Frequently Asked Questions About Home Energy Performance
Doesn’t my home need to breath in order to provide fresh air?
There is a big difference between a leaky home and a properly ventilated home. While a home must meet the standard for airflow, many homes leak much more than they need, resulting in wasted energy. Even worse, air leakage patterns may result in what we believe to be fresh air being air that has entered through old wall cavities and cracks that could be full of mold or other potential contaminants. Since air leakage doesn’t ventilate all areas equally some spaces end up drafty and others stagnant and polluted. Mechanical ventilation overcomes these problems by providing the right amount of ventilation on a constant basis, exhausts wet areas to control moisture in the home and provide fresh air to the right places. Tightening up your home with the addition of mechanical ventilation can result in both lower bills and improved air quality.
Source: Natural Versus Mechanical Ventilation, http://www.hvi.org/assets/pdfs/HPAC_CookeJanFeb05.pdf.
Will new windows make my home more energy efficient?
Sure they will, but it is important to remember that replacing your windows has a long payback period. If your home is already well sealed and insulated and has energy-efficient appliances, heating and cooling then new windows could be the next logical step, but it is rarely the first one. It’s not uncommon for a window salesperson to say that new windows will result in lower bills, or a HVAC contractor to suggest that a new furnance will, and in both cases they may be correct. But it is important to recognize that some of the lowest cost improvements may give you the most return on your weatherizing dollar. When you have a whole-house performance test your auditor will recommend retrofits to your home with the most cost effective ones first. That’s why we say getting a home energy performance audit will help you lower your bills to RIGHT way.
What does a blower door do?
Professional energy auditors use blower door tests to help determine a home’s airtightness. These are some reasons for establishing the proper building tightness:
Reducing energy consumption due to air leakage
Avoiding moisture condensation problems
Avoiding uncomfortable drafts caused by cold air leaking in from the outdoors
Making sure that the home’s air quality is not too contaminated by indoor air pollution.
A blower door is a powerful fan that mounts into the frame of an exterior door. The fan pulls air out of the house, lowering the air pressure inside. The higher outside air pressure then flows in through all unsealed cracks and openings. The auditors may use a smoke pencil to detect air leaks. These tests determine the air infiltration rate of a building.
There are two types of blower doors: calibrated and uncalibrated. It is important that auditors use a calibrated door. This type of blower door has several gauges that measure the amount of air pulled out of the house by the fan. Uncalibrated blower doors can only locate leaks in homes. They provide no method for determining the overall tightness of a building. The calibrated blower door’s data allow the auditor to quantify the amount of air leakage and the effectiveness of any air-sealing job.
Blower doors consist of a frame and flexible panel that fit in a doorway, a variable-speed fan, a pressure gauge to measure the pressure differences inside and outside the home, and an airflow manometer and hoses for measuring airflow.
Source: Energy Savers, http://www.energysavers.gov/your_home/energy_audits/index.cfm/mytopic=11190
Why does my home have icicles?
With the recent cold and snowy weather we have been experiencing here in Pittsburgh it is not surprising that we have been treated to a stunning display of icicles. Huge spears hanging from gutters and eves, some long enough to reach the ground. While many people assume that these wintry spikes are just par for the course, the truth is that they are symptoms of a larger issue.
Icicles and Ice dams, that thick ice edge that forms in your gutters, are a result of warm air leaking from your home. This warm air melts the snow that falls on your roof, which runs down the roof to the cooler edge by the eves and then refreezes. When just a little snow falls this phenomenon is most visible when snow melts off the roof even though the outside temperature is below freezing. After all, the heat that melts that snow is coming from somewhere, and that somewhere is from your home. When the snow really piles up, the problem gets worse since every inch of snow actually insulates the roof a bit more, in turn, keeping more heat in the attic, which makes the roof warmer, which melts more snow and causes more damming – a vicious cycle.
This damming eventually becomes serious enough to rip gutters off, damage eaves and back water up into the house causing damage to the attic, insulation and walls. Sometimes you can’t see it, but it may appear as blistering paint and soft spots on your walls and ceilings as the moisture looks for a place to escape. Other times it shows up as leaks from your ceiling and rafters. While shoveling snow off the roof may bring quick relief to the some of the problems (be careful not to damage the roof while shoveling), the best way to address the problem is to prevent warm air from escaping with proper air sealing, insulation and attic venting.
Think of your home in terms of inside, heated space and outside, unheated space. Your living space is warm and your goal is to keep as much of that warm, heated air inside. Other areas of your home, like your attic, and possibly your garage, are unheated and should be thought of as outside your home. Your goal is to seal and insulate the heated space from the unheated space.
Common suspects like unsealed and un-insulated ductwork, un-insulated wall and ceiling penetrations from outlets, recessed lighting, ventilation fans and attic access panels, just to name a few, all allow heat to escape into those unheated spaces. When that heat escapes, it is not only a cause of icing problems, but also a waste of money and energy.
Similar air leaks from penetrations in your basement walls, around the rim joist of your home and from doors and windows serve to pull cold air from outside into your home and create drafts and cold pockets inside your home.
To find all these leaks and the proper location for insulation improvements, start with a home energy audit. Through diagnostic testing with a blower door, duct blaster and infrared camera an audit can uncover hidden leaks and poorly insulated areas of your home and give you a roadmap to improvement, focusing on the most cost-effective updates first.