Yes, a house can be too airtight if it lacks proper mechanical ventilation, leading to poor indoor air quality, condensation, mold, and build-up of pollutants like CO2 from occupants and VOCs from materials. The goal is "seal tight, ventilate right," meaning a tightly sealed building envelope needs controlled ventilation (like Heat Recovery Ventilators/HRVs or Energy Recovery Ventilators/ERVs) to bring in fresh, filtered air and exhaust stale air, ensuring health and comfort without energy loss.
Your top concern is whether a house can be sealed too tightly, which could impact air quality and humidity. While very rare, this can happen when the home's building envelope is air sealed with foam insulation.
Mechanical ventilation. Mechanical ventilation generally uses fans to introduce air from the outside and distribute it in the building. Examples of mechanical ventilation systems include exhaust air ventilation, positive pressure air replacement and mechanical ventilation heat recovery systems.
How to tell if your house is poorly insulated
High humidity in a house can be caused by many things, but the biggest reason is poor ventilation—in other words, air isn't being circulated properly, which causes the air in your house to become stagnant and humid. The other major reason? Too much air exchange with the outside.
Symptoms of excess home moisture include window condensation, mildew, mold, peeling paint and excessive dust mites. To control a moisture problem, first identify the source and remove it. If not possible, use ventilation or a dehumidifier.
Opening windows promotes more airflow, which enhances ventilation inside the building. This guides in eliminating sticky, humid air and supplanting it with drier external air. Ventilation is essential in regions like kitchens, showers, pantries, and other rooms where dampness is delivered.
Common symptoms may include irritated, itchy, watery, or burning sensation of the eyes, nose, or throat, or itchy skin or skin rashes. Occasionally, some people report breathing difficulties, especially if they are asthmatic or have other breathing disorders.
Here are the top 7 ways to tell if your home is under-insulated:
Old insulation materials can become more flammable over time. By removing outdated insulation, you reduce the potential for fire hazards, creating a safer home environment. If the old insulation was installed incorrectly, it might have gaps or compressed areas that reduce its effectiveness.
5 Signs Your Home Needs Better Ventilation
The Three Degree Rule states that a cargo hold should be ventilated when the dry bulb temperature of the outside air is at least 3°C lower than the temperature of the cargo.
Checklist for Protecting Your Vacation Home
Does your place have one of the 7 symptoms of an unhealthy home?
In homes with poor ventilation, it can be difficult to maintain a comfortable temperature. With insufficient ventilation, warm air lingers in summer, which can lead to overheating and the need for more cooling. In winter, a lack of ventilation can allow cold air to enter, requiring more heating.
High humidity can cause problems in your home if relative humidity regularly exceeds 60%. When the air contains water vapor above that level, mold and mildew start to grow, while excess moisture can cause rot, damaging your belongings.
Cold or Hot Walls, Floors, and Ceilings
Take a moment to touch your walls, floors, or ceilings. If they feel cold during winter or hot during summer, this is a strong indication that your insulation is insufficient.
Cold exterior walls are a telltale sign of poor insulation, as they indicate that heat is escaping from inside your home. External wall insulation adds an extra layer of insulation to your exterior walls, preventing heat loss and keeping your home warmer and more comfortable.
Without insulation, your home struggles to retain warmth in winter and cool air in summer. This forces your heating and cooling systems to work overtime, leading to higher energy consumption and hefty utility bills. An uninsulated home has little to no defence against outdoor temperature fluctuations.
Fiberglass isn't the worst thing you could be inhaling, but it's certainly not benign. According to multiple states' health departments, inhaling fiberglass can cause coughing, wheezing, and itching. The fibers can also exacerbate existing bronchitis or asthma, cause a sore nose or throat, and irritate the eyes.
Unlike asbestos, fiberglass and rock wool insulation have been determined to be not permanently harmful because the macrophages in the lungs are able to break them down and carry them away within about 10 days. Yes, people with sensitive lungs can be bothered and they should limit contact.
No, fiberglass insulation should never be left uncovered. Why? Health Hazards: Exposed fiberglass can release fine particles and fibers into the air, which can cause respiratory irritation, skin rashes, and eye irritation. Long-term exposure can lead to more serious health problems.
Use exhaust fans in bathrooms and kitchens to remove moisture to the outside (not into the attic). Vent your clothes dryer to the outside. Turn off certain appliances (such as humidifiers or kerosene heaters) if you notice moisture on windows and other surfaces.
"Lüften works simply by manually opening your windows either in the morning or in the evening to release an excess build up of carbon dioxide, mold, bacteria, allergens or condensation, while also allowing oxygen back into the interior environment," Riddei says.
Don't try to offset the problem with heavy curtains or nets as these can keep the glass cooler and increase condensation. If you have mould or damp as a result of the condensation, invest in a good mould and mildew spray to help combat the problem and reduce the threat of lasting damage.