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Common Sense - An Efficient Furnace in an Efficient Home

Replacing your old furnace with a new one will make your heating more efficient. However, you won't start seeing the energy savings you expect until your home is as efficient as your new furnace. Let's see how efficiency with both the furnace and your home is essential for maximizing your energy savings and comfort level.

New Furnace Efficiency

Furnace efficiency is measured by the Annual Fuel Utilization Efficiency, or AFUE, rating. The closer the percentage is to 100 percent, the more efficient the furnace is. Most older furnaces are 70 percent or less on the AFUE scale. Modern furnaces can be as efficient as 98 percent. The difference in efficiency – basically how much fuel gets converted into heat – translates to lower operating costs.

Sizing your furnace is critical. Your HVAC contractor should take careful measurements before recommending the size of your new efficient furnace. If you install a furnace that's too large, you will be wasting money running a system with too much capacity for your home. If you install a furnace that's too small, the system will need to work overtime but may still have trouble keeping your home comfortable.

It is also important for your furnace contractor to make sure your ductwork and venting system are designed and sized for the new efficient furnace. Blindly installing a new system on an old infrastructure can decrease your new furnace's efficiency dramatically.

Filtering incoming air is another consideration when it comes to your furnace's efficiency. If your filter is clogged with dirt, your furnace will struggle to meet your temperature demands, dirt and grit will coat furnace components, and your indoor air quality may suffer. Basic fiberglass filters are not enough to keep the dust out of the system. However, going with a filter with too high an efficiency (Minimum Efficiency Reporting Value - MERV) rating can cause the blower to work overtime to push air through. That can significantly shorten its life.

Home efficiency

When your home has air leaks, inadequate insulation and other problems, even a new efficient furnace is not going to make much difference in your energy bills. It's important to improve your home's efficiency level when installing a new furnace.

Here Are Some Ways You Can Do That:

  • Weatherstrip doors and windows. Air can easily travel around the edges without weatherstripping. Check it every year and replace it if damaged or missing.
  • Plug air leaks with caulk or foam insulation. Check the edges of door and window openings. Air leaks there can silently rob your home of heat. Check places where pipes and vents penetrate the walls, also.
  • Check your attic insulation levels. Enhance if needed. You can add blown-in insulation in hard-to-reach areas or over top of existing batts. Spray-foam insulation provides both insulation and air sealing.
  • See if your exterior walls have any insulation. The walls of many older homes have little to no insulation. If there is no insulation in place, you can have loose-fill insulation injected into the wall cavities.
  • Check your basement or crawl space for floor space insulation. Cold air can infiltrate through the wooden subfloor. Batt or spray foam insulation can help.
  • Replace old appliances with new Energy Star rated ones. As older appliances come to the end of their useful life, or when you are remodeling, getting more efficient systems and equipment is a good investment.
  • Upgrade single-pane windows with Energy Star rated ones. A single pane of glass has an R-value of 1. The only thing lower is an open door. An Energy Star rated window will have an R-value of 3 to 5. That means up to 40 percent improvement in the window's efficiency.

An easy way to check your home's efficiency is to have a home energy audit done. The auditor will perform tests and use equipment to measure where your home is losing energy, with the most common culprits being air leaks or poor insulation. The report that the auditor makes will include a list of recommendations on how to make your home more efficient.

Making your home more efficient is essential to maximizing your potential energy savings. Going through the installation of a new highly efficient furnace is a major home project. It is a great time to assess the efficiency of the rest of your home and to make the changes needed to keep your energy bills down for many years to come.

To find a contractor to help make your home more efficient or to conduct home energy audit, please visit us at We can help you find a contractor in the Chicagoland area.

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