Quote:
Originally Posted by ecomodded
That sounds like the way to go with the insulated ducts laying in wait.
Imagine its the most affordable way to add a pump giving the situation.
Im sold on it !
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Using the existing ducts is the cheap way to go about it. but he won't be gaining any sort of performance improvement. He'll still be negatively pressurizing the house (drawing in a trapping soil gasses, and outside air that needs to be conditioned), he'll have a lot of energy use due to pumping the air through ducts, you have energy loss due to a higher delta-T across a lower R-value, etc... If his ducts were inside the conditioned envelope of the house then sure just adding a heat pump would be a great option.
With the ducts outside the conditioned envelope you then have to look at what the real cost is to provide performance improvements. With that the least cost for highest performance improvement is to bring the ducts inside the conditioned envelope or almost eliminating air leakage and drastically increasing the effective duct insulation. Likely for him the lowest cost way to do this would be a sealed and insulated crawlspace. The average cost to that is around $5,000 and for that you can get a couple of mini-splits installed.