February 3rd, 2014

Save Money By Sealing Holes In Your Home

Home Owners Network

Insulation gets most of the coverage when it comes to reducing heating/cooling bills.  Adequate insulation is an important part of saving money on utility bills; however, many homes lose more energy from air flow between the outside and the heated/cooled interior than from inadequate insulation.  Sealing holes in your home provides a great “bang for the buck.”  Not only does sealing holes save money, it reduces uncomfortable drafts, and it helps prevent moisture damage and mold growth.

 hon 5 air sealing pic 2

All homes have holes between the outside and the heated/cooled interior.  Although each hole is usually small, when you add them together, it’s like having a window, or even a door, open 24/7.  Every cubic foot of air that flows through this open window is air you must pay to heat or cool, over and over again.


Holes in finished walls are difficult to access, thus difficult to seal.  You can partially seal some of these holes from the outside by applying exterior caulk around openings such as windows, doors, and pipe penetrations.  Don’t try to save a few bucks on the caulk; buy the best quality caulk you can find.  Caulking these holes brings an added benefit of sealing against water penetration.


Holes in crawlspaces are usually easy to find and seal.  Apply caulk or foam sealant around where plumbing pipes and electrical wires penetrate the floor.  Holes for tub drains can be a square foot or more.  Seal these with foam.  If the hole is too large to seal with foam, you may need to partially seal the hole with plywood or oriented strand board (OSB), and then seal the remaining space with caulk or foam.  Also, apply caulk or foam to seal around where air conditioning ducts penetrate the floor.


Holes in attics can be more difficult to find because they are often covered by insulation.  Apply a sealant around where pipes, electrical wires, and air conditioning ducts penetrate the attic floor.  The sealant (usually caulk or foam) should be rated as fireblocking material because it also serves as a barrier against fire spreading from the home into the attic.  If the hole is too large to seal with caulk or foam, partially seal the hole with ½ inch thick drywall or ¾ inch thick plywood or OSB, and then seal the remaining space with caulk or foam. 

 hon 5 air sealing pic 1

Attic holes caused by chimneys and vents, such as those for furnaces and water heaters, create a special challenge for air sealing.  These components can get hot enough to damage some insulation and can set other insulation on fire.  Seal holes around metal vents and chimneys using sheet metal that is at least 26 gage.  Keep insulation at least two inches away from metal vents and chimneys. (Picture 2)  Seal holes around masonry chimneys using a fireblocking-rated material.


The Bottom Line


Be careful in attics and crawlspaces and on ladders.  Serious injury can befall the inexperienced and the unlucky.  Attics and crawlspaces, and to a lesser extent basements, may contain substances that could be hazardous to your health.  You should wear a face mask, gloves, and a long sleeve shirt when entering these areas.  Hire a contractor to do the air sealing if you’re not comfortable going where you must to do the work.

  Air sealing is usually good, but too much air sealing can be very bad.  In fact, it can make you sick or kill you.  You should have your home tested for combustion safety immediately after finishing your air sealing if you have any fuel-fired appliances.  These appliances include gas and oil furnaces, boilers, and water heaters, and systems such as wood-burning fireplaces and stoves.

 We’re here to help at Homeowner’s Network.  Use our Ask The Experts service if you need help.  Please include as many details as possible about your situation so we can provide you with our best advice.

 If you need a qualified technician to help you, try our Red Beacon referral service.  Log on to your Homeowner’s Network account to access the Red Beacon page.

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