The correlation between ACH50 reduction and energy bill savings?
It is well known that if we reduce air infiltration in a building will reduce the cost of heating/cooling that building. In fact, energy cost can be calculated by plugging in variables such as, Degree Days, cost of fuel, BTU per unit of fuel, etc. We also plug in pre- and post-measure CFM values, subtract one from the other and the difference will be the anticipated savings resulting from the preformed measures. But this is based on CFM’s and does not take into account the volume of the home.
On my manometer, one of the parameters I can read to measure air infiltration is ACH50. I enter the volume of the home and the manometer will calculate the air changes per hour at 50Pa.
What I would to know is if I reduce ACH50 in half on a 24,000cuft home and this results in a dollar savingsof X%, could I expect X% savings on a home with a volume of ANY size if I cut the ACH50 in half? That is, if I cut infiltration rate the same percentage on each home then the percentage savings of each will be the same?
Also, as we reduce ACH50, does the savings increase in direct proportion or at an increased rate? For example, if we reduce ACH50 by 25% and this results in a $300/yr savings, will a 50% ACH50 reduction result in a savings of $600. Or would it be more (or less)? Assume variables to be the same.
The bottom line is, with objective data in hand, I would like to give my clients an likely idea of what savings can be expected based upon ACH50 reduction. Thanks in advance to all. Bob
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