What Are Construction Thermal Bridges in Buildings?

Do you have a random “cold spot” in your dining room or perhaps in an area where a sweater is always needed, no matter how high the thermostat is set?  Thermal bridges may be at play.

If you don’t work in or around construction, you may have never heard the term “thermal bridging”–but you’ve likely felt its effects. In a nutshell, it’s the movement of heat across an object that is more conductive than the materials around it.

Thermal bridging not only causes a loss of heat within the space, it can also cause the warm air inside to cool down. As we approach the coldest season of the year, this means higher utility costs and potentially uncomfortable shifts in temperature inside your home or building.

Keep reading to find out exactly how thermal bridging works and what you can do to stop it:

What is thermal bridging?

When heat attempts to escape a room, it follows the path of least resistance. Likewise, the same process occurs during the summer, only in reverse, allowing heat to enter your otherwise cool building.

Thermal bridging happens when a more conductive material allows an easy pathway for heat flow–usually where there is a break in (or penetration of) the insulation. Some common locations include:

  • The junctions between the wall and the floor, roof, or doors and windows.
  • The junction between the building and the deck or patio
  • Penetrations in the building envelope to include pipes or cables
  • Wood, steel, or concrete envelope components such as foundations, studs, and joists
  • Recessed lighting
  • Window and door frames
  • Areas with gaps in insulation

Impacts and risks assumed due to thermal bridging

What does all of this mean for you? In addition to poor climate control, there are several other lesser-known (but still serious) effects caused by thermal bridging.

Thermal bridges can increase the risk of condensation on internal surfaces, and also cause condensation within the walls.  Both can lead to mold growth, which in turn can cause unpleasant odors, poor air quality, and most importantly long-term health problems. Additionally, unchecked condensation may eventually cause rot and structural damage.

Thermal Bridging in windows

Thermal bridging can have a significant effect on the energy efficiency of windows. The frames and spacers are the primary culprits.  Spacers are the, typically metal, “strip” that goes between and separates the glass on double and triple pane windows.  Different materials have different conductivity and impact the performance of the windows differently.  Condensation on a double pane window is generally due to the spacers.

With retrofit situations, knowing exactly how old a window is, as well as the component materials, can provide you with a general idea of its efficacy. Unfortunately, if your windows are rather dated or just poorly made, it is nearly impossible to add thermal breaks into an existing framing system.

Issues with roofs and foundations

By their very nature, roofs and foundations present a large number of challenges in terms of maintaining a thermal boundary. Drains, vents, and holes for pipes and wires (amongst other things) create unavoidable penetrations in the building envelope and insulation. Heat transfers from the building into the ground or from the building into the air are often inevitable, though they can be minimized.

Strategies and methods to reduce thermal bridges in buildings

Bottom line? In new construction, design it right which a whole topic in itself. With existing homes, if you suspect there is thermal bridging occurring in your space, you need to eliminate or reduce the effects as much as possible.

Proper planning, design, and construction can help remedy thermal bridges in new structures. However, if you live in an older home, there are still steps you could take. These strategies include:

  • Performing an energy audit to identify thermal bridges in your home
  • Installing double or triple pane windows with argon or krypton gas, better spacers and insulated frames
  • Updating and/or adding insulation to your home – ideally adding a continuous insulation layer.
  • Installing storm doors (especially if you have metal doors)
  • The ultimate remedy is to complete a deep energy retrofit that addresses everything and more than mentioned in this blog

Studies show that in an otherwise airtight and insulated home, thermal bridges can account for a heat loss of up to 30%. Whether you’re building a new home or retrofitting an existing structure, care should be taken to avoid unnecessary breaks or penetrations so that the possibility of thermal bridging decreases.

If you’re looking for ways to minimize thermal bridges in your next project or existing home, contact us today.

Fresh Air Ventilation & Monitoring

Fresh air is a commodity that everyone needs and wants. Who doesn’t like to breathe fresh air? Generally, the best source of fresh air is the outdoors. But since most of us don’t live outside, we can still supply fresh air to our homes by opening windows and doors. However, we all know it’s neither cost-efficient nor wise to leave our windows and doors open during the cold winter or hot summer.

Many older homes are leaky enough that fresh air enters through all tiny cracks and holes in the walls and around the windows and doors. With high-performance homes, the foundation is to build it air-tight and add ventilation. The catch phrase is, “build it tight and ventilate right.” But how exactly do we “ventilate right” in an airtight home when our objective is to keep cold air out in the winter and cool air in in the summer?

We must mechanically bring in fresh air. The Build Equinox CERV system does just that. The CERV recirculates air, brings fresh air in and removes stale air while offering both heat recovery and air filtration. Put simply, the CERV makes sure you have fresh, filtered air and keeps heat where it belongs, in or out based on the setting on the unit.

Designed with sensors to detect VOCs (Volatile Organic Compounds) and CO2, the CERV will “smell” the air and put itself into circulation or ventilation mode appropriately based on the sensor readings. The VOC and CO2 levels drive the demand of the unit based on the thresholds the owner programs on the unit.

A CERV returns air from rooms such as the baths, the kitchen and possibly other rooms that might have more “smells” or humidity such as workout rooms, laundry rooms, etc. It brings that air back to the unit to either simply filter/recirculate it or to replace it with fresh air from outdoors while exchanging the heat that is in the air.  In the winter, it keeps heat in and in the summer it reverses the process and keep heat out of the building.

One of the more unique features of the CERV is that it uses a heat-pump to move heat to the incoming or exiting air stream.  While it is not meant as a primary source of heating or cooling, the CERV actually provides a small amount of heating or cooling capacity.

Components of the CERV System:

Heat-Pump Module (A)
Module A of the unit heats, cools, dehumidifies and exchanges energy between incoming incoming(fresh) and exiting(stale) air streams, with no low temperature operation restriction.  Most H/ERV’s require some kind of anti-freeze function or capability.  This is not necessary with the CERV.

Fresh Air Control Module (B)
Module B of the CERV houses the electronics, integrated pollutant sensors (CO2, VOC, temperature and humidity) and damper, and this is where the CERV intelligently monitors air quality and activates fresh air ventilation. When fresh air is not needed, recirculation adds heating/cooling to unify comfort and indoor air quality. Also, the Fresh Air Control Module is fully insulated with no thermal bridges. It has a very user-friendly color touch screen controller with large print, easy to navigate control and status screens. The controller can also be placed anywhere in the house. In addition, it has an option to connect to the Internet, through the CERV-ICE Online Gateway, making it possible to control the system directly from a smart phone, tablet or computer.

Inline ECM Supply & Exhaust Fans

These are variable-speed ECM fans which balance air flow efficiently, supplying fresh air to the occupants and exhausting polluted air from house.

Inline Filter Boxes
These boxes remove air contaminants from incoming air to the home and are placed where fresh air enters. The CERV uses common filter sizes which can be purchased from several sources.

An important fact to consider in fresh air ventilation is the natural atmosphere CO2 (carbon dioxide) level of outdoor fresh air is 400 ppm (parts per million CO2). At more than 900ppm, a person’s mental performance, sleep quality, and productivity decreases. Currently, the indoor air quality ASHRAE standard for newly constructed homes is 1100ppm! If that is the standard, then we can clearly see why our air quality is a problem (source: https://ehp.niehs.nih.gov/1104789/). The good news is the current average indoor air quality level for homes in the CERV community is 686ppm.

Also note that some homes integrate various accessories that accomplish various objectives.  For example, booster switches can be added to bathrooms and kitchens to help evacuate humidity and pollutants from those spaces.  In addition, there are accessories that either help to pre-condition the air as it comes into the CERV from outside or to heat the air after it leaves the CERV.  Please contact us for more information on these accessories.

In summary, as part of the high-performance home or any home for that matter, the Build Equinox CERV system makes good sense:

  1. Fresh, clean air for the family
  2. Recovers heat/doesn’t lose it
  3. Provides health benefits of reduced CO2 levels (improved brain function, sleep quality and productivity), lowered pollutant/contaminant levels of things we bring into our home (i.e. off-gassing of new items we purchase, paint fumes, as well as pollutants created within the home, such as cooking odors, bathroom and laundry room odors or pet odors).

If fresher, cleaner air in our homes is the goal, then a Build Equinox CERV home makes next-to-outdoor fresh air in a home quite achievable.

For more information about the Build Equinox CERV, call us at 720.287.4290 or visit our website https://aebuildingsystems.com/product/build-equinox-cerv/.

Source: buildequinox.com