High Efficiency Furnaces information for home owners. Most newer furnaces with a AFUE rating of 90% or more are rated as high efficiency furnaces. High efficiency furnaces also have a sealed combustion chamber to prevent heat loss. These high efficiency sealed combustion condensing furnaces utilize a second heat exchanger to capture more heat from the combustion process. The hot flue gasses are cooled down to the point where water vapor condenses. This process allows extraction of additional heat from the combustion process, increasing the unit’s efficiency and venting through PVC piping rather than chimney.
All gas-fired appliances must have adequate supply of combustion air for the combustion process. Atmospheric combustion appliances (80% AFUE furnaces and standard water heaters) pull air from inside the residence for this purpose. Therefore, an outside air intake is usually ducted into the mechanical room of the residence when required.
Most sealed combustion furnaces are provided with 2″ intake and exhaust ports. This does NOT mean that this is the size piping needed for proper venting. For each 90* elbow used, you must deduct 5′ from the maximum allowable length. For each 45* elbow, deduct 2 1/2′ from the length. The vent and combustion air piping will usually be 3″ or 4″. If you must increase size, this must be done at the unit by using a vent increaser. Newer furnaces now require vent pipe to meet the CSA 636 pipe standard which is easy identified as being white PVC pipe with correct markings. If you enclose your furnace during a renovation it is important to ensure that you have an intake vent on your furnace.
The condensate developed by the furnace is required to be disposed of. You can use plastic and some metal drains or you can use a condensate pump to pump directly into one of your drain lines. Keep in mind that regular and proper maintenance of your furnace is relatively inexpensive, but will extend the life of your heating system, save you energy dollars, and ensure your homes comfort and safety. Make sure your home heating system is working at peak efficiency. If you have a humidifier ensure you inspect unit frequently as hard water and calcium deposits may accumulate and cause your unit to leak into furnace cabinet. Moisture can quickly deteriorate your furnaces heat exchanger causing an expensive repair.
Always look for the EnerGuide label. This rating system helps consumers compare the energy efficiency of products. An EnerGuide label with the furnaces AFUE rating is shown on the back page of manufacturers brochures. Included on the EnerGuide label is a rating scale showing the range of efficiency for gas furnaces on the market. Newer furnaces are marked with units AFUE rating. AFUE stands for Annual Fuel Utilization Efficiency and a higher AFUE means higher efficiency.
You can save money on your heating and cooling bills by simply resetting your thermostat when you are asleep or away from home. You can do this automatically without sacrificing comfort by installing an automatic setback or programmable thermostat. In Ontario you can have a new programmable thermostat installed for free if you allow them to cut back use in peak times.
The barrie home inspector will run your furnace and note any irregularities. Remove all panels and check for condensate leaks or rust. Inspect all venting and exterior penetrations.