Caulking and Weather Stripping

Can you imagine having a 9-in.² hole in your wall? Just think of the costs of heating or cooling your house with a hole that big. Now, did you ever think that you just might have the equivalent of that 9-inch hole in your house?

Experts tell us that a quarter-inch crack around the perimeter of a typical 36-inch entry door can leak as much air as a 9-in.² hole. And that’s only one door. Any air leaking around other doors or windows just makes that hole bigger.

What This Means for You

Since the typical US family spends close to $1,500 annually on home utility bills—and it’s estimated that air leaks can account for 20% to 50% of a building’s fuel costs—you can see how your money could be literally flying out the door.

The good news is, you can cost-effectively close up that gaping hole, conserve energy, and start saving money. Just make sure to have adequate weather stripping around doors and windows, and that your home’s caulking is in good repair.

What is Caulking and Weather Stripping?

Caulking and weather stripping work together to stop air leaks, making your home as airtight as possible. Weather stripping seals around doors and windows, while caulking is used to seal the small cracks and holes that are inevitable where different types of materials come together—like where window frames join up with brick siding.

How Do I Know I Have Leaks?

Generally speaking, older homes have more trouble with air leaks than newer homes, but it’s always a good idea to check out the situation. If you have any big leaks, you probably already know about them. On cold days if you feel a draft around your outside doors or windows, those are air leaks. You might use a lighted incense stick or a lighted candle around the edges of doors and windows to detect leaks you don’t feel. The moving air will blow the smoke or make the candle’s flame flutter.

Other places you should look for air leaks are where different types of materials meet, such as:

• Brick and wood siding
• Mail chutes
• Electrical, gas, cable television, and phone line entrances
• Outdoor water faucets
• Dryer vents and fan outlets
• Air conditioners

What Do I Do Once I Find the Leaks?

Once you find the leaks, you need to seal them. How you close up the air leak depends on where it is. Caulk forms a flexible seal between joints, cracks, and gaps less than ½-inch wide. Weather stripping seals leaks around the edges of movable pieces like doors and windows.

Choosing Caulking

Caulking usually comes in disposable cartridges that fit into a caulking gun. Some types of caulking are also available in squeeze tubes, aerosol cans, and ropes for special applications. Probably the most important quality to look for in a caulk is its life expectancy. It’s best to use caulking that remains flexible over the longest time.

There are a variety of options in a caulk, so ask a professional at your local hardware store, and be sure to read the packaging carefully to determine if it is:

Suitable for the materials you need to caulk: Some caulks are made specifically for selected materials, while others can be used on a wide range of different materials.

Interior or exterior grade: Exterior grade caulking is designed to resist weathering, so if you need to seal any exterior surfaces, this is a very important distinction.

Latex or oil/resin-based: Latex cleans up with water, while oil-based requires using a solvent for clean-up.

Paintable or non-paintable: Caulk is available in many colors, including clear, but often if you want a perfect color match for the caulking to blend in with the surrounding surfaces, you will need to paint it.

Selecting Weather Stripping

Similar to caulking, you have a number of options. You need to choose a weather stripping that can stand up to its environment. For example, weather stripping placed around doors is subjected to repeat opening and closing, as well as exposure to temperature changes and weather. Window weather stripping needs to seal out air movement while still allowing the window to open and close easily.

Weather stripping is available in a variety of materials. Some of the more common are:

Vinyl: Usually comes with an adhesive backing on half of the strip; simply peel off the backing and apply to the edge of the door or window.

Adhesive backed foam or tape: Similar to adhesive backed vinyl, but wears out quickly and is not impervious.

Felt: Either plain or reinforced with a flexible metal, is nailed or tacked into place. 

Interlocking metal: This type of weather stripping is considered the most effective, but is also the most complex to install. The concept is two pieces of V-shaped metal placed all around both a door and the doorframe. When the door closes, the strips interlock to effectively block any air movement.

Getting the Job Done

Replacing or repairing caulking and weather stripping are jobs that most homeowners can do themselves. While the repairs and installation can be tedious and time consuming—especially caulking—they don’t require any special training or skills. And if you are using caulking, just have a few rags on hand, in case you need to clean up any excess—and remember to release the pressure from the caulking gun, or it will continue to flow out of the tube, resulting in a gooey mess.

The complexity of installing interlocking metal weather stripping is the exception to the rule that homeowners can do it themselves. Because there is so little margin for error, it is usually installed by professionals.

It’s hard to believe that little cracks you often can’t even see can have such an impact on heating or cooling your home. However, by investing a little money and some of your time, you can make your home comfy and energy efficient. Plus, there’s an added bonus—the savings you achieve on your energy bills quickly repays your investment and more.

 Let us take for instance the R-30 loose fill in most attics; it takes just a couple of hours for the radiant heat from the attic to build to 140 degrees and go completely through the R-30 and start heating up your house and running up you power bill, most especially if your HVAC system and ducts are in the attic. When the sun goes down and your house should be cooling off the air-use insulator is holding the heat in and therefore not allowing the house cool off for several hours.

Winter time is the time of year that conventional insulation really becomes an energy eater. When the air in a home is heated the house becomes a hot air balloon, even though it will not raise off the ground, all the same physics of lift apply. When you heat the air; it wants to rise and it passes through the loose fill or batt insulation in your attic flooring. When this happens it takes the temperature and moisture that has accumulated in the living envelope and moves into the attic. Because of the air mass expanding (static pressure) in the summer months, we have had to vent the attic to relieve the pressure outside instead of it pushing into the living area. These same vents allow the pressure, temperature, and moisture you just paid to have in your home to escape. When air leaves the vents in the roof, replacement air must come in, bringing in cold air to be re-heated (Air Loss/Air Gain).
In retro fitting an existing home you must look first at where your money will be most well spent. The roof area of a house consumes as much as 35% of the energy needed to heat and cool a home. The crawl space of a home can consume up to 30% and the walls, windows and doors the balance. By spraying open cell polyurethane foam against the roof deck of the building you will stop all the radiant energy from entering the structure. In climates like those in the south, the high humidity from outside is prevented from entering the house. If there is no radiant energy there is no expanding air mass. If there is no expanding air mass you do not need vents. By eliminating the vents, you have now stopped your heat rise loss in the winter months and have kept your HVAC system from working overtime in the summer.
The roof area of a house should be the first area sprayed as it is the largest energy consumer of the envelope. The floor or crawl space should be next. We advise not trying to re-insulate walls as the payback on a 18% loss would be cost prohibitive and not practical.
When we heat and cool the air in our houses we are doing so because we don’t like what is going on out of doors. When we do this it puts the building envelope in direct opposition to the most powerful force on earth, the atmosphere.
Installing open cell polyurethane foam allows your HVAC system to work less which saves you money. The energy savings payback on installing this type of foam is 3-7 years.

Use my own home as an example:  100 year old house.  The knee walls and the “peak” in the attic had 12 inches of blown in insulation.  Yet there was constantly a 15 degree difference between the first floor and the attic. Perhaps that is understandable since there is no heat or cooling source in the attic.  Yet, last year, after insulating the underside of the roof deck behind the knee walls, with a couple inches of closed cell foam and 10-12 inches of open cell foam, the temperature differential is just one (1) degree between the first floor and the attic.  The ice damns we had when we started melted and never returned.  And we have only insulated HALF of the attic; I will do the “peak” area this fall.

An Energy Efficient Mortgage (EEM) is a mortgage that credits a homes energy efficiency in the mortgage itself. EEMs give borrowers the opportunity to finance cost-effective, energy-saving measures as part of a single mortgage and stretch debt-to-income qualifying ratios on loans thereby allowing borrowers to qualify for a larger loan amount and a better, more energy-efficient home.

To get an EEM a borrower typically has to have a home energy rater conduct a home energy rating before financing is approved. This rating verifies for the lender that the home is energy-efficient.

EEMs are typically used to purchase a new home that is already energy efficient such as an ENERGY STAR qualified home. The term EEM is commonly used to refer to all types of energy mortgages including Energy Improvement Mortgages (EIMs), which are used to purchase existing homes that will have energy efficiency improvements made to them. EIMs allow borrowers to include the cost of energy-efficiency improvements to an existing home in the mortgage without increasing the down payment. EIMs allow the borrower to use the money saved in utility bills to finance energy improvements. Both EEMs and EIMs typically require a home energy rating to provide the lender with the estimated monthly energy savings and the value of the energy efficiency measures known as the Energy Savings Value.

EEMs (and EIMs) are sponsored by federally insured mortgage programs (FHA and VA) and the conventional secondary mortgage market (Fannie Mae and Freddie Mac). Lenders can offer conventional EEMs, FHA EEMs, or VA EEMs.

Locally, I know that banks like Cedar Rapids Bank and Trust (www.crbt.com) or at 743-7100 can help you.

Visit the energy star website for more information

Both the Federal Housing Administration and mortgage investor Fannie Mae recently launched start-ups in the energy conservation arena. Here’s a quick overview, with some pros and cons.

The FHA’s new program is called “PowerSaver” and allows eligible owners to borrow up to $25,000 at fixed rates between 5 percent and 7 percent for as long as 20 years to finance high-efficiency windows and doors, heating and ventilating systems, solar panels, geothermal systems, insulation and duct sealing, among other retrofits.

Though it is officially a pilot program,Housing and Urban Development Secretary Shaun Donovan estimates that 30,000 PowerSaver loans will be closed in the next two years. It eventually could become a major national program for residential energy upgrades, with total loans extending into “the millions,” he says.

One important element in the program: energy audits. Although the audits won’t be mandatory, most participating lenders are expected to encourage owners to sign up for an energy-efficiency analysis by a certified specialist. The audit should pinpoint where your house is leaky or otherwise inefficient in energy use and should recommend the specific types of upgrades or additions that could help cut your bills and reduce greenhouse emissions.

The FHA will insure loans to cover the improvements up to the $25,000 maximum under the following guidelines:

1)  The house must be your principal residence, detached and single-family only. No rentals, no investor homes, no second homes.

2)  You’ll need to demonstrate that you are a solid credit risk. Minimum FICO credit scores of 660 are required, plus your total household monthly debt-to-income ratio cannot exceed 45 percent.

3) Houses with negative equity will not qualify. You’ll need some level of equity in the property; there is no mandatory minimum stake, but the combined primary mortgage debt plus the PowerSaver second lien cannot exceed 100 percent of the appraised market value of the house. You could, for example, have a 10 percent equity position in a $200,000 home and still qualify for up to $20,000 in a PowerSaver.

4)  Lenders are likely to take an extra hard look at all your income and asset documentation because, unlike other FHA-insured mortgages, PowerSavers will cover only 90 percent of the lender’s loss or insurance claim in the event of a default.

Eighteen lenders around the country have signed up so far to participate, ranging from giant Quicken Loans — a top-10 national mortgage originator — to regional and local players such as California-based Sun West Mortgage, Seattle’s HomeStreet Bank, the Bank of Colorado, Stonegate Mortgage in the Midwest, Pennsylvania-based AFC First Financial and the University of Virginia Community Credit Union. A spokesman for Quicken Loans said the company hopes to offer PowerSaver in as many as 34 states during the pilot period.

Some pros and cons of PowerSaver: The biggest plus is its low fixed interest rate and long term, especially in comparison with most homeowners’ alternatives, such as bank home-equity loans and lines of credit, which typically cost more and may have less-favorable payback terms. The main potential drawback: Since the program permits total household mortgage debt loads of up to 100 percent of market value, there’s the chance that some borrowers could encounter payment problems if they experience even slight income declines or if property values in the area decrease, putting them into negative-equity territory.

Fannie Mae’s “energy improvement” mortgage add-on program is significantly different from the FHA’s. Rather than a separate loan to finance energy retrofits, Fannie folds the cost of the improvements — capped at up to 10 percent of the estimated market value of the home following the energy efficiency enhancements — into the mortgage amount itself.

In effect, Fannie’s program, which is now available through participating lenders nationwide, allows you to purchase an existing house and improve its energy usage significantly with one mortgage at current market rates. Most single-family properties are eligible for the program, except for manufactured houses and cooperative units.

Be aware that Fannie requires an audit by a certified Home Energy Rating Systems (HERS) expert upfront to justify the proposed modifications to the house as truly cost-efficient. The HERS audit must be paid for by the borrower, but Fannie will credit an extra $250 through the lenders to partially defray this expense.

Link to full Story http://wapo.st/kaeEJ9

The average Iowa family spends more than half of its annual household energy bill on heating and cooling. That’s a significant number, but you can dramatically reduce these costs—up to 20 percent, according to ENERGY STAR®—by making some simple energy-saving weatherization and insulation improvements to your home. In addition—with a little attention to proper ventilation—you can protect your home from moisture damage year-round, reduce problems caused by ice dams on the roof during the winter and significantly cut summer cooling costs. As a bonus, these projects can extend the life of your home and may increase the resale value of your property.

If you like to fix things around the house, you can handle many of the projects  and make the most of your energy-improvement budget. However, don’t hesitate to call a professional for help if you’d rather not do the work yourself; the dollars gained through energy savings in upcoming years will be worth the expense.

Check with your utility or bank first

Although many energy-efficiency projects—caulking windows, weather-stripping exterior doors or insulating water pipes—will cost just a few dollars, others—insulating exterior walls, installing ventilated soffits or adding storm windows—will cost considerably more. Some utilities offer rebates on larger projects by giving you a discount on future heating and cooling bills or even sending you a rebate check when the work is completed.  Your bank may be able to help too. Ask about a low-interest loan designed to cover the cost of your energy-saving projects, or consider a home-improvement loan to fund them.  Typically, you can only get a rebate from your heating utility — so you cannot double dip between Mid American and Alliant.  Go to their websites for rebate information and other good stuff about saving money on gas AND electricity.

Be sure to look into the availability of government-sponsored assistance and grant programs designed for low-income and elderly homeowners too. For more information, get in touch with the Iowa Department of Human Rights/Division of Community Action Agencies or a Community Action Agency in your area.

Finally, check on national and state incentives for the installation of energy efficient products. For details on federal income tax credits, visit the Web site of the Tax Incentives Assistance project at http://www.energytaxincentives.org. For state programs, go to the Database of State Incentives for Renewables & Efficiency (DSIRE) at http://www.dsireusa.org.

Get the most for your money

To help you decide which jobs to tackle first, consider more than just the increased comfort you’ll experience; analyze their return on investment too. It usually makes sense to start with the ones that cost the least now but offer the most later in terms of energy dollars saved.

It’s easy to figure how long it will take for your energy improvements to pay for themselves through reduced energy bills. Divide the total cost of each project by the annual estimated energy bill savings—ask your utility for help—to find the payback period. For example, if a project costs $1,600 and you’ll save $200 per year, the payback period is eight years.

Eliminate air leaks—then insulate
You may think that insulating should be the first step in making your home more energyefficient, but consider this: Air leaks through the ceiling, walls, foundation and other areas typically are the greatest sources of heating and cooling losses in a home. So, controlling air leaks is the best way to extend the life of your home, as well as to conserve energy, save money and increase your home’s comfort. The bottom line is this: If you don’t tighten up your home first, money spent on insulation may be wasted.

Air infiltrates into your home through every hole, nook and cranny. About one-third of this air infiltrates through the openings in your ceilings, walls and floors.

According to the U.S. Department of Energy, you can save 10 percent or more on your energy bills just by plugging air leaks in these places in your home.

A good tube of caulk is just a few bucks; Lowe’s sells a “D” shaped EPDM rubber weatherstripping for exterior doors; for about $10 a door, you can make it airtight.

I recieved a lot of comments after my post about my home audit.  If you missed it, Rob Novak of Homestar Iowa calculated after my home energy audit that I would save a whopping $297 a year — $297 a year — if I replaced the windows in my house.  While the savings was sufficiently low, it certainly pales to the cost of such replacement, somewhere well north  of $25,000 — and an 84 year payback.  Just think, if I replaced the windows, I would be “in the black” from this investment when I am 135 years old! 

Last year, renowned historic preservationist Bob Yapp (who now has a segment on NPR) gave a 4 hours seminar on restoring old windows at the History Center in Cedar Rapids.  In fact, he owns the Belvedere School for Hands On Preservation in Hannibal, Missouri, and teaches classes on building storm windows, restoring storm windows, among other things.  See his website at www.bobyapp.com.  His point was well-taken: most existing windows can be restored, and updated — and perform at or above what a new window would do (and with substantially less cost). with some TLC and a storm window.

I look at my windows.  100 years old. No rot.  Plenty of layers of paint, to be sure.  In need of some new hardware and and reattaching the sash weights (my wife would love that since we prop up most windows with her wooden kitchen spatulas).  Probably old growth fir, which is far superior to the vinyl-clad, finger-jointed wood that they now use in windows.

Many people believe the absolutely must have new windows if their home is drafty.  Actually, it should be your last resort: make sure you caulk around all windows and doors on the outside of the house, weatherstrip all windows, add insulation to walls, attic, rim joist, replace light bulbs and seek high efficiency heat sources and appliances.  A couple months ago, a neighbor called to look at her home; she told me it was very drafty, and that they were going to replace the windows.  When I inspected her house, I noticed 1/4″+ gaps between the window frame and the house — nothing that a $5 tube of high quality caulk couldnt fix.  So before you pull the trigger on new windows, make sure you have done all you can do to stop air infiltration in your home.

To be sure, if you like the aesthetics of new windows, and the ease of cleaning — you probably can’t beat new windows.  But if you think they are going to drastically outperform existing windows and save you a bunch of money, call Rob Novak and have him calculate YOUR return on investment.  As a businessman, an 84 year payback does not make sense to me.

See the attached articles from Fine Homebuilding, a reputable magazine in the construction industry

.RH_New Life For Old Windows

FH_Should Your Old Windows Be Saved

So when architect/real estate developer Steve Emerson called, I jumped. 

He had purchased a beautiful spot of land north of Palo, on a high bluff.  The home has a turrent with a copper-clad “witch’s hat” for a room.  The home’s exterior is a combination of rock, limestone and red brick.  The precast first floor meant there were no structural supports in the basement.  And large gorgeous windows, particularly on the southern exposure.

Being an architect, and designing his home for the long term, he wanted spray foam insulation in the walls.

In the basement, we put 3″ of BioBased 1701 closed cell on the studded out concrete walls.  On the first floor, we sealed it with one (1) inch of closed cell and then filled the cavity with BioBased 501 open cell spray foam.  And in the attic (the underside of the roof deck), we put down 2.5″ of closed cell, followed by 10″ of open cell; his attic now has an R value of 55.  An R -55 of spray foam performs like an R – 70 of fiberglass!

On the left, the turret overlooking the east.

On the right, notice the red brick trim, the stone on the bottom and the limestone on the top half of the wall.

Open Cell foam on wall, prior to trimmingAttic Insulation

On the brick walls (first floor), they drilled three holes in each stud cavity — one at the bottom, one at the middle and one at the top. They insert a long drinking straw in the middle hole. Then they inject our Tripolymer 105 injection foam in the botttom hole.  It slowly fills the cavity, creeping upward; when the straw moves, we know the foam has reached that far, and the straw is placed in the top hole, and the foam is injected in the middle hole (again, until the straw at the top wiggles), and then the hose is inserted in the top hole and it is “topped” off with foam.

On the second floor, a 2.5″ hole is drilled in the middle of each stud cavity.  The hose is insert downward into the hole and slowly filled up; then the hose is pushed upward, and the foam injected from the top down.  We place a wooden, pre-primed, pre-painted cedar wood plug in the holes; since we did this in December, I still need to go back and do some minor touch ups when the weather warms up.

I have a 100-year old house and have true 2 x 4 walls (modern 2 x 4 walls are only 3.5″ deep). So with our foam, with an R value of 5.1 an inch, we now have an R-20+.  It was a bit unsettling to peer into one of the holes we drilled and see nothing more than plaster and lathe on the other side.

We did make some mistakes. In our living room, we have a built in bookcase.  A couple weeks after we injected the foam in the walls, my wife was dusting the bookcase and came across a monolithic block of white foam encasing about a dozen books.  It appears that one of the guys drilled a hole a little bit too far, and made a hole in the plaster wall; when the foam was injected, it blew into the bookcase, and encased the books.

In a couple places, the foam seeped through cracks, especially around light switch plates or electrical outlet covers.  But when you think that these cracks were where air infiltrated our house, it makes me glad they are now sealed with foam.

We noticed a dramatically warmer house this winter.  On those winter days when the wind just howled, our house used to be drafty; not this year.  Our heating bills were dramatically lowered. 

My next steps are to spray foam some of the basement walls and the rim joist from the basement.

Sage Companies, in addition to spraying a two-part bio-based polyurethane spray foam, also features Tripolymer injection foam. Tripolymer is a phenolic-based, and not a formaldyhyde-based (like the competition). For more information, go to www.sagemidwest.com.

These guidelines can help make weatherizing your home quick and easy.

Exterior weatherizing

Start by weatherizing the exterior of your home in the back yard – by the time you get to the front and the inside, you’ll be a pro!
The primary areas to seal with caulk are:

• The top and bottom edges of the rim joist – this is the thick wooden board that site on top of the concrete foundation and connects to the floor joists.
• The outside edges of windows and doors. Don’t forget the basement windows!
• Any opening on the wall of your house, including water spigots, electrical outlets, air conditioner hoses, dryer vents, and gas and water pipes.
• Go inside your house with a can of Great Stuff canned foam, and seal all “penetrations”– places were pipes, cables, etc., enter the house from the outside.  On windy days, check to see where drafts are entering your house, and seal them off.

If you find a large hole or crack, use expanding foam. A small squirt is usually enough to seal the opening – too much can damage the surrounding materials. Don’t use expanding foam around any electrical equipment.

If you have storm windows, use them. If you don’t, install plastic window film, especially on north-facing windows. Don’t forget to cover basement windows too.

Weatherizing your windows

• Apply caulk around the outside edges of the window casing.
• Apply glazing around the edges of the windowpanes. Scrape off old glazing and clean the glass; when it’s dry, apply the glazing where the glass meets the window frame. Press it tightly and smooth with a putty knife.
• If you have double-hung windows, open the bottom sash and install adhesive-backed foam weatherstripping to the tracks and to the bottom of the sash.
• Close the window tightly and use rope caulk to seal all the moving parts.
• If you don’t have storm windows, install window film, either interior or exterior. Apply the tape around the outside edge of the window, apply the film and shrink it tight with a hair dryer.
• Heavy drapes or curtains can also help hold back cold air, but remember to open them on sunny days to take advantage of the sun’s rays.
• Don’t forget to caulk around the outer edges of basement windows and cover them with plastic film. Don’t use permanent caulk to seal basement windows shut – you may need quick ventilation in the event of a gas leak or carbon monoxide problem. Use removable rope caulk instead.

Weatherizing your doors

• Apply caulk to the outside edges of the door casing.
• Open the door and install weatherstripping to the inside of the doorjamb.  Lowes sells an “EPDM” “D” shaped weatherstripping that works great; can do a door for about $8 (and about 2 minutes of work)
• If the door has a window, apply glazing or clear caulk to the edges of the windowpane.
• Stop under-door drafts with a rubber or vinyl door sweep along the bottom. In a pinch, a rolled-up towel can work too.
• Replace the threshold under the door with a flexible vinyl gasket. Look for an adjustable model that’s easy to fit to the proper height.
• If you have a side or basement door you rarely use, seal the edges with removable rope caulk.

Other areas to weatherize

• Electrical outlets, especially along exterior walls, are a prime spot for cold air drafts. Carefully unscrew the cover and press a foam gasket around the sockets. Put the cover back on and insert childproof safety caps into all unused outlets.
• The attic opening is another drafty spot. Install insulation over the back of the attic door; if you have hatch-type access, add foam weatherstripping around the top edges of the openings.
• Wood fireplaces are notorious sources of air leaks. Tight-fitting glass doors are the best way to prevent air from escaping or entering. When you’re not using the fireplace, keep the damper closed and close the glass doors tightly. If you never use the fireplace, plug the chimney with insulation and seal the doors shut with silicone caulk

How Stuff Works: How your home’s insulation works

By Marshall Brain



For example, I recently got an email from someone who has purchased an older home (2,000 square feet, one story). He looked in the attic and there is a layer of 40-year-old fiberglass insulation up there that may be 4 inches thick. And he has a reasonable question — how much money could he really save if he beefed up the attic insulation?

That 4 inches of old insulation might be providing what’s known in the United States as an R-10 insulation value. The R system is a way of describing the effectiveness of insulation. The whole idea of insulation is to slow down the movement of heat through walls, ceilings and floors. The higher the R value, the better it is doing that job.

Adding insulation in the attic is usually easy and pretty inexpensive, especially if you can blow in a thick R-30 or R-50 layer. So let’s say you go from R-10 to R-50.

First let’s calculate the cost of heating with the R-10 layer. Say the average winter temperature is 25 degrees F in your area, and you like to set the thermostat at 70 degrees F. So the average temperature difference between the inside of the house and the outside of the house is 45 degrees F during the winter. This person has 2,000 square feet of ceiling in his house. It is easy to calculate the heat lost through the ceiling. You take the square footage of the ceiling (2,000 square feet in this case), multiply it by the average temperature difference (45 degrees F) and divide by the R value (he has R-10 insulation currently, so divide by 10). That means that this house, on average, is currently losing 9,000 BTUs through the ceiling.

9,000 BTUs is a lot. If you divide 9,000 by 3.4 you can convert it to watts, which is something we are more familiar with. That works out to nearly 2.6 kilowatts. There are 24 hours in a day, so that’s 62 kilowatt-hours. And let’s assume a kilowatt-hour of electricity costs a dime ($.10). If you are heating with electricity, it means that it is costing $6.24 per day, or about $187.00 per month, to pay for the heat that is leaking through the ceiling. If the average winter temperature is colder, it costs even more.

If you were to blow in an R-50 layer of insulation, or install an R-50 layer of fiberglass, the amount of heat leaving through the attic goes down from 9,000 BTUs to 2,000 BTUs. In other words, you are saving more than $140 per month in the winter. If it gets hot in the summer and you use an air conditioner, the savings in the summer are comparable. The homeowner might save a total of $700 per year by thickly insulating the attic of this house

So now you look at the cost of adding the insulation. Let’s guesstimate it at $1,500. That means it takes three years to pay back the cost of the insulation, assuming energy prices don’t go up. If energy prices do rise, then it pays back faster.

Since this is an older home, there may be several other easy ways to save money on heating and air conditioning. By far the best bang for the buck, especially if you do it yourself, is to get out the caulk gun. Seal all the cracks around window and door frames. Older homes often have big gaps in these areas and sealing them is cheap. It makes a big difference. Adding weather-stripping to windows and doors is also effective. Next check the floor and see if it is properly insulated. Often there in little no insulation in the floor in older homes.

Then check the furnace. How old/inefficient is it? Replacing an old furnace with a new high-efficiency unit could cut your heating costs in half