The title “home energy audit” sounds exactly like something us geeky building science types would come up with. But the number of problems this testing can solve isn’t explained very well in that title. In the five years I’ve been doing this (20 years for Craig, the owner here at Canella Heating and Air Conditioning), our customers have appreciated the energy savings that show up as lower utility bills of course. But they’ve thanked us for making them comfortable. And there is no putting a price on comfort.
There are four basic tests in a home energy audit: a combustion safety test, an infiltration test (also called a blower door test), a duct leakage test, and a visual inspection. You can get one, two, or all of them; however, if you have a gas burning appliance, furnace or water heater within the heated square footage of your home, we will do a combustion safety inspection before we do anything.
Below you will find more information about each test. Keep in mind that these tests are going to give us measurable results. The big advantage to you is that they can be performed before any repair work is done as well as after to verify the quality of the repair.
A combustion safety test is first and foremost a health and safety check. Sure, we can determine how efficient your gas furnace is by doing this test, but if your furnace isn’t safe, does it matter how efficient it is?
During this test, we try to recreate conditions inside your home that would result in very low inside pressure, such as turning on all the exhaust fans, the dryer, your HVAC system fan, etc. It’s possible that if the pressure drops too low inside your house when you do normal everyday things like dry clothes, your combustion appliances might not be able to get enough air to either burn properly or to vent to the outside like they should. Once we’ve completed the combustion safety testing, we can move on to everything else.
This test measures how much air leaks into and out of your house naturally every day through holes, cracks and gaps. Every house leaks. The question is how much. A blower door test tells us how many times in an hour all of the air that you pay to heat, cool, humidify, dehumidify, or filter leaves your house and gets replaced by outside air. It also gives us an idea about how big the leaks are in your home and can help narrow down where to start looking for them. Every hole that’s repaired means that fewer of your hard-earned dollars are flowing to the outside.
During this test, we close all the outside doors and windows, install the blower door in the frame of one of the doors and use a big fan to suck all of the air out of, or depressurize, your house. Not all of the air is removed of course because all houses leak. If a house was 100% airtight, no air would leak in and we would suffocate while we’re running this test. (I promise you that doesn’t happen. In fact, you won’t even be able to feel the depressurization.) At this point, our instruments will be able to measure how much air is leaking in. We can convert that number to the number of times the air is naturally being exchanged every hour and to how big the combined “holes” in your home are in square inches. It’s a quick test that can give us a lot of valuable information.
This test is designed to check the tightness of your duct system. In many homes, most of the ducts are in the attic, crawlspace or basement. If this system leaks, the air is blowing into one of those places and not the room it’s supposed to be going to. In other words, the money you’re paying to heat and cool the air is being blown into your attic or your crawlspace. Not only does this waste money, but it means it takes longer for your house to heat up or cool down which means your system runs longer which means you’re wasting more money. The EPA estimates that on average American homes lose 20% of the air they’re heating and cooling through duct leakage.
The holes could also be on the return side of your system. Ducts for the return side are also usually located in the attic or crawlspace. The return side is where the air from inside your home gets sucked back in, passes through the filter, goes through the air handler where it is heated or cooled again, and is then sent back into your home. If there are holes in the ducts on the return side, air can come from wherever the ducts are located including your attic or your crawlspace. This air bypasses the filter, dirties the air handler on its way through, and ends up in your home. So not only does duct leakage waste money, but it can contribute to poor indoor air quality and cause equipment to breakdown quicker.
To perform a duct leakage test, we seal off all of the supply and return registers inside your house. We hook up a small fan to one of the returns and pull the air out of the system. With all of the supplies and returns taped off, it should only take a couple seconds to suck all the air out of your system and cause your ducts to collapse. But that doesn’t happen. Like houses, all ducts leak which means there’s air constantly entering the system. Our instruments measure how much air is leaking in. The bigger the number, the bigger the leaks and the more you can save by having them sealed. We are very good at testing, finding, and sealing duct system leakage. If you’re interested in learning more or in having your duct system evaluated, please don’t hesitate to give us a call at 828-327-9680. We would be happy to help.
A lot of problems are easy to spot – if you know what you’re looking for. As Building Analysts, we are trained in building science. We study air flow, pressures, combustion, holes, moisture, walls, ceilings, roofs, floors, crawlspaces, attics, basements, and on and on. We combine all of this to figure out what’s happening inside your house that you might not be able see but that you probably feel and don’t recognize. It’s not only a hot/cold/drafty-type feeling. It could be a health problem including things like allergies or asthma, things you might never associate with problems inside your own home.
A visual inspection is a top to bottom, attic to crawlspace inspection. Once we’re finished, we will have a good idea of how your house is behaving and why, what the trouble spots are, and which ones will give you the best payback for your repair dollars. From there you are free to contract for the repairs yourself, or we can take care of the repairs for you using our network of home performance partners.