Friday, February 5, 2010

A letter from our Construction Dept.

I just wanted to share an email from Justin who is in charge of our construction at Rainey Homes-very interesting--


Many of you know that we use insulated duct board standard in all of our plans.  There are very few other builders that use this system, in fact I think that Anglers HVAC is the only HVAC contractor that does this standard.  Marty figured out some time ago that is was easier for him to work with insulated duct board instead of buying all the equipment to deal with sheet metal.  I think if you look at your competition you will find that nobody else is doing this.  There are multiple reasons why insulated duct board is better but I am going to just talk about a few.
 
Air leakage-  I ran into Bryan Taylor with Questar/Thermwise a couple of weeks ago and I asked him if anyone is using insulated duct  anymore.  He told me that he hardly ever see's it.  A few years ago everyone was required to insulate their ducts in an unconditioned space.  Remember when we used to insulate in between the floor joists?  Those basements were considered unconditioned because there was no insulation on the walls (simply put).  Most builders learned that you could achieve better performance by pin and draping insulation on the foundation wall and that changed the basement space to a  conditioned space.  Most builders quit insulating their ducts because it was not required.  Insulated duct board is an easier product to seal than sheet metal.  If you have ever looked in one of our unfinished basements you will see that all of our seams are taped together.  Sheet metal systems use a mastic paint like product to seal up the ducts.  The challenge with that is sealing the top of the duct when it is installed.  Bryan told me that our systems test very high with very low leakage rate.  You can see how this test is performed at the Energy star web site.  A couple of years ago we did a test in front of the Media and Lt. Gov out in Daybreak on a Bellevue plan.  There were no traceable amounts of air leakage in the system.  Properly sealed ducts are important so that the air you are paying to heat or cool will end up in the destination you are paying to condition.  You do not want that air being lost in an unfinished basement. Most sheet metal ducts are extremely leaky.  http://www.house-energy.com/Insulation/Ducts-Insulation.htm
 
Quieter Vents- I have attached an article about the advantages of insulated duct boards for a quieter home.  We have all been in a home where you can hear someone else's conversation through the duct system.  Insulated duct board greatly minimizes the sound traveling through traditional systems.  This could be a big deal to some potential buyers.  There is also less popping from expansion.
 
Maintains Temperature-  You don't have to be a rocket scientist to figure out that a cold duct will cool warm air as it travels to the desired location.  The initial blast of air that comes through the ducting will be cooler in a basement without insulated ducts.  I think that this one is pretty self explanatory. 
 
 
Last but not least I wanted to make it clear that all builders most likely use some insulated ducts.  Code requires an R-8 duct in unconditioned spaces.  Attic furnaces will need to use insulated flex ducts.  Additionally some builders will use insulated flex ducts in locations that require flex.
 
Let me know if you have any questions. 


http://www.hgtvpro.com/hpro/bp_mechanical/article/0,2617,hpro_20151_3712268,00.html

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