Low Insulation Found During Phoenix Home Inspection
Here in Phoenix it’s important to do as much as possible to stay cool in the summer and to reduce your energy bill. One area that often times can use some improvement is the attic insulation. Since the attic is typically out of sight and out of mind, most people just assume that their attic insulation is adequate to meet their needs and never think about it again. Over the years doing Home Inspection in Phoenix, I have learned that attic insulation can be surprisingly low and even on new houses can be below the minimum recommended insulation standards. One thing to keep in mind is that the insulation standards recommended by the US Department of Energy may not be incorporated into the current building codes where the home is built. While this recommendation is for the most cost effective insulation, if the building code doesn’t require it then it does not have to meet the recommendation.
US Department of Energy Insulation Standards
The US Department of Energy sets insulation R-Value standards, this is based on the zone that the home is in. For this post we will be dealing with Zones 2 & 3 which is where Phoenix is located. The standards change over the years due to improvements in materials, cost of energy and other factors. The last change that was made to the standards was in 2008, the R-values were upped in most zones. We will mostly be dealing with attic insulation since that is the type that can be easily seen and modified.
The current recommended Insulation standard for attics in Zones 2 & 3 is between R-30 and R-60. Visit the US Department of Energy Website on Recommended Insulation Standards.
Determining Your Attic Insulation R-Value
Determining the actual R-value of your attic insulation is one of those things that can be super easy or a little tricky. Below is some information on R-values of certain insulation materials to help you figure out an estimate of the R-value of your attic insulation. Keep in mind that these figures are estimates, all manufacturers have different specifications which make their materials have different R-values. I am only putting the most commonly used types, there are many types available but here in Phoenix we deal mostly with loose fill cellulose and fiberglass (either blown in or batts) on newer construction homes.
- Blown-in Cellulose (Loose Fill): Average R-Value = 3.5 per inch
- Blown-in Fiberglass (Loose Fill): Average R-Value = 2.5 per inch
- Batt Fiberglass: Average R-Value = 3.1 Per inch
Keep in mind that these numbers are estimates, each manufacturer makes their product a little different and that can lead to differing R-Values. On many homes the insulation installer will leave a certificate indicating the type of insulation used, this will usually have a chart that shows the actual R-Value for the brand installed. If you can find this certificate then use the numbers on it for accuracy. Another thing to keep in mind is that these numbers are after settlement, insulation settles quite a bit in the first couple years so the insulation would need to be installed thicker to allow for settlement.
So to figure your R-value you would measure the thickness of insulation in your attic and multiply that times the average R-Value for the appropriate type of insulation. Doing Home Inspections in Phoenix I have found that the thickness of insulation can vary greatly in each attic. Don’t rely on the installers paper tape measures that are stapled to the rafters, these can often times be installed improperly which leads to a false reading.
Plan For The Future
In the past many people have claimed that there is no advantage to increasing the insulation level over the minimum, their reasoning is that the added expense will never be recouped by the improvement in efficiency. While this is true up to a point, this does not take into consideration two very important factors, settlement and energy cost.
Settlement
Over time blown-in (loose fill) insulation will settle, that 8″ of insulation you have now could be 6″ within the next 10 years. Settlement also leads to increased compaction of the insulation which lowers the existing R-Value.
Energy Costs
Energy costs are on the rise and I personally don’t expect that to change anytime soon. At the time the home was built, the insulation may have been adequate to maintain reasonable energy bills but as time moves on and energy prices rise the increased efficiency due to a higher R-Value would be in your favor. Think of it this way…before 2008 the US Department of Energy recommended an attic R-Value of R-30 to R-38, as energy costs rose they increased their recommendation to R-30 to R-60. Their numbers show that the higher R-Values lessen the energy use enough to make it worth the cost of installing additional material.
To Increase or Not to Increase…That’s The Question!
When I do a home inspection here in Phoenix and inform the client that their insulation is below the recommended minimum standard, the question I usually get is “Is it worth increasing?”. This question is one that doesn’t always have a straightforward answer.
Scenario 1: Let’s say the home was built in the 1970′s and it has 3-4″ of cellulose insulation installed, the answer is easy! Yes it would be worth increasing, over time you would benefit from the increased efficiency.
Scenario 2: Now let’s say the home was built in 2008 and has 7″ -8″ of cellulose insulation installed, this one isn’t nearly as easy to answer.
There are allot of factors that would go into making this decision to increase the homes insulation, here are a few:
- Will you be installing it yourself? If so then this brings the cost of the job way down and could make it more worth it.
- Will you be living in the house for more than a couple of years? If so then the savings over time could make it worth it.
- Will you be installing at the higher level of the minimum standard? If so then the increased efficiency could make it worth it.
If you pay a contractor to increase the level of insulation just a couple inches then the expense probably may not be recouped within a reasonable time, that’s why it’s best to maximize if you are having the work done.
Return On Investment
I am always going to recommend that the home be brought up to the current minimum standard, if my recommendation is followed is up to the homeowner. Even if it doesn’t pay you back fully during the time you own the home it can have rewards when you go to sell it due to the insulation being upgraded.
There are currently many tax incentives and rebates that are available to increase insulation, I won’t go into the details of this but if you are considering upgrading your insulation you should look into it.
In a
previous post I talked about attic insulation, this is another take on the subject and a bit more in-depth in some areas.
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