Why you need to include a blower door test in your energy audit
Updated: May 2, 2019
Have you noticed that one or two rooms in your home are ALWAYS hot in the summer? Can you feel a cold draft in the winter? Heck, is your home older than 10 years old?
If you answered "yes" to any of these questions then I'm here to tell you that you really ought to get have an home energy audit (sometimes called a home energy evaluation or home energy inspection) done. You can read a lot more on this in our other informative blog posts about energy audits.
That's step one.
Most companies that do energy audits will offer them in a few different levels. Today, I'm going to explain why step two is to include a blower door test in your energy audit.
First, what is a blower door test?
A blower door test is one of the greatest tools in a building scientist's/home performance specialist's tool box. It depressurizes the home and (through a sophisticated tool called a manometer) is able to figure out how much air is coming into the house. Through some algorithms it then can give a number for how much air leakage there is within a home. Blower door tests are required by building codes to make sure that NEW homes aren't being built too leaky.
How does that help my home energy audit?
That's a great question. Blower door tests aren't just useful tools for identifying how much air is coming into the house, they are also a part of pinpointing where air is coming into the house.
While it's great to know that the home is leaky (and honestly, most pros could probably fix 80% of the problems in the home just by going to the long list of usual places missed/rushed/ignored by builders -- this is done because of steadily improving understanding of building science and good building practices, but also because not every builder makes homes of the same quality), it's critical to pinpoint those leaks so they can be addressed.
Your energy auditor will walk through the home with one or two other tools while the blower door is running. He/she might use a smoke pen, a pressure pan, a second manometer, or a fog machine.
They can even use a thermal camera and be able to see how entire portions of your house are performing, controlling temperatures, air & moisture.
Regardless of which tool they use, they are all meant to figure out where the leaks are. Without running a blower door test during the home energy audit, you really wouldn't be able to pinpoint air leaks. At that point you would be relying on past experience and best guesses.
What happens after an energy audit?
Once the audit is complete you should be walked through your home and have the results/findings of the audit be explained to you. If your auditor is using words you don't understand, or doing too in-depth of an explanation, tell them to bring it down a notch. You aren't a home builder. There shouldn't be any expectation that you know the first thing about building science or building techniques.
You should also get a report sent to you that covers the findings and gives recommendations.
If you are a DIY-er, then head to your hardware store and get to work. If not, bring in some pros.
Either the way, the first step towards improving the energy efficiency of a clean & safe home is air sealing. Always.
I do want to stress that clean and safe part though. If your home has an asbestos issue, high radon, or a mold problem then you really need to get that taken care of ASAP. That poses a very real health risk, and that needs to be addressed.
Bringing it home
Ok, so you've identified that you need a home energy audit. You've found the company you want to use, and now you're trying to pick out which level of audit to buy. Is it really worth the extra charge to have a blower door test included?
A blower door test will:
give you a real number for how leaky your home is...this means that every time you make some major upgrades/improvements you can compare the blower door number from before and after to make sure the problem is really being addressed
allow the auditor to actually find the air leaks as opposed to going off instinct & experience
The biggest loss of money, comfort, and home health comes from excessive air leakage.
Having an energy audit done with a blower door test will allow you to seal those leaks, which means your home will be more comfortable; you'll have healthier, cleaner, less humid air in the home; and you won't be spending as much money on energy bills.
And less spending on utility bills means more spending where ever the heck you want.