Energy Efficient Home Improvements for 2014: Part 2 – Air Sealing

Energy Efficient Home Improvements for 2014: Part 2 - Air SealingCutting your energy costs is a great way to save money especially if you’re facing high electricity bills from cold winter weather. The problem for some homeowners is that they might not be certain about the kinds of energy problems to look out for in their home. This is why we’ve created a 4-part series detailing Energy Efficient Home Improvements you can complete in 2014. This week, we’re covering air sealing for both your home and your heating, ventilation and air conditioning (HVAC) system.

Your Goldilocks Zone

Your home is an enclosed space that you want to keep not-too-hot and not-too-cold. You want to keep the comfortable treated air (whether heated or cooled) inside your home while keeping the moist, cold (or hot) air outside. Unfortunately, not all exisiting homes are air sealed properly, making them drafty and less energy efficient. Cold drafts in your home are a symptom of the “stack effect.”  If you feel a draft flowing through your house, that means that heated air is escaping higher up in the structure. Sealing off the cold draft will slow down the stack effect.

To find drafts, wet the back of your hand and feel around doors and windows. Another hi-tech option that gives better information is the new Flir One Personal Thermal Imaging device for the iPhone 5 and 5s which can detect where and how cold air is entering your home (and where heat is escaping). Fortunately, sealing these leaks can be done by caulking around windows and doors or even stapling plastic sheeting over the outside of drafty old windows.

Hidden air leaks in attics, basements, and around chimneys are typically bigger areas for heat loss. An often neglected place to look for drafts is at the mudsill and rim joists. These are the bottom pieces of your home’s framing where they meet the foundation. Newer homes have excellent sealing in this area, not so new have moderate sealing, and older homes (pre-1950) have little to none. Leaks here can make your home’s basement cold and difficult to keep warm and dry. If your home only has a crawl space, leaks here can make your floors chilly and allow more moisture into your home.

Another place to look for drafts and leaks is any place where plumbing or wiring passed through the wall outside or into your attic. Attics allow heated air to escape where wiring and plumbing emerge through holes from the living space. Seal all these gaps with expanding foam and caulk. Many recessed light fixtures mounted in your ceiling permit heated air to escape as well. Recessed lighting cans should be enclosed above the ceiling with wooden boxes to control the loss of heated air. Also be sure to put weather stripping on the door that leads into your attic to prevent heated air from sneaking out that way.

By sealing and blocking up leaks and drafts, you can save over 18% off your energy bill. Sure, sealing up five or ten tiny leaks may not save you that much money, but finding and sealing up 50 to 70 will.

Air Sealing Your Ductwork

Leaky ducts lose 20 to 30% of the air passing through them. This wastes energy and increases your electricity bill. Sealing your home’s ductwork is one way to ensure that your HVAC system is running at maximum efficiency. The first place to start is to replace your air filter. Most disposable air filters should be replaced every three months; however, some high-efficency filter systems recommend once a year so follow the manufacturer’s instructions.

Next, check the condition of your ductwork. Look for any loose connections or gaps. Also pay attention to areas where dust, dirt, or mold can be pulled in then your ventilation system because this might also be making your family sick. Re-connect any loose or broken connections and seal these with with UL-181 rated aluminum tape (DO NOT USE “duct tape” —it degrades within one to two years). For holes, gaps and seams, coat these with duct mastik or at very least the aluminum tape. Energy Efficient Home Improvements for 2014: Part 2 - Air SealingMastik has the consistancy of thick peanut butter and can be easily applied with a brush or a putty knife. Drying and curing time, however, is up to three days, so only apply mastic when you know you can leave your HVAC system off for that long.

The cold-air-return ducts are sometimes a forgotten part of the system. If your return ducts pass through or are open in a crawl space, make sure the crawl space has been encapsulated in order to better control temperature and humidity so that you can reduce the chance for mold or mildew entering your living space.

You also want to seal all the return ductwork completely. Tightly sealed ductwork enables the blower fan to circulate air more effectively and efficiently through out your home. Just like with air sealing your home, five or ten tiny leaks might not not save you that much money, but sealing 20 to 50 sure will.

Learn more than you may ever want to know about ductwork from Berkley Labs’ Energy Performance of Buildings group.

House leaks image courtesy EPA

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