Energy Efficiency From a Whole-House Systems Approach / How It WorksPublished on: September 2, 2013
When designing or upgrading a home, it’s important that the homeowner and contractors work together to take a whole-house systems approach to energy efficiency. This will ensure that all components and factors related to energy use will be taken into account to provide optimal performance. In addition to improving energy efficiency, a whole-house systems approach will result in a home that’s safer, more comfortable and more durable. Because of the large number of variables, contractors often will use computer programs to assist them in determining what’s best for your home.
It’s particularly important to work with an experienced heating, ventilation and air conditioning contractor (HVAC). Heating and cooling are almost always the biggest users of energy in a home, and their efficiency is affected by every other aspect of the house, including air sealing, insulation, ductwork, windows and appliances, as well as family usage patterns and preferences.
To make your cooling and heating systems as efficient as possible, your home needs to be well sealed against air leakage. Leaks in your home’s outer envelope allow for heated air to escape in the winter and hot air to infiltrate during the cooling season. Improving the air sealing of your home is usually a relatively simple do-it-yourself project. You can examine ceilings, walls, windows, doors and other areas for leaks and seal them with weatherstripping, caulk or spray foam.
Another way your HVAC system’s energy efficiency can be sabotaged is through heat transfer between the inside and outside, and between the attic and living spaces. To minimize how much thermal transfer occurs, your home must have adequate insulation. How much is needed will depend on your local climate. When retrofitting, adding insulation in your attic will offer much more significant benefits than adding insulation to walls or floors, plus it’s usually an easier process. Colder climates are generally recommended to have more attic insulation due to the role it plays in keeping heat from radiating upward into the attic, but it’s important for warm climates as well. The attic can become much hotter than the exterior air during the summer due to the sunlight beating down on the roof, so insulation is necessary to keep this heat from radiating down into your home.
The ductwork that delivers conditioned air throughout your home should be tightly fitted and well sealed. This means joints should be sealed with mastic or certified metal-backed tape. Poor air sealing can contribute to inefficiency the same way poor air sealing in your home does, and it can impede system airflow as well. It’s also important that ductwork that runs through unconditioned areas of the home has its own insulation. This is especially important for ductwork in the attic where extreme summer temperatures can quickly warm up the cool air within the ducts.
In addition to air sealing, energy efficiency concerns with windows include how well they insulate against thermal transfer and how much heat they allow in from sunlight. In the winter, heat from sunlight that gets in is beneficial, but in the summer it adds to your home’s cooling load. Closing interior blinds or drapes will reflect most of the heat, but doesn’t allow for natural light or a view to the exterior. Using awnings or natural landscaping to block sunlight avoids these disadvantages and is more effective at keeping heat out.
The only way to improve the insulation of windows is by upgrading to more efficient options. This is often an expensive retrofit to perform, but can substantially increase the value of your home in addition to increasing its energy efficiency.
There is a two-fold reason to pay attention to the energy efficiency of your home’s appliances. In addition to consuming less energy, more efficient appliances also tend to produce less heat. This important during the summer to help reduce your home’s cooling load. One especially inefficient item found in most homes is incandescent lighting. Most of its energy actually gets released as heat and not light. Light bulbs should be replaced with more efficient options, such as compact fluorescents or LEDs.
Heating and cooling systems require regular maintenance to keep performing efficiently. The air filter needs to be inspected monthly and changed when necessary, and you may occasionally have to clean other components. Your HVAC contractor should conduct pre-season maintenance tuneups for both your heating and cooling systems.
For more information on taking a whole-house systems approach to energy efficiency, contact us at AC Southeast®. We help homeowners throughout the Southeastern United States find quality contractors who can meet their HVAC needs.