Six Common Home Comfort Sources
Pressure, Pressure, Pressure
- The best air leaks to seal are near the bottom of your house (for example, the rim joist or a leaky basement window) and the at the top of your house (gaps and cracks at the ceiling due to penetrations like recessed lights, bath fans & windows).
- Typical air leak points include light fixtures, walls/floors, ducts, fireplace, plumbing penetrations and light fixtures.
- Basement air leakage should also be considered equally important.
- These leaky spots are in the areas of the home where pressure is greatest causing the holes to do the most “damage”.
- Learn about typical fixes and other key building science principles by getting a BGE or Pepco comprehensive home energy audit!
Thermal & Pressure Boundary Investigation
It might surprise you to learn that effective insulation is not as simple as adding a bunch of insulation to what you have and expecting results.
As it turns out there are several important things happening at the attic floor that need to be addressed if you hope to achieve energy efficiency and comfort.
A thorough inspection of your thermal and pressure boundary will uncover the truths about how to best make improvements.
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3. Sealing HVAC Ducts Saves You $$
Poor Connections
Heating and cooling air ducts are one of the most important systems in your home, and if the connections are poorly sealed or insulated they are likely contributing to higher energy bills.
Ducts that leak heated or cooled air into unconditioned spaces can add hundreds of dollars a year to your heating and cooling bills, but you can reduce that loss by sealing ducts.
Often times leaky or disconnected ducts in the attic or crawl space are responsible for high energy bills and uncomfortable rooms and areas of a home.
Missing Insulation
HVAC ducts that run through outside space, such as an open crawl space, should be well insulated to improve efficiency and comfort.
Notice the rust spot on the low point of this duct which is also an indicator of condensation forming. Condensation forms on the outside of the duct when humid air interacts with the duct during HVAC operation. Condensation can lead to growth of microbes and insects.
Treating the crawl space with encapsulation is one option or re-insulating the ducts to R-11 is another way to improve efficiency and comfort.
Attic Ducts
Uninsulated ducts in unconditioned areas such as the attic lose excessive heat/cold resulting in less efficient HVAC units that are not able to work for the full life-span that it is capable of operating. As a result of lost conditioned air, rooms and hallway areas inside the home are likely to be uncomfortable.
Ideally, the air supply and air return duct systems should be an airtight, closed conduit joining the main HVAC system to the different rooms and areas of the home.
Outside Ducts
This duct runs below a first floor kitchen that extends past the foundation. This is also known as a cantilever or overhang.
Insulation on ducts that travel outside of conditioned space should wrap all the way around the surface and seams should be taped with a high quality tape.
Notice the dark/black insulation above the vent which is a result of years of being subjected to a stream of air infiltration. |
Open Vents Cause Comfort Issues
Crawl spaces can present a few different challenges for a homeowner in both cold and hot months.
The logic in the way crawl spaces were built was to vent the space to prevent moisture problems. The idea of allowing air in to keep things dry was not a great way to do it in Maryland. Hot air enters in summer and cold air in winter. Insulation only at the ceiling is not sufficient.
Vented crawl spaces are silent killers. Going down in a crawl space is not a desirable place to go so often times insulation degrades and new problems and disruptions in the already in effective insulation compound the comfort issues and increase energy usage.
Incorrect Insulation Solutions
The winter can also create crawl space challenges due to cold air infiltration and it can be the main reason for uncomfortable winter nights.
Insulation at the ceiling of a crawl space is not necessarily the right solution.
A crawl space should be "cut off" from the outside. Encapsulate the area by sealing it all the way up!
Moisture Migration
With open vents and without a properly installed vapor barrier, humidity is allowed to infiltrate the crawl space and over time it wreaks havoc on insulation by saturating it with moisture, adding to the weight and eventually, gravity takes over.
Insulation installed in a crawl space ceiling is a perfect set up for what is known as a thermal bypass. If not in every location, especially over time, then in several places, the insulation is pulling away from the sub floor creating a gap as seen in this diagram below.
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Attic Ventilation
Proper ventilation has intake (vented soffit) and exhaust (ridge vent). When an attic is properly insulated, baffles are required at the eaves in the attic in order to maintain the air passageway so that the attic is adequately vented. Otherwise, an improperly vented attic can lead to moisture/mold issues and degradation of roofing system components as well as insulation R-Values.
Homeowners that have a minimum insulation level in the attic equal to R-19, reflective roof shingles and proper ventilation can experience up to two-thirds less solar heat gain than those with features such as little to no insulation, dark roofing shingles and no attic ventilation.
- Intake down low (soffit)
- Exhaust high up (ridgevent)
- Proper baffle install
- Optimal attic ventilation
Baffles
Baffles maintain an air pathway up and over the insulation so that it can exhaust up top at the ridge vent.
The baffle also serves the purpose of preventing wind washing of the insulation which makes it less effective.
Baffles are only required if the soffit has intake holes/air passageways that lead into the attic and the area above the living space.
In some cases it is necessary and recommended to have intake areas opened in the existing solid wood soffit panel to create proper ventilation ratios for the attic.
A professional consultation can guide a homeowner to know when the right time to create additional intake areas in the soffit should be. This important decision is often overlooked until after money is spent on remodeling and it likely is too late.
Working with a remodeling company on replacement windows and doors is an important decision. There are literally hundreds of replacement window companies in Maryland that can do a good job on both window and door installations.
Working with a Building Analyst on your next window and door replacement project is a great way to take your understanding about the fenestration's contribution to the overall comfort and efficiency in a home and what choices to make regarding U-Factor and Solar Heat Gain Coefficient (SHGC) to the next level.
A Building Analyst can help you prioritize which windows to replace based on those that have the highest air leakage rate as well as those that are most exposed to the sun for maximum return on investment.
Windows are great for introducing fresh air into a home that has old windows that don't open. Replacement windows are great to improve aesthetics to the interior and exterior of a home. They can inspire a homeowner to reorganize or re-paint. Replacement windows provide a clear view and when old windows are not properly sealed, they account for approximately 10% of a home's air leakage.
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