Building Energy Efficient Homes
In todays world building energy efficient homes has become very trendy. Being trendy doesn’t necessarily mean it’s a bad thing however. People have different reasons for building energy efficient homes, but the end result is a home better built for the consumer and for our environment regardless of the builders reasons.
I want a lower electric bill
This is probably the first and most common reason we see people wanting to build an energy efficient home. There are different factors that go into building energy efficient homes, but this seems to be a very prevalent one.
Building codes have been adjusted over recent years to help this issue. R Values, high efficiency windows and doors, spray foam insulation, ICF walls just to name a few.
A major impact on your electric bill is your heating and cooling system. This system is designed to meet your specific home needs. How many windows and doors are in the home. What direction are they facing and how much overhang is covering them. All these factors are considered in sizing your ac system.
One that is often overlooked is the exterior wall construction. ICF exterior walls are unparalleled when it comes to energy efficiency. The icf walls construction is a thermal break from inside the house to outside the house except for openings in the walls such as windows and doors. ICF walls have the single largest impact on building energy efficient homes.
On a frame home, typically 16″ on center studs are used with insulation between the studs. Heat energy moves similar to water. It takes the path of least resistance, so the heat simply moves through the wall at each stud. Wood studs are very poor insulators allowing the heat to transfer to the cooler side of the wall with relative ease. This is called a thermal bridge.
This simply isn’t possible with ICF construction. There is a complete thermal break with icf construction. Because of this, your ac system can many times be up to half the size needed in an icf home as opposed to a wood frame house.
Will changing my windows help?
Absolutely changing your windows to more energy efficient windows will lower your electric bill. How much? I don’t know exactly. I’m not even sure the savings will pay for the cost of the upgrade in a remodel situation. This needs to be figured on a case by case basis.
However, if you are building you do want to get the most energy efficient window that will fit in your budget, no question about that.
If you are building with icf your window and door openings are your weakest point for energy efficiency, so you want to put in the best you can afford.
What about spray foam insulation?
We love spray foam insulation of the roof deck or in the walls if icf is not used. To date it is the best form of non-structural insulation available. We recommend open cell as opposed to closed cell for two reasons.
1) Cost. Open cell spray foam is less expensive than closed cell.
2) Water intrusion detection. For example if you are insulating the roof deck and your roof leaks. With open cell this leak will make it’s way through the insulation and you will be able to detect the leak and make the repair before too much damage is done.
With closed cell insulation in a leak situation, the water will be held between the roof deck and the insulation and many times will be undetectable allowing further damage to your roof deck and roof framing structure. This can be much more costly to repair once it is discovered.
If icf is a consideration when you build, we recommend using spray foam only on the roof deck to make a complete envelope system of insulation. The Styrofoam insulation on the icf is a more efficient insulation material than spray foam.
Building Energy Efficient Homes Wrap Up
Bottom line is that there are many products that can be utilized in building energy efficient homes. I may be slightly biased toward icf, but that is because it is the product with the single largest impact to this goal. I believe icf should be the starting point and then add as many other efficiency products as the budget will allow when there is an option to do so, but by starting the process with icf, you have already won the war.