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Residential Energy Efficiency Blog
Saturday, November 07 2020
Hometrust sets out into Maryland communities every day to perform comprehensive home energy audits. We work with your BGE and Pepco neighbors by inspecting their attics, crawl spaces and basements.
Each home energy audit requires that a specific set of data points for the house get collected. During that process, it is an auditors job to determine what "opportunities" exist for low cost improvements, also known as retrofits.
Retrofitting is the work that goes into Home Performance. Making a real impact is the overall goal of the comprehensive home energy assessment and the subsequent retrofitting.
Determining how much attic insulation will cost will depend on the solution's complexity. Each home is quite different and getting measurable results requires hiring skilled technicians that are properly trained on how to do the job right.
The Attic Insulation Technician - Required Skills
Sealing and insulating a building shell requires technicians to work in tight spaces. Crews must be in good physical condition.
Often times similar houses in the same development have different problems. Through the years, different owners make changes to the building shell. Each property owner had their own "vision" along the way.
For the best results, technicians must have good general knowledge of residential building construction. Otherwise, important measures required to make the job effective, may not get completed. The quality of the workmanship should and does factor into the cost for attic insulation job.
Proper Measurements Are Key to Providing an Accurate Attic Insulation Cost Analysis
Houses that need pricing for attic insulation usually have lots of twists and turns. This is not because the insulation is different or because the house is older, rather it is a simple fact that all houses are complicated. A residential building is actually a ton of information all attached to form a space inside of a shell. There are so many ways for opportunities to get overlooked.
Missing a measurement or a location where insulation is required could be the difference between not only an accurately price job but also a job that will yield the desired results.
Similarly, if you don't seal all of the holes in a leaky boat then you might as well not seal any cause you're still gonna sink.
The Size and Style of Home Impacts Overall Costs
In all cases, insulation around a home must be contiguous with an air barrier. That is that the insulation and the air barrier must be together wherever the boundary between inside and outside exists.
When considering how much attic insulation costs, it should be understood that the price depends on the style and size of the home.
If a home has high ceilings in a bedroom and a standard ceiling in the hallway, there could be higher costs. This configuration creates a knee wall which also needs insulation.
If a house has a crawl space foundation and also has high ceilings on upper floors, then the cost will be higher than a home that does not have those features.
A good general way to figure out the cost comparison of two insulation jobs is to determine the overall square footage of the home's envelope or building shell.
Do You Need to Have Your Existing Insulation Removed?
In most home renovation projects it is customary to get rid of the old. For example, during a replacement roofing project, the old shingles are stripped off the roof and thrown into a dumpster not to be used again. The old shingles have no value. In fact, adding shingles over top of old shingles will actually lower the value of the project and the overall value of the home.
Insulation, on the other hand, is different. The insulation in your attic, believe it or not, does have some value. For example, if you have 10 inches of fiberglass rolled batting insulation at your attic floor, the R-Value is calculated at 10 inches by a factor of 2.1 to get the R-Value of the material. So, in essence, the insulation is giving you back some insulating qualities.
Unfortunately, as in the scenario above, there is not enough insulation to adequately separate the living space from the outside. But, there is no reason to get rid of the value that you do have. For example, if the R-Value of your existing insulation is calculated at R-20 and the recommended value should be R-49, then you only need R-29 to get where you need to be.
Removing existing insulation actually gets you further away from the mark you need to hit and will end up costing you more.
Here is one key thing to always remember: there is virtually no reason to remove existing insulation at the attic floor. Insulation is on the "outside" of your home.
Insulation that has been subjected to mold growth will not be a threat to your health if the issue causing the mold growth is stopped. Therefore, throwing away insulation that has mold on it once the problem is resolved is a waste of resources.
This insulation has had water droplets fall on it over time.
What Are the Typical Insulation Solutions and How Much do They Cost?
**Pricing listed in this article is based on information gathered in the Maryland market.
There is an expression in team sports like football and basketball. It goes something like this: "let's take what the defense is giving us". Essentially, what the team is saying is let's go after the places that the other team is not guarding. The path of least resistance, so to speak.
In preexisting homes, it is a similar game plan. We have to "take what the house is giving us". This means that careful consideration should be given to treating the areas that are accessible compared to the areas that cannot be reached. This approach will have a significant impact on overall cost.
As a general rule, when you are dealing with a Home Performance contractor, the overall goal is to find the opportunities that:
Let's take a look at what items are on the list and figure out a little more about each, including how much they cost.
Rim Joist Air Sealing & Insulation - the cost of an attic insulation job should also depend on how much unfinished basement areas there are. Great opportunities to seal the basement exist at the top of the foundation wall. Basement work in tandem with attic work will yield the best overall results. The cost per linear foot for rim joist treatment is usually around $5.25 per linear foot.
Knee Walls - You can learn more about knee walls here. Generally, a knee wall is much like an exterior wall. The difference - it is accessible from an attic area. Knee walls are usually insulated, however not well and as a result, they are major sources of energy loss and comfort complaints. To properly "button" up a knee wall, you can expect to pay up to $4.25 per square foot.
Block & Seal Knee Wall Attic Floor Gaps - A big issue that many homeowners don't address is the space between floors. The space between the floors is only accessible if certain types of residential home construction, commonly referred to as Cape Cod. This treatment usually costs $3.50 per linear foot.
Watch this video showing a knee wall attic floor gap in Cape Cod style home.
Attic Access Points - Most homes have at least one way to get to an attic space that needs to be sealed. The best way to determine how many hatches you have is to count. Then for each one, consider where you access the space. If you are inside, then you need to seal the opening to disconnect from the attic. An attic access can range from $175 up to $300 per opening, depending on the size, type and location.
Air Sealing - Air sealing an attic can be broken down into two main parts. General air sealing all top plates, standard penetrations (regular light fixtures, plumbing stacks and general voids and cracks will usually cost $1.00 per square foot. Ala Carte Air Sealing includes items like combustion appliance flues, HVAC chase openings, staircase voids and other thermal bypasses that are created by the construction style of the home. Cost per air sealing solution can range from $50 - $200 depending on the requirements to properly seal the area.
Baffle Installation - Attic ventilation is important for the longevity of your roof, roof deck, insulation and the wood framing. You should expect that for every foot of eave you have around your house that you will need 1/2 a baffle to improve, maintain or in some cases actually create new air intake for ventilation. Each baffle, installed, will cost $4.00 per. Baffles are installed in the toughest to reach places in the attic - at the lowest place the roof deck is in relation to the attic floor.
Cantilever (Overhang) Insulation
Overhangs on the front and rear of your home are wonderful because they add valuable square footage to the inside of the living space it it can really make a difference. The problem, they are susceptible to air infiltration if not insulated properly and they are hard to get to. Pricing for a cantilever can vary depending on many challenges, including the height at which the cantilever is positioned, the type of siding, if any, is in place and the amount of insulation required to fill the cavity. You can expect a cantilever project to cost between $275 - $2000 and more. Analysis should be given to the value vs. cost for a cantilever project. A well trained energy auditor can give you guidance on this type of insulation solution and the cost.
Crawl Encapsulation - A crawl space foundation creates great opportunities for improved efficiency, comfort and indoor air quality. On the other hand, it can escalate the overall cost of an insulation project. Untreated crawl spaces tend to go unnoticed when homeowners are thinking about how much an attic insulation project costs, but not considering the space for treatment could be the difference between an attic insulation job that yields results and one that does not. Crawl spaces have to be broken down into the following components of the job:
Typical Crawl Space Work Scope
Removal of Existing Insulation - $2.00 per sq. ft.
The cost to dense pack a cavity is typically $6.00 per sq. ft.
To understand more about why sealing the top and bottom of a home are most beneficial, read this information about building science.