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Residential Energy Efficiency Blog
Friday, April 03 2020
As a home energy auditor, one of the rewarding aspects of the job is to help homeowners uncover sources to their energy usage concerns. It is especially gratifying when the energy audit was scheduled specifically to diagnose the issue before any big ticket decisions are made to try to solve the problem such as replacement windows or high efficiency heating and cooling unit (HVAC). A well done energy audit can help you prioritize projects around the home in a way that guides you to getting the best return on investment. If nothing else, you can make an informed decision to spend money on an improvement that will not yield an expected result. Getting an energy audit puts you in the driver's seat.
In theory, when the fan gets turned on, the air gets pulled in at the base of the fan and through the blower and into the duct that extends away from the fan to the "outdoors". Unfortunately, this is not happening in most homes that I visit.
If you are not sure if your fan vents to the outside, one easy way to see is to take a look at your roof to see if you have any vents that look like the ones below. If you see these, there is a good chance your exhaust is venting properly.
Another way is to go in the attic and take a look for yourself. Here are a few more things to look for.
As much as 40% of a home's energy use is related to HVAC so the idea is not to replace HVAC. Rather, it is to reduce the amount of time you need to use your HVAC.
Wednesday, April 01 2020
One of the keys to performing a good energy audit is to be consistent. Consistency, yields high quality results for the homeowner. Having a sound routine and being sure to go through that routine for each and every house will serve the most seasoned home energy auditors very well.
As I began the audit and started outside to take a look around I began to get the overall picture of the house now that I was inside and did a full tour throughout. I made my way around the side of the house to the kitchen area.
Two things stand out to me right away. One thing to note there is that the kitchen is at the back corner of the house above the garage. The kitchen window above the sink is the window that can be seen in this photo above the garage door. The general area is inside the red lines.
The second thing that is is less obvious and is something that will require additional investigation is the exhaust hood just above the grill to the right of the sunroom.
For the most part, and of course this is something I mentioned to the homeowner, the problem is never only one thing. There usually are several things working against you and the ideas is to wrestle the power away from as many of those problems that you can in, order of how much they cost, in order to make the problem less of a problem.
So, treating the ceiling of the garage with a proper pressure boundary in addition to the thermal boundary would be a significant part of a project that was going to seriously attack the kitchen being cold. But, in this case the example that I will demonstrate here can be seen in all types of houses and perhaps this might be the only source to your issue.
Let's get back to the exhaust hood on the back, above the grill and next to the sunroom.
At first glance, it might just blend in and some might not even make the connection that it leads to the kitchen and those that do, may not make the connection that it is not connected. What I mean here is that if you turn the vent fan on above you range and if it is blowing air out at you then it is a recirculating fan. Why is this important?
Often times when a kitchen is remodeled little thought is given to the kitchen exhaust requirements. Many times the connection with the preexisting fan is not used. To further the trajedy of not reinstalling proper ventilation, nothing is done to seal and insulate the void leaving a large thermal bypass in a highly traveled area of the house.
Here are a few shots of the kitchen for some more perspective.
Notice the area above the stove top. There is nothing there. Earlier I mentioned that the homeowner just purchased the house so this is the situation they inherited. The story for me was starting to take shape. The kitchen at one time had working exhaust and during the kitchen remodel it was eliminated, but the end result is a big offender when it comes to why the kitchen is not comfortable.
From the outside you can see that the depth of the exterior wall is roughly four inches and seeing the old wiring and the inside panel that this was a source of some of the problems in this kitchen. Thermal imaging confirmed it.
So keep this in mind if your kitchen is cold and drafty. It is possible this issue can exist if a microwave oven or range hood is in place with a new recirculating fan. The old exhaust hood is a gateway to the outside as seen in this example. A clue would be to look outside to see if there are any vent hoods not associated with any appliance.
So, how can you fix this yourself?
Here is how you do it. Find something solid, easy to cut to size and air tight. Sometimes heavy duty styrofoam furniture packaging will work. Another option is a piece of polyiso insulation foamboard from the hardware store, but check to see if you can find something around the house since you don't need much. Be sure to do the blocking part. You don't want to shoot a bunch of foam insulation in the hole and muck it all up in case you need it later or stuff fiberglass insulation in there because that will not work. Cut to size, place in the void and seal around the perimeter with spray foam. This will insulate and air seal at the same time and fix the thermal bypass in that location.
Trust us to put all the pieces together right!
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An Energy Auditor's Purpose
"Energy auditors visit residential buildings and talk to owners and residents. They inspect, test, and measure to decide what energy-efficient retrofits are practical and cost effective." Residential Energy