Seal and Insulate

When you’re ready to upgrade the physical parts of your home, experts agree that it is typically most cost-effective to start with air sealing, duct sealing and insulation. These upgrades will reduce the amount of heat penetrating your home in the summer and escaping from your home in the winter — meaning your air conditioner and furnace won’t have to run so often. This will reduce your energy bills and keep your home at a comfortable temperature year-round.

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  1. Attic insulation. The attic is usually the easiest place to add insulation in an existing home.
    • The quality of the installation makes a big difference in how well it performs; there should be no gaps, compressions or bunching.
    • The R-value measures how much resistance to heat transfer the insulation provides. Your target R-value depends on your climate zone. A licensed, BPI-certified contractor or Whole House Rater can help you determine the best R-value for your home.
    • Fire safety and ventilation requirements are critical. A licensed, BPI-certified contractor can install insulation with health and safety in mind.
  2. Wall insulation. Wall insulation can make a big difference in home comfort and quiet. In existing homes, it is usually installed by drilling holes in walls and blowing in dense-pack cellulose insulation.
  3. Floor insulation. If your home has a crawlspace, consider adding insulation to the top of the crawlspace (also known as the subfloor).
  4. Air sealing. Air sealing means sealing holes and leaks in your home’s shell/envelope.
    • Much of the leakage may be invisible to the naked eye, but there are diagnostic tests that can identify the overall size and location of leaks. (See “Tips for Quality Work.”)
    • In addition to allowing hot or cold air to enter your home, these leaks provide a pathway for attic and crawlspace dust, fiberglass particles, pests, rodent feces and other irritants to enter living spaces. This can affect your indoor air quality and your family’s health.
  5. Ducts. It’s common to find ducts that leak 30% or more of a home’s conditioned air. In addition to wasting energy, leaky ducts can be a cause of inconsistent temperatures and poor indoor air quality.
    • Use approved materials like mastic and foil tape (not duct tape) to seal leaks.
    • Ducts should also be insulated to reduce heat transfer.

Tips for Quality Work

  1. Test, don’t guess. Start by understanding how much insulation, air leakage and duct leakage currently exists in your home. Air leakage is measured using a blower door; duct leakage is measured with a duct blaster. There are two ways to have these diagnostic tests run on your home:
    • Get a home energy assessment from a contractor certified by the Building Performance Institute (BPI). If desired, the contractor can seal and insulate your home after assessing its current condition.
    • Get a home energy rating from a Whole House Rater certified by CalCERTS and BPI. A rating gives you the same information as an assessment and includes a numerical score measuring the energy efficiency of your home. Raters do not perform upgrades.
  2. Hire a licensed, BPI-certified contractor. Not all contractors are trained in building science — i.e., how the components of your home work as a system. The BPI certification lets you know that the contractor understands how insulation, air sealing and duct sealing affect heat transfer, indoor air quality and natural gas appliance safety.
  3. Test again. Have a BPI-certified contractor or Whole House Rater run the blower door and duct blaster tests after the upgrades are complete to make sure leakage was reduced sufficiently.
  4. Get extra quality assurance. The Energy Upgrade CaliforniaTM Home Upgrade program incorporates the three tips mentioned above and a quality-assurance review by an independent third party. It also provides rebates ranging from $1,000 to $6,500.
  5. Do your research. When hiring any professional, talk to multiple companies.
    • Ask how many similar projects they have completed, how long they have been in business, if you can see evidence of insurance coverage and if you can speak with references.
    • Check contractor licenses through the California State License Board.
    • Check BPI certifications through the Building Performance Institute.
    • Check Whole House Rater certifications through CalCERTS (search for “Whole House Raters”).
    • In San Diego County: meet one or more contractors in person at one of CSE’s free educational events.

Tips for Saving Money

  1. “Whole house” rebate. Energy Upgrade CaliforniaTM Home Upgrade offers rebates of between $1,000 and $6,500 for “whole house” upgrades including air sealing, duct sealing and insulation. You must use a Home Upgrade participating contractor to be eligible.
  2. Single-measure rebates. Your utility may offer rebates for single-measure rebates (typically cannot be combined with Home Upgrade rebates mentioned above). Your local government may also offer single-measure rebates. Quick links:
  3. Financing. Many lenders offer financing specifically for home energy upgrades.
    • Click here for information on financing options in California.
  4. Shop around. Get bids from multiple contractors to compare prices. See “Tips for Quality Work” to make sure you aren’t sacrificing quality for price.
  5. Low-income programs. Many utilities offer free or discounted upgrades for income-qualified households. Quick links: