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Keeping a home properly heated and cooled is a complex task—whether you rely on a furnace, heat pump, air conditioner or other any other unit. The entire HVAC system works together to maintain a comfortable temperature and use energy efficiently. A failure of any part of the system may increase your energy consumption and costs. With an understanding of this balance, you can ensure that you get the best home efficiency, from the appliances to the insulation.

Heating

A forced-air furnace works by drawing cool air from outside, heating it and sending it throughout the home. The furnace’s efficiency is measured in the amount of fuel it is able to convert to heat. A natural gas furnace with an Annual Fuel Utilization Efficiency (AFUE) of 95 converts 95 percent of the gas it uses into heat. If you have a heat pump, it runs the cool outdoor air over coils charged with refrigerant. This allows it to pull heat from the air and deliver it inside. The efficiency of the heat pump is determined by the Seasonal Energy Efficiency Ratio (SEER), which measures the energy it consumes in relation to its output through average use.

Air Conditioning

During the summer, you might use an air conditioner or a heat pump to stay cool. An air conditioner uses refrigerant to pull heat from the air and deliver it outdoors, so that cool air can be circulated throughout the home. A heat pump works in much the same way, allowing the system to be reversed for cooling and heating. Central air conditioners and heat pumps often rely on the air handler of the furnace to blow the air through the ductwork.

Filtration

The goal of your HVAC filtration is to strike an ideal balance between efficient filtration and effective heating and cooling. Air filters are rated by the Minimum Efficiency Reporting Value (MERV), which determines how much the filter can pull from the air before it is cycled throughout the home. A filter that is more effective at removing contaminants may be less energy-efficient because it requires more energy to push air through a tighter filter. Similarly, if you have a dirty or clogged air filter with a lower MERV rating, your system must work harder to push air through. The trick is to select an air filter with the lowest MERV rating you find appropriate for your home and family.

Ductwork

Your home’s ductwork is quite possibly the greatest source of lost efficiency. In order for each room to receive the heated or cooled air you pay for, the ductwork has to be efficient at keeping the air inside. Unless you just had your ductwork sealed, you probably have some kinks and gaps that are seriously hurting your energy efficiency. You might be losing as much as 20-30 percent of the air through those leaks, and that stuffy room at the back of your house is your first clue. If your ductwork is properly installed and sealed, you can rest assured that the heated or cooled air will actually reach its target.

Insulation

Once the air has been sent through the ductwork and into each room, you rely on your insulation to keep it there. Heat wants to move from inside the home to the outdoors, and vice versa. This process is called heat transfer, and your insulation is designed to slow it down. Improving your home’s insulation, particularly in the attic and between floors, increases your home efficiency by helping to preserve the desired temperature longer.

Sealing Your Home

There are aspects of your home’s exterior that can subvert the system, decreasing your energy efficiency and your indoor air quality. You probably already know not to leave your door wide open on a particularly cold or hot day. However, there are all kinds of leaks around your home’s exterior that you might not even know about. Air leaks can be very small, but they speed heat transfer and make some rooms harder to heat or cool. Gaps around your windows and doorframes are the most likely culprits, but sometimes you also have small holes in your home exterior that are obscured by your insulation. Sealing air leaks helps the insulation to do a better job slowing heat transfer.

An Efficient Face on the System

The system would not be complete without a way for you to make it work, and that component is your thermostat. The thermostat relies on the efficiency of the rest of the system to change or maintain the proper temperature, but the thermostat itself must also be efficient. Manual thermostats require you to change physically input a new temperature as you need it, prompting the system to kick on and blow hot or cool air at full blast. Programmable thermostats are generally more efficient, partly because they do not need to run full-blast whenever you change the temperature. They are also more convenient because you do not have to sit in a cold home waiting for it to warm up after you get home from work. The latest models are designed to dramatically improve your efficiency, even to the point of creating their own settings based on your preferences.
Your HVAC system has many components that are designed to preserve your home comfort in an efficient manner. If any part does not work properly, you waste more energy. Each step requires regular maintenance and repair to ensure that it keeps the highest level of efficiency possible, from a simple air filter to a complex furnace. With your entire system in an ideal balance, you can conserve energy and save money on your home heating and air conditioning.