Most of us by now know what a blower door is. A tool to measure the air tightness of a house. I’ve owned my Minneapolis Blower Door since 2009. Many states have adopted mandatory tightness testing on all new construction. In my area, the minimum is three air changes per hour at 50 Pascals (3 ACH50), Continue reading “Energy Audit-Advanced Blower Door Testing-Zonal Pressures”
High Voltage, the first thing that comes to mind is AC/DC’s 1976 album of the same name. (I was 7 when that album was released.) An awesome first album from a band that eventually becomes one of classic rocks best. But high voltage can be a big problem with electronics and electrical equipment in houses and businesses. My brother, who is an electrical engineer and master electrician, gave me the idea for this blog post. He had to recently trouble shoot a problem. Continue reading “Energy Audit-High Voltage”
I recently blower door tested the tightest new home I have tested to date. .82 air changes per hour at 50 pascals (ACH50), nearly one-quarter of the code required 3 ACH50 requirement. After the test, the builder and I decided to open a window to see how much additional leakage it would take to get the home to the code minimum 3. Continue reading “Energy Audit-Comparing a Great Blower Door Test to a Code Minimum Test”
This is the first time I’ve been to this home. The first time I’ve met the people living in this home. But I know a little about them. I have two years of electricity use data to form a basic impression. They use a lot of power. Even more in the winter. Continue reading “The Energy Assessment”
I’ve been asked this question a few times. “At what point do I need to add mechanical ventilation to my home?” The answer, it depends. Continue reading “Energy Audit-Ventilation Recommendations”
I recently conducted an energy assessment on a 25 year old home with electric underfloor heat. Back when I was working as a residential electrician, we installed several of these systems Continue reading “Energy Audit-Electric Underfloor Heat”
On occasion I need to look up the heating degree days (HDD) for an area over a period of time to complete an energy audit. Weather data can be useful for estimating heating costs. So, what is a heating degree day?
A heating degree day is a unit of measurement comparing an average outdoor temperature to a 65°F indoor temperature over a 24 hour period. The 65°F temperature is used because this is considered a heat balancing point, or a temperature where heating will not be required inside a home or building. Of course HDD is used if you live in a heating climate like me. If you live in a cooling climate, cooling degree days (CDD) is more important. CDD uses a balance point temperature of 78°F.
HDD are figured by averaging the daily temperature (24 hour period) and subtracting that value from 65°F. Lets say you have daily high temperature of 20°F and a low temperature of -20°F, the average daily temperature is 0°F. Subtract that from the 65°F and you have 65 heating degree days.
A very cold climate, such as one of the colder cities in the US, International Falls, Minnesota has a HDD of 10,000 over the course of a year. In comparison, Washington DC has around 4,200 HDD in a year. Some areas of Alaska see more than 12,000 HDD.
I find HDD data from the Weather Underground web site, https://www.wunderground.com/history/. A very handy tool I use when needing weather related information. A good example is the weather for my area at the end of January of 2019. We were under a polar vortex with average daily temperatures of less than -20°F. These single days were producing 80-90 HDD. Check out zip code 55744 over the date of January 31, 2019, a very cold day in Northern Minnesota.
So, how can this be helpful with an energy audit? Lets say your monthly heating bill is higher than normal. The reason may be outdoor temperature related. Higher than average heating degree days over the course of a month will require more indoor heat to maintain comfort, increasing heating costs. I often compare data from previous years to the current period to confirm heating costs to temperatures comparisons. Weather data can also be used to compare summertime cooling needs and the associated air conditioning costs.
HDD and CDD, another tool used in energy auditing.
During an energy audit, I occasionally come across a homeowner living in a newer home they had built or had purchased that did not received any training on the home’s systems or how to maintain the home. In my opinion, understanding the basics of how your home works is an important detail in owning a home. Continue reading “Energy Audit-Homeowner Education”
Thermal imaging is a tool I use for energy auditing, but it’s usefulness goes way beyond. I often use my camera during building projects and at my own home to help detect problems. Continue reading “Energy Audit-Thermal Imaging”
During an energy assessment or audit, I often test household equipment and appliances for energy usage. Over the years, many people have been surprised that some devices use the amount of energy they do. This weeks blog will be all about how much it costs to operate the electrical stuff in a home. Continue reading “Energy Audit-Common and Not So Common Appliance Energy usage”