Optimizing Your Home's Building Envelope To Maximize HVAC Efficiency

31 July 2015
 Categories: , Blog


HVAC is the acronym for Heating, Air Conditioning, and Ventilation. Together the systems you use to heat and cool your home can hog a disproportionate amount of your budget. While it is wise to buy the most efficient furnace and AC unit you can, your HVAC equipment won't be as efficient as possible if your home is not designed to effectively isolate your home environment from the outside world. If you are trying to reduce your heating and cooling costs, a good place to start is by upgrading your home's insulation envelope. 

The Leaky Attic

When construction workers cut a hole through your drywall for a light fixture, they leave a tiny gap that is still large enough to allow air to leak around the fixture and right through your insulation. For example, hot air from your furnace rises to your ceiling and creates a high pressure zone. This air is then predisposed to flow into the low pressure zone created by the cold air in your attic. Conversely, when your attic heats up during the summer, the high pressure of a hot attic can cause hot air to leak into the low pressure zone of your cooled home.

On the other hand, a small leak can't cause that much of a problem, can it? The government estimates that you have enough leaks between your home and your attic to equal having a window open year round. To decrease the load on your HVAC equipment, you need to access your attic, place a plank across your roofing joists, and use silicone caulk to seal around anyplace where a pipe or wiring comes through your attic. 

Weak Windows

Contractors use r-values to measure how effective different substances are at insulating a home. They also make recommendations about what the r-value of the insulation in your home should be. For example, in the United Sates, you should have a minimum r-value of 13 and maximum r-value of 21 for the walls of your home. In contrast, the r-value of a double-pane window is about 3. Thus, windows are one of the weakest points in your home's insulation envelope. To improve the r-value of your existing windows, one of the best, cheapest upgrades is to apply low-e film to your windows. The right film will reflect the sun's UV rays during the summer and reflect the heat from your furnace during the winter, decreasing your cooling costs by 23% and your heating costs by 25%. 

Your home's HVAC equipment is a key part of keeping your heating and cooling costs low, but you can have the best equipment on the market and still pay too much to condition the air in your home. To reach optimal levels of efficiency, you will need to improve your home's insulation envelope. 

Reach out to a local HVAC contractor, like those at Winters Heating Cooling & Indoor Air Quality, for more details on helping maximize your heating and cooling efficiency.