Ask The Experts
Heating, Ventilating & Air Conditioning
The inspector hired by the buyer of my house indicated that I am missing a firestop at the B-vent for the boiler. I would like to repair this myself if I can, but I am not sure what he is talking about.
The B-vent he mentioned is a double wall metal chimney for your gas boiler that runs via a chaseway from the lower level or basement up through your house to the attic to exit through the roof. The firestop is a sheetmetal pan that seals the bottom of the otherwise open chaseway to prevent a house fire from quickly spreading through the chaseway to other parts of the house. The chaseway itself could become a chimney if you have a fire in the basement, accelerating the spread of the fire vertically, between floors, and increasing its intensity. If the chaseway is open all the way to the attic, flames can spread up the chase and quickly expand throughout the attic. The key concern in a house fire is to have enough time to escape. Any open vertical chaseways, whether for chimneys, plumbing, ductwork, or any other purpose, can significantly reduce the time available for you to get out of the house. All open chaseways should be sealed at the bottom, at minimum. Almost any material will do the job if it fully blocks off the opening and prevents a natural draft up the chaseway, although a non-combustible material should be used if a chaseway is being used by a chimney. Ideally, chaseways should be blocked off at each floor or ceiling level.
Another similar condition that can accelerate the spread of fires is balloon framing. In some older uninsulated houses the exterior wall cavities are open from the basement to the attic. You should check along the perimeter of your basement at the top of the foundation to see if you can look up inside the exterior walls. If you can, you should block them off. Open stairways can also increase the spread of fires. At the very least, we recommend keeping the door from the basement to the rest of the house closed at night.
In modern construction, because flammable materials are often stored in an attached garage, fire resistant construction is required between the garage and the living space. Even though not mandated in older houses, upgrading to provide fire resistance between the garage and the rest of the house would be a wise move. We recommend that everyone review the conditions in their house that might accelerate the spread of fire. And of course, don't forget the most important key to getting out in time; a good working smoke alarm.
The area around my oil fired boiler is smoky smelling sometimes, but I can't see any smoke in the air, and I was told that the boiler was running just fine. My house is only a few years old. Do you have any suggestions? I really don't like the odor.
There are many sources of odor around an oil fired heating unit, but the most common are from oil leakage or improper venting of the combustion products. Since the odor is smoky, we have to suspect that venting is the issue. When we burn fossil fuels to provide heat, we have to vent the exhaust gases to the exterior. Since the odor is intermittent, it is unlikely that you have blockage in a chimney. You don't say, but given the age of the house, we suspect that the boiler actually vents right out the side of the house and doesn't use a chimney. More and more of our modern combustion equipment vents directly to the exterior using blowers, rather than relying on a traditional chimney which uses rising warm air to vent the exhaust. These are called impelled-draft systems. One of the reasons for using impelled-draft venting is that in our modern tight houses, exhaust gases may not be able to rise naturally up the chimney, because there may not be enough incoming air to replace the air going up the chimney. The problem that we now find is that when the boiler or furnace isn't running, the blower isn't running either. Then the smoky odors in the boiler begin to back-vent into the house. That's why you're not seeing anything, and why the technician insists the unit is running properly. This condition is greatly aggravated in a modern house when we run our clothes dryers, bathroom ventilators or range hoods. The replacement air has to come from someplace, and that might be right in through the heating equipment venting system. You need to bring air directly into the area where your heating unit is installed. This could be a simple air duct with a screen to prevent pest entry installed from the exterior to a location next to the heating equipment.
I occasionally have dripping water coming out of my bathroom ventilator. I can't find any roof leaks. Is this condensation, and what should I do to stop it.
Water dripping from a bathroom ventilator is most likely due to condensation. Your unit is venting moisture laden air into a cold area, your attic, every time it is used. Moisture condenses on cold surfaces, and builds up remarkably quickly. We have often found poorly installed plastic ducting from bathroom ventilators filled and sagging with gallons of water or ice when we inspect the attic. They don't work very well when they're full of water. Worse, a small hole in the plastic ducting can result in water damage to the ceiling below.
The best solution is to install as short a run of plastic ducting as possible in the attic, preferably exhausting through the roof at a roof vent, or at the nearest gable end, using a standard dryer exhaust hood. And, you should use either insulated ducting (typically used for flexible heat ducts,) or apply insulation over the ducting to keep it warm.
Ventilators are not the only ceiling penetrations that can drip condensation. Recessed light fixtures will often show evidence of water stains from condensation. A high percentage of our total heat loss is due to penetrations through the ceilings, such as attic access doors, whole house fans, heat ducts, recessed lights, electrical outlet boxes, and of course bathroom ventilators. But just as important as heat loss is the potential for damage caused by the large amounts of water carried by the warm moisture laden air flowing into the attic. Do your best to seal all of these potential breaks in the thermal envelope of your house, and make sure that the moisture you're ducting from your bathroom is making it all the way to the exterior, and not just ending up in the attic.
My bathroom ventilators exhaust into the attic. What is the best way to vent them to the exterior?
There are several different options for ensuring that the warm moisture laden air from your bathroom ventilators is adequately exhausted to the exterior. The principles to keep in mind are that warm air rises, and moisture condenses on cold surfaces. Common four inch flexible plastic dryer exhaust tubing is a suitable material for ducting the bathroom moisture to the exterior, but insulated piping would be preferable. The interior surfaces of insulated duct will be warmer, resulting in less condensation buildup in the vent ducting. The most common error is to vent the exhaust into the eaves. It's easy and the thinking is that the exhaust will go out the vented soffit, but in fact this does not work. Since warm air rises, it simply curls back up into the attic, and, because it is concentrated in a small area of the attic, mold and decay often result on the underside of the roof decking directly above the outlet.
The best approach is to duct the bathroom exhaust to a nearby gable end wall, if your house has gables, using a standard clothes dryer exhaust hood, or to install the vent through the closest roof surface, using a standard roof vent hood. Make sure to keep the ducting as short as possible and avoid any sags that could collect water. Also, do not hook up the bathroom exhaust with your clothes dryer exhaust. Any blockage will cause the fumes and lint from the dryer to be redirected into the bathroom. The same venting principles and the importance of venting directly to the exterior apply to clothes dryer exhaust and kitchen ventilators, but we would recommend using metal ducting, for greater resistance to fire spread if a flare-up should occur from the clothes dryer or while you're cooking.
The family room addition on the rear of my 60 year old house doesn't stay warm enough in the winter. We have warm air heat, but it just doesn't seem to be enough.
This is a very common problem with several likely reasons and several possible solutions. Most houses built in the same era as yours were given a fairly compact design. They were usually two stories and relatively square. This was efficient construction in many ways, including heat retention. Less exposed exterior walls and ceilings meant less heat loss and easier heat distribution. Many houses of that era and older had gravity furnaces; in other words they had no blower to force the heat to extremities, like your addition, but relied on the natural upward flow of warmed air. Assuming however that your furnace is presently a more modern forced air type, it still takes extra effort to push the heat to an addition, and the addition has more exposed exterior surfaces than the other rooms in your house, increasing the heat loss.
There are several steps you should take. Check for sufficient insulation in walls, ceilings, and floors. Generally speaking more is always better. Believe it or not modern codes now call for approximately 15 inches of insulation in the attics of new homes. A high percentage of the heat loss in an older home is actually due to air leaking through windows, doors and other openings or gaps. Check carefully and better seal or update these units if appropriate. Also check to make sure that any crawlspace below the addition is well sealed against exterior air entry in winter.
These actions will help you save energy, but the more immediate concern is to simply get more heat into the room. Most heat ducts have adjustable dampers in them. If you look at the ducts near the furnace you will see little metal handles or knobs that can be turned to adjust the amount of air that can flow through the ducts. If you partially close down the ducts feeding your warmest rooms, you will be forcing more warm air into your addition. If that doesn't do the trick, you can buy a blower, designed to mount in the duct to the addition, that is wired to work with the main blower, to push more air where you want it. If all else fails, you may want to add another warm air duct into the addition, and perhaps a return air duct to allow the air in the family room to more easily recirculate to the furnace for reheating. Take these steps before the next heating season and we predict that you will enjoy your family room a whole lot more.
We need a new heating system. I would like hot air heat because we could add central air conditioning. My wife believes we should stay with baseboard hot water because hot air heat will blow dust around and will be too dry. What are the pros and cons?
There are many positive aspects as well as drawbacks for either system, and for most people the decision is likely to represent familiarity and personal preference. In broad terms forced air heat has the advantage, as you mention, of providing the ductwork needed for central air, has the potential for easy installation of whole house humidification, provides a means for filtering the air, and forced air heat warms the house more quickly when you turn up the thermostat. Baseboard hot water is a much more even heat with less potential for drafts, is easily zoned with separate thermostats in different areas of the house, and if installed correctly is less noisy. I have often been asked which system is more efficient. The efficiency of either heating method varies widely depending on the particular equipment, but in either case in new equipment ranges from standard efficiency in the 70% range through mid-efficiency to high efficiency in the 90% range.
In your situation it will be difficult and therefore expensive to change to forced air heat, since all the ductwork will need to be retrofitted into existing living space. In a two story house, it may be best to install two furnaces (and two corresponding separate central air conditioners), with one in the attic and one in the basement. Your wife's concerns, however, are not really an issue. While warm air heat may blow some dust around, the means for removing dust can be built right in. Box type pleated filters do a wonderful job of removing particles from the air. Filters labeled as HEPA type should work the best. Paper type filters are probably preferable to washable type, since washing is a nuisance. Regarding forced air being drier, it is simply not true in any meaningful way. What makes indoor air drier is the amount of heating that occurs, that is how much you raise the indoor temperature above the outdoor temperature, and how much of the moisture in the house escapes to the outdoors, not the type of system that produces the heat. We generate a lot of moisture as we live in the house, cooking, showering, watering plants, and just breathing. Well insulated and well sealed homes are very rarely too dry. More often they tend to be too moist, resulting in condensation problems in the house.
Make sure your house is well sealed and conserving heat, get several estimates, and know that either system can provide good long term service and efficiency.
We bought a vent free gas log set for our fireplace. It works great, and we get a lot of heat, but I do detect an odor from the unit with the fireplace damper sealed. Is this unhealthy and does it mean it's not operating right?
Vent free units have been allowed in New York State for only a few years. These units are designed to vent the exhaust gases from natural gas or propane combustion into the air in the house, rather than outdoors via a chimney or a horizontal vent. They are inexpensive to install and are very efficient. However, they almost all give off a slight odor produced by trace amounts of alkyds that you may find objectionable. More importantly, they give off large amounts of carbon dioxide and water vapor, which are byproducts of combustion. The water vapor may cause excessive humidity and damage or mold in the house. The carbon dioxide is harmless, but if too much oxygen is displaced, the combustion quality degrades and carbon monoxide (CO) may be produced. (These devices have safety features that should prevent CO from ever reaching a dangerous level.)
These vent free heaters are designed to be used as a supplemental heat source only. Most units are listed to be used for a maximum of 4 hours at a time, with a window open, and not while sleeping. They are not intended for use in bedrooms. These heaters should be carefully sized to the rooms that they are in and should be maintained to ensure that they burn cleanly. Any signs of soot are an indication of poor combustion, and the need for service. They also become very hot, therefore, no combustible materials should be close to them and child protection may be advisable. We recommend referring to the manufacturer's installation and operating instructions for further information about your particular vent free gas log set and to make sure it was installed properly.
I have been unable to figure out where the exhaust from the kitchen ventilator goes. I know that it should go to the exterior, but this would be hard to do. Is a recirculating type worth anything, or should I try to figure a way to get it to exhaust to the exterior?
Exhaust outlets that can't be found are not all that unusual. Most kitchen range hoods are designed to either exhaust to the exterior or to be recirculating, and are converted from one mode to the other by relocating or removing an internal baffle and opening up an exhaust outlet on the body of the hood itself. Often enough however, kitchen range hoods have no ducting installed, and were not converted for recirculation either, so the air has no place to go. They make noise, but they don't actually do anything. Even more commonly, the exhaust is ducted, but only into the attic, and is sometimes buried below the insulation in the ceiling, again to no positive effect. This is actually worse than going nowhere, because any flare-up on the stove top could result in flames being blown directly into the attic. Sometimes the exhaust is ducted into the eaves from the attic, under the assumption that the exhaust will flow out through the vents in the roof overhang. Unfortunately, warm air rises and the moisture and grease just end up re-entering the attic.
If at all possible, we recommend ducting the exhaust directly to the exterior in as short a distance as possible, using well sealed metal ducts and an outlet that resists cold air entry. If this isn't possible, a recirculating hood is better than nothing, providing a means of protecting any cabinets above the stove from grease or a flare-up, keeping the fumes out of the cook's face, and providing some rudimentary filtration. Some better quality range hoods offer filters with charcoal for more effective removal of grease from the air. Range hoods are worthwhile as long as they either recirculate or truly vent to the exterior.
I have baseboard hot water heat in my house. I have water dripping from the plastic pipe from the furnace that exhausts out the side of the house. What's causing this and what's the best way to seal this pipe?
When we burn gas to heat our houses, a byproduct of that combustion is water. In our modern higher efficiency furnaces and boilers, the water vapor that is produced during combustion condenses in the heating unit, or in the exhaust piping, and needs to be properly disposed of. This is the source of the water you're seeing. Usually there is a drain installed on the exhaust piping near the boiler that takes the water to a floor drain, or to a small pump that directs the water to an appropriate location. While there usually is no problem with water dripping out of the exhaust outlet outdoors, it is not a good sign at all if it is leaking inside the house. The dripping water may be the least of your concerns.
It is likely that you have high temperature plastic vent piping or HTPV. This product, which is usually 3 inches in diameter and is gray, or black with translucent amber elbows, is under a nationwide recall since 1998 due to loosening joints. The names Plexco, Plexvent, and Hart and Cooley may be found on the plastic pipes. The fittings are normally caulked and sometimes screwed together, but have a tendency to loosen and leak condensate as you observed. More importantly, they may also be leaking exhaust in the house, even if nothing is dripping. A University of Vermont student was killed and six others injured last spring from carbon monoxide poisoning when one of these loosened joints actually came apart.
If the exhaust piping is white PVC plastic, it should be easy to cut the piping in the affected area and install new fittings that are properly glued together to prevent leakage, but if the plastic vent pipe fits the description of HTPV piping above, take the situation very seriously and call in a plumbing and heating contractor to replace the vent piping with approved materials.
I had air conditioning installed in my house a few years ago, and it has been very poor on the 2nd floor. Now my furnace isn't heating well, and I am told I might need all new ducts. I am thinking of giving up and installing window AC units. What would you recommend?
Retrofit central air conditioning installed to an existing furnace duct system often doesn't work well on upper floor levels. The ductwork was designed for hot air, which naturally rises to upper levels, not cold air which is heavier and sinks. Boosting the blower fan speed can sometimes help push more air where you want it, however the balance is likely to remain poor. Check your registers to make sure they are not blocked, or closed, and check the furnace filters to make sure they are not clogged. Also, check the AC evaporator unit in the ducting above the furnace to make sure that it isn't dust clogged. One aggravating condition, very common in older houses, is the lack of adequate return air ducting, especially in bedrooms on second floors. To operate efficiently ducted air needs to be able to return to the furnace or AC evaporator to be reheated or cooled, respectively. Ideally, each room in the house, except for kitchens and bathrooms, should have a return air register, as well as the heat source register. Without adequate return air ducting your furnace and cooling unit will be starved for air, and will operate very poorly. The air that these units need will be drawn from the basement or utility area, and the air in your rooms will be forced out of the house through windows and doors, as air from the furnace or AC blows into the room. Your heating and cooling bills will be sky high, and you won't be comfortable. If you don't have an adequate number of return air registers, call a heating contractor in to add them. If adding a return duct to each room is impractical, at least add a large register in the central hallway and cut up the bottoms of the doors an inch or so to allow air in the rooms to move to the central return air register and flow back to the furnace and cooling unit.
It gets hot in the room in the basement where the gas boiler is located. Does it make sense to add an air duct from the exterior to this room to cool it off?
It may be a very good idea to add air from outdoors to your utility room. To begin with, it is very important that there be sufficient air for combustion from some source, whether interior or exterior. It takes plenty of oxygen to properly burn natural gas. If the utility room is not open to a large portion of the rest of the house by vent openings, a louvered door, or some other method, there may not be enough air for proper operation. If there isn't enough oxygen, the boiler will start producing large amounts of carbon monoxide. In addition, if there isn't a sufficient air supply to the utility room, the negative pressure created as the exhaust gases attempt to rise up the chimney may cause an inadequate draft. This can reroute some of the exhaust gases, including carbon monoxide, into the living space. So the least of your problems may be the excessive heat.
There are two advantages to bringing in air from the exterior, rather than using the air in the house, to supply the boiler combustion. Since we will be sending large amounts of air up the chimney in either case, it would be far better to send outdoor air up, rather than air we spent good money to warm up in our house first. Also, the chemicals in paints, thinners and cleaning compounds that we store in our basements, as well as any excess moisture in the air in our basements, may accelerate deterioration of the heat exchanger portion of the boiler.
Ideally, the exterior air should arrive at two locations, one high and one low in the utility room to provide balance, and the amount of air necessary to ensure proper combustion will probably necessitate at least two 6 inch ducts, or equivalent, although this should be based on a professional calculation of the actual total BTU ratings of the equipment in the room. By installing an exterior air source, you will no longer be sending heated air from the living space up the chimney, which creates drafts in the house as air enters to replace what is lost. You may well experience less draftiness in your home, and feel more comfortable.
My house is way too dry. I am thinking of changing from hot air heat to hot water heat. Are there other changes you would recommend?
Older houses often become very dry in the winter, resulting in discomfort, nosebleeds, static electricity, and other negative effects. However, this really has nothing to do with which type of heat you have. Replacing the forced air furnace with a hot water boiler will make no difference. How you heat the air doesn't matter. How much air you heat does. Drying is caused by the reduction in relative humidity that naturally occurs as you heat the cold winter air that seeps into your house. The more air you heat per hour, the drier the house becomes. Cold winter air holds much less moisture than warm air, so as you warm that cold air the difference between how much moisture is in the air and how much it could hold increases, even though the total number of water molecules remains the same. This lower “relative humidity” makes us uncomfortable. By better sealing out the cold air, you can reduce the dryness, and save yourself a lot of money in heat bills at the same time.
We actually generate a lot of moisture in our homes during the winter as we cook, shower, water plants, and just plain breath. A reasonably tight home should not need supplementary moisture. However, if you do need more moisture, it can be added by installing a humidifier. Your forced air furnace provides a simple means of installing a humidifier that can cover the whole house. If you install a whole house humidifier, make sure that it is the type that drains away any unused water rather than recycling it in the unit, and be sure to set the humidity level at the humidistat as low as you can, to prevent excess moisture from building up. If your windows are collecting water or ice, you may be adding too much moisture. If you don't have a forced air furnace, you can buy one or more of the many different types of room humidifiers. The advantage of these units is that you will be more conscious of their presence as you fill them by hand, and you will be more likely to keep them well maintained. This will help ensure that you don't over-humidify, and that you keep the units clean, so that mold growth doesn't occur.
Would you recommend getting a whole house fan? I would prefer not to install air conditioning, and am wondering if a whole house fan would be a good alternative.
A whole house fan is a large, powerful fan, usually installed in a central hallway ceiling. The unit is designed to exhaust overheated air in the house to the exterior through the attic. The advantage of a whole house fan is its relatively low cost, and its usage of relatively cool and free evening air to reduce temperatures in the house. Cooling effects of course are limited to some approximation of the exterior evening temperatures, but these fans are a very cost effective way to moderate summer heat buildup in the house.
There are several issues, though, that you should consider before deciding to install a whole house fan. They tend to be quite loud. Look for a model that promises to be quieter. It can't exhaust warm interior air if the attic itself is not well ventilated. You may need to add more or larger vents from the attic to the exterior. Some ridge vents have a mesh insert or screen that can become dust clogged from long term usage of a whole house fan, especially if the attic is insulated with blown-in cellulose insulation. The fan's louvers are generally very poorly sealed, resulting in a lot of heat loss in the winter, unless the unit is properly covered and sealed for the heating season. Make sure the unit you buy comes with a good thermal cover for use in the winter. The fan should have a protective shroud over the top of the unit if it is installed into a readily accessible attic, to ensure that nobody accidentally contacts moving parts. It should also be installed with a separate means to shut-down power to the unit, so it can't be operated when covered or insulated. Whole house fans should only be operated with most of the windows and doors in the house open. If the house is mostly closed up, the fan may end up pulling makeup air down a chimney, potentially causing carbon monoxide poisoning. Lastly, a whole house fan operating during a fire could be a disaster. Some authorities require that the fan be designed to shut itself down if temperatures at the unit indicate that a house fire could be in progress. As with most home appliances, a whole house fan can be beneficial, and a source of increased comfort for the occupants, but the unit must be installed with safety in mind.
I had someone in to service my furnace. He says the heat exchanger is bad, and I need a new furnace. How do I know if this is true? I can't afford a whole new furnace.
It would be nice to be able to trust what your service person tells you, but we are aware of several instances where homeowners were misled about the condition of their heating equipment and had the equipment replaced unnecessarily. The heat exchanger is a critical component in your forced air furnace and is a serious concern if defective. In essence it is a metal vessel inside your furnace that contains the combustion process. The flame and exhaust gases are contained within, and the forced air from your rooms is blown around the outside of this metal container, picking up the heat that is produced. If the heat exchanger is cracked or otherwise breached in any way, exhaust gases, potentially containing carbon monoxide, may escape into the air you breathe, rather than just go up the chimney. In almost all instances, if the heat exchanger is bad, the only cost effective and sure repair is to replace the furnace.
It would be very difficult for you to directly confirm if the heat exchanger is bad, but you can try. The crack or hole may be readily visible by looking up through the inlet area, where you can see the flame, but more often than not it is out of view. Soot buildup in the heat exchanger or around the inlet area is a clue that a breach may have occurred, causing poor flame quality and resultant soot. If the flame significantly changes its appearance or lifts off the burners when the blower kicks on, the heat exchanger is likely to be bad. There are other tests, such as using a small smoke producing device in the burner area to see if the smoke shows up at the registers, or using a combustion gas detector in the plenum or at a register, to help confirm the diagnosis. For your purposes though, we can only suggest that you let your service person know that you are concerned about the cost, and would like him or her to show you the crack or hole. While it may not be visible to you now as the furnace sits, it should definitely be visible once the unit is removed or the jacket taken off, if indeed there is a defect.
If it is any consolation, replacing the furnace with a new more efficient unit will very likely be cost effective, whether the heat exchanger was defective or not, if the furnace is 25 years old or older.
I am getting conflicting information regarding salvaging my flooded appliances. Do the gas water heater and furnace have to be replaced, or can they be repaired?
All of the authorities with which we are familiar, including the American Gas Association and the Consumer Product Safety Commission, agree that the gas safety valves for appliances that have been submerged must be replaced to ensure proper safety function. These valves control the pilot flame and main burner flame. A thermocouple tells the safety valve if the pilot flame is lit, ensuring that the gas will ignite when the automatic safety valve opens. The proper function of gas safety valves is critical in preventing gas leakage or explosion. While the unit may function after being dried-out and cleaned up, it does not mean that critical parts will operate properly when needed to prevent a safety malfunction. Since water heaters generally have a relatively short life and other parts may also be damaged, including the insulation, and since replacing the valve is a significant percentage of the cost of a new unit, it is almost always the best decision to replace the water heater. The furnace or boiler may be worth salvaging, depending on age and type, but expect to replace any pumps or motors and any other safety devices or controls, in addition to the gas safety valve. Any motor that you manage to salvage will be likely to have a significantly shortened remaining life.
Incidentally, electrical breakers or fuses should not be salvaged either, according to the Consumer Product Safety Commission. In most instances, this would mean that replacement of the electrical service panel is recommended if it has been submerged. The wiring itself will probably be acceptable once all outlet and junction boxes are opened up and all connections cleaned and inspected.
In any case, extreme care should be taken when energizing any equipment that has been submerged. Shock hazards are very likely. We highly recommend professional help.
I'm planning on installing a humidifier on my furnace so the house won't be so dry this winter. Is there a brand or type that you would recommend?
In most cases we would recommend against installing any whole house humidifier at all. Most whole house humidifiers mount on the furnace ductwork and use the forced air furnace to blow moisture from the unit through the house. While most older homes do tend to be too dry for personal comfort in winter and humidifiers can alleviate the discomfort, they bring their own set of problems. Most humidifiers do not adjust themselves to appropriate moisture levels based on outdoor temperature, and because whole house humidifiers are out of sight and mostly out of mind, we don't usually adjust them properly either. Consequently, as the exterior temperature drops, excess moisture tends to condense on the colder surfaces in the home, resulting in condensation on windows, in walls, and in attic spaces. This process can result in mold buildup, stains and decay. In addition, we don't maintain and clean them adequately. Most humidifiers eventually leak due to mineral buildup and clogging. Depending on the location, the leakage can destroy an otherwise good furnace. Most importantly, poorly maintained humidifiers can pose a health risk. One of the most common humidifier designs consists of a plastic “hamster wheel” with nylon mesh wrapped foam applied around the circumference. This then dips into a pool of water, picking up the moisture which is blown into the ductwork as the furnace blower operates. The problem with this is that the foam acts as a filter and collects mold, bacteria and viruses which then proliferate in this constantly warm moist medium, only to be blown through the house on the next cycle.
If you must add moisture to the house, one option would be to purchase a room sized unit that you will be filling frequently, and which you will presumably monitor and clean as necessary as you add water. If you believe that a whole house unit would be appropriate for you, we recommend the type that uses a vertical mesh with a drain at the bottom. Water dribbles through the mesh from the top, and any that doesn't get picked up as the air blows through simply drains out the bottom. You will need a floor drain nearby, or a condensate pump to handle the unused water.
I have forced air heat and my house is very dry in winter. What type of humidifier do you recommend?
We actually would recommend against installing a humidifier if at all possible. Whole house units in particular are usually poorly maintained since they are out of sight and out of mind. They can become contaminated with mold, viruses, or bacteria, they often leak, causing damage to the furnace, and they may add too much moisture to the house if poorly adjusted. If a humidifier is absolutely necessary, we would suggest using a small portable unit, since it will be far more likely to receive adequate maintenance.
The type of heating system does not affect the humidity in a house, but there is usually a correlation with the age of the house. Older houses are generally drier than newer homes because they require more heating. When we heat the cold dry winter air that enters our house, we lower the relative humidity. The relative humidity is lower because warm air is capable of holding more moisture than cold air. So, if we warm a smaller total volume of air, or reheat it less frequently, by better sealing and insulating the house, we will reduce the dryness and save money at the same time.
We add moisture to the house as we breathe, cook, bathe, wash clothes, water plants, etc. This moisture can be sufficient in a “tight' house to prevent excessive dryness. The key is to keep the cold dry air out, and keep the moisture that we naturally generate in, by maintaining a well sealed and insulated house.
Is it acceptable to run the exhaust ducts from my bathroom ventilators to the roof overhang, or do they have to go directly outside? My contractor says it's okay to go the eaves; my buyer's inspector says it isn't.
The bathroom ventilators are intended to exhaust warm moisture laden air from the bathrooms out of the house to prevent excess moisture and resultant mold and decay. The ventilators should exhaust directly to the exterior, not into the attic or the overhangs. The attic should be kept as dry as possible. When warm moist air enters the attic in winter, the moisture condenses on cold surfaces, resulting in mold and decay. If your ventilators exhaust into the attic, you've simply moved the problem from the bathroom to the attic. Even though there are vents in the overhangs of most homes, the exhaust will not leave the attic if directed to these areas. This is because air normally enters at the ventilated eaves and leaves the attic at the ridge or gable vents near the peak. This natural flow of air simply pulls the moisture from the ventilator exhaust ducting right back up into the attic.
The best approach is to direct the exhaust from the bathrooms to the exterior directly through the roof, or through a gable end wall. We have occasionally found ducts in the attic that are full of ice or water, making the ventilators useless. The ducting should be insulated and should be as short a route as possible to avoid moisture buildup in the ducting itself.
We have a two story 3,900 sq. ft. home built in 2005 with 19 foot ceilings in the Great Room. Our propane bills are way too high, and the furnace cycles on and off all the time. Our house is tight and well insulated. What could be the cause of such high bills?
Historically, propane has been the most expensive of the standard fossil fuels. This, combined with the size of your house, probably accounts for most of your high heat bills.
However, the rapid cycling of the furnace that you mentioned can reduce its efficiency and increase your costs. This is usually caused by either of two problems. One is insufficient air flow through the furnace. If too little air moves through the unit, it will overheat. A safety device then shuts down the burners, which turn back on as soon as the furnace cools a little. Clogged furnace filters, a clogged AC evaporator coil, too few return air registers, too many closed registers, or registers covered with boxes or other clutter, all slow down air flow through the furnace.
Another potential cause for the cycling of the furnace that you mention may be a misadjusted heat anticipator in the thermostat. This device places a small electrical current through the coil in the thermostat to turn off the furnace slightly before the thermostat actually reaches its set temperature. This helps prevent wide swings in room temperatures, but if out of adjustment, can cause the furnace to turn on and off way too frequently.
If the furnace overheats or turns off before the blower delivers much heat to the rooms due to cycling, you're going to lose your heat and your money up the chimney. Have your furnace serviced with these issues in mind. You may be able to save some dollars after all.
I just received my latest fuel oil bill and went into shock. I can't afford to heat my house at this cost. What other type of heating system would be cheaper?
There are many different options that may be available to you. Assuming that you heat with forced hot air, we can make some simple comparisons that might be helpful when reviewing these options. At the present time the cost per BTU for fuel oil heat in a modern standard efficiency furnace is roughly equivalent to the cost of basic electric resistance heat at NYSEG residential rates. Electric resistance heat, except in local special rate districts, has been by far the most expensive heat type for many years, so it is no wonder you went into shock.
High efficiency oil furnaces tend to be problematic, if available at all, so your best bet is probably to change fuel type. Propane is roughly equivalent in cost to oil in a standard efficiency furnace, but with propane you can upgrade to a high efficiency furnace which will lower the cost per BTU to heat your house at present rates by 15 to 20 percent. Given the volatility of the markets though, this cost advantage could disappear.
If you are lucky enough to have natural gas available, you would be wise to convert. With a standard efficiency furnace you would pay less than half the cost of oil heat. With a high efficiency gas furnace you would save even more, resulting in heat at a third the cost of fuel oil per BTU. We know that natural gas prices are likely to go up, but we suspect that the cost will remain considerably below that of fuel oil.
Your other choices generally involve space heating rather than central forced air heat, and will require some attention and physical labor on your part to keep them running. But they can save significant money. Wood heat at 60 percent efficiency at current prices per cord is roughly one third the cost of fuel oil heat. Wood pellet heat at 80 percent efficiency at current prices per ton, and coal heat at 75 percent efficiency are also one third the cost of fuel oil. If you're shopping for a new heating system, please remember that the efficiencies quoted above are common for the heat source type but may vary, resulting in higher or lower heating costs.
Whatever type of fuel you use, don't forget to better insulate and seal your house to conserve heat.
We have a very large house with just my wife and I home now. We closed the registers in the extra rooms to save on our heat bills, but it doesn't seem to be saving us any money.
Closing off some rooms to save heat can be a good energy saving idea. By concentrating heat in a smaller portion of the house, less heat will be lost through the envelope of the house to the exterior. There are a few things to watch out for however. First, it is important that the thermostat be in one of the rooms that you keep heated. If the thermostat is in a room with the heat supply closed, it will remain cool and will be continuously calling for heat, which the furnace will be unable to satisfy. Your furnace will be working harder and your heat bills will go up.
Another concern is that furnaces need a good flow of air to ensure efficient heat transfer. If you close too many registers, the overall air flow through the furnace is reduced, and heat transfer from the furnace to the air around the heat exchanger is also reduced as a result. The furnace will run hotter and may even overheat. When a furnace runs too hot, a higher percentage of the heat goes up the chimney, and you run the risk of damaging the heat exchanger. This could be a safety hazard as well as an added expense.
As heated air enters the rooms in the house, air should be returning from other registers in those rooms back to the furnace for reheating. Depending on the overall design of the ductwork, closing off several rooms may significantly unbalance the return air, resulting in some rooms that pull cold air in from the exterior through cracks and gaps in the windows and finishes, and other rooms that push heat out of the house through cracks and gaps.
Closing off a couple of rooms in a house may be very helpful, but shutting down heat to a larger portion of the house should be evaluated by a knowledgeable heating contractor to make sure that doing so will result in the safe and efficient operation of your heating system.
My heat bills have gotten ridiculous. I see ads for miracle portable heaters. Are these really as good as they sound?
The primary advantage of portable electric heaters is that they can provide heat right where you are located in the house, allowing you to turn down the thermostat on your whole house heating system. The energy saved by allowing the rest of the house to be cooler will result in lower overall heating bills.
There is a downside however. You won't be saving money under all circumstances, and you may be uncomfortable. For example, when you move from one room to another, there will be a warm up period for the new location. Also, it won't work well for you if you have a larger family using multiple rooms at the same time. In most cases, depending on your utility service provider, electric heat is significantly more expensive per unit of heat introduced into the house than other energy sources, such as gas or oil. So placing several electric heaters around the house may increase your overall heating costs, not lower them.
Another issue is the cost of the portable heaters themselves. All of the electricity that we use in our homes ultimately converts to heat. No portable electric heater is really any more efficient than any other. Every watt of electricity consumed by any portable heater converts to an equivalent unit of heat. The advantages of one heater over another might include nicer appearance, quieter operation, more even temperatures, and better distribution of heat, but not more heat per dollar spent on electricity. Radiant electric heaters may make you feel warmer for slightly less money than units with resistance coils and blowers, because the heat is radiating toward your body directly, rather than simply warming the air around you. But in any case no high priced “miracle” heater is any more efficient at converting electricity to heat energy than a cheap portable electric heater from the discount store.
I discovered that the brick chimney for my furnace is leaking water and ruining the nearby plaster in the house. My roofer insists that the seal at the roof is good and the furnace is new, but it is a very old chimney. Do I need a whole new chimney?
If the water leakage continues, the old chimney could become severely deteriorated and you might indeed need a new chimney. At this point, however, you may simply need to have the chimney relined. Houses from the early 1900's or older usually have unlined chimneys. The interior surfaces of unlined chimneys, which are exposed to the exhaust gases from the furnace, are just bare brick. Brick is reasonably durable and resistant to deterioration from the hot gases that were produced by old inefficient furnaces. But modern furnaces extract more heat from the fuel, resulting in a cooler and wetter exhaust. Burning natural gas produces a lot of moisture. The moisture in this cooler exhaust condenses in the cold portion of the chimney in the attic and above the roof line. The moisture soaks the brick, deteriorating the masonry, as well as adjacent interior finishes. More recent masonry chimneys include a clay tile flue liner. The liner is much more durable and moisture resistant, but even so water can build up and damage can occur. High efficiency furnaces should never be vented to a masonry chimney due to the moisture. Modern mid-efficiency furnaces may be vented to a clay tile lined chimney if certain critical conditions are met, but never to an unlined chimney. In any case, if your chimney is getting excessively wet, the furnace was improperly installed. There are two possible solutions. One is to reline the chimney with a new stainless steel flexible liner. The new liner is typically installed from the top of the chimney down and tied directly to your furnace exhaust. The other method is to abandon the chimney and vent the furnace exhaust directly out the side of the house, using a special power blower unit to force the exhaust gases through the vent pipe to the exterior. Either method may work for you, but as houses become tighter and furnaces more efficient, chimneys will become obsolete. Power vents will be the more common way to vent exhaust gases from homes.