Of all the power-consuming components in your home, the one that is most important – and most expensive – is your heating and air-conditioning system.
While it's essential to your home comfort, your HVAC (heating, ventilation and air conditioning) system is a significant cost. So when it comes time to upgrade your HVAC system it's worth considering the type of technology that is heating and cooling your home.
All HVAC systems use a series of fans and blowers to force hot and cold air through your ventilation system to heat and cool your home. These components use motors that are powered by electrical currents. The type of current and the amount of electricity it draws is what ultimately can determine your home energy costs.
There are two types of electrical currents that can power your home heating and air conditioning system, alternating current (AC) or direct current (DC).
Direct current technology is the simplest and oldest form of electricity transmission. Essentially electrons flow in one direction, propelled by a steady magnetic field. With alternating current technology, electrons flow back and forth, powered by a constantly changing magnetic field.
In systems like your furnace and air conditioning system, direct current technology generally uses a permanent magnet to power the motor, while alternating current technology uses coils.
AC technology has long held a traditional advantage over DC in many cases, because less power was lost when transmitting electricity – especially over long distances.
Even now, most furnaces are powered using AC technology. However, advances in research and design have made direct current technology a viable competitor in the home heating and cooling market.
There are advantages and disadvantages to both systems.
AC-powered fans have a mechanically simple design that is cheaper to install and maintain, making them cost-effect in the short- or medium-term. However, AC-powered motors also consume more energy and are generally noisier than their DC counterparts.
DC-powered furnaces are more expensive to buy, but use less energy and last longer than AC motors. They are also quairer.
Now with the advent of high-efficiency furnaces, direct current technology is becoming even more attractive for homeowners looking to cut down on their energy expenses.
Many high-efficiency furnaces use variable speed motors, which will run slower and draw less energy depending on the air-flow requirements at any given time. Put simply, variable-speed motors are a good choice for homeowners who want to run their furnace fan year-round, since they can run the fan at a lower speed and therefore draw less energy. Running your furnace fan continuously can be a good idea if you want to keep the temperature in your home constant and comfortable.
In this case, DC-powered high-efficiency furnaces can be cheaper in the long run, although your initial installation costs may be higher.
DC-powered furnaces can also be a good idea for homeowners wanting to power their HVAC systems using solar panels, since these already run on DC power and typically need to be converted to AC HVAC system.
While there are advantages to both AC and DC-powered fans, they depend on your home energy requirements. Talk to a reputable HVAC supplier about the benefits of AC or DC powered systems for your home.