True Energy Efficiency is very cost effective if the solutions are based on substitutions of materials and systems rather than simply adding on materials or expensive systems because the manufacturer says they are energy efficient in nature. True energy efficiency is really more dependent on the construction details as well as treating the house as a "System" rather than individual parts.
Too many times I have seen houses designed and built with energy efficiency in mind and the end product, and the decisions that it is based on, just becomes too expensive to build. When energy efficient decisions are made they are usually made based on treating the symptoms instead of the core problems. A Doctor would never do that, so why do it here? A few great examples that I avoid is simply adding more insulation, adding housewrap, and installing a higher efficiency furnace. If these are the decisions that are made in the name of energy efficiency, all that happens is increasing the cost to build while while reducing the energy cost by a minimum. These decisions are "bandaid" approaches to permanent problems. They don't work.
The key is to treat the house as a system of systems and individual parts that make up that system. In other words, don't make your decisions of which insulation product to use based on the different costs of the products. Make that decision based on the effect that product has on the rest of the house. I always use blown in insulation for this reason. If I can get the same R-Factor in a 2 x 4 wall with a blown insulation product as I can get in a 2 x 6 wall with a roll of fiberglass, even if the blown in product costs more, this is the most cost effective decision to make. Why? Simple, the added cost of the blown in product is offset by the savings of not going with the 2 x 6 construction. No, it's not the framing cost difference that saves you money, it's the lack of having to add extension jambs on all you windows that does it. What is important about this, is the blown in product is a much better product than the roll because of the tightness of the fit. This decision of product is a better choice because the installation is much better, and that will contribute allot more to energy efficiency than a higher R-Factor. You can't possibly install a roll of insulation as well as you can a blown or sprayed in product.
Your HVAC decisions are important for more than just the heating/cooling unit chosen. That unit is only as efficient as the rest of the system...like the design and placement of the ductwork...especially the sizing of the cold air returns. Also, you can't size the unit based on the square footage of the house if you have designed and energy efficient house...it will almost always be too big. That will result in spending too much money on the unit and running a very inefficient system wasting allot of money for heating and cooling you don't use.
The housewrap issue is just an example of great marketing. The only time I use it is when I need it behind a brick veneer finish. It's supposed to stop air infiltration...called leaks...but by the time it works (if it did), it would already be out of the house, past the insulation, and no good to me. Besides, the only way to install it is to staple it to the sheathing...meaning you are now putting more holes in it,...and, have you ever talked to any carpenter that liked installing it? It shows. Like I said, it's supposed to stop the air from leaking out or into the house. Since it doesn't work, why not leave it off the material list altogether and substitute with something that does work...like a foam sealant? Why? The foam sealant works. It fills in all the gaps and seams where air passes through and actually helps to turn the wall into a monolithic system as opposed to a series of individual parts. Think of it this way. First, the air/heat passes through the drywall then it avoids the roll of insulation and just leaks through the gaps between the insulation and the studs, then it hits the sheathing, then the houswrap, then the finish. What this means is each component of the wall is acting independently...no team work so to speak. By using the foam sealant in conjunction with the blown/sprayed insulation, you now have a monolithic system where the components work together instead of on their own.
This foam is also used to fill the gaps around every penetration there is on the house. This includes, but not restricted to:
What about those windows? I don't look at the R-factor as much as I look at the air infiltration rate. Not only does this tell you the obvious...that this is an energy efficient window, but it also tells you how good the quality of the window is. It still comes down to the installation as the potential, and usual, weak link here. You can have the most energy efficient window on the planet, but if the installation is poor...meaning there are gaps unfilled between the frame and the rough opening (and "stuffing insulation into it is just as bad as not filling it at all) the air just goes around the window and escapes through the cracks.
The rest is really just framing the house in a way to eliminate the ares of the house that should be insulated...but isn't. Floor bonds, wall corners (actually this method costs less), locations where the interior wall intersects with an exterior wall (this method also cost much less than what we do now), headers and the "heels" at the cornice/soffit area. All of these areas are areas where there is either little or no insulation, but the construction methods that are substituted allow us to insulate these areas fully...while the cost is far less.
Here in Michigan, as part of the seminar I spoke at, our local electrical utility company did a year (December 1993 to December 1994) long study on one of my houses to see the effects of what I described above was on the energy bills. The house in question was a 4800 sq ft house with walkout basement using the above methods to build. The cost to build this house was actually less than if we hadn't done the "energy substitution" decisions above. The energy cost...?, how about an average of only $30/month. Keep in mind this included a time in January 1994 when for a couple of days the actual recorded temperatures was in the forty degrees below Fahrenheit range...you read that correctly. It was a time of record lows in the state.
Treat the house as a system when it is designed, with no weak links, and you'll end up a winner...now and into the future.
This foam is also used to fill the gaps around every penetration there is on the house. This includes, but not restricted to:
- plumbing stacks
- sill plates
- electrical boxes
- behind trims and moldings
- utility feeds
- headers...and more
What about those windows? I don't look at the R-factor as much as I look at the air infiltration rate. Not only does this tell you the obvious...that this is an energy efficient window, but it also tells you how good the quality of the window is. It still comes down to the installation as the potential, and usual, weak link here. You can have the most energy efficient window on the planet, but if the installation is poor...meaning there are gaps unfilled between the frame and the rough opening (and "stuffing insulation into it is just as bad as not filling it at all) the air just goes around the window and escapes through the cracks.
The rest is really just framing the house in a way to eliminate the ares of the house that should be insulated...but isn't. Floor bonds, wall corners (actually this method costs less), locations where the interior wall intersects with an exterior wall (this method also cost much less than what we do now), headers and the "heels" at the cornice/soffit area. All of these areas are areas where there is either little or no insulation, but the construction methods that are substituted allow us to insulate these areas fully...while the cost is far less.
Here in Michigan, as part of the seminar I spoke at, our local electrical utility company did a year (December 1993 to December 1994) long study on one of my houses to see the effects of what I described above was on the energy bills. The house in question was a 4800 sq ft house with walkout basement using the above methods to build. The cost to build this house was actually less than if we hadn't done the "energy substitution" decisions above. The energy cost...?, how about an average of only $30/month. Keep in mind this included a time in January 1994 when for a couple of days the actual recorded temperatures was in the forty degrees below Fahrenheit range...you read that correctly. It was a time of record lows in the state.
Treat the house as a system when it is designed, with no weak links, and you'll end up a winner...now and into the future.
