Attic Fans and Flexible Ductworks


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Attic Exhaust Fan

Attic Rafter Insulation

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Attic Fans and Flexible Ductworks

Just how Hot should Your Furnace Ducts be?

Furnace ducts perform the important function of carrying warm air from your furnace to the other unheated rooms. It also carries cool air from the central air conditioner to each unconditioned room. Ducts are made from a number of materials including fiberglass and sheet metal.

Poor Insulation

One of the biggest causes of inflated energy bills is the lack of a properly insulated system. Ducts that release warm air into unheated spaces will cost you dearly in terms of energy bills. It makes sense therefore to insulate ducts especially those that are in unconditioned spaces such as attics or vented crawl spaces. The type of insulation that you use also matters. Avoid using rubber-based adhesive tapes. The recommended ones are the heat-approved types. Where there is a leakage in the supply duct system, heated air is forced out into unheated areas through unsealed joints. Air that has not gone through the conditioning system can also find itself into the return ducts through the same unsealed joints. This invariably leads to higher bills in summer since the air conditioner works extended hours and likewise the same in winter when the furnace works for extended periods to keep the house warm.

How hot the furnace ducts get depends on the method of heating in use. This includes gas, electricity or fuel oils. Ideally the ducts would not very hot especially to touch. Ducts should feel warmer close to the furnace and cooler further from it. However, where there is poor insulation the furnace ducts are bound to be very hot.

Repairing a Hole in a Furnace Duct

If there is a hole in your furnace duct you can get it fixed yourself. With the right tools and this guide you will be able to fix it in a short time. Here’s how you do the job.


Inspect the area in question. Ascertain the size of the hole on the furnace duct. Head to the nearest hardware store and buy metal sheet, caulk, screws or rivets, drill and duct tape. These are the materials that you will need.


Cut the metal sheet. Make sure the size of the metal sheet is bigger that the existing hole on the furnace blower. Place it on the hole. Now you have to make the sheet stay in place. Screwing the sheet in place will work better in the long run. In order to place the screw you need to drill holes. Be careful while using a drill this time around. Make holes that leave a gap of two or three inches. With a brush, apply caulk around the hole's opening. Place the cutout metal sheet over the hole. Use screws or rivets to screw the metal sheet in place. Now use the duct tape to seal the edges of the metal patchwork.