When you're in the market for the most efficient heating system you can find, you may quickly learn that it's a complicated process. While you can start the search on your own, it's faster and more convenient to involve an HVAC specialist at the beginning of the process. Doing so will help you avoid a steep learning curve, and ultimately, choose the best system for your home and lifestyle.
Because our winters typically aren't as severe as those in locations north and west of here, your options are many. Pinpointing the best system involves assessing fuel availability, your comfort preferences, budgeting considerations and the characteristics of your home and family.
When you work early on in the process with an HVAC contractor, you'll go over these issues associated with choosing the most efficient heating system carefully.
Fuel Type
Taking stock of the fuel availability and cost is one factor that will help determine the most efficient heating system for your home. The most common types of fuel include natural gas, propane, fuel oil and electricity. Basing your choice on what you have on your property is usually the most affordable option, since it costs to have the necessary infrastructure brought to your home, whether it's a gas line or a storage tank for propane or fuel oil.
- Natural gas – Natural gas is by far the most common fuel used for winter heating across the nation. It's currently one of the most affordable fuels available thanks to an ample supply being provided domestically.
- Propane – Propane needs to be delivered to your home and costs slightly more than natural gas. In the past, older natural gas and propane furnaces were interchangeable with a few adjustments, but today's systems aren't. The advantage of propane is that it burns cleaner than natural gas or oil.
- Fuel oil – Fuel oil is a form of diesel, and its price is tied to the cost of oil that's been on the rise in the last decade, but which has fallen dramatically in the U.S. over the past year or so. The advantage of a fuel oil furnace or boiler is that it provides more heat per unit of fuel consumed than either kind of gas. Its disadvantage is that these systems require a little more frequent maintenance, including oil filter changes, just like vehicles do; although all HVAC systems require professional annual maintenance to run as efficiently and safely as possible.
- Electricity – The only way that electric heating competes as a fuel source in terms of cost per unit of heat produced is if you use a heat pump. Many heat pumps can create three to four times the heat from one unit of electricity compared to electric resistance systems. As an end user, a heat pump may be the most efficient heating system for your home because it's clean, safe and electricity is available nearly everywhere.
Heating System Types
- Forced-air – A forced-air system is by far the most common type of heating system in use today. It uses fuel or electricity to generate heat, which is then blown through ductwork by a fan. A forced-air furnace is often combined with a central air conditioning system because these systems need fans and ducts for air delivery, as well.
- Boilers – Instead of blowing warmed air, boilers heat liquid that flows through a series of pipes that radiate heat. It's possible to install these in both new and existing homes. They have several advantages over forced-air systems in that they distribute no dust and allergens throughout the home, are exceptionally quiet, and provide even warmth. Their main disadvantage is that it will take longer to warm a cold home initially compared to a forced-air system.
Energy Efficiency
The U.S. Department of Energy (DOE) establishes minimum standards for energy efficiency for central heating systems in order to help consumers save energy and money. The DOE estimates that heating and cooling homes accounts for about half of the annual energy budget of the typical household.
Curbing the consumption by making HVAC appliances more efficient is a win-win for everyone, since consumers have lower energy bills and utility providers don't need to plan as much expansion, which can cost billions of dollars. The DOE recently increased minimum energy efficiency standards for combustion heating systems and heat pumps.
As of January 1, 2015, the new standards will require:
- Fuel-based systems to have an annual fuel utilization efficiency (AFUE) of 80 or higher. The AFUE reflects the percentage of fuel the system uses that translates to heating the structure directly, not what's being wasted up the chimney. A system that has an AFUE of 80 loses 20 percent of its heat as waste, notably as water vapor that's exhausted up the flue. The current standard requires at least a 78 AFUE. This increase is small, and may rise by 2021 or 2022 to much higher AFUE.
Furnaces and boilers are available that have AFUE ratings that reach nearly 99 percent, which means that the equipment converts nearly all the fuel it uses to heat your home, making this type the most efficient heating system for your home.
These systems reach such high efficiency by removing the heat from the water vapor burned fuel creates through a second heat exchanger. Called condensing furnaces and boilers, they have a more elaborate installation and initial cost, but since their efficiency is so high, those who choose them recoup the investment in lower fuel bills.
If a condensing furnace won't work in your situation, other forced-air systems use energy-saving technologies, like modulating gas valves and multi-speed blowers aimed at increasing comfort while lowering energy bills.
- The efficiency standards for heat pumps will go up January 1, 2015, from a seasonal energy efficiency ratio (SEER) of 13 to 14 (for cooling). For heating, the heating season performance factor (HSPF) will move from the previous minimum of 7.7 to 8.2. In our climate, a heat pump with a higher HSPF will be capable of heating your home, except during the coldest weather.
Carrier, a leading manufacturer of HVAC equipment, offers heat pumps with HSPF ratings as high as 13, which has earned this heat pump the Energy Star's Most Efficient label. Heat pumps work by extracting the heat from the air. A system with such high efficiency offers more heating capability than one with a lower HSPF.
A heat pump with a lower HSPF can also be combined with a combustion furnace, called a dual-fuel system, to become an efficient heating system. You can take advantage of the natural heat in the air until temperatures fall below 30 degrees. It will automatically switch to the combustion furnace at that point, so your home will always be comfortably warm without having to rely on using nonrenewable fuels all winter.
Sizing the System
Regardless of the type of system you choose, your HVAC contractor will need to size it carefully using Manual J software. Although this step requires detailed information about your home, the analysis results in a heating system that matches your home's heating load. Influencing factors include:
- Cubic footage
- Overall energy efficiency
- Floor plan design
- Heat-producing appliances and activities
- Family size and thermal preferences
- Landscaping factors
Going through this analysis gives you the opportunity to learn if you could choose a smaller system that will cost less initially and use less energy as it runs. Improving insulation and sealing air leaks are easy and affordable projects that may reduce the size of the system needed. Besides saving money initially by using a smaller system, one that's precisely sized helps you avoid short cycling, which is caused by heating systems that are too large.
Many people think that the most efficient heating system is one that's oversized, but in reality, one that's too large is inefficient. It won't run long enough to evenly heat all the rooms in the home. It will also create moisture damage on the system's components and start and stop more frequently, which causes excessive wear on the mechanical components. One that's too small won't handle the coldest weather we experience, leaving you uncomfortable.
The pros at Griffith Energy Services, Inc. can help you put together the elements that contribute to the most efficient heating system for your home. We have 12 offices throughout the Maryland, Dover and Martinsburg areas and have provided exceptional HVAC services for the area homeowners for more than 100 years.
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