It is generally not recommended to keep your attic door open unless your entire home is naturally ventilated and not air-conditioned. Even in those instances, it may be better to simply open the windows on either side of the attic and keep the door closed.
Yes! Pulling air in through the windows and out through the attic cools the attic space. It also creates a breeze across your skin which evaporates moisture on your skin making for a noticeably cooler indoors. They are especially effective at night when the outside temperature is lower than the inside.
Proper ventilation in your attic helps address excess heat and moisture that can otherwise wreak havoc on your home. Heat and moisture buildup in an attic cause predictable but different problems in hot and cold climates; areas with hot summers and cold winters can suffer the effects of both.
Humidity and Moisture Issues: Warm air can carry moisture, which may lead to higher humidity levels in the living spaces below. This can promote mold growth and damage to insulation, wood, and other materials. Pest Intrusion: An open attic door can provide easy access for pests such as rodents, insects, and birds.
Note excessive heat – if it's 90 degrees outside, the attic temperature shouldn't be more than 110 degrees. More often than not, attic temperatures will be in excess of 125 degrees on a 90 degree day. This will overwork your air conditioning equipment, run up your utility bill and shorten the life of your roof.
On a 100-degree day, an attic can reach temperatures of 170 degrees or more due to the radiant heat effect.
If it's 90 degrees outside, most people would set their AC to a perfectly comfortable temperature of 68-72°F.
The ideal attic temperature should be no less than 60 degrees in the winter and no more than 10 to 20 degrees above the outdoor temperature in the summer. If your attic temperature climbs above 130 degrees, you may start running into issues with your energy bill, as well as the integrity of your roof.
During hot weather, keep interior doors open to help your air conditioner circulate cool air more effectively. Closed doors can trap heat in certain rooms, forcing your AC to work harder to maintain a consistent temperature throughout your home.
Boost Property Value
Converting your attic can also increase the value of your home. An attic turned into a functional room adds to your home's overall square footage, making it more appealing to potential buyers. This can be a wise investment if you plan to sell your home in the future.
Why are attic fans not used anymore? Due to inefficiencies in relying on existing attic vents for air intake, attic fans have lost popularity. These vents often aren't designed for this purpose, resulting in inadequate replacement air supply.
The primary function of attic fans is to promote airflow within the attic, which can help reduce temperature and moisture levels and provide several valuable benefits.
Exhaust vents are best positioned near the ridge or peak of the roof, where hot air can easily escape. This placement leverages the natural flow of hot air rising to create a continuous airflow, which reduces the workload on cooling systems and improves energy efficiency.
By improving ventilation in your home's attic, installing an attic fan can help reduce moisture and even lower the temperature within your entire house.
Opening the loft hatch can allow the air to rise further and away from the bedroom. "If you're able to invest, installing extra insulation in your home will help keep heat out in the summer as well as reduce your energy bills and usage in the winter," says Joanna O'Loan, from the Energy Saving Trust.
The Problem with an Overheated Attic
The hotter your attic is, the harder it is to cool the rest of your living space. And, not surprisingly, the colder your attic is, the harder it will be to heat your living space. An HVAC system housed in the attic has to work extra hard to compensate for extra toasty conditions.
Slow Down the Spread of House Fires
Sleeping with your bedroom door closed is a practice that significantly improves your chances of surviving a house fire. According to the FSRI, closing your door can greatly decrease carbon monoxide levels from 10,000 PPM to 1,000 PPM when compared to leaving it open.
Obviously on a hot summer day, the outside air will take lots more energy to cool than already-conditioned inside air would. This again means that you'll be wasting energy. To maximize the efficiency of your HVAC system as well as your comfort, don't close off unused rooms.
The thought process goes like this: Your air conditioner uses up energy to cool your home, so by closing off a room to the rest of your house, your system will have a smaller amount of space to keep cool. This will give your air conditioner less work to do, which will lower your energy bills.
Essentially, if you have one, yes it's worth opening. It's often recommended you crack open the hatch when it's too hot outside.
If your attic temperature is consistently hitting 130 degrees or hotter, damage to your home and a high utility bill is very likely. You can keep a thermometer in your attic to check – it doesn't have to be an expensive one and will give you a better idea of how hot things really are.
During heat waves, experts, including utility companies, recommend keeping your thermostat no more than 20 degrees cooler than the outdoor temperature. For instance, if it's 100 degrees outside, aim to set your thermostat to at least 80 degrees.
Your AC might not cool properly due to thermostat issues, an undersized unit, or extremely high outdoor temps—so check those first. Keep an eye on airflow—replace clogged filters every 3 months, and make sure vents and ducts aren't blocked for efficient cooling.
How often should AC run on a 90-degree day? On a 90-degree day, your AC system might need to run more frequently to maintain a comfortable indoor temperature. Typically, an AC unit should run for about 15-20 minutes per cycle.