It is important to have a clear understanding of where the material is going to be applied. Cellulose provides good value and performance for the price. Closed cell foam provides exemplary air sealing and a high R value of 6.5/inch. We are not in favor of fiberglass (except on the kneewall). We have observed many attics with the thermal camera and could see enormous amounts of energy perculating up through the fiberglass. Cellulose is much denser and does a much better job at air sealing. Fiberglass also has this unfortunate property of loosing substantial r-value when it gets cold outside due to the convective air currents that pass through it. The colder it is outside the more air pressure from the house pushing air through the insulation. .After testing various materials we determined that cellulose and closed cell foam performs the best although we do use fiberglass that is sealed with building wrap on the kneewalls.
It is often asked what is better fiberglass or cellulose insulation? We have done analysis on many attics that are loaded to capacity with blown fiberglass insulation. We have seen with our thermal camera vast quantities of energy leaking up through the fiberglass. This does not happen with cellulose, since the cellulose is much denser and does a much better job of the air sealiing.
A home leaks considerable air and it is our objective to tighten the homes envelope so that there is less energy leakage. We have found that fiberglass does not allow us to be as effecfive in achieiving this objective.
In the winter, when there is a substantial temperature differential between the outside and the inside (known as the Delta T) there is considerable air pressure pushing against any leaks or gaps. We have seen with the thermal camera heat that is perculating up through the fiberglass.
What is interesting and somewhat insidious is that both cellulose and fiberglass have the same R-value of 3.4 per inch. (R value is an insulating material's resistance to conductive heat flow.) The key point here is that R value is a measure of conductive heat transfer and fiberglass is very porous. The gaps in the fiberglass allows for air to easily push up through the material, significantly degrading the insulating properties. According to the Oak Ridge National Lab a federally funding research facility, fiberglass loses up to 30-50% of its R-value in very cold conditions. So why do fiberglasss and cellulose both share the same R value of 3.4 per inch? Good question. Perhaps the folks over at the ASTM.ORG can shed some light on this. The ASTM defines the specification for how you determine the R value of insulation and they decided to require that the test or experiment be done in a lab that is 70F degrees. In Minnesota we don't worry about our insulation when it is 70F degrees but very much are concerned about it during a sub-zero polar vortex. It is when the temperatures are cold that the air flows through the material and it is key to have a dense insulation like cellulose.
Most older homes do not have vapor barriers. We are often asked if it is necessary to have a vapor barrier. The manufacturer of our insulation states, "With Cellulose insulation we do not recommend a vapor retarder unless there is extremely cold weather or a high humidity area such as a pool or a spa. However, many building codes do require an Air barrier or Vapor retarder to be installed. Check your local building codes for compliance."
For attic work the energy code minimum for our region is R50, which is 15" of cellulose (or fiberglass). Insulation follows a law of diminishing returns, which means that the energy saving benefits of going from R40 to R50 is better then from R50 to R60. The energy companies require that the attic be brought to at least R50 to be eligible for rebates. This is the baseline minimum. The cost difference to go from R50 to R60 is typically not a large increase and so we recommend bringing the attic to R60 when possible. R60 is the requirement for compliance with LEED, EnergyStar, GreenPath and MNGreenStar.
Our cellulose insulation has been treated with borates for fire protection, a naturally accuring mineral often used in organic gardens and eye drops. Homes that have been insulated with cellulose are safer in a fire then homes insulated with fiberglass. Cellulose is a dense material and prevents the flow of air and hot gasses through it. An interesting video shows a controlled fire with cellulose, fiberglass and no insulation. The structure built with cellulose has vastly superior fire prevention properties.
Check out the following 'Big Burn' demonstration
https://www.youtube.com/xwatch?v=bIayU7N9e34One could argue that any insulation is green, since it helps to retain energy. Cellulose is especially notable since it is made from a recycled product, paper, treated with borates for fire protection (borates are used in organic gardens). The amount of energy that goes into the manufacture of cellulose is an order of magnitude less intensive then fiberglass which requires melting glass. Be wary of some of the foams that claim to be green since they are made from soy oil. These foams are open cell (and have no better R value then cellulose) and also contain petroleum products in combination with the soy.
Buildings consume a substantial amount of the U.S. energy budget. In 2014, 41% of total U.S. energy consumption was consumed in residential and commercial buildings, or about 40 quadrillion British thermal units. Improving the efficiency of our homes and commercial buildings will provide significant energy savings. It is also a fairly inexpensive measure and the payback rewards can be substantial.
This really depends upon how poorly insulated the building was before it was treated. We measure the air tightness of the buildings before and after our work and often will find air leakage improvements of 20% or better. On occassion we'll even see results of 60% improvement. The payback is very much dependent upon the convective and conductive energy loss improvements. We typically like to see a 4 year or better return on investment (with rebates).
Ice dams are caused by the attic roof decking with a temperature over the freezing point. The snow pack melts, the water drips to the eaves and often refreezes building up icicles and ice dams. The roof decking can increase in temperatures when there is heat leaking into the attic, when the insulation levels are low and when the attic is not breathing properly. The attic should ideally be close to the temperature outside in the winter. A properly treated attic must be sufficiently ventilated.
Generally the best method for air sealing is to clear out all the old insulation and then apply a 2"-3" layer of closed cell foam over the entire attic floor. This does an exemplary job of sealing the leakage. The foam also serves as a vapor barrier. On top of the foam is applied loose blown cellulose to build up the r-value to R50 or R60. Applying foam is not alway economically viable and so the next best approach is to tactically seal off the leakage under kneewalls, electrical conduits, recessed lights, plumbing and flue stacks, top plates and large structural leakage that we refer to as bypasses. Foam is often used as is caulk, tin, Sheetrock and other materials. Special care is given for heat stacks which are treated with metal and heat caulk.
Much care and thought must be given if the plan is to convert a basement into liveable space. There are many issues that must be considered such as water trying to push through the foundation (hydrostatic forces) or moisture getting trapped behind the insulation in the wall and condensing against the cooler foundation wall. This creates a fertile environment for mold. This is especially a problem in the summer months. If you are interested in doing a basement project give us a call so that we can better understand your needs.
There has been a fundamental change in the industry. As of late 2014 insulators must be certified by CenterPoint, Xcel or Minnesota Energy Resources, to offer rebates on behalf of their customers. Prior to this any insulator could apply for the rebate and there were plenty of bad practices as a result. To be certified the insulator must have people on the team who are BPI certified. BPI RBE-WHALCI Certification is done by the Building Performance Institute a national accredidation body. The insulator must adhere to best practices and have diagnostics tools such as blower doors. At the Green Home Doctors we take education seriously and invested in diagnostic tools and BPI certifications years before this became an energy company requirement. It has been gratifying to know that the Green Home Doctors were ahead of the maturity and evolution in the industry. It is a bad idea to simply engage an insulator based on price. If an insulator is significantly less expensive, this can often mean that they are cutting corners which can create other more costly issues later.
A bad insulator is often known in the industry as a "blow and go". They are interested in getting in and out of a project quickly and will often engage on multiple projects in a day. This usually means they do a poor job in air sealing. We have been called into numerous projects to clean up the mess often left by a bad insulator. One of the big issues is that they can choke off the ventilation and breathability in the attic. An attic must ventilate to release moisture. Otherwise the moisture condenses on the roof decking, frosts, builds up and then melts. This can cause all sort of problems from water infiltation into the house, mold in the attic or rotting of the structural wood and roof decking. We have seen some examples of this that are so bad that the homeowner had to have plastic suspended under windows to collect the drips and water leakage.
We have also seen cases where the attic was loaded to capacity with fluffy fiberglass, but with the thermal camera could see enormous amounts of energy leaking into the attic.
A good starting place is to have an energy audit. The Center for Energy and the Environment provides energy audits for the Minneapolis and St. Paul areas. These audits will provide valuable insights into energy loss and opportunities for improvements. Some specific things and clues to look for are spider webs and dirty fiberglass. If you see plenty of spiderwebs in the basement along the rim joist, this often means there are some significant leaks. The basement draws in air from the outside and fiberglass along the rim that shows dirt, indicates leakage. Dirty fiberglass in the attic or kneewall area also indicates air that is flowing through this material. If the floors are cold on the main foor, there is evidence of air flowing up and out (through the hatch or doors) or the furnace cycles frequently when it is cold out, these all indicate a leaky house. We will validate whether walls are properly insulated or whether there is heat leaking into the attic, as part of our diagnostic assessment.
You bet or as they say around these parts 'you betcha'. An improperly insulated attic will allow for much heat and solar gain to pass through the attic. Many of our clients have told us that there is a significant improvement to their homes in the summer. The air conditioner will not have to cycle on as frequently and in many cases may not have to be used at all. Cellulose also has this wonderful property of making the home feel tighter and mitigating noise from outside the home
Yes. We are BPI contractors, are certified and can provide rebates for CenterPoint, Xcel and Minnesota Energy Resources. We will also help in the documentation process. It is a simple process and the rebate check will be sent directly to the homeowner.
Typically not from a return on investment perspective. Windows and doors are expensive and the payback period is much longer then you will find for air sealing and insulation. We advise people to change windows for other reasons, such as aesthetics or if they are damaged. Air sealing and insulation will provide you with better cost saving benefits and 'more bang for the buck. If your windows are leaky, you are cold in front of them or there is a lot of noise through them, we do offer a proven economic solution that could very well be the answer.
This depends upon the community that you live in and the type of work that is being done. Some communities such as St. Louis Park and St. Paul require permits for any insulation work. Other communities require permits for new work, such as converting a room to livable space. We will take care of the permitting needed for the work we do.
We would love this. Drop us a note or call us and we can discuss options. We get a tremendous amount of business through referrals for our work and we are open to providing a commission for new business that happens through your network of friends and colleagues.
We love what we do, we get outstanding reviews and we believe that it makes sense to work towards improving the global climate challenge even if it means correcting the problem one building at a time.
