Home Comfort Issues: Potential Causes & Solutions
Many residents whose homes we visit describe specific comfort issues in one or more localized areas of their home. This article seeks to synthesize some of the more common comfort issue causes we witness in the field so that if your home has comfort issues you may begin to think through possible solutions. As building scientists we seek to assist in identifying possible causes and recommend long term solutions for a more comfortable home and increased energy efficiency.
First, consider the difference between localized comfort issues and whole home comfort issues. For example, a specific room of the home may experience consistent and noticeable discomfort compared to the rest of the home. Another example would be a large space (such as a combined living room, kitchen and dining room) but with a corner of the space noticeably less comfortable. In this article we are going to focus on localized comfort issues. If you have whole home comfort issues then you may consider referring to a professional HVAC contractor.
Once a localized comfort issue is identified consider the following:
- Does the space struggle with heating, cooling or both? This is an important first step in attempting to identify potential causes of discomfort.
- What is the current season? Summer, winter or shoulder (spring or fall) season? Depending on whether the comfort is related specifically to heating or cooling it may be difficult to conduct proper and thorough evaluations based on the current season.
With these factors in mind, we begin identifying possible causes and solutions.
Inadequate supply air:
1) Leaky or disconnected ductwork (How strongly is air blowing out of supply vents?)
2) Inadequate supply ducting to space
1) If you suspect that your ductwork is leaky or worse disconnected somewhere, we recommend consulting a professional HVAC contractor at your earliest convenience. Loss of air to unconditioned space (i.e. attic, wall cavities or crawlspace) puts additional strain on heating and air appliances and may cause discomfort. The best way to seal ductwork is using mastic, a robust and long lasting putty-like material.
2) You may consider utilizing dampers off the supply plenum in order to better re-distribute and increase supply air to the space. If dampers are not an option for you, another consideration would be adding an additional supply duct to the space.
Inadequate sized ductwork
You may consider an evaluation of whether replacing undersized duct runs is a good option for you. As previously mentioned, other considerations would be additional supply ducts to the space in concern or duct damper adjustments.
Supply air is an appropriate temperature compared to other supply air in home
During summer seasons, warm supply air may indicate a lack of ductwork insulation. Another possible cause is inadequately sealed ductwork. Please consult a professional HVAC contractor at your earliest convenience.
Improperly designed supply plenum
An improperly designed supply plenum can lead to an imbalance of pressure as air is “pushed” through supply ducting throughout the home. Air, like water, tends to follow the path of least resistance. If a plenum is not designed so that air distributes evenly throughout the home you may experience comfort issues. If you suspect that this may be a problem, consider adding ducting dampers at the supply plenum in order to more evenly distribute air throughout the home.
Insufficient return air
When a home lacks sufficient return air capacity or return air pathways an imbalance of pressure within the home occurs. The results of pressure imbalances tend to lead to discomfort, poor air quality and sometimes humidity issues.
One solution is to install jumper ducts so that air has an open pathway to the return vent when room doors are closed. Another solution is additional return ducting. Please consider consulting a professional HVAC contractor and ensure that a proper load calculation using ACCA software is used. This will help ensure that your home has the proper amount and distribution of air.
Inadequate structural insulation
Please consider the space in concern regarding insulation. Are the walls, floor and ceiling insulation levels adequate? Inadequate insulation levels can lead to discomfort. Generally speaking the more insulation you have the greater your thermal barrier and the longer it will take for extreme temperatures to adversely affect conditioned spaces. How many sides of the space or exterior? Remember to consider that garages are considered exterior and unconditioned spaces so any space buttressing the garage would be considered an exterior wall. The more exterior walls a space has the greater the possibility that the space will experience difficulty maintaining similar comfort levels compared to the rest of the home.
Although walls can be very difficult to insulate after a home is built, you may consider whether to add insulation to the crawlspace or attic. We recommend crawlspaces be insulated to R-13 on the underside of the floor and ceilings be insulated to R-38.
Improper knee wall construction
Proper knee walls construction is always a difficult topic to wrap one’s mind around. A knee wall is a vertical wall with conditioned space on one side and unconditioned (attic) space on the other side. A common example of a room with knee walls that may struggle with comfort is a room above a garage. Here is great article describing best practices for insulating and treating knee walls that may help with comfort issues.
Learn more by reading this article.
Windows receive several hours or more of sunlight each day (summer only)
Another consideration is the effect of windows on a given space. We rarely recommend window replacement, however for some homes solar screens may have a positive effect. Solar screens are made to reduce heat gain on a home during hot months so are therefore best for windows that receive several or more hours of sunlight each day. During cold months, however, we want to take advantage of solar heat gain on the home. If you have solar screens please consider removing and storing them during colder months. If considering solar screens consider installation very carefully. In order to make seasonal transitions as easy as possible, consider rotating clips to secure the screen to the exterior frame rather than screwing the solar screen directly to the frame. As the season changes and warmer months return simply reinstall your solar screens.
Improper utilization of solar screens (winter only)
We often see solar screens being utilized less than optimally. Specifically during cold months of the year we see many solar screens have not been removed. Solar screens are made to reduce heat gain on a home during hot months so are therefore best for windows that receive several or more hours of sunlight each day. During cold months, however, we want to take advantage of solar heat gain on the home. If you have solar screens please consider removing and storing them during colder months.
Where is the thermostat location relative to the uncomfortable space?
Sometimes a thermostat is not placed in the most ideal location and fails to evenly regulate temperatures throughout the home. Depending on your home, this can be a somewhat challenging issue to resolve. In short, please consult a professional HVAC contractor and possibly an electrician about the cost versus benefit of moving your thermostat. If your home is equipped with a zone HVAC system or multiple HVAC systems, a thermostat issue can sometimes be resolved by simply adjusting temperature settings to offset adverse effects.
Has a load calculation been conducted on the home?
Many homes have never had a proper load calculation conducted using ACCA software. A load calculation is meant to evaluate how much air a home needs and how best to distribute that air throughout the home. The load calculation also tells us what size heating and air appliances are needed for the home. If you suspect a load calculation has never been conducted on your home or was perhaps not conducted properly please consider consulting a professional HVAC contractor to ensure your heating and air appliances are properly sized and that air is being evenly distributed throughout the home.
Feeling of Discomfort
Different than an actual temperature difference we may experience the “feeling” of being warmer or cooler than actual temperatures. For example, 100 degrees in Arizona doesn’t “feel” as bad as 100 degrees in Georgia because Arizona is a more dry climate with lower humidity levels than Georgia. When considering an uncomfortable space in your home, ask yourself whether the space “feels” warmer or cooler. If actual temperature differences between the space and the rest of the home are different, please refer to the list above, if however temperatures are relatively even throughout the home, but the uncomfortable space “feels” warmer or cooler, then please consider the following.
Improper humidity levels
Humidity control is one of the most difficult aspects of building science. While we address several specific aspects of humidity control here, we thought it best to share some of our favorite resources on humidity control. Please see these links for further information regarding humidity control.
“The Four Factors of Comfort” by Energy Vanguard
“Relative Humidity” by the Building Science Corporation
“Moisture Sources, Relative Humidity and Mold” by Green Building Advisor
While not common, water buildup will naturally cause higher humidity. Please consider ensuring that water pipes are not leaking, roofs are not leaking and that water is not seeping under the home (if you have a crawlspace).
Over-sized AC unit
One of the jobs of an Air Condenser (the outside unit) is to assist in removing moisture from the home during times when cooling the home. If a home has an oversized unit, it may tend to “short cycle”; a process of running for very short periods of time because it is able to cool the home very quickly. The downside of short run times is that not enough time is provided to remove moisture from the home. Generally, humidity levels between 40 and 60 percent will provide optimal comfort.
Please consider that these are not exhaustive lists. When in doubt or for technical questions please consult a professional HVAC contractor or consider having a professional energy auditor examine your home.
We hope you found this article helpful. If you have any questions, comments or concerns please feel free to use our contact form here or reach out to firstname.lastname@example.org.
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