Improving the energy efficiency of your furnace is one of the best ways homeowners can reduce their energy bills and make their homes more comfortable. Key methods to boost furnace efficiency include sealing ductwork, replacing air filters regularly, cleaning registers, installing a smart thermostat, improving insulation, keeping up with annual tune-ups, and more.
There are several steps you can take to your furnace and home in general that will allow you to get the most heating and cooling out of your HVAC system for the least amount of energy.
1. Home Energy Audit
Have an energy audit of your home conducted. You may be able to receive an energy audit at no charge from your utility company. If not, you can hire a private company to conduct one for under $600. An energy audit is a great way to find any problem areas that need to be addressed in your HVAC system and house. Read more data on how much energy audits can save you in our home energy facts and statistics guide.
2. Seal Ductwork
Make sure the ductwork for the HVAC system in your home is completely insulated and sealed. Older ductwork has fiberglass insulation over metal pipes that may have gaps or leaks in joints and loose connections at registers. Use foil tape to seal joints, followed by a coating of duct mastic. Properly sealed ducts can cut your heating and cooling costs by up to 20%!
3. Replace Air Filter
Change your HVAC return air filter regularly (every 2-3 months) with a high-quality filter to reduce dust in your home and allow your heating/cooling system to run more efficiently and provide better indoor air quality. Check your furnace air filter monthly and replace the dirty filter as needed.
4. Clean Registers
Clean all the registers on your heating/cooling system, and make sure they are not blocked by furniture, carpet, drapes, etc. Consider cleaning the inside of your air ducts, too, if they look dusty. Hire a duct cleaning company every 5–10 years for a thorough cleaning.
5. Install a Smart Thermostat
Getting a smart programmable thermostat can provide energy savings by automatically adjusting temperatures based on your habits and allowing remote control via your smartphone over Wi-Fi.
6. Seal Cracks
Seal up any gaps or cracks around windows and doors with weather stripping or caulking to reduce air infiltration into and out of your home.
7. Insulate Attic
Make sure you have adequate insulation in your attic to retain the heat and air conditioning inside your home, which will cause the HVAC unit to run less often.
8. Annual Tune-Up
Have your furnace professionally inspected and tuned up once per year by an HVAC technician, ideally before the heating season begins. This will make sure it runs safely and at peak efficiency.
9. Upgrade to High-Efficiency
If your furnace is over 15-20 years old, consider upgrading to a new high-efficiency model. Today’s best furnaces are up to 98% efficient, meaning they waste very little energy.
10. Properly Size Your Furnace
Make sure your furnace is the right size for your home. An oversized furnace will cycle on and off frequently, wasting energy. An undersized one will run constantly without adequately heating your home.
Both can lead to shorter life spans and higher repair costs — hire an experienced HVAC company to get the right size for your home.
11. Reduce Heat Loss
Reduce heat loss from your home by keeping fireplace dampers closed when not in use, closing off unused rooms, and avoiding the use of kitchen and bath ventilation fans in winter.
12. Maintain Proper Humidity
Maintaining a relative humidity level between 30-50% in your home during winter can help you feel warmer at lower thermostat settings, reducing furnace run time. Use a whole-house humidifier or room humidifier as needed.
13. Consider Zone Heating
If you have a larger home or areas that are used infrequently, consider adding zone heating with a ductless mini-split heat pump, radiant heat panels, or space heaters to reduce reliance on your central furnace when heating the whole house isn’t necessary.
14. Draw Your Blinds
Keeping your blinds, shades, and curtains closed during the winter could help insulate your home. This takes some stress off your furnace, making it easier to keep your home comfortable and warm. That said, if it is a bright sunny day, consider opening your blinds to let the sunlight heat the inside of your home.
Final Thoughts
Getting the most efficiency out of your furnace requires a combination of proper maintenance, smart upgrades, and energy-saving habits. Consider using this guide as a checklist as you prepare your home for the winter. Not only will doing these tasks keep your home warm and comfortable, but it will also decrease your energy bills and save money.
Frequently Asked Questions
What is the ideal furnace filter MERV rating for efficiency?
For most home furnaces, a MERV 8–11 filter provides the best balance between filtration and airflow for furnace efficiency.
Is it worth upgrading my older furnace to a high-efficiency model?
If your furnace is 15–20+ years old, upgrading to a 95%+ efficiency model can cut your heating costs by 20–40%. The savings can payback the cost within 5-10 years, depending on your climate and energy costs.
What is the most important weatherization step for furnace efficiency?
Sealing air leaks in your home’s exterior walls, windows, doors, and attic are the most critical, as this keeps heated air inside where it belongs.
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