your thermostat calls for heat from a dual-fuel HVAC system, it will turn on one of its two heating components. It decides which to use based on a preset outdoor temperature threshold. On milder days, it will turn on the heat pump. This runs solely on electricity and gathers heat energy from the outdoor air to heat your home. Heat pumps take advantage of the refrigeration cycle to do that. They’re mechanically similar to air conditioners, with a few added components. One of those components is a reversing valve. It’s a valve that can alter the direction of refrigerant flow through the system.

In heating mode, the reversing valve directs hot refrigerant from the system’s compressor to the indoor unit. There, it travels through a large heat exchanger while a blower fan circulates indoor air across it. The process warms the air and sends it into your home while cooling the refrigerant. Next, the cooled refrigerant goes back outside and through an expansion valve. It lowers the refrigerant’s pressure, reducing its temperature in the process. It’s the same effect you’d notice when you use a metal aerosol spray can. The can gets cold as you reduce the pressure by using the spray. The heat pump will continue working as long as the refrigerant gets colder than the outdoor air.

The greater the difference between the refrigerant and air temperatures, the more efficiently the heat pump operates. In optimal conditions, the heat pump in a dual-fuel HVAC system will achieve 300% to 400% efficiency. As the outdoor temperature drops, so does the heat pump’s efficiency. The average heat pump will operate more efficiently than a gas furnace when it’s 25 degrees Fahrenheit or higher outside. That’s where the gas furnace built into the system comes into play.

When temperatures get too cold, a dual-fuel HVAC system will switch from its heat pump to its gas burner. It does so once the outdoor temperature reaches the preset switchover point. That temperature will depend on the system’s performance specifications, local energy costs, and homeowner preferences. The idea is to use the gas burners whenever they’re a more energy-efficient option than the heat pump. The gas burners also guarantee that a home has ample heat no matter how cold it gets outside.

A dual-fuel HVAC also has a cooling mode. In that mode, the reversing valve changes the direction of the refrigerant. Instead of collecting heat outside, it does so inside. Then, it carries that heat outside to expel it into the surrounding air. It’s the exact inverse of the process used in heating mode.

Why Not Use a Heat Pump Alone?

At this point, you may be asking why you can’t just install a heat pump instead of a dual-fuel system. After all, a heat pump’s high average efficiency should offset any efficiency losses on cold days, right? Unfortunately, that’s not always true. Standalone heat pumps contain backup heating elements to supplement heat production on cold days. Those heating elements are typically electric resistance heat strips. They consume a considerable amount of electricity when they operate. As a result, the coldest days of winter will make your home’s electricity use skyrocket. Depending on the season, that may completely wipe out all the energy savings the heat pump otherwise achieved.

You should know, however, that there are now cold-weather heat pumps that promise greater efficiency than standard ones. They’re capable of remaining efficient at temperatures well below zero. However, they cost significantly more than standard heat pumps. Plus, they may still occasionally rely on heat strips to keep your home warm.

Other Dual-Fuel HVAC Advantages

Dual-fuel HVAC systems have some other advantages besides their efficiency. One of the most important among them is security. With a dual-fuel system, there’s less chance you’ll get stuck in the cold due to a malfunction. For example, the system can rely on the gas burners if something goes wrong with the heat pump component. Or, it could run exclusively in heat pump mode if there’s some interruption to your natural gas supply.

Also, many homeowners enjoy having a gas-fired heating system on cold days. These operate at a much higher temperature than heat pumps. The average gas-fired furnace will produce air that’s as hot as 170 degrees. By comparison, a heat pump rarely outputs air above 110 degrees. That difference may seem insignificant, but it can lead to a heat pump creating a drafty feeling in your home. That extra heat makes a significant comfort difference when the temperature gets cold enough. Plus, the hotter air from a gas-fired system makes it possible to raise the temperature in your home quickly. So, if you use a setback temperature overnight or when you’re not home, you don’t need to wait long for warmth.

Finally, a dual-fuel HVAC may qualify for Federal tax credits aimed at boosting heating efficiency. Sufficiently efficient dual-fuel HVAC systems can net you a tax credit worth $2,600. That can lower their total cost of ownership and make them an even more attractive option.

Local Dual-Fuel HVAC Experts

If you’re interested in the benefits of a dual-fuel HVAC for your Wisconsin home, our experts at Southport Home Services can help. We’ve been a leading HVAC company in Madison, WI, since 2005, specializing in efficient heating and cooling systems. We also offer complete HVAC repair and maintenance, plumbing, and commercial services, as well as expert heat pump services. We sell and install HVAC systems from today’s leading manufacturers like Carrier, Ruud, York, Goodman, Rheem, and Lennox. We even offer a 100% satisfaction guarantee on all new systems we install. Our HVAC technicians undergo background checks and drug testing and receive ongoing training. We can even offer financing on approved credit if you need help paying for a new dual-fuel HVAC. We also have BBB accreditation with an A+ rating. So, if you want a dual-fuel HVAC system for your Madison home, call us at Southport Home Services today! We’ll set up a personal consultation.

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Thomas Suchla
Thomas Suchla

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