When an HVAC Unit says it is “energy efficient” – like the “18SEER High Efficiency Air Conditioning Unit” or the “95% Efficient Gas Furnace” – how much truth is in that? Each year, the HVAC industry changes out thousands of systems around the country, and with the new and growing trend of energy efficiency in the home – combined with utility rebates from both the public and private sector – more and more contractors are selling high efficiency equipment.
The problem is that if your contractor replaces your old system with a new high efficiency system, the savings you think you are getting may not jive with what you are getting in reality. Why? Because, as we said in our last post, what also needs to be taken into consideration is how the heated or cooled air is distributed throughout the house, otherwise known as Ductwork. The average house in the United States shows a duct leakage rate of about 30%. So, only 70% of the conditioned air you are paying for makes it to the intended space in your home, rendering even the most state-of-the-art systems pointless. If it is leaking outside the conditioned spaces, in places like an attic or crawlspace, it is simply a waste of money. If it is leaking inside the conditioned spaces, like into an interior wall, this can cause a severe comfort issue or temperature differentials from room to room.
The solution is, of course, sealing the ductwork. If your contractor can get to the ducts, the only way to properly AIR seal is with mastic adhesive (ironically, despite its name, “Duct Tape” will not air seal a duct). If the ducts can’t be accessed, new technology such as AeroSeal is a perfect solution (think of “fix-a-flat” but for your ductwork).
Beyond leaks, the other problem that needs to be addressed is what separates good HVAC experts from great HVAC experts.
The good ones will simply test the duct system for leaks. The great ones, before they test for leaks, will first determine if the duct work is sized properly to handle the amount of airflow needed to distribute btu’s (heat/cool) to each room, based on the heat gain/loss of each particular room. Just like the duct leakage problem we have throughout the country, ductwork being undersized is also a trending problem. If an overzealous contractor seals ductwork without first determining if it was sized and designed properly, it will not be worth the investment.
The good news is that there are solutions to all of these situations, all of which can lower your energy bill and help make your home more comfortable. You are not the only person with these potential problems, so don’t be afraid to contact an expert in your area that can help you quickly address whether there is a problem, what it is and how it can be fixed.
energyMusings is written by Sean Schmidt, President of Holistic Home Energy Services, an Energy Auditing & Home Performance Contractor in Maryland. In addition to being a certified Building Analyst and Envelope Specialist, Sean has been in the HVACR field for 20 years. He is currently the President of Heating & Air Conditioning Contractors of Maryland, sits on the Board of the Maryland Alliance for Fair Competition (MAFC) and is an active member of Efficiency First.