Understanding the House as a ''System''
December 26, 2016
From a building science perspective, a house is considered a multi-component system, where all of the components are interactive. The building envelope, for example, comprises the roof, walls, and foundation. These components essentially separate the inside of the house from the outside. Mechanical systems are also important components. These comprise heating/cooling equipment; ventilation/exhaust systems; even humidifiers/dehumidifiers. Their task is to properly regulate the indoor temperature of the house, overall air movement, and indoor moisture levels. The way a house is laid out, and the way that residents live in the house, also impacts the system. In short, every component influences and affects the overall performance of the system. Not to forget, a house also interacts with the outside environment - particularly in cases where winters are freezing cold and summers are stifling hot. Sometimes, home renovations can also impact the system, and with unpredictable results. For instance, upgrading insulation without considering ventilation, can affect the operation of the HVAC system (heating, ventilation, air conditioning.) The key for a homeowner is to understand what the professionals call the "house-as-a-system". It means that insulation, air sealing, and ventilation work together to provide optimum operating performance for all of the mechanical systems. In this way, heating/cooling issues are addressed, as well as indoor moisture and air circulation concerns. A contractor who is not accommodating the "house-as-a-system" approach is not adequately achieving home energy goals, and is inviting additional rework and revamp for an unsatisfied homeowner.
The idea behind the "house-as-a-system"
Although the typical homeowner might not understand the nuances of building science, it's still a good idea to understand the basics of the "house-as-a-system". Simply put, on a day-to-day basis, there are three main processes going on inside a house: heat flow; airflow; and moisture flow. All three have a significant affect on the indoor environment: on energy efficiency; on air quality; on resident comfort; even on the structural durability of the house. The key, of course, is to ensure that all three flows are well balanced. If this is the case, the house performs well. If not, problems can ensue, and various retrofits will be necessitated.
Applying the "house-as-a-system" concept
Contractors or renovators who subscribe to the "house-as-a-system" concept can easily identify potential problems early on, and offer viable solutions for the homeowner. This is all done prior to any work being started, and serves to address central issues that may not be readily obvious or apparent. More importantly, the "house-as-a-system" approach ensures the long-term success of any renovation or retrofit, and with far less contractor follow-ups to fix, rework, or redo. For homeowners who are planning to renovate or retrofit, the "house-as-a-system" philosophy makes for a project that is focused on specific objectives, and is well planned. The final result: greater home comfort; enhanced indoor air quality; and dollar savings on seasonal heating and cooling. Professionally undertaken from start to finish, this approach to renovating/retrofitting is purpose-driven, assuring optimum energy efficiency in all parts of the house.