The Reason Your New Windows Feel Drafty Is Convection, Not Heat Loss

Window convection is a natural heat transfer process that can make your home feel drafty, even with new windows. 

Window convection and heat loss are related but distinct concepts in how heat moves through windows. 

Here's a simple breakdown.

What Is Heat Loss?

Heat loss is the transfer of heat energy from inside a building to the outside environment through the window's components (glass, frames, or gaps). 

It occurs via four mechanisms: radiation, conduction, convection, and air leakage.

1. Conduction: Heat moves directly through materials like glass or frames.

2. Radiation: Heat radiates through the glass to the colder exterior.

3. Convection: Air movement between window panes transfers heat from the inner to outer glass.

4. Air Leakage: Heat escapes through gaps or poorly sealed areas around windows.

Impact of Heat Loss

Heat loss reduces indoor temperatures and increases energy costs as it involves heat leaving the home entirely.

What Is Window Convection?

Convection refers to the movement of air as it transfers heat. 

In the context of windows, it occurs when warm indoor air cools upon contact with a cold window surface, sinks, and is replaced by warmer air, creating a continuous cycle of air movement.

Why Does Window Convection Happen?

1. Hot air molecules near windows cool down when they come into contact with cold glass.

2. Cooled air falls, pushing warmer air upward.

3. This creates a continuous air circulation cycle.

This process happens entirely within the room and does not involve heat escaping to the outside. It creates a sensation of drafts but does not directly contribute to the total heat lost from the home.

Key Difference

While window convection describes air circulation within a room caused by temperature differences near windows, heat loss encompasses all processes by which heat escapes to the outside environment. 

Convection can contribute to heat loss when it occurs between panes of glass in multi-pane windows but is not synonymous with overall heat loss.

How Does Window Convection Impact Energy Efficiency?

Window convection impacts energy efficiency in homes by creating air currents that transfer heat, leading to increased energy consumption for heating and cooling. 

The impact of window convection on energy efficiency includes:

• Increased heating costs: In winter, convection currents near windows can make rooms feel drafty, causing homeowners to raise thermostat settings and use more energy for heating.

• Heat loss: Convection contributes to heat transfer from the inside to the outside of a home, accounting for a portion of the total heat loss through windows.

• Uneven temperature distribution: The air currents created by convection can lead to temperature inconsistencies within a room, potentially increasing reliance on heating and cooling systems.

• Perception of drafts: Even with airtight windows, convection can create a sensation of drafts, which may prompt occupants to increase heating unnecessarily.

How to Reduce Window Convection

So, now you know: When warm air inside your home touches a cold window surface, it cools down, drops to the ground, and creates a circular air movement. 

This isn't a window defect but a normal physical process. Still, it is an issue.

Fortunately, there are ways to prevent window convection to improve your home's comfort and energy efficiency.

Improve Air Circulation

• Ensure proper air circulation in rooms by unblocking vents and positioning furniture away from windows.

• Use ceiling fans and air purifiers.

Manage Window Coverings

• Use window coverings like insulating shades or curtains to create an additional barrier against convection currents.

• Slightly open blinds or curtains to help regulate the glass temperature and reduce the rate of convection.

Install Energy Efficient Windows

Install energy-efficient windows with multiple panes, low-E coatings, and insulating gas fills to reduce heat transfer.

Multiple-pane windows with insulating gas (like double or triple-pane windows) can help minimize convection by maintaining more consistent glass temperatures.

Contact Tony’s Lifetime Exteriors for Windows Near Sauk Rapids

Remember, window convection is normal and doesn't mean your windows are faulty or leaking heat. That said, you should work to minimize its impact. By addressing window convection, homeowners can significantly improve their home's energy efficiency, reduce heating and cooling costs, and create a more comfortable living environment.

Do you have a window issue we can help you with? 

Window condensation is another tricky, common problem we hear about this time of year. If you see condensation between the glass of your multi-pane windows, that might be a sign that their seal has been broken. 

However, as odd as this may sound, condensation on the inside of your windows often indicates they are simply working as they should.

We're ready to assist with all your window projects at Tony’s Lifetime Exteriors in Sauk Rapids, Minnesota! If your windows and doors have been damaged in a storm, or it’s time for replacements, choose our team to install the most energy-efficient and stylish window options. 

Our window products are also proven to hold up through the harshest weather conditions, because we know how important it is to conserve energy and save on bills! 

Enjoy quiet winter days in cozy comfort this season – Call our Sauk Rapids office now at 320-252-9086.