Do You Need A Home Inspection?

Before you buy a home, one of the things you should do is to have the home checked out by a professional home inspector. Buying a home is expensive enough as it is - why would you choose to fork over another $400 (Citadel’s base charge is only $375) if you're not required to? In this article, we'll delve into what a home inspection can reveal and why you shouldn't forgo this optional procedure.

SEE: 10 Worst First-Time Homebuyer Mistakes

The Home Inspection Contingency

Your first clue that a home inspection is important is that it can be used as a contingency in your purchase offer. This contingency provides that if significant defects are revealed by a home inspection, you can back out of your offer, free of penalty, within a certain time frame. The potential problems a home can have must be pretty serious if they could allow you to walk away from such a significant contract.

What a Home Inspection Examines

Inspectors vary in experience, ability and thoroughness, but a good inspector should examine certain components of the home you want to purchase and then produce a report covering his or her findings. The typical inspection lasts two to three hours and you should be present for the inspection to get a firsthand explanation of the inspector's findings and, if necessary, ask questions. Also, any problems the inspector uncovers will make more sense if you see them in person instead of relying solely on the snapshot photos in the report.

The inspector should note:

• whether each problem is a safety issue, major defect, or minor defect
• which items need replacement and which should be repaired or serviced
• items that are suitable for now but that should be monitored closely

A really great inspector will even tell you about routine maintenance that should be performed, which can be a great help if you are a first-time homebuyer.

While it is impossible to list everything an inspector could possibly check for, the following list will give you a general idea of what to expect.

Exterior

• Exterior walls - The inspector will check for damaged or missing siding, cracks and whether the soil is in excessively close contact with the bottom of the house, which can invite wood-destroying insects. However, the pest inspector, not the home inspector, will check for actual damage from these insects. The inspector will let you know which problems are cosmetic and which could be more serious.
• Foundation - If the foundation is not visible, and it usually is not, the inspector will not be able to examine it directly, but they can check for secondary evidence of foundation issues, like cracks or settling.
• Grading - The inspector will let you know whether the grading slopes away from the house as it should. If it doesn't, water could get into the house and cause damage, and you will need to either change the slope of the yard or install a drainage system.
• Garage or carport - The inspector will test the garage door for proper opening and closing, check the garage framing if it is visible and determine if the garage is properly ventilated (to prevent accidental carbon monoxide poisoning). If the water heater is in the garage, the inspector will make sure it is installed high enough off the ground to minimize the risk of explosion from gasoline fumes mingling with the heater's flame.
• Roof - The inspector will check for areas where roof damage or poor installation could allow water to enter the home, such as loose, missing or improperly secured shingles and cracked or damaged mastic around vents. He or she will also check the condition of the gutters.

Interior

• Plumbing - The home inspector will check all faucets and showers, look for visible leaks, such as under sinks and test the water pressure. He or she will also identify the kind of pipes the house has, if any pipes are visible. The inspector may recommend a secondary inspection if the pipes are old to determine if or when they might need to be replaced and how much the work would cost. The inspector will also identify the location of the home's main water shutoff valve.
• Electrical - The inspector will identify the kind of wiring the home has, test all the outlets and make sure there are functional ground fault circuit interrupters (which can protect you from electrocution, electric shock and electrical burns) installed in areas like the bathrooms, kitchen, garage and outdoors. They will also check your electrical panel for any safety issues and check your electrical outlets to make sure they do not present a fire hazard.
• Heating, ventilation and air conditioning (HVAC) - The inspector will look at your HVAC system to estimate the age of the furnace and air conditioner, determine if they function properly and recommend repairs or maintenance. An inspector can also give you an idea of the age of the home's ducting, whether it might have leaks, if your home has sufficient insulation to minimize your energy bills and whether there is any asbestos insulation.
• Water heater - The home inspector will identify the age of the heater and determine if it is properly installed and secured. The inspector will also let you know what kind of condition it is in and give you a general idea of how many years it has left.
• Kitchen appliances – The inspector will sometimes check kitchen appliances that come with the home to make sure they work, but these are not always part of the inspection. Be sure to ask the inspector which appliances are not included so that you can check them yourself. (Citadel does check the appliance and also checks for recalls on any appliances that have a model and serial number)
• Laundry room - The inspector will make sure the laundry room is properly vented. A poorly maintained dryer-exhaust system can be a serious fire hazard.
• Fire safety - If the home has an attached garage, the inspector will make sure the wall has the proper fire rating and that it hasn't been damaged in any way that would compromise its fire rating. They will also test the home's smoke detectors.
• Bathrooms - The inspector will check for visible leaks, properly secured toilets, adequate ventilation and other issues. If the bathroom does not have a window and/or a ventilation fan, mold and mildew can become problems and moisture can warp wood cabinets over time.

Home Inspection Shortcomings

A home inspection can't identify everything that might be wrong with the property - it only checks for visual cues to problems. For example, if the home's doors do not close properly or the floors are slanted, the foundation might have a crack - but if the crack can't be seen without pulling up all the flooring in the house, a home inspector can't tell you for sure if it's there.

Furthermore, most home inspectors are generalists - that is, they can tell you that the plumbing might have a problem, but then they will recommend that you hire an expert to verify the problem and give you an estimate of the cost to fix it. Of course, hiring additional inspectors will cost extra money. Home inspectors also do not check for issues like termite damage, site contamination, mold, engineering problems and other specialized issues.

SEE: 10 Reasons You Shouldn't Skip A Home Inspection

After the Inspection

Once you have the results of your home inspection, you have several options.

• If the problems are too significant or too expensive to fix, you can choose to walk away from the purchase, as long as the purchase contract has an inspection contingency.
• For problems large or small, you can ask the seller to fix them, reduce the purchase price, or to give you a cash credit at closing to fix the problems yourself - this is where a home inspection can pay for itself several times over.
• If these options aren't viable in your situation (for example, if the property is bank-owned and being sold as-is), you can get estimates to fix the problems yourself and come up with a plan for repairs in order of their importance and affordability once you own the property.

The Bottom Line

A home inspection will cost you a little bit of time and money, but in the long run you'll be glad you did it. The inspection can reveal problems that you may be able to get the current owners to fix before you move in, saving you time and money. If you are a first-time homebuyer, an inspection can give you a crash course in home maintenance and a checklist of items that need attention to make your home as safe and sound as possible. Don't skip this important step in the home-buying process - it's worth every penny.

SEE: 7 Smart Steps Every New Homeowner Should TakeCitadel Home Inspections has reposted this article By Amy Fontinelle , Investopedia Articles

March 23, 2016

---

Ice Dams - Preventative Maintenance

By Geoff Gordon, Citadel Home Inspections

With snow in the winter and the buildup of that snow and ice on your roof, ice dams can cause your home significant damage and cost you thousands of dollars in repairs.  While you may have insurance to help mitigate the cost to you the homeowner, there’s still your deductible, the possible premium increase for submitting a claim and then there is always the massive headache involved in the cleanup and repairs.

The best way to avoid all of that is to avoid the ice damming damage altogether.  Here are a few steps to help avoid the interior damage caused by ice damming;

• Before the snow flies in the winter install roof and gutter de-icing cables.  These essentially keep channels thawed in areas that are susceptible to damming so that water can continue to drain thus avoiding the damming.  If you do buy these make sure you are buying CSA approved products.
• With a roof rake keep the soffit areas clear of snow.  Although the melting snow may still freeze up on the soffit, any sun hitting the shingles will quickly melt that away.  If possible and if safe to do so clear as much of the snow on your roof as possible.  Always make sure you’re working with the roof slope so as not to damage your shingles.  Best to use plastic or push brooms vs a metal shovel.
• If there is already an ice dam carefully chip away at it in several areas to allow water to flow through and not back up.  The flowing water will quickly erode larger channels.  Be very careful again not to damage your shingles.
• As with the roof if you can safely remove ice buildup in the gutters do it.
• There are a couple things you can do on the inside of your home as well to help avoid ice dams;
• Prevent the warm air in the house from escaping into the attic which causes the heat loss and the snow melt.  The first place to look is the attic hatch.  Is it as air tight as it can be?  Make sure it has weather stripping and is insulated.  If it is in your budget, then upgrade your attic insulation.  Current Ontario Building Code standards are R-50 for the attic.  This R value can vary depending on certain things but R-50 is the amount for a Zone 1 home with an attic.
• Make sure your attic has enough ventilation.  A good rule of thumb is 1 square foot of ventilation for every 150 square feet of attic floor.  If part of the ventilation are soffit vents make sure they are free of insulation. 

As with most things home maintenance related, a little preventative maintenance or sweat equity goes a long ways in avoiding costly repairs, both in terms of time and money, in this case water damages.  And last but not least always remember safety first if you are working on your roof.

Wood-Burning Stoves

A wood-burning stove (also known as a solid fuel burning appliance) is a heating appliance made from iron or steel that is capable of burning wood fuel. Unlike standard fireplaces, wood stoves are typically contained entirely within the living space, rather than inset in the wall.

Wood stoves come in many different sizes, each suited for a different purpose:

• Small stoves are suitable in single rooms, seasonal cottages or small, energy efficient homes. These models can also be used for zone heating in large homes where supplemental heating is needed.
• Medium-size stoves are appropriate for heating small houses or mid-size homes that are intended to be energy-efficient and as inexpensive as possible to maintain.
• Large stoves are used in larger homes or older homes that leak air and are located in colder climate zones. 

To ensure safe and efficient use of wood-burning stoves, inspectors can pass along the following tips to their clients:

Never:

• Burn coal. Coal burns significantly hotter than wood, posing a fire hazard;
• Burn materials that will emit toxic chemicals, such as wood that has been pressure-treated or painted, colored paper, gift wrap, plastic, plywood, particleboard, or questionable wood from furniture;
• Burn wet wood. Generally speaking, it takes six months for cut, stored wood to dry out and be ready for use in wood-burning stoves;
• Burn combustible liquids, such as kerosene, gasoline, alcohol or lighter fluid;
• Let small children play near a lit wood-burning stove. Unlike standard fireplaces, the sides of which are mostly inaccessible, all sides of wood stoves are exposed and capable of burning flesh or clothing; or
• Let the fire burn while the fire screen or door is open.

Always:

• Use a grate to hold the logs so that they remain secured in the stove and the air can circulate adequately to keep the fire burning hot;
• Keep the damper open while the stove is lit;
• Dispose of ashes outdoors in a water-filled, metal container;
• Check smoke alarms to make sure they are working properly; and
• Periodically remove the stovepipe between the stove and the chimney so that it can be inspected for creosote. Homeowners may want to hire a professional to perform this service.

Efficiency and Air Pollutants

In Canada the federal government is set to come out with their own tightening of emissions from solid fuel burning appliances. Some state laws further restrict airborne particulates, and many new models emit as little as 1 g/h. These two approaches -- catalytic and non-catalytic combustion -- are described briefly as follows:

• In catalytic stoves, the smoky exhaust passes through a coated, ceramic honeycomb that ignites particulates and smoke gasses. Catalysts degrade over time and must eventually be replaced, but they can last up to six seasons if the stove is used properly. Inadequate maintenance and the use of inappropriate fuel result in an early expiration of the catalyst. These stoves are typically more expensive than non-catalytic models, and they require more maintenance, although these challenges pay off through heightened efficiency.
• Non-catalytic stoves lack a catalyst but have three characteristics that assist complete, clean combustion:  pre-heated combustion air introduced from above the fuel; firebox insulation; and a large baffle to create hotter, longer air flow in the firebox. The baffle will eventually need to be replaced as it deteriorates from combustion heat.

The following indicators hint that the fire in a wood-burning stove suffers from oxygen deprivation and incomplete combustion, which will increase the emission of particulates into the air:

• It emits dark, smelly smoke. An efficient stove will produce little smoke.
• There is a smoky odor in the house.
• There is soot on the furniture.
• The stove is burning at less than 300º F. A flue pipe-mounted thermometer should read between 300º F and 400º F.
• The flames are dull and steady, rather than bright and lively.

To ensure efficiency, practice the following techniques:

• Purchase a wood-burning stove listed by ULC, CSA, WH(ITS), UL or OLT. Stoves tested by these laboratories burn cleanly and efficiently. These are the recognized testing facilities of the CSA B365-10 the Code Book WETT Inspectors go by.  Generally listed stoves also are tested  and approved for closer clearance to combustibles.
• Use double walled flue and chimney pipe whenever possible.  The insulated pipe keeps the flue gases hotter for better draw which means cleaner pipes with less deposits and a more efficient burning fire.
• Always have you appliance inspected by a WETT certified inspector to ensure the appliance is installed properly and has the correct clearances to combustibles. (Citadel/Geoff is of course WETT Certified)
• Burn only dry wood. Wood that has a moisture content (MC) of less than 20% burns hotter and cleaner than freshly cut wood, which may contain half of its weight in water.
• Burn hardwoods, such as oak, hickory and ash once the fire has started. Softwoods, such as pine, ignite quicker and are excellent fire starters. 
• Make sure the stove is properly sized for the space. Stoves that are too large for their area burn inefficiently.
• Burn smaller wood rather than larger pieces. Smaller pieces of wood have a large surface area, which allows them to burn hotter and cleaner.

In summary, wood-burning stoves, if properly designed and used appropriately for the space, are efficient, clean ways to heat a home.

(This article was prepared by Nick Gromicko of InterNACHI with edits and additions by Geoff Gordon) December 14, 2015

---

Wood is not a perfect fuel, but there really is no such thing.

Wood is the most accessible and affordable renewable energy resource for home heating in much of North America. Its use can help us to reduce greenhouse gas emissions because its net carbon dioxide emissions are far below those of all other fuels. It provides heating security during electrical power failures. Its use strengthens the rural and small town economies where wood heating is most prevalent. Wood that is cut and used locally means money does not leave the community to pay for oil and gas.

Wood heating is as much a lifestyle choice as it is a heating fuel option, so wood heating is not for everyone.

Wood is not a perfect fuel, but there really is no such thing. All fuel burning, indeed all energy use, causes environmental impacts. The most often cited impact, is from old-style wood heating, visible as smelly smoke curling from chimneys. The new advanced technology wood stoves, fireplaces and furnaces that are certified low emission by the US Environmental Protection Agency can burn with no visible smoke and ninety per cent less pollution than appliances of thirty years ago.

When various energy sources are assessed according to their environmental impacts, the entire fuel cycle must be considered. The serious environmental impacts of fuel oil and natural gas consumption are largely ignored, partly because most occur upstream during production, refining and transportation. The greenhouse gases released when houses are heated with oil and gas are easy to ignore because they are invisible.

Although wood is a good fuel with advantages for individual families, it is not a good fuel for all families in all regions. For example, wood is not a good fuel for serious heating in multi-family dwellings or in the downtown core of our large cities. Wood is best used as a fuel outside cities, in small towns and rural areas, where the cost of firewood and population density are lower.

Wood heating is practiced on a small scale, the fuel is usually harvested from a local resource, and the users gain a more complete understanding of their impacts on the environment than users of other energy sources. As environmentalists have suggested, these are some of the very features needed for economic and environmental sustainability. Families who heat their homes with wood responsibly should be recognized for their contribution to a reduction in greenhouse gas emissions and a sustainable energy future.

You will find more good reasons to heat with wood in the articles in the menu list to the left.

This article is taken from: The Wood Heat Organization Inc. 2013 July 2, 21013

---

On the other end of your mental image scale might be thoughts of the lakefront mansions that were built around the turn of the previous century in many parts of the country.  These were lakefront homes built as summer houses for wealthy city dwellers, and they were majestic and expensively outfitted.

Those images of waterfront property may well represent many people's ideas of contemporary lakefront homes, but the current reality couldn't be farther from the truth.  While today some of both mansions and cottages are being built, there is a definite trend toward a middle ground-large upscale lakefront homes that you might mistake for a primary residence.  Sometimes these lakefront homes are designed to be a primary residence, but more often they are meant to be vacation houses.

Like most vacation homes, lakefront homes nowadays are being designed with the needs of the multi-generation family in mind.  Your grown children may desire a spot to vacation with the grandchildren, even when you aren't there, or perhaps you want to be able to host multiple family members and friends at the same time.  And don't forget holidays-most families gather as many family members as possible to the same place for such holidays as Christmas and Easter.  A lakefront home is a perfect place to celebrate these traditions. 

These kinds of needs mean that lakefront homeowners require space-more space than those old waterfront cottages could offer.  Also, lakefront property has a high value, and people are building upscale homes to match those higher values.  Homeowners ask, why erect a tiny cottage on an expensive piece of waterfront property? It doesn't make sound economic sense.

Even if they can't build as big a lakefront home as they might want to, homeowners are opting for the absolute best they can afford.  The lakefront cottage of today is a far cry from the lakefront cabin of yesterday.  In the old days, cottages were apt to be dark and cramped, with few modern appliances and amenities, and unfinished attics.  Nowadays, waterfront properties are being built with all the conveniences of a primary residence and then some.  Every room is finished and many are outfitted with bunk beds in order to accommodate visitors.

One thing, though, that the larger lakefront homes have in common with their cottage-type predecessors is a casual interior.  All the modern amenities and conveniences are present, but they are presented in a casual, artful way befitting the lakefront lifestyle.  Today's lakefront homeowners want upscale style and elegance, but they want it in a casual way, with easy upkeep.  After all, the goal of owning waterfront property is to be able to enjoy the benefits of living on a lake, not to have to spend all your time cleaning and fixing up the house. 

If you've always dreamed of owning a lakefront home, now is an excellent time to start looking.  You'll be thrilled with all of the options you'll find in the market for waterfront property. 

Don’t forget though, as important as a Home Inspection is on an urban home, that Home Inspection by a certified Home Inspector may well be more important on a lakefront or seasonal property than on the urban home.  Seasonal and or rural properties often have additional systems that need to assessed by a Home Inspector that urban home may not have.  Such as septic systems, water softeners, wells, pressure tanks, wood stoves etc. 

So before investing in your future lakefront home have it inspected by a certified Home Inspector.

Geoff Gordon, April 15, 2013

---

Other types of gas used in this space have various effects on heat gain or loss through the window. Some windows also have a thin film installed between panes that separates the space between the panes into two spaces, further reducing heat loss and heat gain through the window. If multiple-pane windows appear misty or foggy, it means that the seal protecting the window assembly has failed.

Silica Desiccant   A desiccant is an absorbent material designed to maintain dryness in the space it protects. In a double-paned window, silica pellets inside the aluminum perimeter strip absorb moisture from any incoming air that enters the space between the panes. If not for the silica desiccant, any moisture in the space between the panes would condense on the glass as the glass cools below the dew point temperature.

Silica gel has an immense surface area, approximately 7,200 square feet per gram, which allows it to absorb large amounts of water vapor. As the sealant protecting this space fails over time, increasing amounts of moisture-containing air will enter the space between the panes, and the silica pellets will eventually become saturated and will no longer be able to prevent condensation from forming. A double-paned window that appears foggy or that has visible condensation has failed and needs to be repaired or replaced.

Why Double-Paned Windows Fail:  Solar (Thermal) Pumping   Although double-paned windows appear to be stable, they actually experience a daily cycle of expansion and contraction caused by thermal pumping. Sunlight heats the airspace between the panes and causes the gas there to heat up and expand, pressurizing the space between the panes. At night, the window cools and the space between the panes contracts. This motion acts like the bellows of a forge and is called thermal pumping.   Over time, the constant pressure fluctuations caused by thermal pumping will stress the seal. Eventually, the seal will develop small fractures that will slowly grow in size, allowing increasing amounts of infiltration and exfiltration of air from the space between the panes.

Failure Factors

Windows on the sunny side of a home will experience larger temperature swings, resulting in greater amounts of thermal pumping, seal stress and failure rates.

Vinyl window frames have a higher coefficient of expansion resulting in greater long-term stress on the double-pane assembly, and a higher failure rate. Windows also experience batch failure, which describes production runs of windows, especially vinyl windows, that are defective, meaning that the pane assemblies have been manufactured with seals that have small defects that will cause the window to fail prematurely.

The Nature of Damage

If it’s allowed to continue, window condensation will inevitably lead to irreversible physical window damage. This damage can appear in the following two ways:

• riverbedding.  Condensed vapor between the glass panes will form droplets that run down the length of the window. Water that descends in this fashion has the tendency to follow narrow paths and carve grooves into the glass surface. These grooves are formed in a process similar to canyon formation.
• silica haze.  Once the silica gel has been saturated, it will be eroded by passing air currents and accumulate as white “snowflakes” on the window surface. It is believed that if this damage is present, the window must be replaced.

Detecting Failure

Condensation is not always visible. If the failure is recent, a failed window may not be obvious, since condensation doesn’t usually form until the window is heated by direct sunlight. Windows in the shade may show no evidence of failure, so inspectors should disclaim responsibility for discovering failed double-paned windows.

Thermal Imaging as a Detection Tool

Under the right conditions, it’s possible to use an infrared (IR) camera to detect failed windows. IR cameras are designed to record differences in temperature.

InterNACHI provides a thermal imaging course that includes information on using IR cameras for this purpose, and has a message board forum devoted to IR.

Recommendations for Failed Windows

According to industry experts, the glazing assembly can be replaced  approximately 75% of the time.  Occasionally, the sashes must be replaced, and only about 5% of those cases require that the entire window be replaced.

Inspectors should be aware that there are companies that claim to be able to repair misty windows through a process known as “defogging.”

This repair method proceeds in the following order:

1. A hole is drilled into the window, usually from the outside, and a cleaning solution is sprayed into the air chamber.
2. The solution and any other moisture are sucked out through a vacuum.
3. A defogger device is permanently inserted into the hole that will allow the release of moisture during thermal pumping.

Inspectors should know that there is currently a debate as to whether this process is a suitable repair for windows that have failed, or if it merely removes the symptom of this failure. Condensation appears between double-paned windows when the window is compromised, and removal of this water will not fix the seal itself. A window “repaired” in this manner, although absent of condensation, might not provide any additional insulation. This method is still fairly new and opinions about its effectiveness range widely. Rfegardless, “defogging” certainly allows for cosmetic improvement, which is of some value to homeowners. It may also reduce the potential for damage caused by condensation in the form of mold or rot.  Some skepticism exists about the effectiveness and cost effectiveness of this method of repair.

In summary, condensation in double-paned windows indicates that the glazing assembly has failed and needs repair or replacement. Visible condensation can damage glazing and is the main indication of sealant failure.

From Condensation in Double-Paned Windows - InterNACHI http://www.nachi.org/condensation-double-paned-windows.htm#ixzz2LVDMdzKf

Estimating the Lifespan of a Water Heater

While the typical water heater has a lifespan of about 10 years, careful consideration of the factors that pertain to its lifespan can provide the InterNACHI home inspector and the homeowner with information about the potential costs that would be incurred by replacing the water heater. These factors include: correct installation; usage volume; construction quality; and maintenance.   Correct Installation

A water heater should generally be installed upright. Installing a water heater on its side will place  structural stress on it due to inadequate support for the heater and its pipes, and may cause premature failure.

Water heaters should be installed in well-ventilated areas -- not just for fire safety requirements and nitrous-oxide buildup, but also because poor ventilation can shorten the lifespan of the water heater. 

Usage

The life expectancy of the water heater depends a great deal on the volume of water used. Using large quantities of water means that the water heater will have to work harder to heat the water. In addition, the greater the volume of water, the greater the corrosive effect of the water will be.

Construction Quality of the Water Heater   As with most household systems and components, you get what you pay for in a water heater. Cheaper models will generally have a shorter lifespan, while more expensive models will generally last longer. A good indication of a water heater’s construction quality is its warranty.  Longer warranties naturally imply sounder construction. According to a 2007 Consumer Report that deconstructed 18 different models of water heaters, it was determined that models with longer warranties invariably were of superior manufacturing quality, with nine- and 12-year models typically having larger or higher-wattage heating elements, as well as thicker insulation. Models with larger heating elements have a much better resistance to mineral buildup or scum. 

Pay attention to the model's features.  Porcelain casing, for example, provides an additional layer of protection against rusting, and a greater level of heat insulation. Some models come with a self-cleaning feature that flushes the pipes of mineral deposits, which is an important consideration in the unit's lifespan.  Models with larger or thicker anodes are better-equipped to fight corrosion.

Maintenance and Parts Replacement

The hardness of the water is another consideration when looking at estimating the lifespan of a water heater.  In areas where there is a higher mineral content to the water, water heaters have shorter lifespans than in other areas, as mineral buildup reduces the units' efficiency. Even in areas where the water is softer, however, some mineral deposition is bound to occur.  A way to counteract this mineral buildup is to periodically flush the water heater system, which not only removes some of the buildup, but, in tank systems, the process heats the water in the tank. Higher-end models typically come equipped with a self-flushing feature.  In models for which manual flushing is required, it is important not to damage the water heater valve, which is usually made of plastic and is easy to break.

Although an older model may appear to be well-maintained, a question arises:  Is the maintenance worth it? Warranties often exclude labor costs, so a good rule to follow is that if the total repair cost per year is greater than 10% of the cost of buying and installing a new water heater, it is probably not worth replacing damaged parts. 

It is debatable whether the cost in time and money of replacing the sacrificial anode in a water heater is worth the benefit of prolonging the use of the existing water heater by a couple of years. In the tricky process of emptying the tank and replacing the anode, it is easy to damage the unit, and, as some warranties can be voided by anode replacement, the cost of future repairs or maintenance that might otherwise be covered must be considered. 

In summary, there is a variety of factors influencing the lifespan of a water heater. Beyond the basic telltale signs, such as a leaky puddle under the heater or cold showers in the morning that indicate that a new water heater is probably in order, the homeowner should consider the age and warranty of the model, and carefully weigh the cost-benefit of maintaining an existing heater versus buying a new one. 
by Nick Gromicko and Barry Fowler    
From Estimating the Lifespan of a Water Heater - InterNACHI http://www.nachi.org/lifespan-water-heater.htm#ixzz25oWbVDPn