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How the Stack Effect Raises Your Energy Bills

Of all the things that can seriously impact and damage your home, the stack effect is one of the least commonly discussed by professionals and homeowners alike. This may be because of the relatively invisible nature of the issue, but being hard to spot doesn’t make it any less dangerous. In fact, the stack effect is one of the most dangerous issues a property can deal with because it impacts every area of a home. 

Homes dealing with the stack effect are more likely to suffer from dampness, humidity, and all of the many issues that are commonly connected to them. As such, it is advisable for homeowners to know what the stack effect is, what causes it, how it affects a property and the problem signs that are likely to show themselves. If you want to protect your Grand Junction, Colorado, home from the stack effect this is what you need to know. 

stack effect

What Is the Stack Effect? 

Sometimes called the chimney effect, the stack effect is essentially a phenomenon that drives airflow through a property at an accelerated rate. By impacting the rate and speed of airflow, as well as creating channels of moving air in a property, the stack effect impacts every part of a home. This is caused by thermal differences in the air inside and outside of your property but requires corresponding ventilation points in order to take effect. 

A property that is dealing with the stack effect will find that airflow works in one of two ways and will either bring in cold air from the bottom of the property or pull in warm air from the top of the property, depending on the season and how you are using your HVAC system. Whether the stack effect is making your home colder or warmer, however, it poses a risk to every part of your property. 

How the Stack Effect Works 

In order to take effect, the stack effect requires ventilation points at both the lowest and highest levels of a property. It is reliant on how thermal changes impact the air in a property. The ideal is for a property to exist at a neutral pressure level (NPL). This means that the air pressure inside the property is the same as the pressure outside. When this happens, the climate in your home will be stable and airflow will be minimized, allowing for consistent heating and cooling. 

The stack effect disrupts this by allowing artificially heated or cooled air to escape a property and draw in air from outside the home. This impacts your energy efficiency and HVAC system, but can also cause dampness, spread germs and bacteria, and generally make your home unhealthy and uncomfortable. As such, it is best to deal with the stack effect as soon as you notice it.  

What Can Cause the Stack Effect? 

While the stack effect requires corresponding ventilation points in a home, the actual causes can vary. After all, not all ventilation points are installed intentionally. Any gap in the structure of your property can allow enough airflow to create a stack or chimney effect. In most Grand Junction, Colorado, homes the cause is uncovered crawl space vents. 

What You Need To Know About Open Vents 

Crawl space vents were installed in properties across the U.S. between the 1950s and 1990s because they were believed to increase airflow and prevent dampness and humidity in a property. They do increase airflow (they cause the stack effect, after all), but this was later found to be actively damaging to a home. As such, vent covers are commonly found in properties that previously had exposed crawl space vents. 

Simply covering your vents is not a good idea. Vent covers are best installed as a part of a wider process of waterproofing and insulation, as this will deal with the issues that the stack effect can cause. If you have an external access point that is generally unsealed, you can also get crawl space doors that allow access while sealing the space properly. 

Structural Damage and the Stack Effect 

While the stack effect is caused by unsealed vents in the vast majority of cases, there is a possibility that the increase in airflow is being caused by structural damage or weaknesses of some kind. After all, all the stack effect requires is a gap big enough to allow significant airflow. This can be caused by many different issues in a home. 

For example, movement in the structure of your home can lead to gaps between your floors and walls or cause large cracks to open up. This can allow increased airflow. Likewise, damage to the sealant around utility inlets and window frames can contribute to the formation of the conditions needed for the stack effect in a home. 

Why Worry About the Stack Effect? 

So what’s the real issue with the stack effect? The main side effect of this issue is a change in airflow, after all. This may not seem like a big issue, but it could actually be the cause of a lot of damage and grief in your home when allowed to percolate. Here are some of the issues that can arise as a result of the stack effect: 

Lower Energy Efficiency 

One of the most subtle and frustrating issues connected to the stack effect is a general reduction in energy efficiency as a result of increased humidity and lowered stability. This makes your HVAC system, in particular, work harder to produce the same results and will cause increased wear and tear as well as higher energy usage. 

Higher energy consumption means that your energy bill will start to rise over time. In fact, the issue can lead to quite a sharp increase in your costs. 

Increased Humidity 

One of the main side effects of the stack effect in a home is an increase in humidity in a property. This happens because of how air reacts to thermal changes. When your HVAC system heats the air in your home, it rises. This leads to it exiting the home and drawing in cold air from outside. Likewise, when your HVAC is cooling air in your home, it will sink and draw in warm air from above. 

This leads to condensation as the cold and warm air clash and moisture is displaced, gathering on cool surfaces. This creates a generally damp atmosphere and can contribute to the formation of mold and the spread of wood rot. Finally, while this may not seem like a big issue, humidity is incredibly uncomfortable for many people and will make your home less pleasant to be in. 

Mold and Mildew Formation 

Mold and mildew go hand in hand with the stack effect in many cases. That’s because of how it brings moisture and spores into a property that would otherwise be sealed. Fungal spores of all kinds really only need organic material and moisture to thrive, and once they take root, they will spread with alarming speed. 

Most forms of mold are not harmful to wood, but some can be incredibly toxic to people and animals. Black mold is the most seriously toxic and can cause skin and eye irritation, respiratory infections, migraines, and even seizures. Wood rot fungi, by contrast, are generally not toxic to people but will cause serious damage to the wooden surfaces in a home. 

Airborne Allergen Invasion 

A slightly less severe issue than fungal growth, the incursion of airborne allergens into a home that is being impacted by the stack effect nonetheless makes the interior climate uncomfortable for anyone with allergies. For those with hay fever and seasonal allergies, living in a property that is dealing with the stack effect can be hellish. 

For those who have compromised immune systems, however, this is more of an issue. Even when mold and mildew aren’t present, the increase in allergens and airborne germs may lead to people in these homes becoming sick more often. As such, it is best to act quickly and deal with the stack effect when it first presents itself. 

Fluctuating Interior Temperatures 

Finally, the stack effect in a property will lead to fluctuating temperatures and a generally unstable climate. This happens because the artificially heated or cooled air is continually being pulled or pushed from a home by the stack effect and being replaced by air from outside. This means that your HVAC system will be unable to create consistent temperatures. 

This is especially concerning in winter. The Colorado winters can be fairly harsh, and the frequent fluctuations in temperature can cause illness in those who are vulnerable, as well as general discomfort for everyone else on a property. The most worrying possible outcome of this, however, is that the cold in your crawl space suddenly reaches a breaking point and causes a snap freeze in your pipes. This will cause some pipes to burst and lead to a plumbing flood. 

Each of these issues can cause more problems of its own. This will create a wide net of issues throughout your home and lead to serious deterioration within your home. Learning to spot the problem signs of damage is all-important to preventing ongoing issues in your home. 

Problem Signs To Look For 

Spotting the stack effect is very tough if you do not know what you are looking for, but the issues it can cause are generally less subtle. Here’s what you should be looking out for in your home: 

  • Drafts 
  • Slamming doors 
  • Condensation 
  • Sudden temperature changes 
  • Mold formation 
  • Wood rot 

If you see any of these issues, or you see more than one in conjunction, please reach out to a professional to make sure that you are aware of all the issues that could be at work in your home. Acting quickly could save you a lot of time and money. 

Stack Effect


Yes. You can put a stop to the stack effect in your home and prevent it from impacting your property in the future. It’s all a matter of waterproofing, encapsulation, and proper and regular maintenance within your crawl space and property as a whole. The stack effect may be common, but it is not inevitable. 

Waterproofing and Encapsulation 

Crawl space encapsulation and waterproofing are the most reliable ways in which to prevent the stack effect (as well as a number of other issues) from damaging your home as a whole. Covering exposed vents is a large part of this process, but there is a lot more to it. As such, there are many different benefits to undertaking this process. Better still, this is not a hugely lengthy or invasive process; crawl space encapsulation can generally be undertaken in a day or less. 

The benefits of waterproofing and encapsulation go far beyond the prevention of the stack effect. Homes with fully encapsulated crawl spaces are less at risk of dampness, mold formation, and pest infestation. They also enjoy generally higher levels of heat and cold retention and will be more energy efficient as a result. Encapsulated crawl spaces can even be used for seasonal storage. 


Once waterproofing and encapsulation have been undertaken, maintaining the products and appliances that were used will be key to preventing a recurrence of the stack effect and its associated issues. A robust and regular maintenance schedule will ensure the benefits of your crawl space encapsulation process last. After all, while most insulation will last indefinitely, sump pumps have a life span of roughly eight to 12 years. 

As such, you should make seasonal inspections of your crawl space, drains, sump pump, and dehumidifier to look for signs of damage. Likewise, booking a maintenance appointment for your appliances on a seasonal basis will ensure that small issues are rectified quickly before they can snowball into larger ones. This will save you time, money, and stress in the long term. 

There can be cases in which the stack effect is a minor issue or has a negligible impact, but it can never really be classed as benign or positive. This is a fundamentally disruptive process that will cause deterioration throughout your home if you let it. 

Cumulative Damage 

The stack effect is a subtle issue that does not always seem to be a problem until it is too late. The damage that it does to a property is cumulative and grows exponentially past a certain point. For example, the stack effect causes condensation. This alone is not a huge issue, but condensation increases humidity and creates dampness. This can allow mold and wood rot fungi to flourish. 

By the time mold has formed or wood rot has taken root, the damage is likely to have spread to other parts of a home. If left to grow unchecked, these issues can cause health problems and even lead to structural collapse in and around an affected property. So as you can see, acting quickly is key when it comes to the stack effect. Time really is money when it comes to these kinds of issues. 

Health Concerns 

Structural damage is a concern for any homeowner, but the stack effect can have far more concerning implications for your health. A home dealing with the stack effect is more likely to deal with airborne allergens, bacteria, and a generally unstable or unpleasant climate. For those who are healthy, this is not necessarily a big issue. However, there are those who are more vulnerable to consider. 

People who have underlying health conditions that impact their immune system, those undergoing intensive cancer treatments, and those with respiratory issues like emphysema and bronchitis are all at a higher risk of infection and illness in a home that is dealing with the stack effect. This can cause minor discomfort and illness but can also cause serious reactions and even lead to hospitalization (especially if there is black mold in a home). 

While we understand the temptation of using DIY to save money and time, we recommend that you do not try to undertake waterproofing and encapsulation alone. If you try to go it alone, you could cause more damage or run into issues you are not equipped to handle. 

The Dangers of DIY 

There are many different issues with DIY when it comes to waterproofing, but the most pressing is the fact that your crawl space must be in good health before you can begin. This may seem like a small thing to ask for, but many crawl spaces that have been exposed for a number of years have hidden issues and structural damages that are complex and hard to repair without professional training and tools. The most serious example of this is foundation damage. 

If you try to deal with serious structural damage alone, you could end up causing more damage to your home or even cause injury to yourself and anyone helping you. This is partly because of the instability of damaged structures and the likelihood of collapse should you put pressure on the wrong part of a damaged surface, but also because of the nature of the equipment. Issues like foundation damage often need heavy excavation equipment, as well as specialist tools that most homeowners simply will not know how to use. 

Professionals Get Results 

As well as being trained to deal with all of the underlying issues that can be found in any crawl space, professionals have the tools and equipment that they need on hand already. This actually brings the cost down, as you will have to hire these tools if you try to go it alone. This experience is what enables professionals to work quickly and effectively in cramped conditions that the average crawl space offers. They are also able to get the best waterproofing products from professional supply stores or even direct from the manufacturer. Finally, hiring a professional offers a level of convenience and confidence that DIY repairs simply cannot. 

Call Foundation Repair of Western Colorado for Crawl Space Repair & Encapsulation

If you have uncovered crawl space vents or damage to your home that you think may be contributing to the presence of a stack effect in your property, please reach out to Foundation Repair of Western Colorado immediately. Our team has years of collective experience and has been helping homeowners in this area since 2005. You can rely on us to know just what to do, no matter how complex the situation is. 

All you need to do in order to start the repair process is book a free inspection appointment online or by calling directly. Our team will arrange an appointment for a time and date that suits you. Once they arrive, they will assess your home for signs of dampness and damage and provide you with a written estimate for the cost of their suggested solutions. This is provided to ensure that you have all the information that you need to make an informed decision about what is best for your home. 

Michael Wilcher

Michael Wilcher

Michael Wilcher is the Content Lead at Groundworks, helping us to answer all of our customers biggest questions about foundation repair, basement waterproofing, crawl space encapsulation, and concrete lifting. In his free time, Michael enjoys collecting vinyl records, watching Formula 1 Racing, and reading philosophy. He holds an MPhil from the University of Cambridge.

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