The obvious - and not so obvious - ways that air leaks in and out of your home.

With the arrival of chilly weather, we become aware of cold air leaking into the home, and our instinct is to plug up the leaks.  But sealing the house too tight can be more harmful than a leaky house.  Controlled ventilation and proper air sealing is the goal.

What is Air Leakage?

Air leakage – also known as air infiltration – is unwanted amounts of outside air entering the house through cracks and small openings.  A leaky house allows moisture, dust and allergens into the home, making it unhealthy.  As air pressure changes in your home, these same leaks also allow heated air to escape outside. These air leaks waste energy dollars because it costs more to heat a home that’s letting air sneak out through cracks and openings.

Where Does the Air Leak?

Air leakage can account for 50% of your heating costs, and the pie chart above shows the most common areas where unwanted cold air seeps into the home.

A good analogy is to think of going outside on a cold, windy day wearing an expensive, good quality winter coat all decked out with thermal fleece and water repellent, but if you don’t zip it up, you get none of the warmth benefits you paid for.

You need to zip up your home by sealing air leaks.  The most efficient replacement windows and extra insulation cannot help reduce your heating bills if the areas around them let in the cold air.  You can have reduced energy bills, and increased comfort and health by identifying air infiltration points and sealing them up.

How Do I Find the Air Leaks?

A home energy audit can include infrared detection and a blower door test.

Two of the most effective ways of finding air infiltration weaknesses in your home is with a blower door test and infrared thermal imaging. Both of these tests can be performed during a home energy audit.

Testing the air-tightness of a home using a variable speed fan called a blower door will help reveal air leakage sites.  A door-panel system with a calibrated fan and pressure gauges is set up in an exterior door and is typically used to create negative pressure that will pull air through cracks and penetrations in your home. The tighter the building, the less air is needed from the blower door fan to create a desired change in building pressure.

Left, a patio door. Right, same door as seen by infrared camera reveals air infiltration.

An infrared thermal camera shows surface temperature differences, which pinpoints exactly where air leaks compromise efficiency.  The pictures above show a patio door as seen through the infrared camera, with the blue areas revealing cold outside air leaking in. Solutions for stopping this leak include adjusting the door and the threshold, and repairing and/or replacing the weather seal around the door.

Start with a Home Energy Audit

A home energy audit by an experienced and certified energy auditor who will assess and recommend solutions is the best way to take control of your comfort, health and energy bills.  Choosing a company that can assess, recommend and perform the solutions increases your efficiency and peace of mind.

Mosby Building Arts has a deep bench of Certified Green Professionals, and energy auditors trained and authorized by the Building Performance Institute, Energy Star and the Missouri Department of Natural Resources.  Take advantage of their knowledge and experience to perform the solutions that will benefit you the most.  You can work the Mosby energy experts to develop a master plan of which improvements will bring immediate results, and which improvements will create a larger return-on-investment.

The first step of making your home energy efficient and comfortable begins with a Mosby Home Energy Audit.  To schedule an audit, call us at 314.909.1800, or contact us here.

Time for a new roof?

When is it time for a new roof? New gutters? More insulation? You may think of them as individual home improvements, but they are really one system, one protection, one comfort… or can be one nightmare.

Did you know that the roof is a system that not only keeps the inside dry by deflecting water away from your house but it should also allow your house to “breathe?” The roofing system is only as good as its weakest link, and if it has any flaws, water seems to find it.

When thinking of a roof, most people visualize roof shingles. The Roof System is made up of many parts, and the finished roofing material comes in many shapes, sizes, colors and materials. Other parts of the roofing system are:

• Flashing
• Soffit, Fascia & Gutters
• Attic Ventilation
• Air Infiltration
• Insulation

Each component works together to protect your home… or not.

TYPES OF ROOFING MATERIALS

Asphalt Shingles Also known as composition shingles. Wide variety of styles, colors and textures an affordable price. Installation adapts to most roof configurations. Low maintenance. Can last 12-30 years, with shorter life expectancy in Greater St. Louis due to extreme weather conditions, and poor – or no – roof system design.

Wood Shake Has a natural look with lots of character and helps insulate the attic. Durability depends on proper installation (which can be complicated) and quality of wood used. Requires constant maintenance.

Slate Made of sliver-like rock. Colors are limited to those found in nature, but can be laid in a variety of patterns. Very expensive, but can last 100 years, is resistant to rot, insects and fire. It is a very heavy and fragile material so can complicate accessing the roof.

Clay Tile Natural clay is resilient and withstands harsh weather. Lends historic charm to a home. Costly, but can last up to 50 years, is extremely durable and easy to maintain. Installation and repairs of this heavy and fragile material can be tricky.

Metal Choices include steel, aluminum or copper, in a wide variety of styles and appearances. Reflects heat from the sun and good in high wind and wet areas. Costs more than asphalt shingles but can last up to 50 years with very little maintenance.

A ROOF IS ONLY AS GOOD AS ITS FLASHING

It takes more than a roof to keep the water out. At the intersection of planes and wherever opposing materials meet is where water will try to get in. Strips of a rust-resistant metal are formed into these areas to move water away from the roof. When flashing is applied the wrong way, it will actually help water invade the interior of your home.

Mosby Home Consultants keep a file of photos of bad flashing they have seen while driving around Metropolitan St. Louis. Once you know what to look for, it’s easy to spot it from a moving car. It’s also cause for concern because bad flashing means water damage is in that homeowner’s future.

GUTTERS ARE PART OF THE ROOF SYSTEM

The duty of gutters is to move water away from your roof and onto the ground. Many foundation problems can be alleviated by diverting the water collected in the gutters away from the house.

At the roof level, gutter placement and maintenance is important. If the gutter is placed a little too high on the roof line, water and ice damming can damage the underlayment. If you allow the gutters to get clogged, the overflow water backs up, jumps the gutter trough and can rot both wood and aluminum soffit and fascia.

THE ATTIC IS THE INTERIOR OF YOUR ROOF

The flow and temperature of air in your attic has a direct impact on the performance and endurance of your roof. Improper ventilation causes the roof to overheat which then shortens the life span of roof shingles. When attic air flow is tampered with (by, for example, sealing intake vents) it reduces the effectiveness of your insulation.

A common problem we encounter during a Mosby Home Consultation is homeowners covering attic vents and air stacks in the winter to keep the attic warm, mistakenly believing a warm attic will keep the whole house warmer.

Covering the wind turbines, attic vents or any other air portal prevents moisture from escaping, which can cause wood rot, mold and other moisture-related problems. Improper attic ventilation will cause your HVAC system to work harder to heat or cool the house. The attic must maintain a delicate balance, and adequate air ventilation prevents condensation and moisture from accumulating.

Since the roof is one of the most important external elements of a house, it should not only be durable, but also have an aesthetic appeal. Schedule a Mosby Home Consultation for a full Roof System evaluation. Not only can we replace your roof, we can make sure the entire system is working correctly to give you maximum comfort and peace of mind.

A South St. Louis City homeowner recently had us out for an energy audit, and was kind enough to let us photograph the process so we could share the details of some of the testing that can happen during an audit.

The home was built in 1939, and is in great shape for its age, but the owners had a few concerns when it came to energy efficiency. A partial list of their issues included:

● Vinyl replacement windows were installed in the early 1990s, and they seem to work fine, but cold drafts pour in during the winter
● Are there other air leaks in the house?
● Is the water heater still working right or is it time for a new one?
● The gas oven is old but still does a good job; can it stay or should it be upgraded?

A blower door test measures air tightness, calculating how much air is lost based on square footage of the house.

Eric, a Mosby energy technician, came to their house, and after measuring the house and reviewing utility bills with them, set up the blower door test in the front entry door. This tool measures air tightness and calculates how much air leaks out based on the home’s square footage. This test confirmed what the owner suspected: the windows themselves are still good, but cold air is coming in through leaks around the frame. The blower door also showed major leaks around the back and basement door frames, as well.

An infrared thermal camera takes images that show surface temperature differences. This helps pinpoint exactly where air leaks compromise efficiency.

An infrared thermal camera, which takes snapshots showing temperatures as colors, is used to pinpoint exactly where air leaks. Turns out the dining room and living room window frames are compromised, and the basement door frame, according to the homeowner looking at the thermal images, “leaks like a sieve!” In all cases, the windows and doors themselves are good. It is a case of sealing up and weatherproofing the frames around them, and the client put that on the list of items for Mosby to repair for them.

In the kitchen, the gas oven was turned on and tested for carbon monoxide. When the carbon monoxide levels leveled off, Eric indicated that it was producing unsafe levels, and should be checked out by a service technician or replaced with a new Energy Star model.

A Mosby energy auditor checks a gas water heater for carbon monoxide levels. The heater is safe, but working past its life expectancy.

In the basement, there were no carbon monoxide problems at all, and all tests confirmed the water heater was perfectly safe, but it is working several years past its normal life expectancy. Now would be the time to consider replacing it with a new sealed combustion or tankless version to increase energy efficiency.

A combustible gas leak detector is used to check the safety of a home's gas lines.

Using a combustible gas leak detector, Eric found 5 areas around connector joints leaking minor levels of gas. These leaks aren’t large or dangerous, but they are wasteful, and that adds up on the gas bill!

With the testing done, Eric gave the homeowners a brief written summary of the energy audit. Within two weeks, they will get a detailed report on the findings and, most importantly, a list of recommendations on how to improve the safety and efficiency of their home.

This energy audit confirmed a few things the owners already suspected, highlighted what they do right, and revealed a lot that was unknown. The follow-up report and recommendations will give a clearer understanding of which repairs should be done immediately and what to plan for in the near future. For instance, they will begin shopping for new Energy Star appliances, and asked us to take care of sealing air and gas leaks. They told Eric that one of the reasons they chose Mosby Building Arts for their energy audit was because they like dealing with only one company that they trust to take care of it all, from research to repair.

Click here to see more pictures of a Mosby Energy Audit.