• Contractingbusiness 1440 43189ctech0300j00000019471

    Infiltration and Insulation: How to Clear These Comfort Hurdles

    Nov. 1, 2006
    BY FRANK SPEVAK AND BRUCE MANCLARK table width="200" border="0" align="right" cellpadding="5" cellspacing="0"div align="center"img src="/images/archive/43189ctech0300j_00000019471.jpg"


    Common air leakage sites to be aware of in customers' homes.

    You've no doubt heard about the importance of selling comfort, and treating the house as a system.

    If those concepts are beginning to lose their impact or sound clichèd, maybe it's time to look at it another way: Your customers likely don't understand how their HVAC system and their home work together (or, more likely, don't work together). All they know is that they're not comfortable. And when they're not comfortable, whose fault is it? That's right — yours.

    Customers don't know about how the person who framed their house left it wide-open to infiltration of outside air, or how the cable TV installer crushed the flex duct in their attics. They don't distinguish between the house and your HVAC system. As far as they're concerned, it's your HVAC system that's not making them comfortable and causing high fuel usage.

    That's why it's important for you to understand what's going on in a customer's home. You must test both the house and the system before you can accurately tell customers what's wrong and give them an estimate of what it will take to make it right. You must determine:

    • Which items need fixing
    • Which items need replacing
    • What steps you need to take to make the system work properly.

    To test the house, measure infiltration and insulation, and recalculate a Manual J based on your findings. To test the system, identify system components and sizing, and measure total external static pressure, total air flow through air handler, air flow to each register, and duct leakage.

    Test the House
    Insulation and infiltration can dramatically change the heating and cooling needs of your Manual J calculations.

    Measure infiltration to find out how the house is actually operating. Infiltration is the uncontrolled air that's moving through a structure. Use a blower door to find out how much a house leaks, because that's air you're not going to be able to control, and that your system is going to have to compensate for.

    Look at how much insulation the house has, and how well it has been installed. And while you're taking that look, examine exhaust fans and dryer vents that may have been covered by insulation and thus aren't working properly, once again adding to your comfort challenges.

    Check out the windows. The percent of the solar radiation that makes it into the house decreases dramatically with "low-E" glass. Double-pane windows let in about 75% of the solar radiation that hits them. Newer, low-E glass has a much lower solar gain coefficient — generally around 0.35. That's about half the heat gain of old double pane windows in the summer.

    Once you've considered infiltration, insulation, and windows, recalculate a Manual J to arrive at the right system to match the house.

    Test the System
    Measure total external static pressure, airflow, and duct leakage.

    Does the cooling coil match the compressor? Is the system the right size? Most systems are oversized.

    Total external static pressure is like a house's blood pressure. It's a basic measurement of a system's health. Yet it's remarkable how many contractors don't insist that their technicians measure it on every call.

    Measure total air flow through the air handler. What's the system's capacity? Is this system even capable of delivering the proper airflow?

    Measure airflow at the registers to find out if air is being delivered in balanced proportions.

    Studies have shown that most systems are not capable of delivering the rule-of-thumb 400 cfm per ton. Oversizing has not helped to deliver more air. The main reason for low system air flow is undersized or incorrectly installed ductwork. You know all the negatives associated with low airflow. Size it right and install it right.

    Use a blower door to measure duct leakage. Leaky ducts directly relate to high energy costs, poor indoor air quality, and inability to deliver air to the conditioned space.

    Leaky ducts in hot humid climates add to the latent load and the sensible load. A duct leakage of 25% of system flow, on a house with ducts in unconditioned spaces and 30,000 Btus of peak gain, would add another 7,500 Btus of sensible gain. A return leak of 100 cfm in Corpus Christi, TX would add 3,800 Btus of latent gain

    The Business Side
    Becoming a true comfort provider involves some up-front costs. The test equipment will cost about $7,500 per truck.

    Then there's the training. Simply buying the testing equipment and having it at your company isn't going to make it work. Whole house training can seem expensive, but you have to look at the big picture of the benefits it brings to your company and amortize it over several years.

    Finally, keep in mind that when your technicians are trained and start testing, you're going to find they'll be spending more time at each house, which will force you to do fewer bids.

    While this all sounds like it won't add up to a positive, over time the business opportunities far outweigh the up-front costs.

    Involve homeowners in your testing. Let them know that you're committed to making their system work properly, and to really making them comfortable.

    If you perform the tests, involve the homeowners, accurately predict what corrections (to the house, the system, or both) are going to cost, and what the results will be, you'll close more sales. This keeps you out of low price battles. You're saving the homeowner money because you're installing correctly sized systems.

    Also test afterwards, to illustrate to the customer what you've done. This is the testimonial. The proof of how you're different, and how you improved their system, their house, and, most importantly, their comfort.

    It's all about differentiation. You'll find more opportunities for work at more homes than your competitors who just sell boxes. If you're selling the same box, the price is going to be the same. But if you're providing more services to the customer, you can bid higher because you're delivering more. Look beyond the box and do whatever is necessary to ensure that your customers are comfortable.

    When you understand what's going on with both the system and the house you've taken a huge step in front of your competitors. That's a business opportunity you can't afford to pass up.

    Bruce Manclark is co-owner of Delta-T, an energy services company in Harrisburg, OR. He can be reached at 541/517-5779. Frank Spevak is marketing and sales manager at The Energy Conservatory, Minneapolis, MN. He can be reached at 612/827-1117.