Controlling humidity is very important and many of the houses we audit have moisture or dryness problems. I was just in a house today that had two very large humidifiers in the master bedroom. I knew they had a big problem with dryness. Many homeowners and some heating and air conditioning professionals will try to address humidity and dryness issues symptomatically by adding equipment such as humidifiers or dehumidifiers. Building scientists will attempt to address the root cause of these problems rather than patch them with a band-aid. By thinking of the house as a system we can more
easily find and address the root cause.

A good building performance contractor will look at what is causing the problem rather than try to mask it. The root cause of moisture issues can vary from house to house and requires a thorough investigation to be certain. Many of these problems are the result of either incorrectly sized HVAC systems (heating, ventilation and air conditioning) or excessive leakiness of the building envelop. If the air-conditioning system is too big for the building, the unit will cycle off too soon. The unit will cool the air and satisfy the thermostat before it has taken the humidity out of the air. This results in a cool but damp feel and sometimes a musty smell in hot weather months.

If the building is too leaky it will feel humid in summer and too dry in the winter. Take the example of the house I noted above with the two big humidifiers. Diagnostic testing with a blower door showed that the master bedroom space was not very airtight . It was also built over the garage. As a result, in the winter the heated air would rise and escape into the attic. This would cause cold and dry air to be pulled in from the garage space below. The root cause is the leakiness and we can address this directly, once and for all.  I know that these homeowners will be able to get rid of their humidifiers when we complete our work since we will directly address the root cause. The answer to excessive winter dryness often is to tighten the building envelop so that the humidity that is naturally created in the home, stays in the home.

Additionally moisture and temperature interact. The higher the temperature the more water vapor the air can hold. When warm moist air cools and reaches its dew point, the moisture condenses into water droplets. We see this phenomenon many times in the summer in crawlspaces where there is duct work. The moisture laden air from the crawlspace ground encounters the cold metal duct work in the crawlspace and water droplets form creating dampness in the crawlspace.

Some traditional contractors may recommend placing dehumidifiers in the crawlspace. This solution can work if the crawl is tightly sealed. However, it uses energy and is really just a cover-up in many cases. The root cause can be addressed by covering the ground with a plastic vapor barrier and making sure the duct work is sealed and insulated. In some cases it may be necessary to bring a small amount of mechanical ventilation to the crawlspace. Sometimes moisture in the crawlspace is the result of condensation on leaky air ducts or bulk water flowing from clogged gutters or poor landscaping. Sometimes we find that a poorly aimed irrigation jet is pouring water in through a crawlspace vent!

Lets fix these problems first before spending a lot of money on a sealed crawlspace and dehumidifiers.

It now appears the for the first time in several years there will not be a tax credit for insulation products next year. As of December 31 the tax credit will go away and there is no certainty at all that it will ever return This mean that procrastination could cost you up to $500, the maximum amount of the current tax credit amount.

If history is our guide, we will get dozens of calls in November and December from homeowners who are recognizing two things;

1: It is getting cold outside.
2: The Federal Tax Credits are going away.

Unfortunately, we may be unable to accommodate these homeowners and may be turning away dozens of jobs because we will be booked solid to the end of the year doing work for homeowners who have work orders that were contracted weeks prior. Please do not be left behind! Even if you do not choose to work with us, all of the energy efficiency contractors in the area are very likely to be similarly busy as was the case last year when the tax credit was getting reduced.

As we all realize:
1: It WILL get cold outside.
2: The tax credits are GOING AWAY.

To add to the urgency, if you live in the Progress Energy service area, you may be eligible for up to $615 in rebates. With the merger with Duke Energy now imminent, we don’t know what will happen to those rebates. This means that procrastination could cost you over $1000. Don’t miss out, call today and schedule your free energy audit then, if it makes sense to you, pull the trigger and get it done!

Much of our success can be directly attributed to the Federal Energy Efficiency Tax Credit. At the current time (and mood of the new legislative shift), it does not appear that these tax credits will be extended. That is very unfortunate when you can clearly see that the program was extremely effective at reducing the local energy consumption / overall carbon footprint and stimulating the local economy.

So act now to take advantage of this program before the December 31, 2010 deadline. You too can reduce your monthly energy bills by up to 30% and improve the comfort and indoor air quality throughout your home!

Frequently we are asked about the cost effectiveness of replacing old windows. In spite of all of the hype and wild claims about replacement windows saving energy, new windows are frequently very low on my priority list for home owners who wish to reduce their energy consumption. Often our customers are surprised to learn that their windows are really not that leaky (as proven by the blower door test).  I contend that replacing windows in your house before you air seal and insulate the attic is kind of like replacing the washer on a garden hose that you just ran over with your lawn mower. The washer will do nothing to stop water loss from the cut up hose. Your best plan would, of course, be to splice the damaged hose first, then replace the washer if you saw water leaking from the connection.

Most building performance studies have shown that the first step in energy efficiency begins in the attic. As a general rule about 60% of a homes energy is lost through the attic while only 30 percent is lost through the walls, windows and doors. A leaky attic will allow rising warm air to escape. As warm air escapes through the attic, colder outside “make up” air will be drawn into the building below the attic. This is the so called “stack effect.” Since much of the leakage attributed to a window is from the area around the window rather than the window itself once the top plates of the wall are sealed in the attic, the window is often no longer a problem area.

Other building science organizations have also found that windows are not the energy robbers they were once thought to be. Consider what Arnie Katz of Advanced Energy out of Raleigh, NC has to say about windows. Advanced Energy is a non-profit organization with connections to North Carolina State University. They have no reason to overstate or understate the effectiveness of any energy efficiency interventions since they are dedicated to research and consultations.

“So first, let’s get rid of one of the big myths out there: In most existing homes, replacing the windows is not a high priority for saving energy.”

Consider also that a single pane window has an R value of “1.” R values are a measure of the ability of a material to block the flow of heat. A new high efficiency window may have an R value of 2 or 3. This is a very small increase compared to what can be done in the attic where a typical inefficient home may have only enough insulation to create an R value of 19 but we can easily raise that R value to 40 or 50. Doesn’t it make more sense to spend your hard earned money raising your attic more than 20 R value points compared to spending money raising your windows only 1 or 2 R value points?

Why then do so many homeowners believe that the windows are the culprit causing high energy bills? In my personal opinion I believe the window industry itself has propagated a lot of misleading information. A quick internet search will reveal many window companies claiming energy use reductions of 30%.  Consider again what Advanced Energy has found in their research of energy efficient buildings.

” If your total utility bill (gas and electric) is $2,000 a year, approximately $1,000 of that will be for heating and cooling. Approximately $200 of that is caused by heat loss or gain through the windows. Good, new energy efficient windows can save you 50 percent of that, or $100 a year.”

So a typical new array of windows will save a homeowner about $100 per year while adding insulation, attic air sealing and duct sealing will save about 3-5 times that amount at a fraction of the cost of replacing the windows.

To be very clear, windows are indeed an important part of a homes building envelope and for a house to be as energy efficient as possible, the windows must also be efficient. The point here is that windows are rarely the “biggest bang for the buck” when it comes to home energy efficiency and comfort. Instead, ask a professional energy auditor in your area for a consultation. If you live in the central North Carolina area we would be happy to provide this service for free. Otherwise you can consult the Building Performance Institute for a professional in your area.

With that said, I believe it is hard to overstate the power of using “found” money, a little discipline and the power of compound interest as a wealth-building tool.

Consider the following example:

Lets assume that today, you have exactly $4000 to invest in your 3-year-old child’s college account. You find a nice safe investment plan that earns an average of 6% rate of return per year on average. If you do nothing but invest this money in that account, in 15 years you will have $9,816.35 to put toward college expenses.

Next, consider that you invest that same $4000 into making your home more energy efficient. You then take the money you save each year and invest it into the same college account earning the same rate of return.

On average, we achieve between 15% and 30% energy use reduction for each home in which we install our Energy Barricade system. The average annual energy cost for the homes we work on is about $2500. If we achieve a conservative 20% reduction in energy use then the customer has $500 per year that they can invest in our hypothetical college fund.

Lets not forget that energy costs rise, on average, about 4% per year. (This is a low-end estimate.) So now we can set our college account up to automatically deduct the money we would have been paying in energy costs and put those to use earning money for our three year olds college education. We start in year one with a $500 contribution and we increase that contribution annually by 4% to account for the increase in energy costs we would have paid. This scenario looks like the following.

Initial deposit
$1155.00 (This is the amount we got back in tax credits and energy company refunds)
Annual contribution
$500 plus 4% each year.

By leveraging our energy savings and accounting for increasing energy costs we have really maximized our return. In 15 years we will have $18552.

So we might then believe that the gain between investing in the typical way versus investing our energy savings is about $8700 ($18552 – $9816) ….

But we would be WRONG!

Remember that since you did not install the Energy Barricade system in the first case you still had to pay for all of that energy that was lost through your attic. That energy will end up costing you a whopping $10,013 over the 15 years!! This means that your typical investment scenario actually ended up costing you more than you ended up earning. All of that opportunity simply went up in hot air right through your attic.

The message here is clear. Energy efficiency improvements are one of the best investments you can make and will protect you against the sure rise of energy costs in the future.

He further described just how completely ineffective regular fiberglass insulation is at blocking the most prevalent method of heat movement, that is, radiation and how aluminum can reflect nearly all of the radiant heat that hits it. By using this material he was able to stop heat from getting into his insulation in the first place. This got me thinking about how I would hear my air conditioner cranking away at one o’clock in the morning after it had already cooled down outside. I learned that fiberglass insulation works just like a sponge. It does not stop or block heat it merely absorbs it. Once the insulation has as much heat as it can hold, it lets any additional heat “drip” out, right into the living area. Of course, at one in the morning, the a/c was working hard to remove the heat that had absorbed into my fiberglass insulation throughout the previous day.

I was even more interested when my neighbor got his first electric bill after installing the “radiant barrier.” He had reduced his electrical consumption by over 25%. Since that time I have installed radiant barriers in my house and in several rental properties. The savings on air conditioning are significant. The method makes so much sense and is so cost effective one wonders why all States with warm climates do not require radiant barriers in their building code. Part of the answer is that it just takes a while for NASA spin offs to take hold. The other part of the answer is that, I suspect, fiberglass insulation manufacturers have much more lobbying clout in State legislative houses than the much smaller radiant barrier industry has. Nevertheless, radiant barrier has proven so effective that it is now incorporated in California building codes and is required in new structures in the City of Austin Texas. I suspect the “gold rush” is just beginning as people discover this effective way to put more of what glitters back into their pockets.

Dr. Zande is co-founder of ProActive Energy Systems, Inc. located in Raleigh, NC. ProActive Energy Systems, Inc. specializes in energy efficiency upgrades for existing homes and office buildings. Go to www.proactiveenergysystems.com for more information.

When he arrived what he saw (and smelled) was one of the worse mold contamination problems he had ever seen. The house had to be immediately condemned. There was mold growing out of the electric receptacles, up the walls, through the carpet and inside all of the cabinets. There was a dank humid feeling to the home even though the AC was running. There was even water inside the clothes dryer!

Scott interview the homeowner and asked him if he had made any changes to the home in the following several months. The homeowner said that the only thing he did to the house was add a “few attic fans.” In fact, he had added 3 attic fans and this was the source of the problem.

The fans were not only removing hot air from the attic, they were also sucking cold conditioned air right out of the building envelope. This was creating a powerful negative pressure in the house. This negative pressure was drawing in damp air from the crawl space and through any other penetration from outside the building to the inside. The water in the clothes dryer was caused by the warm moist outdoor air condensing on the cold metal tumbler inside. The mold coming through the electrical outlets was fed by moisture coming from outside to the cooler inside.

Attics certainly need ventilation or they will get very hot. Heat can degrade shingles prematurely and heat in the attic can move into the living space. Many attics have built in passive ventilation, usually soffit vents and a ridge vent or gable vents. Some people feel their attic should have a power vent to remove the hot air that builds up. Or, in the case of the above homeowner, 3 attics vents.

In most cases, the combination of a ridge vent and soffit ventilation is adequate. If a homeowner wants a power vent we strongly urge them to make certain there is enough soffit ventilation to accommodate the output of the fan. We also recommend a pressure test to make sure the negative pressure in the attic is not transferring to the house. We often will recommend a solar attic fan for homeowners that want a fan. Solar attic fans start when the sun rises and they turn off when the sun sets, keeping ahead of the heat during the day and “self adjusting as the strength of the solar energy increases.

If a homeowner wants a cooler attic for storage or future renovation, then we recommend the installation of a radiant barrier such as our Energy Barricade ™. Radiant barrier shields the interior attic space from radiant heat (the main source of heat in an attic.) It still allows the flow of air from the soffits to the ridge, unlike spray foam insulation. And, it will not void your shingle warranty like some spray foam installations.

Overall, while powered attic fans are popular with some people, they are rarely needed or useful and they do not reduce energy costs very effectively.

Michael D. Zande, Ph.D. is VP and co-founder of ProActive Energy Systems, Inc. A Raleigh, NC based company that specializes in residential energy efficiency retrofits for existing homes.

What we know about this topic now is that crawl spaces can be safely and effectively sealed from the outdoors. Keep in mind however that the crawl space can also be effectively segregated from the living space simply by tightening the air barrier between the crawl and the living space. That is to say,  seal the crawl space ceiling.

But some homes have a moist crawl that can encourage mold growth and sweating of the air handler and ducts if they are located in the crawl. Some companies specialize in the sealing of crawl spaces. What they often will do is remove all of the old fiberglass insulation in the ceiling of the crawl, insulate the walls of the crawl, seal off the crawl space vents and add a dehumidifier. Sometimes they will extend an HVAC supply vent to the crawl space area. This actually expands the amount of volume that the HVAC system must address.. It is not an energy saver per se but it can be a very effective indoor air quality fix. It can also be very expensive. We have met homeowners who have spent upwards of $5000-7000 to accomplish this.

We have what we call our “hybrid approach.” It is a much less expensive method of accomplishing what most homeowners are really seeking, that is to seal the crawl from the rest of the house and to keep the crawl clean and dry. By sealing the crawl from the rest of the living space you are greatly reducing the overall leakage of the building envelope. Keep in mind that, for energy efficiency, sealing the attic is the first  priority since hot air rises and builds positive pressure on the upper levels of a structure. Address the crawl if it is an immediate problem due to moisture or if you have already addressed the attic and are going for a second “phase” of efficiency retrofits.

A case study conducted by Centex Homes and Appalachian State University, funded by the U.S Department of Energy Building America Grant provided through the North Carolina Energy Office, recently announced their results.

The purpose of the study was to measure the benefits of adding radiant barriers in attic applications. The research was conducted using a total of sixty-one sensors in two, side by side, identical four bedroom model homes in the Charlotte area. One home had radiant barrier. One did not.

The conclusion of the study resulted in these findings.

1. Peak attic temperatures dropped by 23%.
2. The reduction in the air-conditioning unit’s run time during the seven hours of peak attic temperature dropped 20%.
3. The efficiency improvement in the cooled air delivered through the air ducts was 57%.

The study was conducted last summer and as of January, Centex began building homes with radiant barrier roof decking in conjunction with their Centex Energy Advantage suite of features.

What this tells us is that if a home has the air handler and duct work in the attic and there is little or no tree cover, a radiant barrier such as our Energy Barricade ™ is a very needed retrofit to obtain maximum home energy efficiency.

Radiant Barrier Blocks Radiant Heat in Attic

Here in Raleigh and most of Eastern North Carolina we experience a mixed humid environment. In the summer it is typically not only very hot but also very humid. This places a great strain on our air conditioning units as they not only must remove heat from the air they are also called upon to do double duty as dehumidifiers.

If we have a customer who is reporting difficulty cooling their home in the summer, or if their summertime bills are disproportionally high we will often suggest the installation of a radiant barrier in their attic. This is especially true if they have no trees shading their house and their duct work and air handler are in the attic where they are exposed to extremely hot temperatures. It seems to make little sense that we place a machine that is designed to cool our homes by sending 55 degree air through ducts into an environment that can reach 140 to 160 degrees.

The application of radiant barrier technology can really help reduce temperatures in the house and help the a/c handle its’ cooling load by blocking radiant energy from the attic space. However, I was in a house just today that we had done a lot of work on. The house was on a heavily shaded lot so we did not recommend radiant barrier. (Since the trees were an effective barrier to radiant energy.) But yesterday it felt really uncomfortable and muggy in this particular home. Today when I visited it was a totally different story. It seemed like a different house simply because the extensive air sealing that we did in the attic and crawl space. This had substantially reduced the humidity of the house and the results were excellent.

Heat moves from hot to cold and humidity moves from high humidity to low. In the summer, humid air migrates from the outside of the house to the inside. This can be impeded by air sealing.

If a house only has a radiant barrier there will likely be a great increase in comfort and decrease in energy used in air conditioning. However, the humidity still presents a load on the a/c and a perceptual discomfort. The combination of air sealing and radiant barrier technology is a one-two punch for summertime home comfort!