The scary thing is that this builder is considered better than most of the others around here. I found all of the major problems before purchase, and these sorts of problems are why we purchased the house for wayyyy less than it originally sold for so I am OK with it. The bank couldn't sell the house because home inspectors caused previous buyers to back out due to very scary errors in their reports.
The original post on the thread concerned our other house which we are selling. That house was built for us, and I inspected it while it was being built so most of these problems don't exist there. This new house was originally a spec home so nobody cared enough to do the quality control. The house we are selling is a lot cheaper to cool and there are virtually no leaks in the system. Our neighbor, in fact, is rather envious of our cooling bill which is 2/3 or his on the same size house. Still, most of the ducts in the house we are selling exhaust with a temperature in the mid 60's on a 100 degree day, with the shortest run exhausting at 59 deg F and the longest supply duct run exhausting at 71 degrees F. This is with an air temp just downstream of the evaporator of 56 degrees F and a return temp of 78 degrees F. The buyer's home inspector stated that this is defective and caused by a low refrigerant charge which will destroy the HVAC equipment, so now I have to go through a bunch of hassle and expense to prove otherwise. Grrr. That is why I will never use a home inspector again, I have never benefited from using one, but they cost a lot of money and their mistakes always cost me even more. The frustrating part is that I consider this amount of energy loss to be thoroughly defective so it is rather hard to argue otherwise even though it is standard practice.
I am sure that sealing up all the attic leaks in the new house and getting someone to clean up the ductwork will cause the energy usage to be the same or less than the one we are selling, and that energy usage will be within the range considered acceptable. I think maybe the range of what is considered acceptable needs to be moved up a notch or two.
"How about disconnecting one end of an 8" insulated duct and slipping a 10" insulated duct over the 8". Pull the 8" through the same length of 10". Seal both ends of the 10" to the 8" at the ends to prevent moisture from entering the space between the ducts. Regards TB "
As much as I have learned from you TB your RH info has been excellent!....our climates are different.
a double vapor barrier (or ducts located in insulation) causes problems for us
hot humid climate folks. Also it is double work! This ole gal is not looking to
work the same area twice!
It is amazing that the OP is going to all this touble for a house he plans to sell.
We need more people with this line of thinking!
Too tired to write more tonight...but this is a very good exchange of info.
Hope everyone has a great holiday weekend.
And OP....best of luck.
The cure of the part should not be attempted without the cure of the whole. ~Plato
Do you think it is predictable that a double vapor barrier would cause problems? I assume you mean condensation.
Originally Posted by energy_rater_La
Is it kosher to assume the outer vapor barrier is intact and if so, how can that not prevent condensation from occurring inside? Most of these building science issues can be boiled down to really simple principles, I am trying to see the problem here but having difficulty.
Best wishes -- Pstu
We are selling a house here in Houston which was just inspected by a potential buyer's home inspector...
G-e-t o-u-t, g-e-t o-u-t!
Seriously, someone asked why such low R value codes in the oil state?
In your next house - closed cell to the roof deck. Condensation does not occur within a solid. Keep your dew point within solid insulation. Do it right the first time and put-er-to-bed.
Which makes more sense to you?
- turning your thermostat back and being uncomfortable. Maybe saving 5-10%
- leaving your thermostat where everyone is comfortable. Saving 30-70%
DO THE NUMBERS! Step on a HOMESCALE.
What is comfort? Well, it AIN'T just TEMPERATURE!
Energy Obese? An audit is the next step - go to BPI.org
, or RESNET
, and find an auditor near you.
Sounds like the way to go. Let the roof deck dry to the exterior or attic, whichever has the lower vapor pressure.
Originally Posted by Carnak
And can we get HOA's and folks in general to wake up and give asphalt shingling the heave-ho? Get enough of us demanding light colored standing seam roofs and perhaps the cost of them will move down from the realm of "green elite". That and we won't keep sending roofing material to the landfills every twenty years or so...sooner if one lives in hail or high wind country.
Building Physics Rule #1: Hot flows to cold.
Building Physics Rule #2: Higher air pressure moves toward lower air pressure
Building Physics Rule #3: Higher moisture concentration moves toward lower moisture concentration.
hailstorm could make standing seam look like there was a driving range near by
Standing seam stays on in a hurricane
Hard to tell people here not to use ice and water shield.
The felt is gone about 2 seconds after Ivan peeled off their shingles
As we recovored from Ivan the roof lines morphed from blue tarps to ice and water shield to the final roof covering. Ice and water shield got quite a UV test down here
The way we build has a greater impact on our comfort, energy consumption and IAQ than any HVAC system we install.
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