Wednesday, December 9th, 2020 by Brandon Newton
Wintertime is when most families turn up the heater and let the house get cozy. When the temperature drops outside are exactly when your home's insulation and airflow matter the most. A well-built home both holds in the heat and helps it circulate comfortably throughout the rooms in your house. However, not every house has been built (or maintained) with energy-efficiency in mind. If your house gets uncomfortably cold in the winter and the heater just can't keep up, heat is escaping through your attic by means of the “stack effect”. Fortunately, this problem can be fixed with a few repairs and improved insulation.
A cold house can also be an unexpected sign of mold growth. When hot air escapes through your attic, it carries moisture which nurtures mold spores. Mold especially likes to grow on moist wood, which could be your attic floors and beams. We're about to explain how hot air escapes, how to insulate your home, and what to do if escaping heat has created a mold colony in your attic.
In the winter there is a specific flow of heat and moisture through the home. Cold seeps in through the ground, windows, and ambient air temperature. It is more likely to enter through the lower portion of the house. Heat is generated in the center of your home and distributed through your ventilation system to push hot air into every occupied room.
Hot air naturally rises above cold air, and incoming cold air creates pressure that pushes the hot air up into the upper floors and/or your attic. Hot air also has a tendency to grab any moisture in the house and carry it upward with it. This is called the stack effect, which combines the natural flow of air with the home's internal air pressure created by seasonal temperatures.
As cold air falls and hot air rises, your lower floors may become frigid while the upper floor swelter - even with well-designed home ductwork.
Within the stack effect, hot air doesn't just rise - it is pushed. This pressure upward creates a motive for air to escape. Any cracks in the upper floors, between floors, or between the house and attic will create opportunities for your warm air to escape. In this all-too-common scenario, you now have cold air pushing into the house near the ground and hot air pushing out of the house through every crack and gap in the insulation that it can find.
This ultimately results in your home being uncomfortably cold in the winter and your furnace working double-time to try and keep up.
Everyone knows that moisture in the attic is a bad sign that could lead to mold or rot. Most don't realize that hot air escaping through the attic can also lead to mold and dry rot. The reason? Warm air picks up moisture as it rises, carrying your home's humidity in droplets. When the hot air forces its way up through the ceiling and cracks, everything passed by the air picks up that moisture.
Subtly, without a roof or plumbing leak, your attic beams and structural supports can become suffused with enough moisture to grow mold or begin to rot.
If your attic has been collecting moisture from rising hot air, it may also have been growing mold. A wooden attic filled with warm, moist air is the ideal nursery for a colony of mold. Mold is a fungus that exists - in various species - across the world. Every region and, therefore, every home contains a few natural mold spores drifting around looking for a place to grow. Most of the time, homes are dry and clean enough to discourage mold growth.
Mold's niche in nature is to break down dead trees, which is why it grows so often in homes made of wood and drywall. Mold grows best in warm, moist environments, making a heater-moistened attic ideal. Homes that have been leaking heat through poor attic insulation are also very likely to have a colony of attic mold.
Not sure if air pressure and attic design is the problem? The stack effect is easy to prove if your home is subject to this common problem - all you need is a pack of thermometer/hydrometers. Pick up a pack of temperature sensors - they almost always come with humidity detection as well. Place one in your living area, one in your attic, and one on the porch. If your attic is both warmer and more humid than all other home areas, then there are cracks or poor insulation allowing the stack effect to freeze the rest of your house. Any easier solution is to call and schedule a free attic efficiency inspection.
Mold in the attic is often apparent, covering a large section of beam, wall, or roof underlayment board. But it can also grow on the underside of floorboards and the backsides of walls. It may be difficult to inspect every surface of your attic, but you can still test for mold.
Mold is found using air samples - testing for the concentration of spores. With a few samples, you can determine if your attic has an elevated spore count and if a colony may be hidden behind moistened boards.
If your home is freezing and your attic is warm and humid, it's time to enact some solutions. There are three steps to solving the chilly house problem. The first is sealing all the cracks where hot air is escaping or where cold air is getting in. The second step is improving your home insulation so that temperature can't travel between the walls and the structure of the home. The final stage is to ensure that your ventilation and ductwork are in good repair (and well-designed) to provide even heating to a well-sealed home.
Air sealing starts with an inspection and study of where your home could be allowing pressurized air through. Minor repairs throughout the house can improve your home's total energy efficiency by sealing in air. This both prevents cold air from coming in from the bottom and prevents your heated air from escaping into the attic. You may want to re-floor the attic, sealing the space be
TruSoft Cellulose insulation is currently the top choice for improving your home's efficiency. With a higher R-value than fiberglass and made of recycled paper materials, TruSoft cellulose insulation is an easy choice. Blown-in cellulose goes in after air sealing which will significantly improve the insulating quality of your entire attic.
The final stage of comfortably sealing your home is ductwork. Inspect your duct for leaks that contributed to the heat leaks, then reconsider the duct design. You may need to re-balance air pressure in your ducts now that air is no longer escaping. You may also want to improve the attic's built-in ventilation as part of your overall home maintenance.
A home that leaks heat through the attic has a high chance of also growing mold. If you have found or recently repaired heat escaping through the attic, mold remediation may be on your list. TCI is here to help. Contact us today for more information on attic mold removal and inspection services.
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