A dual-fuel or hybrid system is the combination of an electric heat pump and a natural gas furnace. This system uses the heat pump’s outdoor condensing unit to heat your home using only electricity. The gas furnace comes into play when temperatures are below 35 degrees.
When using an electric Heat Pump as your primary fuel source, adding a gas furnace, as a secondary source can supplement your heating system when the temperature is colder than optimal for a Heat Pump. The fuel-efficient gas furnace can be used when it is coldest (usually below 35F). It will heat your home more efficiently and will have more capacity to bring your home to a comfortable temperature in less time. Once your home is at a more comfortable temperature, you can then switch over to your electric heat pump system and, if paired with a solar system, can utilize the energy efficiency of these combined systems.
By switching to the high-efficiency natural gas or propane furnace during colder periods, the combined system (Heat Pump, Furnace & Solar) is more energy-efficient, provides greater comfort, and has a smaller carbon footprint.
When it’s warm outside, your heat pump will reverse direction and act like an air conditioner removing warm air from your home.
Hybrid heating systems provide homeowners with an energy choice. As energy prices fluctuate, or, if the homeowner prefers the warmer air delivery of the furnace, the transition point between the two systems can be adjusted upward or downward. Hybrid systems also provide a redundant heating system should a problem arise with either one.
Systems and Controls
Some systems you might consider are the Mitsubishi Temperature Control, Trane Comfort Control Model 950, Carrier, Bryant Heat Pump and furnace Evolution system with the Evolution Connex thermostat. All of these are compatible with the NEST thermostat. We can help you select the hybrid system and controls that will best suit your needs.
Builders who adopt a whole-home approach to building design consider the home as a single system consisting of interdependent parts. Framing, walls, insulation, windows, doors, lighting, HVAC and other components of the built environment are evaluated for how they perform in relation to each other, to the local climate and expected occupant behavior.
Previously, some builders may have selected oversized HVAC systems in the hopes of guaranteeing comfort and limiting callbacks, but this approach is costly and inefficient, particularly in homes with tight thermal envelopes. An oversized system is likely to waste energy and cause temperature swings along with ineffective moisture removal by short cycling: constantly turning on and off. HVAC systems specified for high-performance homes must be able to accommodate low loads. In high-performance homes, the interdependent parts work together to produce personalized comfort, healthy spaces, and energy efficiency. The foundation of energy efficiency is a tight thermal envelope designed to reduce cooling and heating loads.
Load and Lifestyle
Room-by-room load calculations (ACCA Manual J®) and the process of identifying the right system size (ACCA Manual S®) are both based upon ASHRAE design temperatures which account for the coolest and hottest days of the year. For most of the year, temperatures will not reach either extreme. Also, loads will change over the course of a day, varying based on how occupants use a space. The homeowner’s bedroom and home office will have radically different conditioning needs than a 50-person dance studio built in a basement, for example. High-performance HVAC systems with variable capacities, such as Zoned Comfort Solutions®, are able to limit energy consumption to the amount needed to cool and heat rooms to their set point and immediately vary capacity as loads change. Coupled with zoning, this level of precision means builders can reduce the risk of callbacks by specifying systems that align with room-by-room load calculations and keep occupants comfortable whether they are in the kitchen or a bonus room turned yoga studio.
If you’re looking for a new heat pump, the first thing you need to do is identify what features matter to you most. Do you want the best value? Do you want the most energy-efficient? Or maybe a bit of both? In order to make your choice a little easier, we’ve identified the heat pump that performs the best in three important categories: energy efficiency, quiet operation, and value. We’ll explain what those categories mean and explain how our best heat pumps perform so you can make the best decision for you and your family.
Heat pump features you need to know
The technical terms and features of heat pumps can feel like a foreign language. Even if you begin to understand them, how do you know what features are right for your home? Honestly, your best resource for a thorough understanding of the latest equipment and what your home needs is your local HVAC specialist. However, there are a few basics you should know.