Your House as a System
You probably don’t think of your house as a group of interacting components, but taken as a whole your house is actually a system comprised of several elements which at times may have fairly complex interactions, influencing each other in ways you may not expect. Here are three typical scenarios:
1) Many homes are equipped with a gas furnace and / or water heater which is vented via a vent pipe at the top using the air in the room to supply the burner (this is called “atmospherically vented). If someone were to turn on a leaking heating or cooling system, while simultaneously operating a range hood in the kitchen and a clothes dryer, there could easily be a significant enough pressure drop in the house that these combustion appliances (gas furnace and gas hot water heater) could vent exhaust gases into the house rather than up the pipe as intended, since replacement air will be drawn in from the vent pipe to equalize the pressure inside the house. This can cause a very dangerous back draft where either flames could roll out into the room where these appliances are kept or carbon monoxide could be drawn into the living space.
2) Another more typical scenario, especially in older homes with attached garages, is where a pressure imbalance occurs between two areas of a house, which results in “bad air” being drawn into your home from the garage. Pressure will always seek to equalize, either by forcing air out of a space or by drawing air into a space.
3) A homeowner complains that his or her home is too hot in the summer and doesn’t get adequate cooling from the air conditioning unit. The heating and cooling contractor sells the home owner a bigger system with more cooling capacity because it’s a simple and profitable solution for the contractor. The homeowner now has a unit that cools the house quickly and so doesn’t run for very long. The resultant effect is a house with higher inside humidity since the air conditioning unit does not run long enough to properly remove moisture from the air and increased power bills due to the high start-up costs of running an air conditioner.
Just like designing a car, for a home to work properly and efficiently, all elements of the house must be considered in the design and must be working correctly. When looking at home repairs, upgrades or maintenance, it’s important to work with knowledgeable contractors who understand this and take the time to ensure the work is done properly. There are many professionals out there who are competent and take pride in their work. There are unfortunately many unscrupulous ones also who will give you a lower price to get the work but who don’t either understand this concept or care to. While you may pay a little more up front for a qualified technician, in the long run it will save you money.
Mechanical Systems
When people talk about your “Mechanical Systems” in your home, they are typically talking about your heating and cooling systems which account for the majority of your home’s energy use in a year. Many things influence how well these systems perform and ultimately how much energy they will consume. Depending on who installed your systems and the care they used in properly sizing (getting a system that is not too big or too small) and installing the various components, your system could be performing well below its’ rated capacity and in some cases may be physically damaging your home or drawing in unhealthy fumes and gases.
Building code stipulates that very specific calculations be performed when determining the size of a system, unfortunately many contractors simply use a “rule of thumb” to install a system, which when it reaches the end of its life years later, is often simply “replaced” with a similarly sized system thus perpetuating the problem. The topic of heating and cooling is actually rather complex if it’s done right, here is a list of things to think about when considering the overall functioning of your heating and cooling system. We’ll cover each in more detail in the weeks to follow.
Supply and return locations and quantity, size of the system, SEER ratings and what it means, proper sealing of the duct system, duct location, type of system.
When dealing with a heating and cooling contractor or company, he or she should be able to account for these variables and be able to explain to you whether the system is properly sized and whether it’s working correctly as a system. If you get the sense they simply want to sell you the biggest system they can, then find another contractor.
