Houses are being built tighter and tighter to provide cost savings on heating and cooling. This in turn has increased the need for more effective ventilation. Quality ventilation however, comes at a cost. How can you manage these costs and appeal to homebuyers’ budgets?
Tight homes, an air quality challenge
Proper air quality can be a challenge in tightly sealed homes. In such a sealed environment, moisture buildup can lead to condensation, which in turn can be a source of mold.
This wasn’t so much a problem in earlier homes, which naturally allowed a freer exchange of inside and outside air, evacuating contaminants.
The ASHRAE standard
But with the advent of vapour barriers, urethane insulation and high performance windows, Indoor air quality (IAQ) had to be addressed. The American Society of Heating, Refrigerating and Air-Conditioning have issued a standard called ASHRAE 62.2, which defines residential ventilation standards, applicable to new or existing homes.
Under this code there are three types of acceptable ventilation systems:
This type of system simply sucks air and its contaminants out of the house. Fresh air then gets brought in through passive intakes, or air leaks naturally occurring in the home. This type ventilation is good for existing homes but not recommended for new home construction.
2. Supply system
This system sucks air out but also brings fresh air in through a dedicated duct, connected to the return-air plenum of the house’s HVAC unit
3. Balanced air system
An ideal system for new houses, this system not only pulls air out and in, it also conserves energy through a heat exchanger. This allows maximum control over the air quality and maximum savings.
The balanced air system requires more ducting and more labor. The most effective way you can offset these costs is by using a floor system that won’t get in the way of your installers or their installations. Open joists do away with complicated drilling, and allow much more freedom in the choice paths for ducts, essential when installing these more complex ventilation systems.
A detail of a balanced air system. The use of open joist Triforce could have saved space.
Using open joists for balanced air homes
Using joists with an open design will also accelerate installation and save on labor costs. This in turn will give you more wiggle room on your total project cost.
Not all open joists would be ideal in such a situation however. Steel plated joists are known to be troublesome to HVAC installers because of their sharpness; sometimes ripping open ducts and increasing the potential for injury. Because of its all-wood construction, open joist Triforce is the ideal choice.,
The new ASHRAE standard isn’t enforced as a code yet, but there is increasing demand for efficient and healthy houses. If it becomes mandatory, be prepared, with an optimal floor system design.