ANNOYED WITH LEAK

A. Keep the service man coming back until the thing is fixed. Small leaks have a habit of becoming bigger, and with oil, any leak is a hazard, especially to the environment. Oil dealers are well aware of this hazard, so yours should continue to seek a solution.

The leak sounds as if it is coming from the line from the tank to the burner. Tightening the connections may be all that is needed. Or, replace the line. Or, as a last resort, replace the line and burner. That burner should work right and not leak. Don't take less for an answer.

Q. There's an old oil tank in the cellar of my parents' house in Peabody. It must be more than 50 years old. When it leaked 35 years ago, the oil man put in some plugs, and they have lasted up to now. If and when the tank leaks again, can I have it patched or must it be replaced?

J.K., Marblehead

A. It ain't broke, so you don't have to fix it. If it leaks, you have to replace it because it is now illegal to patch. So, you can wait, but that in itself is a hazard because, if it leaks and you don't know it, oil can saturate the concrete and seep under the floor into the ground water, an environmental no-no. If it does happen, your parents are liable for any leaks and cleanup. So, for you and your parents' peace of mind, have it replaced.

Q. In my six-room house, all the steam radiators have covers, but I don't get much heat from them. Would it be the fault of the covers?

MARY McKENNA, Cambridge

A. If the covers cover just the tops of the radiators, it is not the fault of the covers; it probably is the fault of the steam valves, those shiny valves at the high end of each radiator. They are not opening when the steam comes up, so little or no steam gets into the radiators. To fix, try this: Unscrew a valve and boil it in vinegar or just plain water; sometimes a bit of grit gets into it and disables it. If that doesn't work, replace the valve.

If your radiators have enclosures, covering the entire radiator, it still probably is not the enclosures' fault, if the enclosures are designed correctly. An enclosure should be open in the front (there is usually a grille), with a three- to four-inch opening along the bottom of the front. This allows cool air to enter at the bottom, be heated by the hot radiator, rise up, and come out the front.

Q. I have baseboard heat, and had linoleum ripped up and ceramic tiles put down. The installers laid the tile up to the baseboards, but not under them, where there is a three-quarter to 1-inch space from baseboard bottom to the floor. Would it be OK to extend the ceramic tile completely under the baseboard radiators?

L.W., Beverly

A. It certainly would, because with the tile extended, there still will be a half-inch to three-quarter-inch space between the baseboard and tile. Some space is required for proper air circulation around the baseboards, and the space between the extended tile and baseboards is more than adequate.

Q. I have a number of steam radiators, which are not terribly attractive. Can I put enclosures over them? What kind? Can I use a wood enclosure on a steam radiator, which gets very hot?

BRYAN HARRINGTON, Roslindale

A. You not only can put enclosures over steam radiators (or any other kind), but you can also use wood ones. Make sure there is no wood touching the radiator. Check out ``Radiator Covers, Enclosures'' in the Yellow Pages.

Q. I am having a hot-air furnace installed, but the installer said it is too small for the size of the house, and will wear out quickly, just as the original one did. The options, he said, are to put in a bigger furnace in the basement, or keep the smaller one in the basement and put in another in the attic. Is this feasible?

B.B., Arlington

A. It is feasible, all right, but not practical, and I suggest that you do not put a furnace in the attic. A bigger one in the basement should be adequate to provide enough heat and it will last longer than the original. After all, thousands of furnaces and heating systems have been installed in the basements of small, medium, and large houses with the ability to heat the entire space.

Some large houses have been built recently with hot-air furnaces in both basement and attic. Two furnaces work well in heating a large house, but one in the attic can cause problems such as ice dams, from warm roofs. The roofs are made warm because, while the attic furnaces themselves are well insulated, the open flame of the furnace cannot be insulated, and the heat from the flame makes the attic and the roof warm. This encourages the development of ice dams and resulting leaks when snow piles up on the roof and the water backs up above the dams, even if the attic is properly ventilated.

So, in the handyman's opinion, no furnaces in the attic.

Q. My 30-year-old, split-level house has electric heat, and I was thinking of converting to another kind of heat for a better resale value. I had an offer of $11,700 for oil-fired hot-water heat with an air handler in the attic; the air is heated by the boiler and high-velocity ducts in the attic deliver the heat to the house. Is that a reasonable offer worth doing to facilitate a resale?

S.M., Medfield, Mass.

A. Considering the price of the house, the $11,700 figure is reasonable. High-velocity systems are good, but I don't like the idea of the air handler and ducts in the attic. They can be used for air conditioning some day, but in any case they should be heavily insulated to prevent heat loss to the attic. If your split level is a split-entry (raised ranch), then I would seek more offers, such as a boiler in the basement and baseboard heat on the main floor and the basement, or a hot-air furnace with ducts leading to the house and basement. I suggest this because I think they might be less costly than the high-velocity system.

Q. There's a bad smell in my furnace room, but only when it rains. It's sort of a sulfur smell, like rotten eggs. Four men checked the hot water boiler fired by oil, and found it OK, but one man said, ``You have a mouse [a dead one] way up in the insulation of the boiler.'' In fact, I have found six mice. How can I get to the dead one and eliminate the odor? And why does the odor occur only when it is raining?

J.A., Derry

A. Decaying matter usually smells worse when it is damp, and when it's raining, things in your furnace room are damper than when it's not. It may be difficult or impossible to get into that insulation, so I suggest waiting a while; if it is only one dead mouse, it should stop smelling in a few days. And to help dissipate any odors, open the window to the furnace room, if you have one, to allow air to circulate. In fact, if the basement and the room are that tight, the burner may be starved for air, and if that is the case, there might be partial combustion of the oil, with the residue giving off that sulfur smell. If there are no windows, install an air vent to allow the proper ventilation. A final thought: Sometimes there is hydrogen sulfide in the water and if any water is exposed in the furnace room, it will smell like rotten eggs, especially when it is heated. This is a natural occurrence, and ventilation will help dissipate it.

Q. Whenever the heat is on, I find little pieces of fluff on the kitchen floor. They are grayish in color. How can I keep them from appearing? They occur only in the ktichen.

M.W., Newton

A. They are dust kittens, usually found under beds, but they are loose strands of dust. Wherever there is evidence of these dust devils, try this: Lift baseboard heater covers and vacuum and clean the fins and other parts of the baseboard. If there is an under-the-counter heating unit, clean it thoroughly.

Q. I have forced hot air heat in my two-story house, which contains 2,800 square feet of living space. I am not getting enough heat in some rooms on the second floor. Balancing the system does not help. What else can I do?

G.W., Lexington

A. Wait'll summer. But seriously, folks, it sounds as if the furnace is not big enough. Balancing usually works; balancing is partially shutting off the ducts to the rooms that are adequately or overheated, and fully opening ducts to the cold rooms. A larger furnace may the answer, although you might run the risk of overheating the first-floor rooms. You could try adding duct-booster fans in the cold rooms.

While a 2,800-square-foot house is fairly large, a single furnace should be adequate. Another technique on larger houses (3,000 square feet and up), is to install a second furnace in the attic. It must be gas fired but even then, it should not be done in an area where there is a goodly amount of snow, because a warm attic (warmed by that furnace) is a virtual guarantee of ice dams and their resulting leaks. You can insulate the ducts and the furnace itself to keep the attic cool, but you cannot insulate against an open flame.

A way to get around a furnace-in-the-attic disaster is to locate the furnace on the second floor, if you can spare the space. Such a furnace can be a direct vent unit; no chimney is needed. One more thought: Install gas-burning direct vent stoves in the cool bedrooms.

Q. My mother has a problem. She is getting greasy deposits on her refrigerator and stove. It cleans off, but the spots also show up on furniture and carpet, as brown stains, harder to clean. The health department said the spots might be the result of a cracked heat exchanger in the hot air furnace, which is 20 to 30 years old. The heat exchanger checked out OK. What else would cause the spots?

M.R., Framingham

A. A good question, said the handyman. First, check out the heat exchanger again; that part of a standard hot air furnace is the first thing to go, usually closer to 20 years than beyond. A cracked heat exchanger would allow fumes from the fuel to get into the house through the ductwork, and that is a deadly hazard because those fumes contain carbon monoxide. If the fuel is oil, the heated air could be carrying small drops of oil or soot or both that could drop any place in the house. However, if the drops are oil, you would smell it very quickly. Gas fumes are just as deadly, and contain a lot of water vapor that could condense on cool surfaces, causing the spots.

If the furnace is OK and there are no fumes getting into the hosue, one other thing might be causing the spots. And that is water vapor condensing on cool surfaces after picking up dust or dirt, causing the brown color.

A lot of cooking with oil may also be the culprit.

Q. Would radiant heat in the wood floor work for my kitchen? I don't want to do it for the rest of the house, but it would be nice in the kitchen.

ESTHER, Sudbury

A. Yes it would, but it has to be hooked up to a hot water heating system. (If you have a hot air system, it won't work.) And, it will work nicely under wood. Another important point: The ceiling below the floor in question must be heavily insulated, so the radiant heat in the floor goes up through the kitchen wood floor, and not down, wasting all that heat, into the unheated basement.

Don't even think about electric radiant heat in the floor. It is outrageously expensive.

Q. I have a problem with a direct vent heater; it just doesn't seem to work very well. I was told to open a window in the cellar so the unit can use its own air when burning. Another alternative is to build a chimney and take out the direct venting system. What would be best?

JOSEPH GILLIS, Bridgewater

A. I think opening a basement window is the best idea; these direct vent systems use a fan to power the exhaust outdoors, and with that extra power venting, the heater is not getting enough air. An air source could cure the problem. And even better than opening a window is to extend a pipe from a window, or at least from outdoors through the foundation and ending up near the burner. That way the burner will get its own adequate air without super-cooling the basement, which is not a good idea in winter, especially if the basement ceiling is not insulated.

Q. My family room is over a two-car garage with an attic above. It is always cold. A heating man found there are enough baseboard heaters for the room. Will putting a heater in the garage help? One would cost $1,900.

STEVE DINN, Milton

A. Don't waste your money because a heater in the garage will not work, especially since there is probably insulation in the garage ceiling, which would prevent any heat from coming up through the garage ceiling and the family room floor. And, even if there is insualtion, the heating pipes might be below the insulation, which would make those pipes lose heat very quickly. Find out if there is any. If not, have some blown in, and make sure any pipes are inside the insulation. And make sure the walls and ceiling of the family room are well insulated.

Another reason for the cold is that the boiler is far from the baseboards, and water may cool by the time it reaches the family room. You may have to add heat to the family room. One good way is to install a gas fireplace that exhausts under power to the outdoors through a PVC pipe; such a fireplace does not need a chimney. Short of that, any auxiliary heat may help some.

Q. My furnace is in the same room as living space converted from a garage. I want to enclose that furnace not only to block it off from living space but also to reduce sound transmission. How small can I make the enclosure? Also, squirrels are making a mess of wood slats on a vent, and I'm afraid they will get in eventually. How can I squirrel-proof that vent? The vent is about 16 by 16 inches.

HARRY MELKONIAN, Hingham

A. Give the furnace 2 feet of space all around it. Insulate the walls, put in a tight-fitting door, and caulk all joints, where walls meet the floor and the ceiling. This will provide good sound reduction if the burner is not excessively noisy. If you do this, you must provide the furnace with its own combustion air. Cut an opening in an outside wall, as low as practicable -- 6 by 6 inches will be adequate. That way the burner will use this incoming air instead of trying to pull it out of the living space.

For the damaged wood-slatted vent, replace it with a new wood vent, then cover the vent on the outside with hardware cloth. This is 1/2-inch steel mesh, strong enough to deter any critter. Or, replace the wood vent with an aluminum one, but cover it with hardware cloth.

Q. I was told that if I want to sell my house, I would have to convert the electric heat to another, less expensive kind of heat such as a gas or oil furnace or boiler. Which would be less expensive to install: a hot water or hot air system? And, will either system be less expensive to heat the house than the electricity?

CAROL HENRICH, Lexington

A. Let's put it this way. Any system will be less expensive than that electric monstrosity. And since the house is electrically heated, it is pretty well insulated, which will make any other system that much less expensive to operate.

And, a hot air system and a furnace is considerably less expensive to install than a hot-water baseboard system and a boiler. As for which heat is better, it's a toss up, in my opinion. Suppose a new system -- new ducts or pipes plus the heater -- costs $5,000 to $10,000 and saves you $1,000 a year (and that is possible when you convert), you will pay off the system in 5 to 10 years, an economical time span.

Q. My house is heated by steam, and on very cold days it is too hot upstairs and too cool downstairs. I tried shutting off the upstairs radiators part way, but they leaked. I was also told that we should not shut off valves on an old system. Is there any way to balance that system so the rooms will be evenly warm?

ELAINE ROSSI, Melrose

A. Shutting off radiators in an old system may cause leaks or put too much pressure on the pipes, resulting in leaks.

So, you do one of two things: Nothing, or shut off the radiators in the upstairs (all except the bathroom, of course) and see what happens. If you get leaks, then you have to replace or repair the valves. You may be surprised that turning off the upstairs radiators will not cool off the upstairs too much; too much cooling is unlikely to happen if the house is fairly well insulated. The handyman did this on his hot-air-heated house, and the upstairs is not more than five degrees lower than the downstairs. The bathroom, with vent still open, is comfy.

Q. I plan to build a house. What are the pros and cons of hot-air vs. hot-water heat? Will the hot-air heat be drier, and will it stir up and deliver more dust?

S.B, Westwood

A. Let's take the heat systems one at a time, giving the pros for each.

Hot air heat: It is less expensive to install than hot-water heat. A furnace (for hot air) is less expensive than a boiler for hot water. It is fast in warming up the house, faster than hot water. A hot-air system can be used for air conditioning. An electronic air cleaner and humidifier can be installed to combat dust and other air pollutants, and to humidify the air when needed, mostly in the winter.

Hot-water heat: It is an even heat. A tankless hot-water heater is built into a boiler, precluding the need for a separate hot-water heater. Air heated by hot water is generally less dusty than with hot air, but not necessarily less dry.

Q. I'll be away for six weeks this winter and am wondering how low to keep the heat. A friend said to keep it at 50-55 degrees; I say 40 degrees is OK.

KENNETH STILLMAN, Cape Cod

A. A thermostat setting of 40 degrees is enough to keep house pipes from freezing, if you have not experienced frozen pipes in the past. One thing I would recommend, however, is to hire or use a house sitter to check your house every other day. The more frequent the checks, the better you will feel.

Q. I want to paint my baseboard heaters dark green. My husband says no, because dark colors do not reflect the heat. What do you say?

L.H., Winchester

A. I say the handyman is loath to come between husband and wife, but what the heck, he'll jump in with both front feet and take his chances.

Your husband is wrong. Actually, he is right in his opinion that dark green does not reflect heat, but that is not what is needed with baseboard heating. What is needed is heat absorption, and dark green and other dark colors will do that better than light colors. Actually, the differential is minor, so that you may not notice the difference in the heat, or the heating bill. If you had big, fat cast-iron radiators, then the differential would be more, but even so, you don't see a lot of radiators painted dark colors.

So the handyman, peeking out shyly from between husband and wife, says go ahead and paint the baseboards dark green.

Q. The heating system on the third floor of my three-decker is hot water baseboards fired by gas. When the system failed to provide heat, I called the gas company, with which I have a service contract. The gas company bled the system. It worked for 48 hours, then stopped again. The gas company, on its second visit, said I need a plumber. A friend, a self-proclaimed plumber, suggested changing valves in the system. Now I really am confused, and cold, to boot. What can I do?

VIRGINIA GOUVEA, East Boston

A. The gas company is saying, ``Not my job'' and is ducking the issue when it suggests you need a plumber. That attitude is mind-boggling; what in the world is the service contract for except to provide help when you need it. Maybe it's because the gas company handles only problems with the burner, not the boiler or heating system itself; that may be in the service contract, but it is still mind-boggling.

The gas company is right abut one thing, though; you do need a plumber. Try to find a professional experienced in plumbing and heating so he can get to the bottom of this comedy, which is certainly not comic to you.

Q. Do heat exchangers for fireplaces, the type that heat up in the fire and blow warm air into the room, really work? Do they produce much heat and soot?

A. The heat exchangers I am familiar with work, to a degree, but in my experience not very well. I bought one during the energy crisis; it was one of the rare handyman's blunders, a $500 one at that. And my wife hated it to boot. It had to be used in conjunction with glass doors, and any heat it produced was not worth the aggravation. I still have pictures of it, opened and closed. Nero, the cat liked it, but no one else did. So I gave it the heave-ho. New ones may be more efficient. If a unit is properly installed, there will be no soot.

Q. I have an opening in the floor as a part of my hot-air heating system that is 18 by 17 inches. Where can I find an old cast-iron register to cover it?

L.L., Framingham

A. Try the Norfolk County Courthouse in Dedham. It's a fine old building, with a sort of dignified decadence, and it's full of cast-iron grilles or registers. The handyman noticed this when he was on jury duty not too long ago. But don't be tempted; they are not for sale.

You might find old registers or grilles in antiques and collectibles stores, but more likely in one of those junk antiques stores, usually labeled junque. That would be hit or miss, mostly miss.

So, check out Reggio Registers, makers of cast-iron, brass, and aluminum registers in many sizes and styles. The nearest one for your opening I could find in the Reggio catalog has an inside measure of 18 by 18 inches. While this is obviously bigger than your opening, you might be able to make a cutout 1 inch wide on one side of your opening, deep enough to accommodate the lip of the register.

Call the Reggio Register Co. of Ayer at 508-772-3493. The registers are expensive, but worth the price. I don't think it's practical to have a register custom-made, and it would be even more expensive.

Q. I am building an addition with walls that will be mostly glass, to take in the sun's heat in winter. The heat is radiant, with hot water in plastic pipes under the floor. What tile is best for the floor? I know I should not use glazed tile. I was shown porcelain and clay tile that is dull but glazed, that will absorb the sun's heat. Would such a floor work, and would the radiant heat go through the tiles?

AUDREY DIMITRY, West Newbury

A. Things will be fine with those dull but glazed tiles. It's the shine of the glazing that reflects the sun's heat. A dull finish will asborb the heat, even if that finish is glazed. The radiant heat will go through any ceramic tile. These materials are excellent transmitters of heat.

Q. My son had a new boiler and oil burner installed. I noticed the exhaust pipe has a half-inch hole in it. He said the contractor said it was there for inspection purposes and causes no harm. It looks as if it were a part of the pipe, not that it was a hole caused by exhaust gases deteriorating the metal. It is between the damper and the boiler. Is it safe?

C. W., Framingham

A. I think it's safe. After all, the damper is a bigger opening nearby, designed to increase and control the draft of the chimney by bringing in air from the basement to boost the gases on their way up the chimney. The half-inch hole does the same, bringing in air as the exhaust gases go up the pipe. The only thing that bothers me is the size of the hole; I am not sure what any inspector will see by peering into a half-inch hole.

Q. My electric baseboard heaters are 20 years old; bills are sky high. Would it help if I replaced them with modern, more efficient ones?

B.R., Braintree

A. I doubt it. I don't think modern electric heaters are any better or more efficient than old ones; it still takes a certain amount of electricity (a lot) to create a certain amount of heat through high-resistant wires. Some years ago, during one of the energy crises, manufacturerscame out with new electric heaters, such as a quartz heater; later a miniature super heater with blower; they claimed great things for these heaters, such as ``efficiency'' and lots of nice, often instant, warmth, but never did they say you'd save anything, because they do not save. Those heaters are now in dumps, attics, and other storage places to which they were relegated, sometimes when their owners got their electric bills. Some owners of electrically heated houses gave up in disgust and installed hot-water or hot-air heat fired by gas or oil.

Q. The kids have flown the nest, so there is no need for heating the upstairs of my house. I have steam heat. Is there any harm in shutting off radiators on the second floor?

TOM FLYNN, Arlington

A. Go for it, there will be no harm done and it'll save you a bundle. The handyman has hot-air heat, and he has shut off his upstairs for years; there is enough heat going up the stairs and through the floor to keep the upstairs from being too cold. Well, he did keep the heat on in the upstairs bathroom. It is very welcome on a cold winter's day.

As for freezing pipes, it is unlikely, because there will be enough heat to prevent that.

Q. The electric baseboard heat in my condo is very old, and dirt has settled in the mesh. As a result, the walls are very dirty, for quite a few inches above the baseboards. The old baseboards are about 3 inches thick. I keep washing the walls, and cleaning the mesh but soon the dirt returns. Is there a baffle I can install over the baseboard to divert the air from the wall? What should I ask for in the store? The windows are very close to the floor, so there is not much room for a baffle.

SHIRLEY PERRY, Lincoln

A. I doubt if there are any standard baffles sold, so you have to have one made.

I suggest this: Buy aluminum flashing at a building store, cut it to 5 inches wide, and have it folded into an ``L'' shape, with one leg of the ``L'' 1 inch wide, the other 4 inches.

Set this makeshift thing to the wall parallel to the baseboard, 2 to 3 inches above it. Nail or screw into the one-inch flange, and bend up the 4-inch flange, slightly. Have the edge of the 3-inch flange rolled (bent over) to prevent being cut by it. The flange will stay in position without sagging.

Under those windows very close to the floor, simply put the baffle as close to the baseboard as necessary, but still bent up a little.

This baffle will divert the air from the wall without reducing the efficiency of the baseboards, whether it is 2 or 3 inches from the baseboard, or touching it.

Q. We moved from Dublin last summer and don't know much about central heating systems. We're surprised to hear about those fuel containers that break and split along with the fact that it is the law to have such spilled fuel cleaned up no matter what the cost. We checked our container and found out it was put in sometime in 1955. It looks good, but what should we do to keep it that way? We also heard about sludge in the container and wonder if we should clean this out every year when we have the burner cleaned? We asked our fuel delivery driver about all these things but he just shrugged his shoulders and said we'd be better off burning turf.

MICHAEL REDMOND, Boston

A. Welcome, Michael, to New England, winter and oil heat. That fuel container you mentioned is an oil tank, and you are right: If there is a spillage of oil, the owner is responsible and liable. And that can be a serious problem.

However, all is not doom and gloom. Your oil tank is made of steel, and is designed to last for a long time. It is 42 years old, and there is no sure way tell how long it will last. So, perhaps it's time, for your own sense of well-being, to install a new one. It's not inexpensive to do so, but you will feel a lot better about it. As for sludge, I don't think sludge is cleaned out of the tank when the burner is inspected, adjusted and cleaned, which should be done once a year, but I don't think it is a widespread problem. There are filters on the feed line to the burner, designed to filter out sludge and keep the old burner going. For any sludge or potential sludge, and for the tank, check with your oil company, not the driver.

Q. I had a new heating system installed, and now I can't get the temperature higher than 62 degrees. The system has a new boiler and baseboard radiators, and is also heating a sunporch, which the old system was not doing. How can I bring that temperature up? It was suggested to make the sunporch a separate zone.

T.T., Wakefield, Mass.

A. Sounds as if the system is undersized, but zoning for the sunporch is a good idea. Or, shut off the heat in the sunroom and be content with the sunroom as a 3- or 2 1/2-season room. If the system is undersized, then it's back to the drawing board for the heating engineer.

Q. I have a soot problem. My building has two apartments. My tenant's apartment is fine, mine is plagued by soot. Both apartments are heated by one gas burner. I had the burner cleaned and the stack checked and cleaned, without success. What is wrong and how can it be corrected?

B.B. Boston

A. Another good question that may not be answered easily. So the Handyman can only guess, or at least present some possibilities.

Gas burners can produce soot, especially if they are out of adjustment, producing a yellow, sooty flame, just as a candle produces a sooty flame, instead of the normal clean, blue flame. And, if there is just a small leak in the chimney or smokepipe, enough of the soot can escape and find its way into one unit and not another. These are the things to check, including ducts in a hot-air system that might be dirty, and can be cleaned.

Q. I bought a house with radiant heat, but I know nothing about it. Is there anything to be aware of or anything special to maintain the system? It is hot water pipes in a concrete slab.

WANDA COX, Stoughton

A. There is little you have to do, just as there is little you have to do with any hot water heating system. Some specialists suggest draining the system, or at least ``bleeding'' the system every now and then, but it is not essential. One thing about radiant heat: You don't want to put too many rugs down because that could reduce the radiation; that is, the heat coming up through the floor. Some carpeting is OK, but generally, not wall-to-wall.

Q. The baseboard heating unit in my bedroom goes behind the bed, making it much too hot at that end of the bed. Is there a baffle I can put over it to divert the heat away from the bed?

J.R., Wakefield

A. You'll have to make your own baffle, but it's easy. If you can't move the bed, and pulling it away from the heating unit is impractical, and you can't shut off that part of the baseboard unit, you can set up a baffle of sorts: Make a two-sided wood box, L-shaped in profile and as long as the bed is wide, or a little longer. Set it over the unit, with one side touching the wall, the other touching the floor. Secure it to the floor with finish nails driven at an angle. Make the half-box maybe 12 inches high and 12 wide; a half-box of 1 x 12 boards gives dimensions of 11 1/4 inches. Keep it open at each end. It will get warm, but not so warm that it is a fire hazard, and the air will flow out the ends, away from the bed. You may want to make the half-box low enough so the bed frame will clear it.

A simpler baffle is a board or piece of plywood set at a 45-degree angle over the baseboard unit. Keep the baffle away from the unit.

Q. I had a new heating system installed, hot water by gas. It takes three hours for the house to heat up from 50 to 70 degrees. It never took that long with the old system. The installer said it's the fault of the knotty pine paneling in three of the five rooms. What's wrong?

R.O., Dennisport

A. Huh? That excuse is one for the books. If the knotty pine is real boards and not thin plywood, it's actually a pretty fair insulator, but in any case it is not the fault of the paneling, because the old system worked better than the new.

If the old system was hot air, it would naturally warm up the house faster; in fact in 15 to 30 minutes. Hot-water heat is notoriously slow in heating the house, but three hours is too much. All other things being equal, I think the new system is undersized.

Q. I am a first time home owner, and my house has a hot-water boiler fired by oil, and an electric hot-water heater. Is it OK to switch off the boiler in summer? Someone told me that the boiler could get rusty because of the great humidity in the basement, and if the boiler ran a few times in summer, it would help prevent that. I was also told that the oil burner standing idle all summer would also collect rust.

R.G., Braintree

A. There is some truth that idle equipment will collect rust, but the cure is not to run the unit (it won't hurt), but rather ventilate the basement from May to October. Keep windows open for cross-ventilation; provide screens and security as needed. Putting a fan on the floor to get that low air moving will help, too. If you have no windows or vents in the basement, put some in. This ventilation will also reduce, possibly eliminate the musty smell basements get in summer, and will also reduce or eliminate the growth of mildew. A dehumidifier in the dead of summer (July and August, when it is most humid), also will help, but with good, steady ventilation with moving air, a dehumidifier may not be necessary. To illustrate the value of ventilating, the Handyman put two vents in his basement on a wall opposite two existing ones, and has had no problem with humidity since. An addition built 25 years ago has a crawl space with four vents, and that space is like the Sahara. The earthen floor is covered with polyethylene, and is the space is so dry that the earth under the poly has about 3 inches of dust.

Q. The power vent on my oil-fired heater sticks out of the house about 6 inches, 4 or 5 feet above the ground, under an overhang. The clapboards are stained white, and that vent has stained the siding on an area 3 by 4 feet. How can I prevent this? It is also happening to everyone else in the area.

MARK GAUVAIS, Peabody

A. It's a design failure, that's for sure, and the designer should be sent packing. A power vent that comes out under an overhang will guarantee staining. To cure it, try one of these things, and the builder should do it for zilch: Extend the vent so that it juts out 1 or 2 feet from the house, if possible and legal. Better would be to relocate the vent above the overhang.

Q. My boiler leaked rusty water on the concrete basement floor. The leak has been fixed; how can I clean the rust spots on the floor?

BILL WEEMS, Duxbury

A. Mix 4 ounces oxalic acid in a quart of hot water. Apply this to the spots and let dry. Oxalic acid is a crystaline bleach sold in hardware and building stores. When it dries, the crystals may reappear; sweep them up and throw them away; the rust stains should be gone.

Q. The oil tank has been in my house for at least 50 years and I am wondering if it might be in danger of leaking. An oil man said he thought it was leaking because he felt some oil on the bottom of the tank. I put some absorbent clay under the tank and got no oil. But considering the age of the tank, what can I do: Nothing, or should I get a new tank?

ANNA McKINNON, Quincy

A. Wel-l-l-l, hard to say at this time. Many tanks are old like yours and have given good service all that time. The question is, how much longer will they last before leaking? It is an important question, because a leak that spills oil on concrete and later into the ground is the owner's responsibility, and cleanup can cost thousands of dollars, even tens of thousands. It is no laughing matter.

Actually, no one knows how long a tank will serve, although Tony Markarian of MetroEnergy, an oil company in South Boston, says tanks can be good for 20 to 30 years.

In the good old days, oil companies used to strap liners under the tanks to fix leaks or potential leaks, but Markarian said that most no longer do this, mainly because a repair to an old tank is iffy.

So, you could do nothing and hope for the best, or, for your own peace of mind, install a new one. They are expensive, but you'd be getting 30 more years' peace of mind.

Here's one thing you could try, and this is risky too, so the handyman suggests that if you have any doubts at all, don't do it: Tap the bottom of the tank ever so lightly with a hammer; if it rings, the tank is probably sound. If the hammer tap creates a dull, nonmetallic thud, that part of the tank might be starting to decay and rust. The risk here is that if you tap a hole in the bottom, you'd better get a big bucket under it in a hurry, then call your oil man for a new tank.

One positive note about all this: A leaking oil tank will not explode, and is unlikely to burn.

Q. I read your story about oil tanks and leaks and other problems. I have to replace my oil-fired house heater, and am wondering if now is a good time to stay with oil or switch to gas. What are the advantages of each?

DEBBY HARRINGTON, Charlestown

A. The ony advantage to switching to gas, in my opinion, is getting rid of the oil tank in the cellar, which is not only an eyesore but a space-taker as well. But, also in my opinion, this is no reason to switch, mainly because gas fuel is more expensive than oil.

Q. When I was in my house in Marlborough with a hot-air system for 16 years, I got a lot of dust. Now, in my house in Sharon with hot-water heat, I am getting even more dust. How come? Is there anything I can do about it?

STEVE MARKS, Sharon

A. The kind of heating system has little to do with the production of dust. The hot-air system moves air faster than a hot-water system, and you might get more of a distribution of the dust with the hot-air system, but I don't think there is any greater amount of dust. Your proposal to vacuum the heating fins in the baseboards is a good one, to try to reduce the amount of dust being blown up by the rising warm air in the hot-water system. You can take off the sheet-metal baseboard covers and carefully vacuum the fins; I say carefully because the fins can be bent easily. Try a brush attachement; if that doesn't do a thorough job you can use a wand attachment.

As far as I can determine, there is little else you can do.

Q. I have an old house with forced hot air heat and some ugly vent covers and grilles. I have to find some metal grilles more appropriate for the house. I have in mind the rather elaborately decorated and scrolled cast iron covers, but I don't know where to look. Do you?

J.S., Dover

A. Search no further; you have come to the right place, or the right person, for the handyman has replaced all his ugly vent covers and grilles with Reggio Registers. He even asked for, and received some, as Christmas presents some years back. They are heavy-duty cast iron grilles, handsome, elegant, and appropriate for old and new houses. They come in many sizes and shapes, varied enough to fit your needs. They also are expensive, but what isn't these days? You can also get aluminum grilles that can be painted, solid brass, and a limited number of styles in wood. Call the Reggio Register Co. of Ayer (the founder and president of the firm is named Reggio, which is appropriate for a register company). Call 978-772-3493.

There are other uses for the grilles and vent covers. The handyman has used them for basement vents. They add a certain elegance to an otherwise plain (1768) colonial, even though they are not colonial in design or style.