How to Stop the Stack Effect from Sending Warm Air Over Your Roof

Stack EffectThe furnace is responsible for heating your indoor space, but as the homeowner you also have a role to play to keep that warm air inside. If you don’t do this, then you are losing out on the heating benefits and ultimately you will pay the price in utility bills.

Multistory homes face a challenge when trying to keep the warm air indoor and this is because of the stack effect.

Understanding the Stack Effect

While skyscrapers have been seen to be among the most vulnerable when it comes to the stack effect, two story homes also face a similar challenge. Basically, the stack effect is a condition where the house acts like a giant chimney which funnels warm air up towards the roof until it leaves the structure altogether.

This effect takes place when the outdoor temperature is significantly lower than that of the indoors. Because of the fact that cold air is denser than warm air, cold air enters the home at the ground level and pushes the warm air up. This movement creates an airflow which results in more cold air being pulled in and drafts intensified. Taller structures tend to experience much stronger air flows.

This is the reason why revolving doors were developed immediately after the first skyscrapers. The suction force at the ground level was exceptionally strong especially during winter that people would literally struggle to pull the doors open.

The Stack Effect Problem

Obviously, the stack effect makes you lose treated air and thereby wasting energy and incurring lots of heating expenses. In addition, the stack effect problem tends to worsen overtime.

Stronger airflows put lots of pressure on fine cracks, cracking weather stripping, crumbling masonry, and other vulnerable areas where drafts barely get through. When this pressure is sustained, the gaps widen and expand thereby intensifying the airflow leading to an accelerated energy loss.

What You Should Do

The single most valuable and effective solution to the stack effect is insulation. The reason you have the stack effect is because warm air manages to escape once it reaches the highest level or floor of your house. In most cases, the escape happens through leaky air ducts, cracked ceiling, recessed light fixtures, or even insufficiently insulated attic floors. Once the warm air gets to the attic, it finds spaces through which it can escape to the outdoors.

It is therefore important to seal drafts and maintain insulation in every space all over your home. The barrier between your top floor and the attic is a critical area you should consider in your fight with the stack effect. Where insulation has degraded or there are certain air leaks you probably can’t locate, you can contact  a local HVAC professional or a climate control specialist to help you.


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