Efficiency is a significant factor when choosing between an electric heater or a heat pump. Since both operate solely on electricity, you may assume they boast similar efficiency. However, nothing could be further from the truth. Here’s the difference between electric heat and heat pumps and the efficiency you can expect from each.
What Are Electric Heaters?
Most homes with electric heating systems in Shreveport, LA, generally have one of two system types. One is an electric furnace. They produce heat inside a centralized unit and distribute it via your home’s ductwork. The other type of system is an electric baseboard heater. As their name suggests, baseboard heaters run along the bottom of the walls in your rooms. Each includes an electric heating element surrounded by a metal casing and has its own thermostat. Both types of heating systems generate heat in the same way.
How Electric Heaters Work
Electric heaters rely on the concept of electric resistance to generate heat. Basically, it works by passing an electric current through a metal element that isn’t highly conductive. Being a poor conductor, the element resists the flow of electricity. That resistance converts the energy in the electrical current into heat.
Most electric baseboards and electric furnaces use heating elements made of an alloy called Nichrome 80/20. It’s a blend of 80% nickel and 20% chromium. The alloy can withstand temperatures up to 2,200 degrees Fahrenheit without degrading. Plus, it builds an outer layer of chromium oxide when first exposed to heat. That layer prevents further oxidation of the underlying metals, making for a long-lasting heating element. Most last between 20 and 30 years before showing signs of degradation.
How Efficient Are Electric Heaters?
It’s easy to measure the efficiency of any electric resistance heater. That’s because they’re always 100% efficient. The reason for that is a scientific principle known as the conservation of energy. Broadly speaking, it states that energy is neither created nor destroyed. So, in a closed system like electricity running through a heating element, you get a one-for-one energy conversion into heat. Roughly speaking, you will always get 3,412 BTUs of heat from 1 kWh of electricity with an electric heater.
What Are Heat Pumps?
A heat pump is a mechanical device that collects heat in one location and transports it elsewhere. Although you don’t know it, you’ve likely relied on heat pumps in your home for years. For example, your refrigerator and freezer are heat pumps. In that case, they collect heat from their sealed inside compartment and release it into the room’s surrounding air. Your home’s air conditioner is another type of heat pump. It collects heat from your home’s indoor air and carries it outside.
When you hear heat pumps mentioned as an HVAC system, however, they generally refer to one specific type. They refer to bi-directional air-source heat pumps. They work like a conventional air conditioner but with a twist — they can also operate in reverse.
How Do Heat Pumps Work?
Heat pumps exploit the refrigeration cycle to work. That cycle relies on a closed system containing refrigerant. Heat pumps manipulate the pressure and temperature of their refrigerant to make it capable of either collecting or releasing heat. In heating mode, the process begins with the system’s refrigerant passing through an expansion valve. As that happens, the refrigerant turns into a cold, low-pressure liquid/vapor mixture. That mixture then passes through a heat exchanger in the heat pump’s outdoor unit.
As the refrigerant moves through the heat exchanger, a large fan blows outdoor air across it. Since the refrigerant is colder than the outside air, it absorbs heat as it travels. As the low-pressure refrigerant has a low boiling point, absorbing that heat causes it to vaporize fully. Afterward, the warm vapor passes through a compressor, which increases its pressure and temperature. It’s that now-hot vapor that travels into your home to warm it. The indoor unit of a heat pump contains another heat exchanger and fan. By blowing cooler air from inside your home across the exchanger, the air warms as the refrigerant releases its heat.
How Efficient Are Heat Pumps?
Although heat pumps use electricity to operate, they don’t convert electricity into heat. Instead, they use it to collect already-existing heat from the outdoor air and bring it indoors. As a result, the one-to-one energy-to-heat conversion ratio specified by the law of conservation of energy doesn’t apply. By contrast, heat pumps’ heating efficiency depends on how efficiently they can extract heat energy from the outdoor air.
To understand heat pump heating efficiency, you must first start with the fact that outside temperatures fluctuate. The colder it gets, the less heat energy exists in the air. As a result, the colder it gets outside, the less efficient a heat pump becomes. The average heat pump sold today can achieve efficiencies approaching 400% at outdoor temperatures of 40 degrees Fahrenheit and higher. By the time the outdoor temperature drops to 20 degrees, the same heat pump may be only 150% to 200% efficient or less. When you apply that performance over a heating season, you typically end up with an average efficiency of around 350%.
Other Important Considerations
Now that you know how efficient electric heating and heat pumps are, you likely think a heat pump is the only logical choice. However, before you reach that conclusion, you should know a few things. One is that electric heating systems often last twice as long as heat pumps. The other is that electric heating systems typically cost a fraction of what you’d pay for a heat pump. If you invest in the latter, the odds are you’ll more than recoup your costs through energy savings over the system’s life. The Department of Energy estimates that the average household uses 75% less electricity annually with a heat pump versus electric heat. However, you’ll still have to come up with the money to pay for a new heat pump. Electric heating may still be preferable when dealing with a restrictive household budget.
You should know, though, that various tax credits and rebates are available to help pay for a heat pump. One is a federal tax credit worth up to 30% of the cost of a new heat pump up to $2,000. You can use the credit to reduce your tax liability in the year of your installation. Soon, another federally backed rebate program could provide up to an $8,000 point-of-sale discount based on your income.
Electric Heating and Heat Pump Experts
For over 60 years, Bobby L. Greene Plumbing, Heating & Cooling Co. has specialized in efficient heating and cooling solutions in Shreveport. We offer same-day appointments and free estimates on HVAC system installations. Our HVAC technicians have years of experience dealing with electric heaters and heat pumps. Plus, we’re Better Business Bureau accredited with an A+ rating. We offer discounts for senior citizens, military members, first responders, and churches. We even offer financing options on approved credit to help you cover the cost of a new heating system. So, if you’re looking for a new heating system for your Shreveport home, contact Bobby L. Greene Plumbing, Heating & Cooling Co. immediately!
