Heating & Cooling Efficiently
Did you know that half of the energy used in our homes is for heating and cooling? In the U.S., residential energy use accounts for roughly 20% of greenhouse gas (GHG) emissions.
How do I know if my home is energy efficient?
Learn how energy efficient your home is by performing a DIY home energy assessment, or hire a professional to do it for you. Your local utility company may offer a low-cost or free home energy audit. I had one done through our gas company done for only $25.
If you don’t already have Energy Star heating and cooling elements, consider upgrading as able. Exchanging your HVAC, appliances, and electronics to Energy Star certified products can save as much as 20% on your utility bill. Learn more about energy efficient appliances and electronics here.
HVAC preventative maintenance is key
Besides upgrading to Energy Star heating and cooling systems, staying on top of HVAC maintenance is the most important thing to keep things running smoothly. The biggest causes of heating and cooling system failure and inefficiency are dirt and neglect. Dirt, dust, and grime create air flow resistance which makes the system work harder. Regular maintenance of your equipment keeps the system running properly and efficiently, prolonging its life and decreasing costs.
It is recommended to have HVAC serviced in the season preceding its use; tune up and clean cooling systems each spring and heating every fall.
Change air filters regularly
Having an clean furnace filter is one of the most important things you can do for HVAC energy efficiency. It is recommended to change air filters at least every three months. I was terrible at this until I set a reminder on my phone to help me remember. There are filters available that can be washed and reused, but I have never tried one, as I only recently learned about their existence.
Make sure you are using the correct size of filter for your system. Air filters are graded by a Minimum Efficiency Reporting Value (MERV) from 1 to 16. The lowest rated filters might only filter out large particles like hair. As the numbers increase, the more pollutants are filters out. This can include things like dust, pet dander, pollen, cigarette or wildfire smoke, textile fibers, and mold spores.
If you can see through the filter, you’ll probably want to skip it as it won’t actually filter much from the air. The most efficient filters are pleated, creating more surface area to filter pollutants out. The EPA recommends filters rated MERV 13.
Some manufacturers have their own rating systems. The equivalent of MERV 13 for these are FPR 10 or MPR 1900.
Seal and maintain air ducts
Ensure joints, seams, and screwheads in the ductwork are adequately sealed. Up to 20% of air can escape through leaks in the system. Keep air vents and registers free from obstruction as much as possible to decrease resistance and allow consistent, even airflow.
The EPA recommends to only have air ducts cleaned as needed, stating that dust in the system generally stays where it is unless disturbed, and no research shows cleaning helps the system operate more efficiently nor helps prevent health problems.
Anectdotally, with my unprofessional opinion, I beg to differ. I think that at the very least, it’s not a bad idea to have an air duct cleaning at least once after moving into a new home. When I was in high school, my family moved into new house and I remember cleaning and finding a petrified hamburger in one of the air vents.
The house I live in now was completely gutted and remodeled before we purchased it, and they definitely did not close up the duct work during construction because the amount of dust and dirt that was removed during a duct cleaning was appalling. Prior to being cleaned, one of the registers had very weak airflow, and afterwards it was noticeably improved.
Learn about improving the air quality in your home here.
Upgrade to a smart thermostat
An Energy Star thermostat doesn’t save energy itself but makes it easier to manage the temperature in your home efficiently.
In the cold months, set the thermostat as low as you can comfortably manage, maybe wearing a sweater or slippers and using extra blankets around the house. The Dept. of Energy recommends 68 degrees while you’re home and awake. Save up to 10% on energy bills per year by adjusting by 7-10 degrees for 8 hours per day, saving 1% off your energy bill per degree you turn the thermostat down.
One common myth is that keeping thermostat at the same temp all day saves energy because the heater or a/c won’t have to work as hard to bring a room or house to the desired temperature. It’s actually more efficient to heat or cool your home as needed, which means turning the heat down or a/c up when leaving the house. Make sure when you leave town to do the same. Indoor temps are ok to drop around 55 degrees in the winter and up to 85 degrees in the summer. When we are on our way home from vacation, I adjust the thermostat to normal from an app so it is comfortable when we arrive.
Keep fan on ‘auto’ setting. ON keeps the fan constantly running and pulling air through the filter, decreasing humidity, and should only be used if there is a concern about air quality.
The importance of insulation
Proper insulation makes a big difference in the efficiency of heating and cooling inside your home and decreasing usage from HVAC systems. There are many types of insulation, and if you aren’t familiar with them or where they are needed, this is where a home energy audit can really be helpful.
Find out how to detect air leaks. Weatherize your home by filling cracks and crevices and ensuring tight seals around door and windows using weatherstripping, expanding foam, backer rod, or caulk.
Decor can make a difference in insulating your living space. Arranging furniture, such as bookcases, and wall hangings on exterior walls, rugs on floors with hard surfaces, and heavy curtains can all act as insulation. Keep window coverings closed at night to help prevent cold air from entering, and make sure to open those on south-facing windows during daylight hours in wintertime to allow sunlight in the help heat the home naturally. Conversely, keep them shut to keep sunlight out during warmer months, or install energy-efficient window coverings that let natural light in and prevent solar heat gain. You can also cover windows with plastic sheeting.
Fireplaces are a common area that allow air leaks. Keep the fireplace damper closed unless a fire is burning. If the fireplace is never used, plug and seal the chimney flue. Make sure the flue damper and hearth are sealed adequately.
Energy saving landscaping
You may not have thought about the impact landscaping can have on your home’s energy requirements. Strategically placed plants can have significant benefits when it comes to energy conservation. According to the U.S. Forestry service, the average reduction in national residential energy use due to trees is 7.2%.
In summer, trees directly cool the air through transpiration, where water evaporates from leaf surfaces, similar to how our skin is cooled when we sweat. And of course, they provide shade. Planting deciduous trees on the sides of a house where there is the most sun exposure helps to cool the home. Conversely, in winter, the lack of leaves allows the penetration of the sun’s heat indoors.
Trees and shrubs can provide wind protection during the cold months. Wind can force cold air in through cracks and holes in walls and around windows and doors. A well-designed windbreak can reduce heating costs as much as 30%. Evergreens, especially those that have crowns close to the ground, are the most effective windbreak choices since they keep their foliage in winter. Examples are junipers, spruces, firs, and evergreen shrubs. Consider what direction the local winter winds come from to determine planting site.
Find sustainable gardening tips here.
For more guidelines and instructions on how to place trees for energy conservation, visit the Arbor Day Foundation.
Heating considerations
According to the U.S. Department of Energy, heating your home uses more energy and therefore costs more money than any other system in your home, typically making up about 29% of your utility bill, increasing as much as two-thirds in colder areas. This makes having a clean, energy efficient heating system all the more important. Heating with electricity is optimal, as it creates 36% less carbon emissions than natural gas.
There are many different types of heating systems. Some types create less emissions and pollutants than others, and there are variations within each category.
Furnaces & Boilers
The heating systems that are the most common are furnaces and boilers. The least efficient type of furnace is a single-stage motor, which essentially switches on and off like a light bulb, always at 100% speed. The two-stage starts at around 60-70% speed, and if the desired temperature isn’t reached in a set period of time (usually 8-12 minutes), then it increases to full speed until the goal is reached. Variable speed systems are the most efficient, and of course the most expensive of the three. These furnaces can operate at a wide range of speeds.
These different models are also offered with standard options, which convert 80% of the energy from gas to heat, while high-efficiency converts around 95%, therefore uses less fuel and creating less emissions and costs to you.
Heat Pumps
Heat pumps are another common option, but are not always well-suited to cold climates. For a comparison between furnaces and heat pumps, check out this article by the U.S. News and World Report.
Wood or Pellet Burning Appliances
Supplemental heating such as wood- or pellet-burning appliances may be the worst heating options in both efficiency and pollution. Smoke from these heat sources contains multiple chemical compounds, pollutants, and particulates. Traditional wood-burning fireplaces are not efficient at heating a home as most the heat goes up through the chimney.
The EPA reports that residential wood smoke emits more PM2.5 pollution than both on-road (cars & diesel trucks) and non-road (tractors and bulldozers) vehicles combined, and five times more PM2.5 pollution than petroleum refineries, cement manufacturers and pulp and paper plants combined. And nationally, residential wood combustion is the second largest contributor of wintertime PM2.5 emissions.
Appliances found on the EPA wood stove database burn much more cleanly than open fireplaces and non EPA-certified stoves. Check the EPA wood-burning appliance FAQ page for more information.
The wood pellet (or biomass) industry have been making some noise as of late, with some governments and organizations pushing to switch to this energy source instead of coal. Highly compacted wood pellets are burned instead of the classic log, but it is also possible to create pellets of other organic materials such as grasses, nutshells, corn kernels, and small wood chips. Most models require electricity and are a cleaner and more efficient heating option than wood-burning, but not a good replacement for coal. A PFPI study states that burning biomass creates 150% the carbon dioxide of coal, and 300–400% the CO2 of natural gas, per unit energy produced.
Natural gas fireplaces are a much more efficient and cleaner heating method.
Geothermal heating
Geothermal heating is the cleanest, most eco-friendly heating option of all, but it is by far the most expensive. Installation requires significant excavation.
Cooling Tips
On average, cooling accounts for about 6% of a household’s energy usage. This of course increases in homes located in hotter areas. The cooling industry is responsible for 10% of global CO2 emissions, which is expected to increase as the planet warms.
Ventilation is cheapest and most efficient way to cool a home.
- Open windows to create a cross-wise breeze, especially at night.
- Using a ceiling fan will allow you to raise the thermostat setting about 4 degrees without impacting your comfort. Turn off when leaving a room—fans cool people but not rooms.
- Whole house fans pull air in through windows and exhaust it through a home’s attic and roof.
- Use the bathroom fan when taking a shower or bath and a range hood when cooking –this helps remove heat and humidity from your home.
Other energy saving cooling tips include setting the thermostat at 78 degrees, choosing the recirculate option instead of constantly cooling hot air from outdoors, and using the fan-only mode at night. In addition, providing shade for an air conditioner unit can also save energy, increasing its efficiency by 10%.
Energy Star-qualified AC units are, on average up to 15% more efficient than standard models
Summary on heating and cooling efficiently
Taking the time to research the most appropriate heating and cooling systems for your situation, investing in Energy Star products, and ensuring HVAC efficiency by regular maintenance and adopting energy-saving practices can significantly decrease your carbon footprint as well as saving you money.
It is easy to mindlessly push a button and adjust the thermostat when we are uncomfortable, but make it a goal to utilize the other tips here to improve the ability of your living space to maintain a desired temperature for your comfort and the health of the planet.