Air leakage happens when outside air enters your house through openings and cracks. These drafts replace the conditioned air in your home, affecting the indoor environment you try to control with your heating and cooling systems. But there are also less obvious spaces that let air in and out of your home. These gaps can be anywhere on your walls, basement, attic, and even ductwork.
Why Air-Seal Your House?
Some homeowners rely on drafts to try and improve their ventilation, but this is an unwise strategy. Too much cool air can enter your house during the colder months. And when the warm season comes, humid air can make your home feel hotter, creating an uncomfortable indoor environment.
Air leakage also carries moisture into your house. High levels of moisture can damage your home’s foundation. Water vapor settles on various surfaces, causing wood to rot, paint to peel, and electrical wirings to malfunction. Pest infestation also becomes more probable, since termites, cockroaches, and other bugs thrive in damp areas.
Aside from compromising your home’s structural integrity and your health, indoor moisture can cause your energy bills to soar. Humid air feels heavy on the skin, forcing you to up your cooling system usage thus increasing your utility bills.
Finding and blocking those air leaks is imperative to reducing your heating and cooling costs, helping you achieve maximum energy efficiency. The Environmental Protection Agency (EPA) estimates that air-sealing your home can cut 15 percent off your heating and cooling costs.
With summer still several months away, now is the perfect time to conduct a thorough air leak detection in your home.
How to Detect Air Leaks
You can either perform the inspection yourself or hire an energy auditor to do it for you. A home energy audit provides the most accurate measurement of air leakage in your home. Some home insulation companies offer energy evaluations to determine areas in your home that aren’t properly insulated
Home Energy Audit
A qualified technician will conduct an energy audit to see the whole picture of your home’s energy use. This assessment determines how much energy is used and lost, as well as the problem areas you need to address to make your home more efficient.
The professional energy auditor will do a blower door test. A powerful fan will be mounted into the frame of an exterior door. It pulls the air out of the house, decreasing the pressure inside. The outside air, which is higher in pressure, will rush in through the unsealed cracks. A smoke pencil will be used to locate the openings.
If you’d rather assess the house yourself, you have two ways of locating air leaks: visual inspection and the pressurization test.
Below is a checklist of all the areas of the house where gaps commonly form. These are spots where two different building materials meet. Due to poor construction or craftsmanship, the two surfaces may have lined up unevenly, creating spaces where air can pass through.
Outside the house:
- All exterior corners
- Faucets connected to exterior walls
- Joints where chimneys and the siding meet
- Areas where the foundation and the siding or bottom exterior brick meet
Inside the house:
- Vents and fans
- Door and window frames
- Weather stripping around doors
- Electrical outlets
- Switch plates
- Fireplace damper
- Attic hatches
- Mounted conditioners
- Where dryer vents pass through walls
- Electrical and gas service entrances
- Cables that extend outside
Make sure the weather stripping and caulking, especially around doors and windows, are applied properly. If you can rattle your windows or doors on their frames, it means they’re not properly fitted into the wall.
You can perform a simpler version of the blower door test on your own. Decrease the pressure inside your house to increase air infiltration through the gaps. You can achieve depressurization by doing the following steps:
- On a windy day, shut off all combustion appliances, such as stoves, furnaces, and water heaters.
- Close all exterior doors, windows, and fireplace flues.
- Turn on all exhaust fans that blow outside to suck the air out of the house.
- Pass a lighted incense stick around the common leakage spots. If the smoke is sucked out of the room, there’s a draft.
Once you’ve located the air gaps, it’s time to reseal them. Below is a rundown on best air-sealing practices for different areas of your house, from the attic and basement to the exterior.
Exterior Air Sealing
Siding panels, especially vinyl ones, expand and contract due to changes in temperature. That’s why you have to nail the cladding down with enough room for the panels to move accordingly. Otherwise, they’ll get warped.
Warped siding creates spaces between the panels where air and water can get in. Repair the damaged part immediately to seal these gaps. You don’t have to replace the entire siding system if the deformation is concentrated on one area. You can cut a small portion from a new, similar panel and patch it onto the affected part.
Another method is to replace individual siding planks if the damage is too big for the cut-and-patch technique. But a system replacement may be necessary when a large part of your wall cladding has been abused by time and temperature changes.
For the outside of your home, you also want to examine the exterior sheathing, or the nailing bed of the siding. If your house is slightly old, it probably uses solid board lumber for its sheathing. This material is prone to shrinkage and cracks, so be sure to check for air gaps. Caulking can easily seal these holes, reducing air infiltration.
Wall Air Sealing
Apart from the exterior of your house, the walls are also known to have tiny cracks that let air in and out.
When it comes to interior walls, your first line of defense against drafts is insulation. It helps maintain a pleasant temperature in your home by preventing the warmth from passing through the walls. Aside from reducing heat transfer, insulation seals up the spots where cool air can enter.
Insulation comes in a variety of options. Choose from loose fill, spray foam, batts, or rolls. Consult a professional to determine which type is most suitable for the structure and location of your house.
Strengthen your wall’s defense against air leakage further by installing foam gaskets behind all light switches and electrical outlets. These minimize the air flow between the indoors and outdoors, reducing the chances for leakage. Child-proof plug covers also perform the same function, keeping air from passing through unused outlets.
For wall air sealing, replace all windows that are more than 20 years old to increase their energy efficiency. Because they’re made of glass, windows absorb more heat during summer and lose more in winter than any other surface in your home. Installing storm windows further reinforces your home’s insulation and airtightness.
Attic Air Sealing
Another part of your house that’s prone to air leakage is the attic.
Warm, humid air rises naturally since it’s lighter than dry air. The airflow going up the attic and out the roof draws cold breeze into the openings at the lower part of the house. This phenomenon is referred to as “stack effect,” which is how drafts get into your home.
Prevent the consequences of the stack effect by insulating your attic. Blanket insulation comes in rolls or batts, so they’re easy to install by yourself. But this type only works for attics with evenly spaced beams and joists. The large space ensures that the batts of insulation fit the vents tightly for maximum efficiency.
If your attic has plenty of obstructions and very limited space, loose-fill insulation would be the better option. The loose material easily stuffs tight spaces, effectively insulating even the smallest nooks and crannies of your attic.
Meanwhile, spray foam insulation offers the most impenetrable protection from drafts. With foam cells that expand, this insulation creates a solid barrier against air leakage. But unlike blanket insulation, spray foam requires professional tools and gear. Hire an insulation technician to make sure that the foam is installed properly.
Basement Air Sealing
To fully safeguard your house from the stack effect, insulate your basement as well for further protection from drafts.
Your crawlspace has a close relationship with your attic, since the two spaces push air in and out of your house. You need to air-seal both the top and bottom parts of your home to eliminate the sources of airflow.
The rim joists, or the lateral support of your entire floor, normally has plenty of holes for wires, pipes, HVAC lines, vents, and other utilities. Block these openings by caulking them. Air-seal the rest of the rim joist cavities with spray foam insulation. The expandability of spray foam ensures that every crevice in the joists are well insulated.
For most parts of your house, insulation is the optimal solution to air leakage. But insulation systems depend on your home’s foundation, style of construction, and the local climate. An experienced insulation contractor will help you determine which air leakage solution is best for your home.
A+ Service from A+ Insulation
A+ Insulation is a trusted insulation expert in Kansas City. Our team of experts will examine your house to locate the air leakage, so we can arrive at the best solution. We use only quality materials and tools, guaranteeing the longevity of your insulation.
Schedule an appointment today and have one of our consultants do a free, no-obligation home energy assessment. Contact us here.