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Issues with wood heater

I have an opportunity to purchase a used wood stove that I intend to use to heat my garage / workshop. Are there any possible problems I should be aware of before I make the purchase? There are a few issues you may want to consider and be aware of before you purchase a used wood heater. First, there is the issue of insurance. If you require or want insurance on the building where this appliance is installed the insurance company usually wants an inspection report from a municipal, regional district or WETT certified technician.

If the wood heater is not certified by a testing agency like ULC or Warnock Hersey or if it is UL rated (american standard) then you may have trouble getting an inspector or a WETT technician to certify that the appliance is sound and that you have installed it correctly. This is due in part to the usual absence of specifications for clearances to combustibles that were listed in the original manual that was long ago lost or discarded.

There is also reluctance on the part of inspectors and technicians to say everything is okay when hidden damage may exist. There are, none the less, generally accepted generic clearances to combustibles for uncertified wood heaters contained in a wood burning appliance manual which is usually available without charge at most municipal and regional district building departments. However, some inspectors and WETT technicians will still refuse to inspect these uncertified heaters. This manual, by the way, is full of useful tips about all aspects of installing and using wood heaters and fireplace inserts. I recommend it as a “must read” for all new and experienced wood burning folks.

If the heater is certified (check for a label on the side or back of the heater) then it will usually specify the minimum required clearances to combustibles (drywall is considered combustible because of the paper facing) as well as hearth protection requirements. Try to get the original owner’s manual from the seller. Check inside the heater firebox for cracks and warped or fatigued metal. If there are cracked or missing firebrick don’t be alarmed. Firebricks are readily available at most building and hardware stores and they can be easily removed and replaced. Then install the heater to the manufacturer’s specifications. Connect the heater to a certified metal wood burning chimney or a conventional ceramic lined chimney flue (read last week’s column for details) and have the manual, with the clearances you used, ready when the WETT technician or inspector comes for review of the installation. Happy wood burning. ‘Tis the season!

Refrigerator maintence

Our refrigerator is only five years old and just before Christmas it stopped working. Is there anything we could have done to prevent this or help extend its life beyond five years?There is very little maintenance any homeowner can implement on a refrigeration system that will extend its life. The central and most vulnerable component in any refrigerator is the compressor, a complex piece of machinery similar mechanically to a pump. However, you can increase the life expectancy of the overall system by cleaning the refrigerator coils.

The coils are located either on the backside or underneath your fridge. To locate them remove the kickplate under the fridge door. If they aren’t there then pull the fridge out. They will be fastened vertically to the back of the fridge body. Usually the coils in this location are quite clean. If they are under your fridge near the floor they will probably be covered in dust. This makes the compressor unit work harder to achieve the same cooling effect. So it is a good idea to clean these coils at least twice a year. To do this, unplug your fridge and use a vacuum cleaner to remove all the dust balls and debris on and around the coil unit. When you put your fridge back into its usual location make sure there is a good air flow all around the body of the fridge including over the top (a favorite kitchen clutter collector).

If you own a fridge that is more than twenty years old you may want to consider replacing it with an energy efficient unit. Newer compressor units use less than half the electricity of older models. These savings on your monthly power bill can pay for the fridge in a relatively short period of time.

Forced-air heating system causing illness?

Our family has been experiencing a lot of colds and minor lung-associated problems, which seem to be increasing in frequency over the years. A friend suggested that our forced air heating system may cause it, but I’m not sure what that means or how it could be related to our illnesses. Do you see any possible connection(s) here?There are only a couple of things that come to mind. Your friend may be referring to the potential for air borne contaminants to be spread through your home by the furnace duct system. The furnace fan is re-circulating house air (with some additional outside air) throughout the whole heating season. Apart from the obvious re-circulation of air borne bacteria there can be quantities of contaminants in the sheet metal ducts that carry the heat to each room and living area.

The main plenum ducts that carry the heat are large rectangular sheet metal boxes with lots of horizontal surfaces. Just like undusted shelves and ledges in any house, these flat surfaces load up with all sorts of air borne contaminants over time. Even along the troughs of the smaller round branch ducts heavy particles constantly settle out of the air and create dusty deposits in the troughs of the ducts. Germs and bacteria can easily transfer to the warm furnace air circulating over the duct surfaces so if you haven’t had your heat ducts cleaned recently this would be a good place to start.

As well, if your furnace is equipped with a built-in or after market humidifier consider disabling it by turning off the water supply, drying out the water tray and cleaning the unit thoroughly. Drum roller humidifiers can increase the opportunities for bacteria to spread through the house heating system because the water trays often collect and re-distribute bacteria through the heat ducts. Besides, most houses in the Kootenays do not need additional humidity. If a single room requires additional humidity consider installing a small portable humidifier and run it as little as required to satisfy the demand.

Inspecting asbestos wrappings for risks

We bought our house almost 18 years ago. At the time we were told that the wrappings on the basement pipes were asbestos, but that as long as it was not disturbed it was okay. Is this true? If it must be removed, who does one call and what does such an operation cost?Asbestos wrappings are most commonly found on older hot water boiler heating systems. So I’m assuming this is what we’re dealing with. If the wrappings are in good condition and they are left undisturbed then removal is not necessary. However, check the wrappings for cracks at the elbows and bends in the piping. These are the most common places for damage. Also check along the straight asbestos sleeves for cracks, tears and mechanical damage. If you find these kinds of defects then consider removing or encapsulating the wrappings because the “friable” asbestos can become airborne and the heavier dust on the floor can be readily tracked, undetected to other parts of the house.

There are products available through Hazmasters Abatement Supplies (1 800- 663-7685) in Vancouver that you can use to encapsulate asbestos wrappings on pipe. But if you intend to remove the asbestos wrappings I suggest that you hire an asbestos abatement professional because containment and disposal are critical and these folks are trained in the appropriate strategies. Please feel free to call our office at 352 2300 for referrals to these companies. Cost for removal ranges from a few hundred to several hundred dollars depending on the amount of pipe and boiler wrapping to be removed.

For a comprehensive review of asbestos control strategies visit the Occupational Health & Safety Regulation website at You’ll find very useful charts that recommend the specific types of encapsulants, types of protective clothing as well as personal and site decontamination methods for a variety of asbestos containing products.

Inadequate and leaky flashing details

Last year I had two friends help me put new asphalt shingles on my house roof. Our roof has two levels, one second-storey gable roof above a lower gable roof. Now I have leaks at a plumbing vent and where the lower roof meets the gable stucco wall of the second storey upper roof. This is a brand new roof. Why is it leaking?It is probably not the new shingles that are causing you this aggravation. More likely the problem is inadequate and leaky flashing details. Often when people replace their roof shingles they don’t bother to replace the existing flashings. Unfortunately, they forget that the pipes, chimneys and joints of rooflines to vertical walls are the most vulnerable locations on any roof. In other words, if there is anywhere that water will find its way in to your home, it is most likely to leak at places where the shingles are penetrated and not adequately flashed and counter flashed. Flashings are your first line of defense against leaks at these penetrations and joints so they should be in very good condition throughout when you install new roofing. However, most often they are as old and deteriorated as the shingles you are replacing.

For instance, where your lower roof shingles come up to the second storey wall it’s quite likely there are no step flashings under the shingles. This is a difficult place to install flashings because the stucco coat you mentioned does not permit a person to slip the vertical part of the step flashing under the siding (stucco). So people often just caulk a continuos metal strip on to the wall and over the shingles. This half measure usually leaks. Other folks just caulk the shingle joint to the wall. Over time this will also fail because the caulking will deteriorate. The best solution is to saw-cut a groove in the stucco about 3 inches up the wall and parallel to the plane of the roof. Install the metal lip of custom bent step flashings into the grove as you lay the shingles up the roof. Then grout the groove once all the step flashings have been installed.

As for plumbing pipe penetrations, replace the old flashings with new EDPM rubber “boots”. They are inexpensive and much easier to replace when re-roofing than after the fact when the old flashings leak. If your chimney flashings are bent and worn, it is also worth the effort to remove the old ones and re-grout new metal flashings in as you go. If you have made the extra effort to re-flash the shingles properly you can rest assured that your new roof will be water tight even at these vulnerable locations.

Heat recovery ventilator maintenence tips

We just purchased and moved into a home with a heat recovery ventilator system. I notice a vast improvement in the air quality in the house when we have it turned on, but the former owners didn’t leave us any service manuals so we don’t know if it requires periodic maintenance and /or servicing. Any advice would be appreciated.I’m a big fan of heat recovery ventilators (HRV’s) for the same reason you mention. These units not only improve your indoor air quality; they reduce indoor humidity and re-claim heat from the hot exhausted air before dumping in outdoors. Here are a few maintenance tips that will help keep your HRV running trouble free. Before performing any maintenance be sure to turn off the HRV and unplug it.

Take ten minutes every two or three months to clean or replace the air filters. Older HRV’s have replaceable filters available at your local building supply store. Newer models are often equipped with re-usable filters that can be removed, vacuumed and washed with soap and water before re-installing.

Go outside and locate the intake and exhaust hoods located on one of the walls of your home. Make sure both duct hoods are clean and free of debris so air can move into and out of the system unrestricted. During the winter months ensure that these duct hoods do not get blocked with ice and snow.

Check the condensate drain located at the bottom of the HRV unit. Flush it with warm water to ensure that it is not blocked. This tubing is collecting condensed indoor humidity and delivering the water to a floor drain or laundry tub.

Once a year remove the grilles at the end of each distribution duct and vacuum inside the ducts. Also remove the dust and debris that has built up around the fan blades inside the HRV unit. You may be able to order a service manual from the manufacturer that will provide you with advise on lubricating fan motors (required on some older models) and methods for cleaning the HRV core. Also consider having a certified HRV technician complete an annual tune-up on the mechanical and electrical components. To locate a technician look for air conditioning service companies in the phone book.

Electric baseboard heat and ventilation

I have a 10-year-old home in Blewett that is heated by electric baseboard. Because of the baseboard heat, there is no ducting in the house. There are a couple of drawbacks to this setup:

1. It wastes heat to ventilate with open windows in the winter, and

2. As we close all windows when we go on vacation in the summer, it can be very hot and stuffy when we return. Are there any good options to add energy efficient forced air ventilation without resorting to ripping apart walls and adding ducting?

One of the down sides to electric baseboard heat is the lack of air circulation throughout the house. As well as the drawbacks you mention, the lack of air circulation within the building envelope and the lack of fresh air introduction from outside often causes mould and mildew on windowsills and wall surfaces.

There are a couple of ways to get air moving in a building, but ducts are hard to avoid. Here are a few ideas. If you live in a two-storey house with a basement, there is always a “stack effect” or hot rising air pushing through the highest ceiling in your home. You can capture this heat at the top of the highest ceiling by installing an extraction fan. Then pump the captured heat back down to the basement or a lower floor through one or two small ducts. Or, consider a combination of short feeder ducts from this fan to interior wall stud cavities that you have prepared by cutting out the bottom and top plates. This strategy re-cycles hot air that would be lost through the attic and roof, and it creates airflow throughout the interior building envelope.

Another alternative has been dubbed “the poor man’s ventilation system”. It installs simply but does not recover heat. It goes like this. Install an interval timer that is programmed with 2 four-hour on-cycles. Wire the interval timer to at least one bathroom exhaust fan. I recommend a 90 or 110 CFM fan with a 1 sone rating for a three-bedroom home. Then install a 4-inch sheet-metal duct through the exterior basement wall to a closet, cupboard, or under a stairwell (to temper the cold air). If you want to get fancy, you can install a motorized damper on this pipe and inter-connect the motorized damper to the timer on the exhaust fan. If you install a motorized damper, there is no need to run the duct to a closet. When the fan comes on, the damper opens and outside air is pulled through the house to the exhaust fan. Or without the damper, the air is pulled in passively to the tempering zone (closet etc.) and throughout the house to the fan.

The third option also involves ducts, but these ducts are often small and easily retrofitted into existing buildings. Heat recovery ventilators (HRV’s) can be purchased in a wide range of sizes and prices. The amount and size of ducting varies significantly, depending on the size of the unit you choose and the sophistication of the system. Generally, the larger units are more effective. But any amount of air exchange will make a noticeable difference in your home. HRV’s are my first choice for the problems you have mentioned. But be careful in your selection. There are dozens of brands and sizes to choose from. Before selecting yours, do some research. If you select an “off the shelf” generic HRV start by calculating the cubic volume of air in your home (length x width x height of all rooms including basement area). Otherwise, seek the advice of a heating contractor. Their expertise often ensures that you get the best and most effective system for your particular situation.

Condensation problem

How can I minimize the moisture that shows up on the inside of my good quality, double pane vinyl windows in the winter time when the central air furnace is not in use? I think it is due to not enough air movement but I would have thought the wood stove would have dried the air. Do we need a de-humidifier or are we not getting enough fresh air into the house? The house is only 2 years old and so it is very airtight.Since your house is new it should be equipped with a ventilation system that consists of an interval timer, inter-connected to a bathroom exhaust fan and a motorized damper on a 4 inch ventilation air duct. This duct is connected to your forced air furnace return air duct. The interval timer should be set to two 4-hour-on cycles each 24-hour cycle. This simple mechanical ventilation system should control the common and usual amounts of humidity in modern, well-sealed houses.

First make sure that all these components are installed and working as described above. Confirm that the exhaust fan is at least 90 CFM (with at least a 1.5 sone rating for noise control) if you have a 3-bedroom home. Also consider replacing the interval timer with a de-humidistat located centrally in a hallway on the main or second floor. If you have a severe humidity problem, don’t hesitate to put in two of these de-humidifier controls: one per floor on each bathroom fan. Unlike the timer that simply turns the fan on and off at arbitrarily set times each day, a de-humidistat responds to real and immediate humidity levels in the house levels (it is important to set the de-humidistat to the manufacture’s instructions seasonally). When this whole system is set up and working properly, it should control humidity.

You are right to be concerned about air movement in the house. When you aren’t using the forced air furnace, the wood heater isn’t making the air turn over. There is a common misconception that wood heat is “dry”. In fact, heat is heat. It’s not dry, damp or wet. What makes people think that wood heat is “dry” is often the lack of outside combustion air (4-inch duct) to the appliance. Without this outside air source, the fire pulls moist air from the interior and burns off the moisture in the process of combustion. To counteract the lack of air circulation when you are burning wood, consider setting up your furnace fan to run on a low speed 24-hour-on cycle. This will keep the interior air turning over and compliment the function of your wood burning stove. If your basement is damp, this will aggravate the condensation on your windows. You can help control this source of moisture with (among other things) gutters, downspouts and leaders at the roof eaves. If you have a crawl space, make sure the vapour barrier on the ground is well sealed. In other words, make a list of all the sources of humidity in your house and then set out to control and limit them. As well, make sure you use your kitchen fan (vented to the exterior) and bathroom exhaust fans when cooking and showering. If you put these tips into practice, you shouldn’t have to rely on an “add-on” de-humidifier to control this condensation problem.

Gas furnace not heating all areas of house

I recently purchased a two-storey house with a basement. The gas furnace in the basement isn’t heating the basement or the main floor adequately, but the second floor is too warm. Is there anything I can do to warm up these areas of the house?The first thing you should check is the BTU “bonnet” or “output rating” listed on your furnace specification plate. Occasionally the furnace is undersized for the number of floors and floor areas it is expected to heat. A heating technician will be able to tell you if the furnace BTU output is sufficient to heat your living area.

There are also strategies for controlling the heat flow so you can make better use of the available heat. For instance, close off all heat ducts serving the second floor. This will make more heat available to the lower floors. Consider installing a ceiling mounted fan at the top of the second floor stairwell to help push the heat back down to the main floor.

Check your ductwork in the basement. Often, basements have no dedicated heat ducts because the sheet metal installer thought that the ambient heat from the furnace would be sufficient to heat the basement floor area. Later, these basements are partitioned into rooms and the heat cannot spread evenly throughout the partitioned floor area. You may need to install some additional ducts into these rooms or far corners of the basement. The best part of a well-heated basement (if your walls are insulated) apart from warm floors is that you get to re-use this heat again on the main and second floors before it escapes through the roof.

Asbestos insulation in poor and damaged condition

We just purchased an old heritage house in uphill, Nelson. When we were moving furniture into the storage room in the basement, some of the insulation on the heat pipes from the hot water boiler got damaged by the larger pieces of furniture. When I looked at the rest of the boiler piping, I noticed quite a bit of loose asbestos insulation throughout the basement. Should I be concerned?First you should determine if this pipe insulation contains asbestos. Some older pipe insulation is a fiberglass material with a cloth cover. The two types are readily distinguished because the asbestos pipe insulation is white and crumbly when broken. If you have asbestos insulation in poor and damaged condition there is opportunity for the asbestos to become airborne, which can present a health hazard to you and your family.

However, there are things you can do to eliminate or control this risk. The most expensive and time consuming remedy is to hire a professional asbestos abatement company to remove all the pipe insulation and replace it with a modern pipe insulation. Consider this approach if the insulation is badly damaged or you are particularly concerned about exposure to asbestos products. Because this process requires sophisticated equipment, specialized knowledge and skills I would not recommend that you attempt removal yourself.

A second less expensive alternative, if the insulation is not too badly damaged, is to encapsulate all the insulation. First seal and repair all the broken, loose and damaged insulation with a good quality duct tape. There are different grades and qualities of duct tape, so select the best. Then apply an asbestos encapsulant resin emulsion over all the pipe insulation. These products are washable, fire resistant, hard-surfaced and easily repaired if damaged. One product I am familiar with is “Bakor” 120-18 and “Bakor” 120-19. If you visit the Hazmasters website you can review these products and select the one that best suits your application.

Split coil air conditioner maintenance

It’s getting warm outside and I’m wondering what I should do with my air conditioner unit to make sure it’s ready for the summer cooling season? It has a cooling coil in our gas furnace and a unit outside the house in our side yard.Here are a few tips that will help keep your split coil air conditioner healthy. First,

Be sure to turn on the main power to your air conditioner at the breaker panel and at the disconnect switch beside the outdoor condensing unit at least 24 hours before you intend to use the air conditioner. This activates the heat coil inside your compressor. In turn, this heater warms up the liquid refrigerant that has re-combined with the compressor oil during the winter and turns this liquid back into a gas again. Running the compressor without allowing it warm-up time can seriously damage your compressor motor. As well, during cool weather the compressor oil gets thick and sluggish. So never operate your air conditioner when the outdoor air temperatures are below 18 degrees C (65 degrees F).

Ideally your exterior cooling unit should be sitting on a concrete slab at least three to four feet away from any plants, shrubs, airflow obstructions or household air intake and exhaust ducts. Check the unit with a builder’s level to confirm that it is sitting “level” on the concrete pad so the oil bath for the compressor is lubricating all the working parts. You should have an emergency electrical disconnect switch adjacent to the exterior coil so you can break the power to the unit if there is a problem. Keep the lawn cut close around the condensing unit and make sure the fins that dispel the house heat to the outside air are not clogged with grass clippings. Split coil systems have a life expectancy of about 8 to 15 years. Consider calling your local air conditioning specialist for a service check this year if your cooling system hasn’t been serviced for a few years.

Rumford fireplace: utilitarian, efficient design

We recently purchased an old heritage house in uphill Nelson. In the living room is an old fireplace that hasn’t been used for years. The thing that we can’t figure out is why the firebox is so shallow. There is only enough room to light and burn a few sticks of wood at a time. Why would anyone build such a small fireplace in the centre of such a large living room?From your description I’m speculating that you are looking at a classic Rumford fireplace. The design is odd by our modern conventional standards for fireplace construction. For instance, the firebox is very shallow and the rear vertical wall of the firebox is sloped toward the front face of the fireplace. As well, if you look closely, you’ll notice that the throat of the chimney is almost flush to the front face of the fireplace. Here is a little of the history of this design.

Sir Benjamin Thompson (Count von Rumford), a U.S. born British physicist (born in 1753), spent a significant part of his life inventing modifications to chimneys and fireplaces which would increase their efficiencies. Along the way he also invented the double boiler, a kitchen range and the drip coffeepot. His work in heat transfer led to the Rumford fireplace design, which proved so popular that it became an industry standard on both continents. The design principles of the Rumford fireplace work like this.

A hot fire is lit using a very small quantity of dry wood. The steeply angled rear wall that slopes to the front face of the fireplace and the forward mounted chimney flue force the heat of the small, hot fire out of the fireplace and into the room as the smoke gets captured in the chimney flue. The heat efficiency is so superior to a conventional fireplace with its cavernous firebox and deep-set chimney flue that a small quick fire is all that is required to heat the room. The Rumford design is all about utilitarian function. It was not meant to provide those hours of romantic fireplace musings that we have come to idealize over the years. This was a practical and necessary improvement on the deep firebox in a day and age when the fireplace was the principle source of heat in a home.

Sharing a furnace with “in-law” (secondary) suite: a grey area

We’re thinking of building an in-law suite in the basement to help with our mortgage. Our contractor told us that he has heard the new building code now allows you to heat your basement suite with the same furnace that heats the rest of your house. Is this true or just a new urban myth?To get to the bottom of this story, we should review a bit of Code history. In the past the Code stated that you had to provide a separate heat source for a second suite in your house if your house heating system used ducts to circulate air. The logic behind this requirement was simply to limit the possibility that smoke and fire could spread from one suite to other suite through the common heat duct system. If the furnace served only one suite and the second suite had an independent heat source, the goal of compartmentalizing a fire was much more achievable.

However, in the appendix of past Codes, it advised readers that they didn’t have to install a separate heat source, and they could use the same ducted heat system if they were prepared to install a “system” in the ductwork that would prohibit smoke transfer through the ducts in the event of a fire in either suite. No one paid much attention to this appendix note in the past, perhaps because most people just didn’t know that this advice existed or exactly what a “system” in the ducts would constitute. The new Code (not the Code appendix) now states quite clearly you can use your furnace to heat the second suite if you install this duct “system” that was alluded to in the appendices of previous Codes.

So, here is what one possible duct “system” might constitute. Fire dampers (accordion shaped shutters on heat sensitive links) would be installed in the main supply and return air plenums of your furnace. The heat sensitive fusible links that hold the dampers open would be electronically connected to a duct smoke detector located in the ductwork. The smoke detector would also be inter-connected to a shut-down switch on the furnace fan motor. In the event of a fire or smoke in the supply or return plenums, the smoke detector and / or the heat from a fire would release the fusible links holding the fire damper shutters open. The dampers would quickly close and seal the ducts, preventing smoke and heat transfer to an adjacent suite. As well, the furnace fan would stop pushing air through the ducts. Is this “system” less expensive than installing a separate heat source? I’m not sure. Is this the only “system” that might be acceptable? Probably not. We are in a bit of uncharted water here, and I recommend that you research further. If you choose to install a duct “system” in lieu of a separate heat source, first discuss your proposal with your heating and electrical contractors and the local public building official to ensure that all parties agree that your “system” will work as designed and meet the intent of the Code.

Adding humidity to house can exacerbate other problems

We just purchased an older home and I want to get the furnace ready for winter. There’s an old add-on humidifier attached to the heat plenum and I’m not sure what to do with it. Do you have any suggestions?First I should let you know that the humidifier body should be mounted on the return air plenum and secondly that I’m not a big fan of humidifiers. In most areas of this province humidity in buildings creates problems like mould / mildew, rot, pealing interior paint and poor health. Adding humidity to your house will exacerbate any and all of these problems. The typical drum roller humidifier can be a breeding ground for bacteria. Just look at the water tray after a few months of use and you will see a layer of residual scum. The drum roller is turning through this water and evaporating these bacteria throughout your home. As well, these units often leak because the supply valve sticks open, the drain valve clogs or the drum and pads clog with sediment. Water can then leak on to the furnace heat exchanger. Over time the heat exchanger (which is the “heart” of the furnace) will rust. These rust holes will allow exhaust gases including carbon monoxide into your house. Further, you will have to replace your heat exchanger.

If you would still like to add humidity to your house then make sure you thoroughly clean this unit according to the manufacturer’s recommendations on a regular basis. If you are getting condensation on your windows turn the humidistat dial down and check for leaks throughout the system regularly. Most humidifiers are installed with a bypass damper on the supply / heat plenum. Make sure this damper is closed during the non-heating season and open during the furnace-heating season.

Complimentary heat systems

I recently installed a wood burning stove in my basement fireplace. I also have a forced air gas furnace in the basement. I want to capture the heat from the wood burning stove and re-circulate it through the existing gas forced air supply plenums. Are there any issues I should be aware of before I begin?This is an interesting proposal. I have seen several variations of these complimentary heat systems in use, often installed by country homeowners who want to capitalize on their auxiliary wood heat by distributing the heat more effectively through their existing forced air heat plenums.

Some modifications I have seen include a new opening installed in the return air plenum with an air filter and a suction fan pulling air from the room in which the wood heater is located. Another version of this is the sheet metal shroud over the wood heater capturing passive hot air, coupled to the forced air furnace return air plenum. Here are some issues to consider before you begin this project.

If your furnace is under warranty the manufacturer may not honour that warranty if your forced air duct system has been modified to accept hot wood stove air into the return air plenum. One of their concerns may be that you will create an imbalance in the forced air system. In the original installation the size of the return air registers and ducts is roughly equivalent to the size of the supply registers and ducts. Thus you have a “balanced” system. When you install an additional opening in the return air plenum this can create an imbalance in this closed loop system. As well, you are introducing warm air into the cool air return plenum, pushing pre-heated air across the furnace heat exchanger. The manufacturer will probably absolve themselves of responsibility for any defects in the heat exchanger because of this modification. If your furnace is not under warranty then this may not be a concern.

However, if you are going to make these modifications consider hiring a local heating contractor who specializes in the brand of forced air furnace installed in your home. He will know how to size the new opening and re-balance the system. He will be able to offer you advise on any possible adverse effects of modifying the particular brand of furnace you have installed. If your wood stove is not an airtight model there is a possibility for carbon monoxide from the wood smoke to backdraft and migrate through the forced air heat ducts. You can install CO sensors to help alert you to this problem should it occur.

Gas appliances spilling harmful gases?

Every morning I wake up with a headache. I’m wondering if it is somehow related to the gas appliances in my home. We have to keep lighting the pilot lights on our hot water tank in the basement and gas fireplace in our living room. Is there a possible correlation between my two problems?The short answer is yes, there is a possible correlation, but the explanation is a little more involved. If your gas appliances have “naturally aspirating” B vents (typical standard gas chimneys – not high efficient appliances) then here’s what may be happening.

The chimneys (B vents) serving these appliances carry carbon monoxide and other harmful gases safely out of your living environment. These chimneys may be “back-drafting” or spilling these harmful gases back into your home. Extinguished pilot lights are just a symptom of insufficient fresh air near the appliance to support combustion. Here are a few reasons why this can occur.

There may not be enough fresh outside air near your hot water tank or gas fireplace to support the combustion of natural gas. All fires require oxygen to burn. If your gas appliance is starving for combustion air then it may try to pull that air from it’s own chimney. Because the chimneys of these appliances carry hot toxic gases to the exterior your fireplace and gas hot water heater may be re-introducing these toxic gases to your home. If you sleep in a bedroom located above these appliances (like a second floor bedroom) these toxic gases can drift up to your bedroom. You may be inadvertently compounding this problem if you sleep with your bedroom window ajar. Leaving your window open can create a natural siphoning effect throughout your home. Hot air rising through your home will be drawn to your top floor bedroom window carrying with it the toxic flue gases that have spilled back through the appliance B vent chimneys. In essence your open bedroom window can turn your home into a chimney. This could be the cause of your morning headaches.

Are there solutions? Yes. Begin by ensuring that each gas appliance with a “naturally aspirating” B vent in your home has a source of fresh exterior combustion air. If you’re unsure consult your local gas appliance installer. What you may need to install is a sheet metal pipe about 4” in diameter located near your gas burning appliance. In gas furnaces this duct is often connected to the return air plenum of the furnace. The exact amount of combustion air required for each and all gas appliances in your home requires calculations specific to your home. There are also more complex and compounding reasons for backdrafting B vents so I urge you to contact your local gas technician and Provincial Gas Inspector for specific advise.

However, there are general principles that apply. Any fuel-burning appliance can starve for air. If it starves for air the B vent chimney can backdraft and spill toxic gases into your home. To further complicate matters, any appliance that sucks air from your home, like a clothes dryer, a bathroom fan, a kitchen range hood fan or combinations of these fans can aggravate this problem by creating negative pressure throughout your home, causing B vents to backdraft. So it is important to ensure that you provide sources of air from the exterior to balance any negative pressures created by these fans and open windows. As well, I urge you to install one or more carbon monoxide monitors in your home to alert you to the presence of this toxic gas.

Old-fashioned style vs. programmable thermostat for gas forced air furnace

An old-fashioned style thermostat controls our gas forced air furnace. I’ve been thinking about changing it to a programmable thermostat. However, I’ve heard some furnace technicians say these modern setback thermostats don’t really save you any money in fuel bills. Do you have an opinion about which style best helps reduce heat bills?There are two theories out there that go something like this. Imagine your house is a balloon. The furnace pumps the balloon full of hot air every day during the heating season. A conventional thermostat keeps the balloon at a constant pressure throughout the day and then most folks manually turn it down before bedtime each night.

Some technicians argue that it is more cost effective (uses less fuel) to keep the balloon at a constant pressure. Their logic is that the biggest expenditure of fuel is taken in pumping up the balloon from cool to 20-degree house temperature. Their next argument is that maintaining that temperature takes relatively little energy. Therefore, they argue, it is more efficient to maintain the house at a constant heat throughout the day than to pump the balloon up and deflate it in cycles throughout the day.

The second school of thought argues that when you heat your house and pressurize it to 20 degrees all day the house is under the maximum pressure it ever experiences. Under this pressure the house consequently leaks heat through the walls and attic / roof at a greater rate than if the house were under less pressure. Therefore decreasing the pressure throughout the day by lowering the heat decreases the amount of heat leakage through the walls and attic / roof. Now let’s look at what a programmable thermostat does.

During the times you are at work the pre-programmed thermostat reduces the heat demand from your furnace. The corresponding pressure on the walls and attic / roof is reduced. The balloon shrinks in size and in theory less heat is pushed through the exterior walls and roof. Just before your pre-programmed arrival time the furnace comes on and re-pressurizes the balloon so your home is at a comfortable temperature when you arrive.

So which thermostat is saving you money in reduced fuel consumption? Most engineers and technicians are convinced that the programmable thermostat saves you money throughout a heating season. However, the argument for conventional thermostats still has merit. Consider conducting an empirical experiment by keeping a record of your fuel consumption over a heating season with a new programmable thermostat. (They cost about $50 to $75). Then compare your data against your old fuel bills. Let us know your findings so we can help put this debate to rest.

Testing and/ or venting for radon gas

I was re-organizing boxes of storage in a cupboard under the basement stairs when I came across a plastic pipe sticking about 6 inches out of the cement floor. It looks about 100 mm in diameter and it has a red cap on it. This is not a place where someone would put plumbing for a toilet so I’m wondering if you have any ideas on why this pipe is there?If your house is less than twelve years old the stubbed up service pipe you are looking at is probably a radon gas vent. Since about 1992 the BC Building Code recognized that certain regions of the province, like the Kootenays, have high levels of naturally occurring radon in the soils beneath houses. So the Code authors decided to start requiring all new homes constructed in these regions to be equipped with a 4” (100mm) pipe or series of pipes installed through the basement concrete slab and capped off in case radon gas is detected in the home. The pipe(s) are about 12” (300mm) to 18” (450 mm) long and simply “dead end” under your concrete slab. If this harmful gas is detected (using a radon test kit) then the idea behind this Code requirement goes like this.

The homeowner purchases an evacuation fan. The cap on the pipe you noticed is removed and piping is connected to an evacuation fan that is usually outside of the living area. Another pipe is then installed from the fan to the outdoors. The fan then runs 24 hours a day. The idea is that the fan will continuously de-pressurize the radon gases that are building up under your concrete slab and leaking into your home through cracks and construction joints in your basement. As well, other measures are also implemented to discourage gas leakage into the house.

This all seems a little convoluted. However, we do live in a region noted for high levels of this potentially lethal gas. The provincial government and Code authors felt they were providing some measure of potential protection without driving up the cost of housing by requiring a full radon evacuation system in all new housing in the Kootenays and other known radon gas regions of the province.

Personally, I prefer an approach to radon control that is common in parts of England where high levels of radon gas also occur in houses. The same pipe that our Building Code requires is also installed in these British homes. However, instead of capping the pipe off for possible future use the Brits extend this pipe right to the outdoors immediately during construction of the house. No evacuation pump is installed. The theory goes like this. Radon gas will build pressure against the underside of the concrete slab and finding the path of least resistance it will continue to escape through the passive radon pipe vent to the outdoors.

Wood heat chimney issues

I want to heat my backyard workshop/ car garage with wood heat. Recently in the Buy & Sell I found several lengths of used metal chimney and a used wood heater for sale. Before I buy these items, are there any issues I should be aware of?There are several issues that come to mind. Because I don’t know your exact circumstances I will list a few issues for you to consider. First check out the metal chimney. If it is the old Selkirk brand 1” metalbestos chimney, insurance companies and wood stove technicians (WETT technicians) will probably not insure or certify it. The problem with metalbestos chimneys is this.

Often the stainless steel liners failed when subjected to intense heat from a wood stove or wood heating appliance. Consequently, the stainless steel liners sometimes buckled, creating one or more blisters on the internal liner. The buckled blisters on this liner in turn often created voids that allowed the powdered asbestos between the inner and outer shells of the metal chimney to drop down, filling the blister(s). Unfortunately, somewhere above that blister there was often a void created with no insulation because it had settled into the blister. If that void happened to be at a point where the chimney was near combustible materials, like wood attic ceiling framing or roof framing, then the potential for a fire can be very real. So, do be cautious about purchasing and installing old Selkirk metalbestos chimney components.

As well, be cautious about purchasing and installing uncertified (no ULC or CSA) labeled wood heaters. Your insurance company and WETT technician may not certify or insure the unit. Also be careful about combining wood heat with stored gasoline or diesel carrying vehicles. Lighting a fire in one and storing the other nearby carries significant inherent problems. More on this and insurance issues to follow next week.

Ventilate bathroom to prevent peeling paint and mould

I re-painted our basement bathroom last year. Now I’m noticing that the oil base paint on the ceiling and top portions of the walls is blistering and cracking. Is the paint defective?It’s quite unlikely that the problem has to do with the quality of the paint. In fact, using oil base paint in a bathroom is a good strategy because it less permeable to moisture from showers and baths. Often bathrooms are not equipped with an exhaust fan. This simple omission will allow humidity from showers and baths to linger in the room. Even though your bathroom probably has an opening window, more often than not, during cold periods these windows are not opened during and after showering or bathing.

The effects over time will be pealing paint and mould / mildew on ceilings, walls and windowsills.

If your bathroom is equipped with an exhaust fan, use it during and after showers and bathing. Otherwise, consider installing one. Vent it directly to the exterior through a wall, roof or soffit. Don’t vent it into your attic or an enclosed soffit area. Insulate the duct if it passes through a cool area like the attic so condensation does not build up on the duct and “weep” on to your insulation. Consider inter-connecting the fan to a de-humidistat so the fan can come on automatically if the de-humidistat senses high humidity from a laundry room or another bathroom. Locate the de-humidistat in the central core of the house so it is sampling a large as possible volume of house air. In a standard three-bedroom house consider installing a 90 or 110 cfm bathroom fan with a 1.5 or less sonne rating. This will ensure that the fan is strong enough to do the job and quiet enough that it will not disturb you when it comes on automatically.