Do new windows save you money on your utility bills?
I'm sure you have seen window commercials claiming that they save customers “50% to 60% or even more!!! On energy bills." In return you have not heard them give an actual percentage number on savings in dollars. That is because they have found themselves in some hot water about the claims. In some limited case studies that claim can be true. However in most cases windows are lower on the priority list in an energy upgrade viewpoint for return on investment (ROI). This is not to say that upgrading windows is not a good idea for many reasons, however from a pure energy standpoint and an energy consumption standpoint, it is better to address leakage into the attic space first. Attic air leakage is the primary “driver” for the need to draw in “make up” air, usually felt as a “draft” to the occupants.
Now on the Building Science side of things, with the subject of esthetics aside, we look at the assemblies of systems in the home and can calculate an R-(resistance) Value for that particular assembly. For example an un-insulated 2x4 wall with stucco and drywall still has an R value of Say R 3.5. If you were to fill the stud bays with R-13 insulation, keeping in mind that the wood framing cannot be removed and deducts from the overall assembly R value, the entire wall may now be an R-10 assembly. If you put in a few new windows, you reduce that R-Value again depending on the SF of window area and the R-Value of that window. So now you are down to a R-9 complete wall assembly. If the new window you had installed is an R-3 double pane aluminum window, it may look ugly and not operate well, but if it seals shut and is intact, then the R value is still good.
Continuing from the example above, if you were to upgrade an existing window to say an R-6 window (a good modern window) you have now only increased that specific space's R value. The wall itself it still un-insulated, the new window doesn't effect the overall R value of the entire wall assembly, it only effects the window opening. Lets say after the new R-6 window is installed and the wall interior/exterior is completed, your now back up to a R-10 total wall assembly rating. The cost to achieve that small increase in R-Value does not pencil out in energy savings for several years.
Air sealing the remainder of the home, allowing any air infiltration to occur at windows is a better strategy for a number of reasons;
1. Elimination or reduction of the “stack effect” where air is pulled up into the attic causing drafts from colder areas or crawl space.
2. Allowing for makeup air to be pulled from windows or around doors (if at all) at least knowing that air is clean outdoor air and not from suspect areas, such as dirty attic.
Do new windows save you money?
Window replacement can save money in situations where the old windows no longer close properly or are in seriously bad condition. Otherwise it is a long term investment related directly to looks, value, noise control and others aspects of the home, but not a great investment in pure energy savings and energy efficiency.
Why is Home Performance Evaluation and Testing important?
We livein an age where our cars are diagnosed through a computer connection, most of us carry a supercomputer in our pocket or on our hip, we have hybrid vehicles, home solar panels, home theaters and so many other high tech gadgets. Yet when it comes to information regarding our homes we are often left living in the dark ages. We want our homes to perform in a way that is most beneficial to us, or else why build them in the first place? In order to ensure this is the case, testing should be performed. Especially on all new systems being installed today, i.e. centralized heating and/or air, new water heaters or any other major appliance. Often times a seasoned home performance professional will be able to provide a very accurate evaluation of the home with only a visual review of the systems, providing recommendations from their knowledge base for what is typical of the local housing stock.
Why is it a good idea to have my home performance assessed?
Like every product or system available on the market, continuous improvement is always the name of the game both for competitive reasons as well as regulatory requirements forcing the issue in the case of energy efficiency for example. Everyone can understand the difference between driving a Hybrid vs. an old V8 engine. The same thing is happening in the home performance industry, we are now in the Hybrid age and it is time to look at replacing the old V8 Monsters out there. Homes that have all systems their working together will keep you healthy, happy, comfortable and also cost less to operate, than similar built homes without any retrofit work. Having a home performance professional who is currently accredited by either BPI or HERS review the home is the best way to ensure that all systems are up to date, operating properly ,and coordinated.
How will this help me save money?
While the idea of spending money upfront to save money in the long term is nothing new, it is most obvious when it comes to home performance upgrades. Quality products, equipment and workmanship are never cheap, but when it comes to our homes, and families, why would we want a cheap alternative? The initial home performance evaluation itself will not save any money, and may even cost a small fee depending on who you hire or consult with (typically this is not the case). The improvements themselves will cost money, and one wants to be assured that the money spent was spent on quality workmanship. The best way to ensure quality workmanship is to test the final systems and let the installers know that they will be tested. Testing provides proof, otherwise everything is speculation. To learn about our testing services please contact us and we will be happy to go over your options.
What is air sealing and how does it apply to me?
Should I really do this additional work?
These are some common questions heard during our initial visit to a project/job site regarding home performance upgrades. In a nutshell it comes down to a simple example of a camping cooler: If you have a nice new cooler, and keep it in the shade, it will keep the space inside very well-conditioned, either warm or cold. If you start to drill holes in the cooler, and allow for the air from outside (unconditioned) to mix with the air inside (conditioned) pretty soon all the air is the same temperature. The contents inside the camping cooler is how you can feel inside of your home.
Apply that logic to your home and it is easy to see that an air sealed and insulated envelope is the key to comfort on the inside. We use the heating and sometimes cooling system to achieve this comfort level. All things considered, HVAC are simply energy transfer systems transferring heat either into or out of a space. (Note Cooling is more the removal of heat, than the addition of cool). Heat can only move in one direction, Hot to Cold. Nature wants to equilibrate everything, and the heat wants to move to the cold to even things up. Having a good air barrier and insulation between the two is the only way to feel comfortable.
In Santa Barbara the low hanging fruit of air sealing is primarily in the attic space and accessible crawlspaces as a first priority. Limiting what is known as the “stack effect” is the first line of defense to control air movement. Recessed Can lights are predominant in our indoor design, can light covers, or switching out old bulbs to new single lensed LED bulbs can reduce air leakage in the home up to 20% with this single measure alone. Adding additional air sealing of other penetrations noted from crawl and attic spaces can reduce that number even further. Home systems are designed to breathe through ventilation to the outside world where needed, but it is not designed to leak that air into your living space! Our recommended strategy is to reduce air leakage as much as possible and to provide controlled ventilation as needed. Before air sealing, you should first:
•Detect air leaks
•Assess your ventilation needs for indoor air quality.
Adding mechanical air exchange as required. (And yes that is better than not sealing the leaks). Leakage is uncontrolled air at uncontrolled times from uncontrolled spaces. Ventilation is controlled air at controlled times from controlled clean locations.
How does Air Sealing save me money?
By both reducing the need for space conditioning operations (fuel and electricity costs), and reducing wear and tear on those systems, air sealing saves money both quickly and in the long term for replacement and maintenance costs. Keeping you more comfortable in the home can also improve health, as well as a dramatic improvement to your indoor air quality. Once the sources of potential bad/unfiltered air are sealed off to the inside of your home this becomes precedent. Imagine sitting in your attic or crawlspace, you will quickly realize that you do not want that air in your home where you and your family breathe. Keep in mind that sometimes the answer would be to install a mechanical air exchange unit or ERV, to totally ensure both indoor air quality and a healthy number of air exchanges in the home.