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How to keep that Chimney Safe in a High Performance World

How To Keep that Chimney Safe in a High Performance World

Annual maintenance of your gas or oil furnace is a must for a safe and efficient combustion

Venting systems are designed to properly, reliably and safely vent products of combustion to the outdoors. Yet homeowners give little thought to the chimney or venting system, it's condition, performance, and safety to themselves and their families. This is a mistake, say experts.

"These types of appliances should never be installed and forgotten about," says Brian Baker, President of Custom Vac Limited a Heating, Ventilation, and Air Conditioning (HVAC) Contractor serving Manitoba residents.

The majority of problems found by Technicians are directly related and a result of poor maintenance. Chimneys, venting systems and appliances should be cleaned and inspected every year. It is the Homeowners responsibility to make sure that this happens. Good Contractors such as Custom Vac offer customers an annual appliance maintenance mailing card program. A friendly reminder that says, "it's time again to have the inspection and cleaning preformed on your appliance". "Today with parents both working, everyone is time poor we realized educating and reminding homeowners was the first step, " said Baker.

Attention to Detail is Vital

Proper installation is the key to ensure safe, reliable operation of the chimney, venting system and appliance. "The devil is in the details," says Baker. "Even the most minor thing, not done right, can result in disaster."

Some Homeowners take it upon themselves to replace a chimney, chimney liner or venting to a furnace, fireplace, water heater, etc., thinking that this is an easy way to save some money. The problem is, homeowners are not properly trained. Understanding the basic principals of combustion venting, appliance application, National and Provincial codes and material standards take years for most competent tradespersons to understand. Code changes regarding the venting of combustion products have been the single largest section to be revised in the last 10 years. This is an area that I would recommend a Homeowner leave to the professional Contractor.

Problems that Technicians find on the do-it-yourself jobs:

  • Incorrect sizing (Oversized & Undersized)
  • Improper selection of materials
  • Improper installation of liner and venting
  • Too long venting length
  • Failure to seal the chimney chase or close in chimney
  • No access for inspection of the chimney
  • Failure to properly attach and support the venting system

Energy Efficiency and Depressurization

Today's new appliances are so efficient that it is a battle to get enough heat into the chimney and venting system. A good rule of thumb is, the more efficient the appliance, the less temperature that will be generated. This is where the task of knowing what to do and how to do it comes in. This whole principle of heat rising has been changed somewhat. The temperature of the combustion gases in many cases can fall below (dew point) the point of condensing. "Not only do you get condensation and acid formation that deteriorates the venting materials, but, the serious potential for back drafting of combustion products into the home" says Baker.

Homes built in Manitoba are among the tightest homes built, not just in recent years, but even back 50 years ago. Adequate air for combustion and house depressurization is the single greatest concern when dealing with combustion vented appliances. Homes must strike out a balance of being tight (energy efficient), yet still having sufficient combustion air to ensure proper combustion. This means possibly having to introducing combustion air directly to the appliances to meet code. Symptoms of insufficient combustion include a poorly tuned and operating appliance, condensation on windows, household plants that don't grow well, etc. The most serious and the one that gets the attention of the media when it happens is Carbon Monoxide (CO).

New products are being developed to assist Contractors the Selkirk Inc. model DWC flexible double wall insulated flexible vent connector that minimizes temperature loss. Another item may be relocating the appliance to reduce venting length. When converting an appliance from one energy source to another as with oil to gas, one item that gets overlooked is the cleaning of the existing chimney prior to a new approved liner being installed. It is very important that the chimney be cleaned first because fuel oil is very high in sulphur (S) so, when mixed with a small amount of moisture (water H20) sulphuric acid is formed destroying an aluminum liner in a very short time. This is the reason why fuel oil chimneys are made of stainless steel and not aluminum.

Choosing the Right Appliances for Peak Efficiency

"One of the biggest problems that we face is Contractors over-sizing of appliances," said Baker. The result is poor venting performance, loss of comfort and loss of appliance efficiency. If I were to ask a homeowner to look at three of the same cars and tell me to match up which car gave 25 miles per gallon (MPG), 21 MPG and 33MPG. Could they guess them right? Maybe. Now, if they were able to have someone tell them the condition and efficiency of each car, would they still pick the car with 21MPG knowing the price of fuel to keep it running? I don't think so!

Unfortunately Homeowners every day buy appliances from Contractors who have little regard for their comfort, equipment and energy costs. Why? Most Homeowners don't know that proper equipment sizing can have such negative effects on them. "The Federal Government, "Office of Energy Efficiency" has a program called EnerGuide for Houses that Custom Vac is participating in," said Baker. This is not the only method of determining equipment size or air leakage rates within houses. "It is however, according to Baker the most sophisticated and scientific method approved in use today that takes into consideration the entire building envelope and what is going on within that envelope." A full report detailing what energy efficiency upgrades can be done to reduce air leakage, and energy costs, etc. is generated for the Homeowner after the approximate 3-hour in-home evaluation by a trained Energy Evaluator. In addition, booklets and materials that offer educational information are also left.

Early results show that homes in Manitoba are very tight and that most home are experiencing some level of depressurization of the building envelope. These results prove that no one can guess any more about the need for combustion air, ventilation air, chimney size, appliance size, etc. The program is also noting that some home built in the 1950's are as tight today as new homes. This is why just looking at the car to determine MPG we cannot just look at a home and say "yes" we a need 6" combustion air duct and/or 5" ventilation duct connected to the return air duct from outside. Baker admits, "We used the rules of thumb and tips that we learned on-the-job and through educational and trades training, but, like everything times change and we have had to change. Things that we did as little as 3 years ago are lo longer being done due to better research and testing."

The tools are here today that enable us to help homeowners make better-educated decisions regarding their home and appliances. Homeowners need to ask their Contractor why he is guessing and not using the technology that is available?

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1567 Logan Avenue
Winnipeg, Manitoba
R3E 1S5
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