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weatherization services winona

The Actual Facts about your home:

Let’s look at a few facts that ARE important for you to understand:

Energy & Moisture Movement:

Conduction: Conduction refers to heat movement through solid materials. Conductive heat loss always moves from warm to cold in any material and in any direction. Ever wonder why your feet get cold while standing on concrete? The warmth in your feet is moving into the colder floor making your feet feel cold. When you fill your coffee cup up with hot coffee on a cold day, the heat moves through the cup to the exterior warming up the cup. In a home, we try to use building materials that are poor heat conductors wherever possible.

Convection (The Stack Effect): As stated earlier, most people will say “Heat rises”. And we agree but not always. Let’s think about why that statement can be true – warmer air rises when surrounded by colder air. Warmer air molecules are less dense than colder air molecules so as a result, warmer air becomes buoyant. And the greater the temperature difference, the greater the rising force.

weather balloon

Think of a hot air balloon. If you were the pilot wanting to go higher, you would turn up the heat to create more upward pressure. Similarly, if you wanted to descend, you would open the small flap on top of the balloon to let the hotter air rise out through the open hole. The hotter air lost would be replaced by colder air gushing into the bottom. And the pilot would descend because the hotter air inside the balloon cools down and does not have the upward force it once had because the temperature differential between the exterior air and the interior air became less.

home weather balloon

Now think of your home as a hot air balloon but anchored to the ground. In our Minnesota winters, it gets colder outside in evenings. As that temperature differential widens, the stable indoor air has more upward force. Now if you have flaps in your ceiling like a hot air balloon has, the heat will rise up through those flaps rapidly and colder outside air will come gushing in from wherever it can. Guess what – if your home was not tested & certified by energy-star, it probably has a lot of “flaps” in the ceiling. Problem with your home’s flaps are they are open 100% of the time. We call these flaps “thermal bypasses”. Problem is you cannot see them but our blower door test with our infrared camera can find them.

 

Why is any of this important to you?

1. Because THE FLAPS IN YOUR HOME CAN BE FIXED. Did you answer yes to shutting your refrigerator door when left open? Then how much more would you want to close the flaps in the top of your home? Remember heating & cooling accounts for 55% of your energy bills – food refrigeration only accounts for 10%. And if you need visual confirmation, our infrared can provide that: The first photo shows an attic hatch that we found recently and the 2nd photo shows a top plate leak where cold air can get in:
thermal imaging

2. Health Benefits (Better Indoor air quality) – A home with a lot of thermal bypasses and a large stack effect draws in exterior air to replace the air it lost to its thermal bypasses. Unintended air flowing into the home can definitely contribute to indoor pollution. When exterior air finds random pathways into the home, it’ll continually come in using those same old pathways. That, by itself, may not seem unhealthy but the problem is as colder exterior air meets warm moist air inside the home, condensation will likely occur and when condensation occurs in that pathway, mold will be soon to follow. After mold develops, your home is bringing in unfiltered exterior air that comes into the home through dirty, damp, moldy air pathways. Also if you have an attached garage or are living above your garage, a home with a large stack effect pulls air in from the garage just as it pulls in exterior air. But the garage is where most people keep pesticides, herbicides, oil base paints, paint thinners, anti-freeze, oil, gasoline, pool chemicals, etc., and even that mystery container that lost its label. And don’t forget about their vehicles. Those toxic chemicals can make you sick - there is scientific proof to back up this claim. A study involving 100 houses conducted by Health Canada found that those with attached garages had measurable quantities of benzene inside the house, while houses without attached garages had little if any benzene. Benzene is a gasoline-related pollutant. The study found similar results with other pollutants. According to the U.S. Occupational Safety and Health Administration (OSHA), long-term exposure to benzene can affect bone marrow and blood production. Short-term exposure to high levels can cause drowsiness, dizziness, unconsciousness and death. A survey of Minnesota houses during the winter of 1996-1997 found that 74 percent of homes with carbon monoxide (CO) detectors that went off were triggered by CO leaking in from the garage. Other studies from Iowa, Colorado and Alaska have found substantial evidence of garage-generated CO leaking into houses. And homes with high stack effects pull these chemicals into your home through these unintended pathways for you to breathe. Another place the home will find its replacement air is through the ground. As homeowners place pesticides and herbicides on their lawn, it leaches into the ground. Those toxic chemicals along with radon gas & moisture can be drawn into your home from underground (yes, air does moves underground in many places). If that’s not bad enough, let’s look inside your home a moment – do you still have those outdated combustion furnaces or water heaters that rely on warm air to pull the carbon monoxide gases up out of your home? If the answer is yes, a large stack effect in your home can actually hinder this dangerous gas to safely exit your home. In fact, if your stack effect is great enough, your home can use the vertical stack as replacement air for the warm air lost and the carbon monoxide gases can get pulled into your home.
benefits of weatherization

How do we make the air better for you to breathe?

By reducing the stack effect found in homes, we reduce unwanted air from entering the home but we do still need some fresh air coming into the home for you to breath, to control humidity and to move air around in the home. We accomplish this through mechanical ventilation. An air-to-air exchanger can bring in fresh air in a controlled manner, filters the incoming air and even tempers the incoming air to save on energy costs.

To summarize, What are some benefits of weatherizing your home?

Numerous but let’s name a few:

Energy Cost – Think of your heating system’s main purpose as replacing heat that your house loses. What does it cost you to heat the cold air coming into your home to replace the heated air you lost through thermal bypasses into the attic? Wouldn’t it make more sense to keep that air you paid to heat inside the home? By stopping the stack effect, you benefit by keeping the air you paid to heat inside the home instead of paying to heat new cold air that your home lost. A good way to save energy is to install a digital thermostat and setting the schedule to shut the furnace off for 8 hours while you are sleeping. The clock will turn the furnace on and cycle back the heat before you awake but it is actually more efficient to let the furnace run longer than to have it come on for short cycles throughout the night. By the way, our discussion herein has been focused on winters but the same holds true in summers and cooling – it’s just that the stack effect is reversed in summers.

Better indoor Air Quality – As discussed above, your indoor air quality improves just by reducing your stack effect. Let’s control how much fresh air comes into the home and let’s make sure the passage ways for our fresh air is clean and let’s filter the fresh air coming in. This mechanical ventilation system also allows us to control humidity levels to keep mold in check and out of the environment mold is known to grow in.

Home maintenance – From a moisture control standpoint, you obviously benefit by reducing exposure to mold. For example: have you thought about replacing your windows because you believed they were bad windows? You may want to believe they are bad but first consider what the stack effect is doing to your home. If your home is losing air to the thermal bypasses in the attic creating a stack effect, the home has to find replacement air and it may have found an easy pathway through the frame of your window. So before you invest in replacement windows, consider reducing your stack effect instead – you may be surprised just how well that window actually performs! However, the air continually coming into that window and condensing may have finally deteriorated to where it is bad. But if you replace the window without reducing your stack effect, the new window will likely go bad too.

Increased Comfort – Have you ever been in a room that seems cold or drafty? That room or spot is usually near an easy inlet for exterior air. By reducing the stack effect, you reduce the need the home has to replace its lost air through those air pathways – those pathways are in continual use 24 hours per day. I have a lot of our new homeowners tell me that they used to keep their old home set to 72 or more to stay comfortable. Now, they stay warm in their home with the thermostat set at 65! That’s because they don’t find those uncomfortable cold spots.

Reduction in likelihood of ice dams – by stopping the stack effect, you reduce the liklihood of your attic getting warm and creating ice dams. So when you see an ice dam on your home, think about how you paid for that dam through your utility bills. When you see ice dams on your home, your home is trying to tell you something – please don’t ignore that. Click here for more information on ice dams.

These are just a few benefits of a weatherization project. Obviously there are many more.


Before we go, let’s go back to further address our favorite myths we continually hear:

Myth Buster #1 - “A home has to breathe” – Let’s take a moment to discuss this once again because it is the most misunderstood and most adamantly used phrase by the simpleton. What does it mean for a house to breathe? Animals & people breathe. Houses are complex systems but they are not living organisms. What is meant by this statement then? What someone really means who uses this statement is: “a wall assembly needs the opportunity to dry out”. If moisture develops inside of a tight wall cavity, that moisture must dry out or mold will likely start. We accomplish this by installing building materials that are permeable to water vapor. But this is not breathing. Vapor diffusion does not rely on air movement. By installing vapor permeable building products and controlling the humidity levels inside a home, wall cavities do not have to “breathe”. Building Scientists like to use the phrase: “Build it tight and ventilate it right”. However, we do concur that a house needs a continuous supply of fresh air to dilute toxins in your home and help manage humidity levels & improve indoor air quality. We accomplish this by installing a fresh air ventilation system. Fresh air ventilation is not something you install to compensate for a tight house – “they should be installed in every house and the house must be tight”. Think of the ventilation system as the lungs of a house. And just as humans can adjust their level of breathing, a ventilation system needs to be able to adjust its level of breathing. In leaky homes, the home breathes whenever the wind blows or when it’s cold outside and the stack effect is working – how would you like it if some external source decided when you could breathe and how much you could breathe? We recommend 15cfm of airflow per person and this can be accomplished.

Myth Buster #2: The lure of replacement windows: Don’t immediately blame your windows. The benefits of replacement windows are often overstated and rarely make sense purely from an energy perspective. As mentioned earlier, high stack effects found inside a home decompress the home. As the home loses heated air, the home needs to find replacement air from wherever it can find. And windows can be the easiest draw making you believe you have poor windows. In many cases, the main leak found on older windows was the method of installation – we usually find no air seal between the window frame and the framing members. That gap is now covered up by trim boards. A replacement window does absolutely nothing to address that gap nor does it address window frame flashings. When you spend money on replacement windows, you did nothing to improve your stack effect and you continue to have the same leak around the frame of the window. And even if you improved the leaks around the window, the stack effect still exists and will pull replacement air from other easier places. You may have improved the glass with low e coatings and argon gas however but the energy savings by improving the glass has been estimated at 40+ years payback. Also, be wary of replacing your egress windows found in bedrooms with replacement windows – be sure you receive a guaranty from the contractor that your egress windows will continue to meet egress requirements or you may be in for a big surprise if ever inspected.

If you are a do-it-yourselfer thinking about weatherizing your own home,
first think about these items:

•If you think you can fix ice dams by simply adding insulation, you are wasting your money.

•How much insulation should you have? The first 6” will save you more in heating costs than the next 6” but that doesn’t mean you should skimp. In our climate, we install R-44 in our attics. But remember insulation helps conduction but does nothing for convection!! And convection leaks are the biggest problem.

•Every home I’ve ever seen with rolled out insulation in an attic is a disaster. If you have rolled out insulation, call us – we can really make a difference. The pink panther makes it look easy in commercials but I have yet to see a job perform as intended. Show me an attic with rolled out fiberglass and I’ll show you a major heat loss. Our blower door test has proven this many times over.

•Watch out for vermiculite! It contains traces of asbestos.

•Watch out for guano – it can also be harmful to humans.

•If you still have knob & tube wiring, DO NOT cover it up!!!

•Don’t cover up your ventilation intakes at the eaves. These are necessary and a must have in all attics.

•Be weary of how you insulate around chimneys or vent pipes – do it incorrectly and you can start fires in your attic.

•Attics are complex systems – Adding more insulation is not the answer

If you want it done right the first time, Call us...

contact ellefson builders

Mike Ellefson
Mike@BuildWinona.com
507.474.9060 (office)
507.450.7465 (cell)
507.474.1005 (fax)

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