Not all insulation installations are equal. In fact, there are different grades of installation that your contractor or building inspector may not even know about himself. RESNET, or Residential Energy Services Network is a non-profit organization that sets standards which energy audit inspectors use to evaluate the residential building industry. They define grades of insulation that materially affect the energy scores of a construction project. You can see more of what they do on www.natresnet.org.
For building or remodeling homes in the middle South such as my home in Little Rock, Arkansas, we tend to like the spray foam applications that create a 100% air barrier in the cavities of the structure. Their pricing has gone down in the years, especially with the hybrid applications of a thin layer of foam and a filling application of cellulose. Installation is more consistent. Also, I like the insulation per buck on this rather than the traditional methods.
Still, the most common insulation is inexpensive batt insulation. This is the rolls of pink stuff that you can buy at Home Depot and looks so temptingly easy to install. The manufacture of them have improved so much that they are easier than ever to install yourself. I love DIY projects. However, the insulation companies have such good deals on the pricing of the material, that it is often the case that they can deliver and install for the same or less price than you can buy the material retail. And have you seen how much they haul in one truck? I would never do that to even my own pickup. Let the installers do it. But be aware that there is a wide range of quality in the labor.
Variables one should look for in batt insulation is compression, gaps, air barriers and being inspected. If it is not inspected by a Qualified Energy Auditor at the time of installation, then you can only get the lowest Grade 3 rating on a RESNET rating. This may or may not be significant and could cost you from getting a possible $1500 tax credit for building envelope efficiency for new buildings. Check the IRS or your local Auditor for more information on that. I highly recommend hiring one of this guys. Not only might you qualify for tax incentives, but you get better inspections and therefore better work products. I just want to tell you the criteria that the auditor will look at, so that you can look and know yourself.
You don’t get what you contract for. You get what you inspect.
- There should be no gaps or at least only very very small gaps less than 2%.
- There should be no compression, or at least not more than 30% compressed in spots
- Where there is wiring, the insulation should be split around wire, not compressed.
- The wall needs to be enclosed on all 6 sides with drywall or air barrier
- The insulation must rest against the inside edge of the space that it is supposed to insulate. You would not want to walk outside with your coat loose around you so the wind could whip through your coat, now would you?
- Moderate to frequent defects such as gaps around wiring and pipes is allowed
- Rounded edges over less than 10% of the area and compressed by 30% is allowed. You know, like pushing the edges of the insulation in too much on the sides to make it easier to staple the paper to the studs. Too much ease of installation and your grade goes down.
- Gaps of no more of 2% of the area that have no insulation at all, (not just the compressed amounts allowed in Grade 1)
- More than 2% of areas totally missing
- If more than 5% is totally missing, then the auditor has to count that 5% as not having insulation at all in his energy models, significantly lowering your rating and your energy savings. My wife would not let me out of the house with a coat with more than 5% holes in it!
What is your contractor’s grade? Ask an inspector. For the most part, generals are happy to have a client’s inspectors checking the work. It guarantees better work from his subcontractors. It gets better results for you and saves the planet too.