You are here:

Heating, Air Conditioning, Fridge, HVAC/extending duct work through an addition



I am located in Canada with weather similar to vermont or new hampshire (hot in the summer, cold and snowy in the winter). I have a home with central forced air and A/C. I am planning to add to the house on the first level. Mainly make the living room/kitchen larger.

The addition will rest on an insulated crawlspace. The outside wall i plan to remove and essently push out about 10 feet has 4 registers. The returns are on the opposite wall.

Since the crawlspace will not be heated or cooled, can i  extend ductwork through a insulated crawlspace without loss of hot/cold air? Do i need to insulate the ductwork on top of insulating the crawlspace? Any other options?


I would still insulate, I do not know what your codes are in your area of Canada about insulating or non insulating. Metal round would be ideal ,but if you only plan on going 10 feet I would consider flex duct stretched out to keep resistance to a minimal, it is already insulated,Codes vary on thickness of the insulation. Flex duct comes in 25 foot should have manual balancing dampers on the branch ducts coming off your main duct to help get the correct amount of air in that area

Heating, Air Conditioning, Fridge, HVAC

All Answers

Answers by Expert:

Ask Experts




40+ years diversified experience.An HVAC/Refrigeration Self Employed Contractor since 1986. NATE Certifield. Answer questions pertaining to Residential and Commercial Air Conditioning , Warm Air Heating, Heat Pump systems.Mechanical and Electrical troubleshooting of these systems.Be as detailed as possible when describing problem.Packaged unit or split systems.No appliance questions.


Installation and Troubleshooting, Mechanical and Electrical, in following areas, Refrigeration ( Walk In and Reach In Coolers and Freezers ) Commercial Roof Top and Packaged Heating/Cooling ( Natural Gas,Propane, Electric, and Heat Pumps ) Computer Room Air Conditoning Systems,Commercial Residential Packaged and Split Systems Air Conditoning and Heat Pumps.Warm Air Oil , Natural and Propane Gas Heating systems.

Graduated from Private Technical School in 1975. An HVAC/Refrigeration Contractor . Have Unlimited Heating/Piping and Cooling Contractor License.Limited Sheetmetal Contractors License.NATE Certifield. York Certifield Master Heat Pump Technician 1986. Served 33 years combination Active Duty Air Force , Air Force Reserves and Air National Guard in the HVAC/Refrigeration Shop/Mechanical Shop. Troubleshooting/Installing HVAC/Refrigeration Equiptment Worldwide. Retiring in 2003 as a Senior NCO ,and a Mechanical Superintendent.

©2017 All rights reserved.