QI've seen you help people who write in about ice dams. I just inherited a house that has bad ice dams every winter. I'm going to need to replace the shingled roof soon. Would a standing seamless roof help end this problem?

If you have a house with conditions that produce ice dams, they may occur on any type of roof.

Ice dams form when heat from your home escapes into your attic, warms the underside of your roof and melts snow, which trickles down to the cold edge/eave, where it freezes. The solution is to prevent your home's air (which you'll pay to heat next winter) from reaching the attic.

That's done with a thorough job of sealing anyplace where air can be exchanged between your living spaces and your attic. Then, make sure that you've got sufficient, well-installed attic insulation.

The safest, most accurate, and comprehensive approach to air sealing and insulation is to hire a professional. A Home Performance with ENERGY STAR^® contractor can use diagnostic equipment to find air leaks. The contractor can then fix the leaks and perform any necessary insulation work. Efficiency Vermont offers financial incentives to homeowners for energy-saving improvements completed by these contractors.

QCan  you tell me what a good home energy auditor should do and how I can find one?

Sure thing. A qualified auditor will evaluate the whole house and will identify the causes of and solutions for high energy bills, drafty rooms, moisture problems, and more. The auditor will look at the heating system, lighting, appliances, windows, and insulation and will understand how these elements interact with each other to affect your energy use, comfort, health, and safety. Specifically, the auditor will:

• use a special fan, called a blower door, which fits in an exterior doorway and changes the air pressure in the house so that the tightness of the home is assessed and air leaks can be found and sealed;
• assess the presence and amount of carbon monoxide and gas leaks; and
• help you prioritize recommended, cost-effective energy-saving home improvements.

I suggest contacting a Home Performance with ENERGY STAR^® contractor. These independent contractors are certified by the Building Performance Institute to perform energy audits, diagnose building problems such as moisture, mold, and ice dams, and to make recommended home improvements. Efficiency Vermont offers financial incentives to homeowners for energy-saving improvements completed by these contractors.

QMy house has no attic insulation, so I plan to take care of that this summer. I grew up in a house that had vermiculite insulation, but somebody at the home improvement store said they don't stock it because it doesn't work as well as what they're selling. He also said that it's toxic, which I find hard to believe. Obviously, I need an objective opinion. Can you help?

Glad to. The use of vermiculite as insulation has largely fallen out of favor since it was found that a big percentage of the vermiculite sold in the US between 1919 and 1990 came from an asbestos contaminated mine in Libby, Montana. This is also why vermiculite that's already in a house should be left alone or addressed by a trained professional. Today, vermiculite can be found at some building supply locations as well as some local garden centers.

As for its effectiveness, vermiculite has an R-value per inch of about R-2, making it one of the least effective insulation choices for an open attic. (R value shows you how well a material prevents the escape of heat. The higher the value, the better the material insulates.) Other options include loose fill cellulose insulation which is about R-3.5 per inch. Be certain to seal air leaks first and to see that the insulation is properly and thoroughly installed. To get the most energy savings from this investment, it's best to use a professional. You can find a list of Home Performance with ENERGY STAR^® contractors in Vermont at www.efficiencyvermont.com/homeperformance. Efficiency Vermont offers financial incentives to homeowners for energy-saving improvements completed by these contractors.

Q I  just moved into my house last fall. The floor on the entry level (just above the basement) was so cold this winter. I'm determined to fix it this summer but I'm not sure about the best approach. Should I insulate the basement ceiling?

Generally, the best approach to dealing with cold floors above a basement is to air seal and insulate the inside of the basement walls and the sill beams or band joist area.

The main reason this method is recommended is to keep the basement and the things inside it warm. If you insulate the basement ceiling instead, you'll essentially make the basement an outdoor space, which becomes vulnerable to cold winter conditions.

If your basement is wet, you'll need to fix that situation before attempting an insulation job or you'll risk moisture problems that can create unhealthy living conditions due to mold and mildew. If you can't keep your basement dry, the insulation solution must be approached knowledgeably, to avoid frozen pipes and other issues in the basement. For these reasons, I strongly suggest leaving the job to a professional. You can find a list of Home Performance with ENERGY STAR^® contractors in Vermont.

Q I've lived in old homes in Vermont all my life. I've seen sawdust used as insulation and I've seen something that seems to be seaweed. I figure if it was good enough in the old days, it's got to have something going for it. Do you recommend any natural materials like that?

What a great glimpse into our ancestors' ingenuity! These days, people expect more from insulation than folks did centuries ago. So, today's insulation materials are modified in various ways, to get better performance out of them. I'd like to say that you can get similar results from something you'd collect for free on the beach, but it's not possible to install irregular, unprocessed materials in a way that provides consistent enough coverage to function as well as today's insulation.

I'm glad to point you to some insulation products made with natural materials that undergo minimal processing. Cellulose is ground-up paper, usually made from recycled newspaper, which, of course, is made from trees. Typically, it includes boric acid, a non-toxic material, which serves as a fire retardant and pest deterrent. Fiberglass insulation is made by bringing the mineral silica to high temperatures for long periods of time. Either of these materials can be excellent insulators when installed correctly. Thanks for your interesting question.

QDowindow quilts reduce heat bills enough to make it worth the price of the quilts? Also, is it true that I could get a federal tax break on them?

Window quilts generally will not substantially reduce a home's heating-energy use. However, covering a window can help you feel warmer. Naturally, it's your call about whether or not the comfort is worth the cost of a particular kind of window covering.

Some window quilts are eligible for federal tax credits. I recommend speaking with your tax professional to find out about this. If you'd like information on ways to increase comfort and reduce energy costs in your home, visit Home Heating Help.

Q My folks are hesitating to use cellulose insulation in their attic. Because cellulose is made of paper, they're worried that it's a fire hazard or that it could get moldy or that rodents would build nests in it. I'm all for cellulose, but my word isn't enough. They read your column. Can you back me up that adding cellulose is a good idea?

Sure thing. Your parents are right that cellulose insulation is made from paper; usually about 45-70% recycled, post-consumer newsprint. The other ingredient should reassure your parents. It's a fire retardant - most commonly boric acid - that also acts as a deterrent to rodents and other pests. Boric acid also creates a very unfriendly environment for mold.

Regardless of the kind of insulation your parents select, they should be sure that a proper job of air sealing is done before insulation is installed. A Home Performance with ENERGY STAR contractor can do both the air sealing and insulation jobs and can answer questions that your parents may have about energy-saving home improvements. If you're interested in finding a contractor, visit www.efficiencyvermont.com/homeperformance or call Efficiency Vermont, toll-free, at 888-921-5990.

QIn the upstairs rooms of my Cape-style house, most of the wall space is slanted. In the short, vertical knee walls in each room, there's a small door. I keep those doors closed, but cold air comes from there anyway in the winter. What's the best thing I can do to stop this?

I'm sure that many readers in Cape homes can relate to your situation. There are two ways to address this problem; you can block the cold air at the knee-wall doors, or you can keep the cold air from reaching those doors. The latter is a bigger job but a better approach because it not only stops the door draft but also increases comfort and reduces heating needs throughout a Cape-style house.

To treat the problem only at the little door, glue at least two inches of foam insulation board to the back of the door. Install weather stripping around the perimeter of the door so that, when it is closed, you feel no air leaks.

Now, for the bigger, better project. I should explain that Cape construction enables cold air not only to enter at knee-wall doors but also to flow under your flooring through gaps at the joists. You can fix both problems in either of two ways: Insulate the side-attic rafters, or insulate the back of the knee walls, all the way down through the floor joists. In either option, it's critical to know where to do air sealing, how to properly install insulation, and where to install effective air barriers over insulation.

It's tough working in small spaces like side attics, so if you want to call in professionals to help, review our list of Home Performance with ENERGY STAR^®contractors who can fix the problem and test the finished job for effectiveness and safety.

Q I bought a two-story townhouse condo built in the late '70s that has fiberglass insulation. I'm sure that the batts in the walls have settled by now and have gaps that let the cold in. I've heard that people can come and blow cellulose insulation in from the attic, but does that really work?

A: It's true that blown-in cellulose is used to improve the insulating ability of walls like yours. However, this would be a fairly expensive improvement in a home built as recently as yours, where the job could only be done through the walls (from the outside, or more rarely from the inside), not from the attic.

You see, older home-construction methods, typically used only until the 1930s or '40s in Vermont, allow cellulose installers to reach all walls from the attic.

A less expensive place to start insulation improvements is the attic itself. If you've got fiberglass batts up there as well, you may benefit from a layer of cellulose. Tending to attic insulation is often the most effective insulation job in condos where wall area is small compared to attic area. Work here consists of sealing any gaps in the attic floor and then blowing in cellulose on top of existing insulation.

Whether you decide to improve the insulation of your walls or attic, your best bet is to have a thorough evaluation of your home by a certified Home Performance with ENERGY STAR® contractor. The contractor can identify opportunities to save energy, and help you prioritize them based on costs and benefits.

Q I've been getting estimates from insulation contractors and one of them says that he always does air sealing in the attic, because it saves more energy. I don't know this guy from Adam, but you folks don't stand to make any money if I air seal or not so I'm turning to you. Does air sealing really save energy? If so, why, and what does it entail?

A: Yup, it really does save energy. When air moves between your living space and unheated areas or the outdoors, you're losing hot air you've paid for and bringing in cold air that you'll pay to heat. So, it stands to reason that you'd want to limit this kind of air movement. That's why it makes a big difference to find and fill gaps in the attic floor. It also makes sense to caulk around window and doorframes and to use weather stripping and door sweeps on exterior doors.

Air sealing in the attic is also important because, if warm air is allowed to reach the attic, it can melt snow on the roof. That's a problem, because melted snow can trickle down to the eaves, where it freezes and forms ice dams, which can damage your roof and create a danger from falling ice. Also, air leaks can result in moisture in the attic that can rot wood. So, yes, that contractor is going about this the right way.

Q My sisters and I bought the land next to mine to build a small house for my mother now that she's widowed. We're all in agreement about most decisions on the house, but we're split down the middle about fiberglass batt insulation vs. cellulose. We're aware that other types of insulation exist, but we've narrowed it down to these. Which of the two does a better job?

A: The short answer? Cellulose. Here's why: Both materials insulate well, but there's a difference in their typical performance. That's due to two reasons:

First, the risk of air leaks is higher through fiberglass than through densely-packed cellulose. Second, and more importantly, it's very difficult for fiberglass batts to cover surfaces as thoroughly as cellulose does. A fiberglass batt comes in specific dimensions and must be placed into a wall, floor, or ceiling cavity that has many obstacles, like wiring, that change the cavity's dimensions. Cellulose, which is typically blown in, fills-in more readily around these obstacles. So, cellulose covers surfaces more uniformly.

Regardless of the type of insulation you choose, be sure that a proper job of air sealing is done before insulation is installed. There's more to know about energy-saving insulation installation techniques in new construction. I suggest that you take advantage of Efficiency Vermont's ENERGY STAR^® Homes service for homebuilders. As part of this service, an Efficiency Vermont representative can discuss technical issues like these in detail and will perform a pre-drywall inspection of your insulation to check for air leaks. I hope that your mother enjoys her new home.

QMy brother and I take care of our childhood home so that our elderly parents can continue to live there. Our Dad read somewhere that all water pipes should be insulated in order to save energy. My brother and I want to respect Dad's wishes, but we think that only hot water pipes need insulation. What's the answer? The house needs lots of upkeep, so we want to use our limited fixit time well.

A: You've got a win-win situation here; you can respect your Dad's request to consider both hot and cold pipes, and you'll have a smaller job on your hands than you'd think.

The most important pipes to insulate are the first three feet of cold- and hot-water pipes attached to the top of the water heater. Hot water in the tank can rise into these pipes. That water then cools, and draws heat into it from the water in the tank. After a while, this process repeats a sufficient number of times to cool the tank-water temperature enough to cause the heater to turn on.

Use quality, self-sealing pipe insulation of at least one-inch thickness. Cover the pipe elbows well, and use electrical tape and mechanical fasteners to keep everything in place. Make sure the pipe insulation is kept away from hot surfaces, such as the exhaust hood of a gas water heater.  If you want to end the job there, you'll make a difference in your parents' energy costs. I want to share this info, though: There are benefits to insulating all accessible cold-water pipes. This prevents condensation on the pipes in the summer, preventing the risk of moisture-related mold, which can damage materials and reduce air quality. Let me know if you and your brother have any more questions about helping your parents save energy.

Q What's the most energy-efficient ice-melting device that I can put on my eaves to prevent ice dams?

A: You're wise to address the problem of ice dams, not only because they can damage your roof but also because they're a sign that the heat in your house (which you pay for) is escaping into your attic. The energy-saving solution isn't to pay to buy and operate a device to melt ice dams while continuing to pay more for heating than necessary. The answer is to prevent ice dams.

I'll explain: Ice dams form when heat escapes into your attic, warms the underside of your roof and melts snow, which trickles down to the cold edge/eave, where it freezes. The solution is to keep the heat in your house. That's done by a thorough job of sealing anyplace where air can escape to the attic and then making sure that you've got at least 12 inches of well-installed insulation on the attic floor. Likely places for air leaks include attic hatches, pull-down attic stairs, the attic floor above pocket doors, gaps around chimneys, plumbing and wiring and more.

The most accurate and comprehensive way to seal air leaks is to hire a professional. A Home Performance with ENERGY STAR^® contractor can find and fix leaks and perform any necessary insulation work. You can find a list of these specially trained, certified contractors at www.efficiencyvermont.com/homeperformance. Good luck and stay warm!

Q Years back, we converted part of our attic into a nice guest bedroom for my mother, who visits every June. Now my mother is coming to live with us full time, but that room is uncomfortably cold in the winter, even though we put hot-water baseboard heat in there. What's the best way to insulate the room? We put beautiful wide-plank knotty-pine boards on the slanted ceiling/walls, but without insulation. We don't want to touch those boards, so would it work to insulate the floor of the room instead?

A: Insulating the floor would make the space colder because you would prevent any heat from rising from the room below it. It would also raise your heating bills because the baseboards in the space would have to put out more heat. (Think of the insulation in attic floors. That's designed to keep heat in the house instead of escaping upwards.) You can, however, nicely insulate the walls of this room without disturbing the interior that you love.

A Home Performance with ENERGY STAR certified shell specialist can do the job. ('Shell' is a construction-industry term for a building's skeleton, to which the finished exterior and interior are applied.) He or she can gain access from the roof or the side attics. A tube can be inserted along the slope of the ceiling. Then, insulation is blown-in through the tube. You can find a contractor through ourENERGY STAR page. After the insulation is installed, this beautiful room may end up being the most comfortable part of the house.

 How would you prevent frozen pipes in mobile homes without using heat tape?

A: Some mobile home park owners in Vermont require heat tape on homes' incoming town water pipes. So, you may not have the option to make this change. But if your home isn't in such a park, you can get good results with a thorough job of insulating the pipes and enclosing them (insulation and all) in an air-tight box that extends from a few inches below ground all the way to the inside of the home. The underbelly of the mobile home should be insulated and air-sealed and the skirting around the mobile home slab should be insulated.

If you find that you still need to supply heat to prevent the pipes from freezing, use a thermostatically-controlled heat cable that is inserted into the water pipe, not a heat tape that wraps around it. And don't use an incandescent light bulb to heat pipes. It's both a fire hazard and an expensive way to add heat to a space.

Q I'm buying an 18-year-old log home. I love the look of the interior log walls, but I'm concerned because they're not insulated. Do logs insulate well? If not, is it possible to add insulation?

A. Appealing as they are, log walls typically have less than half the insulating value of standard stud frame walls. So, be sure to air-seal (close-up gaps with caulk or expandable foam) your attic floor, foundation and around windows and doors. As for adding insulation, unless you're prepared to build and insulate conventional walls inside those logs that you fell in love with, your best option is to insulate foundation walls with rigid foam board and the attic with blown-in cellulose.

Q I'm shopping around for replacement siding for my home. Is there a siding product that can help insulate as well?

 A. None of the common siding products used in Vermont help with wall insulation. But if you're hoping to increase your home's energy efficiency, there are a few things you can do to help insulate your walls while the siding is being replaced:

• If your old siding is being removed, you can add foam insulation behind the new siding. This is an excellent way to increase wall insulation. However, with thicker foam insulation panels, the trim around windows and doors will need to be replaced.
  
  
• You can also identify and seal air leaks and add insulation to the wall cavity with dense-packed cellulose. To find out whether this is a good option for your house, contact a certified Home Performance contractor or a qualified cellulose insulator. For a list of professionals in your area, visit the Marketplace.

Q How do I prevent icicles from forming on my roof?

 A. Icicles are a sign that you have heat loss. You're smart to want to prevent them. They form when melted snow trickles down and refreezes at the more exposed and colder eave. Ice that builds up on the edge of the roof and holds back the water is called an "ice dam" and can cause damage. Heat loss into your attic or roof assembly is usually the culprit. The solution is to keep your roof deck cold by sealing leaks between the house and the attic or roof assembly and making sure any duct work in the attic is sealed and insulated.

Wood board ceilings (tongue-and-groove) are notorious leakers. The only way to seal them is by installing a sealed rigid air barrier behind the wood boards (such as taped drywall or foam boards), or by solidifying the rafter cavities with either cellulose or foam insulation.

You're also likely to find heat leaks between the house and attic at the gap between the framing and the chimney, plumbing chases, interior walls open to the attic, pull-down attic stairs, architectural soffits such as those over kitchen cabinets or over the tub/shower, and side attics in a cape-style house.

Resist the urge to add more ventilation to the attic since that can potentially worsen the problem.

Q My house is drafty. What is the best way to correct that?

 A. Quick answer? Air sealing! But let's explore a little more. The first thing you want to do is identify where the drafts are coming from. Check around or between window panes or around the hole where the chimney goes into the attic. Each air leak requires a specific fix, which might be weather-stripping, caulk, expanding foam, or sheet metal and rigid foam insulation. And remember that fiberglass insulation is not an effective air barrier!

You might want to contact an energy auditor for help identifying the source of leaks in your house. He or she will perform an air leakage test using a "blower door." If you prefer, you can perform your own test using a smoke stick (incense) and noting the direction the smoke blows. Visit the Marketplace for a list of energy auditors in your area.

Q A contractor recommended insulating our walls with blown-in cellulose. Isn?t that just chopped-up newspaper?

A. You're right about cellulose insulation - it is primarily recycled newspaper. But it's treated for flame and pest resistance and, when installed properly, it's actually more effective than fiberglass insulation. In general, cellulose offers better coverage because the small chunks can fill behind and between tight spaces in a wall or ceiling in a way that fiberglass insulation just can't. So your contractor gave you good advice.

Q What type of insulation would you recommend using on pipes?

A.  You're smart to insulate your pipes. In warm weather, insulation keeps cold-water pipes from sweating. In cold weather it helps reduce heat loss from hot-water piping and may just help you avoid frozen pipes as well.

Insulation comes in a number of forms, but the best and, by far, the easiest to use is a closed-cell foam insulation which generally comes packaged in three foot lengths. Choose the right size for the pipe diameter. These slip-on pipe jackets are easy to install and cover the entire pipe surface, even when bent around corners. Tape the ends where the pieces meet using electrical tape.

Q I'm concerned about protecting the pipes in my mobile home. Are there alternatives to heat tape?

A. Good question. I can tell you from experience that insulating the pipes alone will not prevent freezing. Instead, you want to create a sealed, insulated enclosure around the pipes that is connected to the heated living space. The better sealed and insulated the enclosure, the more successful you will be in keeping out the cold.

If you find that you still need to supply heat to prevent the pipes from freezing, use a thermostatically controlled heat cable that is inserted into the water pipe, not a heat tape that wraps around it - and definitely not a light bulb!