Category: Energy Audit

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Comparing Your Home’s Energy Use to Your “Neighbors”

This post first appeared on the Green Building Advisor Website

Part of an energy auditors’ job is energy analysis, which includes analyzing historical energy consumption data to determine if usage is as expected.  One method is to compare a home’s energy use to some average (the local rural electricity provider I contract with calls this “compared to your neighbor’s”).  This average could be the national average, but it’s better to compare at a more local level, such as by state.  There are a few sources of this information, one that I have been using is: U.S. Energy Information Administration – EIA – Independent Statistics and Analysis.  This dashboard provides me with several different energy consumption metrics, expressed in MMBtu’s and kWh, broken down by state and also displays national averages for the US (sorry my Canadian friends).

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How to Track Appliance Electricity Use

This post first appeared on the Green Building Advisor Website.

Part of my job working as an energy auditor is educating homeowners on electricity usage, reviewing and analyzing historical electricity usage is part of the process.  Checking service conductors and individual branch circuits in an electrical service panel is also sometimes needed.  This information lets me know if an appliance, motor, or other device is operating as expected.  How about electricity usage of an appliance or other equipment over time?  My visit to a home is usually under four hours, hardly enough time to figure out how often a device operates.  For this, we need tools that can record data.

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Peak Electricity Load Control Programs-a Solution for Home Electrification?

There are times during the day when electrical demand is high, during the morning when a large portion of the population is getting ready for work.  The lights come on, there’s an increase in hot water use, people are making coffee, or using the microwave or an electric stove or oven.  All these add to a morning increase in electricity demand, a peak in usage.  A similar increase occurs in the evening when people return home from work.  The weather can also influence electricity demand, hot weather will increase the need for air conditioning and maybe dehumidification.  Overnight usage is typically low periods of demand.

The hourly electricity consumption from an actual energy audit I recently conducted showing increased usage based on time of day.

A problem with periods of high electricity demand, utility companies often need to bring peaking plants (short term power generating plants) online to satisfy short periods high electricity usage.  These power plants are sometimes only used during peak loads and often have higher air pollution rates than the plants designed to operate all the time.  If demand isn’t met by the peaking plant, the provider must purchase power on the open market.  Sometimes the electricity rates during peak electricity usage are purchased for dollars per kilowatt, and then are sold back to the customer in pennies per kilowatt.  Not the best business model. Continue reading “Peak Electricity Load Control Programs-a Solution for Home Electrification?”

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An Airtight Home, What Do the Blower Door Numbers Mean?

I recently had the opportunity to attend a BS and Beer meeting in Kansas City, MO where the meeting took place in a home under construction.  The home was being built by Aarow Building (Jake Bruton) of Columbia, MO (they recently opened an office in Kansas City).  The home is a single level, slab on grade with around 3,250 square feet.  At the time of the meeting, the home was just finishing the mechanical, electrical, and plumbing systems and about to move to the insulation phase.  A perfect time for a mid-build blower door test.

The purpose of a mid-build blower door test is to confirm that the home is on track to meet the air tightness metric (Jake informed me that all his new homes are contractual bound to achieve 1 ACH50 or less) and to find any missed opportunities in the air sealing of the home.  The mid-build testing can be simple, get the home to negative or positive 50 Pascals of pressure and record the CFM rate, this type of testing is called “single point”.  If you feel the CFM rate (or the calculated air changes per hour at 50 Pascals number) is too high, set the fan on “cruise control” and go find the air leak locations.  There’s no need to perform multi-point testing this early in the build, (a type of blower door testing where CFM rates are measured at progressively lower pressure points, usually starting at 60 Pascals), save that type of testing for the final blower door test. Continue reading “An Airtight Home, What Do the Blower Door Numbers Mean?”

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Energy Audit-Blower Door Testing a Barndominium

This post first appeared on the Rockwool R-Class Website

The first time I visited one of Kyle Stumpenhorse’s (RR Buildings) jobsites was in December of 2022.  I made the trip to Illinois to blower door test one of Kyle’s Barndominium projects, the project he calls “Building a Barndominium”.  The barndo we tested was post and frame construction using closed cell spray foam (CCSF) as both the insulation and air sealing for the project.  The home tested very well, 0.41 ACH50.

Kyle (Left), Dan Edelman from Rockwool (right), and me at Kyle’s first blower door tested barndominium, December 2022.

I got to know Kyle a little on that trip, I was very impressed by his attention to detail and willingness to learn.  He pushes himself to do better on every new build.  I wasn’t surprised to find out his next project he was planning on using Rockwool insulation.  He also had a goal, beat the blower door score of the project using closed cell spray foam as the air barrier.  Could it be done?

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Energy Conservation-Shallow Energy Retrofit

This post originally appeared on the Green Building Advisor website.

Several years ago, I performed a roof replacement for a customer, the customer wanted to change their older and failing asphalt shingled roof to a steel roof.  We stripped the old shingles and existing underlayment off, installed new synthetic underlayment and new steel over the 10/12 pitched roof.  I felt confident that this new roof would last many years.

The following year, the same customer asked if we would replace several windows in the upper level of his story and a half home.  The old windows were due for replacement, the single paned wood units appeared to be from the mid-1900’s.  Woodpeckers had pecked a hole nearly completely through one of the windows.  Several others were painted shut.  Again, a straight-forward job we had done dozens of times before.

The home with the roofing and window replacement that resulted in “attic rain”.

The spring after the window replacement, I received a call from the customer saying his roof was leaking.  He had water dripping in several areas in the upper level of the home.  A visit to his house did indeed show water damage, though it was not the result of a bulk water leak from the roof, but instead, air leaks from the interior had formed frost on the attic side of the roof sheathing, the home had never had this issue before.  I surmised that replacing the five upper-level windows had changed how this home handled air and moisture just enough to cause frost to form in the attic.  My first building science lesson about the unintentional effects of a shallow energy retrofit. Continue reading “Energy Conservation-Shallow Energy Retrofit”

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Recessed Lighting in Older Homes-The Issues and the Fixes

The post originally appeared on the Green Building Advisor Website.  

Recently, I’ve been on a few energy audits and assessments where the homes were built or remodeled in the late 1990’s and early 2000’s.  Electricians working in those times were installing the traditional recessed light fixtures, also known as recessed cans or pot lights.  This type of lighting fixture usually doesn’t have any issues when installed inside the air and thermal boundaries of the building envelope but can be very problematic when they end up displacing insulation and interrupting the continuity of the air control layer.  I’m going to discuss the pros and cons of this type of lighting as well as how we can improve the performance of a home that has existing recessed cans.

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Types of Home Energy Audits

This blog originally appeared on the Rockwool R-Class Program website. ROCKWOOL – R-Class Builder Program – United States (English)

Energy audit, energy assessment and building diagnostics, what are the differences?

Part of my work is in a niche discipline in the residential construction industry where I test and inspect both new and existing homes for construction errors and other deficiencies that cause a home not to meet its owners’ expectations.  A home can have a comfort or cost to operate issue.  There may be moisture or indoor air quality issues that cause health problems for the occupants, or maybe there are structural durability concerns due to water infiltration.  Sometimes this testing and inspecting simply becomes an education session to teach the homeowners how their homes work.

 

There are three different types of analysis I perform, an energy assessment, energy audit and building diagnostic.  They are all related, but a little different.  The first two deal with the movement of energy in a structure, the last is usually more about the movement of moisture, but not always.  Let’s dig a little deeper into each.

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Energy Audit-Calculating the Cost of a Home’s Air Leaks

Air leaking into a home (infiltration) or out of a home (exfiltration) happens naturally in every home, new or old.  No matter how much air sealing is performed, we just can’t make them completely air tight.  I’ve tested some new homes that were very tight, .33 ACH50, (anything under 1 ACH50 is very good) and I’ve also tested many older ones that aren’t so tight, we can use my 1952 Cape as an example, 9.71 ACH50.  In this post, I’m going to discuss how to manually calculate the cost of the air leakage and examine what we can do with that number. Continue reading “Energy Audit-Calculating the Cost of a Home’s Air Leaks”

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Energy Audit-Calculating Electricity Costs

Over the past dozen years of performing energy audit and assessments, I have learned there are three root causes that warrant an audit; there is a problem with the home, a problem with the equipment or appliances in the home, or a problem with the people living in the home.  Often these problems require testing of the homes electrical system and equipment to determine usage and the associated costs. Continue reading “Energy Audit-Calculating Electricity Costs”