We know that older homes can be drafty, making them cold in the winter, hot in the summer and expensive to keep the right temperature year-round. But they don’t have to stay that way. Smart, affordable improvements can make a historic building more energy efficient. But before making any energy conservation changes to your home, first take a good assessment of the structure. 

Insulation can improve a home’s energy efficiency. Before calling an insulation company, though, it’s important to assess where drafts and air leaks are coming into and out of the house. Air leaks can be found in obvious places — around doors and windows — but also less obvious places, such as around electrical outlets. 

“Before making individual efficiency upgrades, it’s important to know how your home uses energy. A home energy audit is the first step to saving energy and money,” according to the U.S. Department of Energy. “Sometimes called an energy assessment, a home energy audit helps you learn how you use energy, determine where it’s being wasted and prioritize your efficiency upgrades,” the department said. “Making energy efficiency upgrades identified in a home energy audit can save 5 to 30 percent on your monthly energy bill while also ensuring the health and safety of your house.” 

An important part of the energy audit can be a Blower Door Test. These tests locate air leaks by using a specialized fan to depressurize the house. Blower tests are conducted before and after air sealing to measure the effectiveness of the work, according to Energy.gov

Once you’ve properly sealed your air leaks, adding appropriate insulation can be a cost-effective way to improve your home’s heating and cooling costs, but be careful. Using the wrong kinds of insulation — or installing it inappropriately — can cause more problems than it solves. Just a few common pitfalls of improperly installed insulation include wood rot, termites, peeling paint and mold. When considering retrofitting your home with insulation, moisture management is key. 

“Trying to save energy while ignoring moisture can cause great harm and may save no energy,” said Myron Katz, a New Orleans building science expert who presented a program for the PRC in 2021. 

Once you’re ready to consider adding insulation, the National Park Service recommends: 

  • First insulate unfinished spaces, such as attics and crawl spaces, with appropriate insulating materials, but ensure the space is adequately ventilated. 
  • Install appropriate wall insulation only if necessary, after lower impact treatments have been carried out. Lower impact treatments may include upgrading appliances or installing weather stripping to your existing windows and doors. 
  • Salvage and replace any interior finishes that are removed during installation, in order to retain the historic character. 

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