The "House As A System"

A house is more than just four walls and a roof. It's a complex system of different components that interact and determine the performance of the home and the health, safety and comfort of the people living in it. Specifically, the system involves:

  • the "building envelope", i.e. the separation between the inside of your home and the outdoors-foundation, walls, roof, windows and doors
  • the mechanical equipment-heating, cooling and ventilation
  • other factors such as structure, plumbing and landscaping, as well as the lifestyle of the people living in the house

The professional renovation industry has long recognized the importance of "the house as a system" concept, and that changes to one part of the system affect others and, hence, the entire house.

Why is it important to consider the house as a system?

Construction technology has changed a lot since the mid-1970s, when tighter construction and greater use of insulation, air/vapour barriers, and energy-efficient windows first became common in new home construction and renovation.

Along with improvements in the technology, the industry has gained a better understanding of air, heat and moisture movement in a home, and the need to manage the indoor environment in a deliberate and systematic way.

Using the house as a systems approach, renovation provides an opportunity to improve the performance of your home to give you a better living environment. Here are a few common examples:

  • Energy upgrades (e.g. energy-efficient windows and doors, more insulation in walls and attic, installation of air/vapour barriers) will improve the energy performance and comfort of your home. However, as the house gets '"tighter", you may have a harder time getting rid of humid, stale air, unless adequate ventilation is provided. If not, you may end up with stuffy, unpleasant air, condensation on windows and sills, mold growth that can affect your health and, over time, damage to your home.

Solutions can be as simple as adding a timer to the bathroom exhaust fan, installing a dehumidistat or putting an extra fan in the laundry room. In most cases, upgraded older homes still let in an adequate amount of accidental "new" air, but care is needed to ensure that the extra fans do not cause backdrafting of combustion appliances such as fuel-fired furnaces, water heaters or fireplaces. Your renovator might suggest a whole house ventilation system, which will provide a steady flow of fresh air. New systems suitable for renovations have recently come on the market.

  • Air flow and moisture problems can also occur with a new addition to an older home if ventilation has not been taken into consideration. You also need to determine how to heat the new space: expanding the existing system, augmenting with a different system or replacing the whole system? A professional renovator might suggest a zoned system that allows you to control the heat in individual areas, or zones, of your home.
  • Proper drainage is important to keep outside moisture away from your home. Some renovations (e.g. additions, decks and landscaping) can change the drainage patterns on your property. Experienced renovators will assess the affect of your renovation and recommend measures to control water run-off and drainage.
  • When you are making substantial changes to your existing space (taking down or building new walls, moving living and working spaces around), it may be necessary to readjust the heating, cooling and ventilation of the new layout.

Large new windows or sunrooms will open up your home and bring in lots of light. They can also lead to overheating, unless you take proper precautions, such as special coatings on the windows, blinds or drapes on the inside, or awnings, shutters or strategic planting of shade trees outside. A renovator may also recommend separate ventilation in sunrooms.

Source: Canadian Home Builders' Association