Renovate Your Home for Optimal Energy Efficiency
Unlock the Energy Saving Potential in Your House
Oct 23, 2009
If your home is older than 25 years and has never been renovated, now is the time to think seriously about making some major energy upgrades. Older non-renovated homes waste energy needlessly through an inefficient heating system, inadequate insulation levels, poor-performing windows and drafty air leaks around windows and doors in the building envelope.
Heating System
Unquestionably, replacing an old furnace or boiler with an energy-efficient unit will overall reduce home energy consumption and heating costs the most, when compared to other major energy retrofits.
The payback through energy savings will depend on the annual energy consumption of the existing heating system, the annual energy consumption of the new system, upfront unit and installation costs, and energy costs. Since a good quality heating system does not come cheap, payback is typically between 10 and 20 years.
Most gas furnaces or boilers over 20 years old are only between 50% and 60% efficient, some even less. As a result, much of the valuable fuel's energy never gets properly used and is wasted.
Luckily, significant technological advancements in the last 15 years have enabled consumers to get more warm air out of their heating system as well as the money they pay for energy each month. For instance, improved heat exchangers in gas furnaces and boilers extract much more usable energy from the fuel, that goes into the system, to be converted into heated air for the home.
Gas furnaces and boilers are designed as being either mid-efficient or high-efficient (also called condensing units). The performance level of each model is reflected in the AFUE (annual fuel utilization efficiency) rating. The higher the AFUE rating, the better the unit is--but the more costly it is to buy upfront. However, your monthly heating bill will be less when compared to a lower efficient unit.
Electric furnaces have also improved over the years, whereby newer systems consume much less energy than older models. Unlike gas heating systems, all electric furnaces operate at 100% efficiency. This means that all the energy that goes into powering the heating system is successfully converted into usable heat for the home.
Not all models are created equal, however. Check the unit's annual kWh rating. The lower the number, the less energy the electric furnace uses compared to similar models. But, expect to pay a little more for a top performing unit.
(Related articles by Heidi:
homerenorepair.suite101.com/article.cfm/the_importance_of_properly_sizing_a_new_furnace)
Insulation
Adding insulation to a non-insulated basement or attic is the second biggest way to achieve energy savings through a major renovation. A non-insulated basement and attic can each account up to 30% of your home's energy loss!
In most canadian attics, the recommended level for optimal energy performance is R40 and R50 for extremely colder regions. In non-insulated basement, the recommended level is R12. (R-value refers to thermal resistance to heat flow. The higher the R-value, the better the material).
Cellulose insulation and fiberglass insulation are just two insulation materials available, but are the most common. Then can be blown into a location or installed as batts, and have an R-Value of about 3.5. To obtain an R-value of 40 in a non-insulated attic, 11.4 inches of cellulose or fiberglass insulation is required. To obtain an R-Value of 12 in a non-insulated basement, 3.4 inches of cellulose or fiberglass insulation is required.
Consult your local government for recommended insulation levels in your area. Some building codes do not require levels for optimal energy efficiency.
Windows
Buying and installing high-performing windows is an expensive undertaking. It takes an extremely long time for saved energy to pay back the cost of the window, regardless of how energy efficient the window claims to be (high-performing double-glazed windows cost about 10% more than standard double-glazed units, but are twice as efficient.)
Nevertheless, high-performing windows do provide the invaluable benefit of improved comfort, less condensation, lower sound transmission and added value for you home over older units, making them a worthwhile retrofit investment--even if you can only afford to replace a few windows at a time.
The special features and coatings of high-performing windows include: inert gas fills, low-emissivity (low-E) coatings, and low-conductivity spacers (the material separating the panes in a sealed unit).
Building Envelope
Sealing air leaks in the building envelope--your home's outer shell--is an energy saving measure that gives you an excellent bang for your buck. Air sealing materials are fairly affordable, plus many homeowners choose to do the work themselves instead of hiring a contractor. The amount of conditioned air (energy) generally saved through air leakage control in an older home is often enough to recover material costs in just a winter!
On a cool windy day, take a lit incense stick or thin piece of plastic and check for potential air leaks in the building envelop. Key locations are windows, doors, electrical outlets, sill and header, attic hatch, ceiling penetrations into attic, chimney, mail slot, exhaust vents, foundation cracks, floor drain, and service entries.
If you need some expert help, make a list of air leakage points and bring it to a local hardware store where an experienced sales representative can help you choose the right product for the job and offer some installation advice. When it comes to air leakage control materials, such as caulking and weather strip, consider paying more for a quality product that promises long-lasting results.
Before you upgrade your heating system, it's a good idea to first seal any air leaks to prevent valuable indoor heated air from escaping to the outdoors.
By installing an energy efficient furnace or boiler, adding insulation to the basement and attic and sealing air leaks, you will be quickly reap the benefits of long-term energy savings. And, don't forget about your windows. High-performing units may be expensive to purchase, but they will greatly improve indoor comfort and increase the value of your home.
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