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Hot Water Boiler Replacement---Need Education

My oil-fired hot water boiler is 40 years old and I'm looking at replacing it soon. I will be looking at putting in an indirect hot water heater at the same time. I'll be getting quotes from HVAC contractors, but before the whole process begins, I want to educate myself about how the systems work, available features, and specs and reviews of particular brands of boilers and h/w heaters. One source I've looked at is the consumer guide website for the American Council for an Energy-Efficient Economy.

What other resources would you recommend I use to educate myself?

Re: Hot Water Boiler Replacement---Need Education

Could you provide more info as to if you have natural gas available, the type of convectors (radiators, baseboard, etc.),
how much roughly you want to spend for a new boiler, and how many gallons of oil you burn a year.

I'm very glad to see you want to move up to a newer unit, & I think it's a good idea to stick with a hot water boiler.

The first thing you should do is spend some money now on INSULATION.

Every one of your exterior walls should have R19 and your attic R40, if you need insulation, NOW is the time to have it blown in BEFORE you order the new boiler.

If you don't know if you have insulation in your exterior walls, take a small diameter drill bit & drill a small hole in an inconspicous place at different parts of the inside of all four of your exterior walls & insert a piece coat hanger bent at the tip ; you should pull out some bits of insulation.

Next, apply heavy cement glue on the coat hanger tip & reinsert & twist around & pull out to see if any insulation sticks to the hanger.

Next, insert a longer piece of coat hanger & twist it around; if you can hear it bouncing around the hollow wall cavity, there is NO insulation in the wall.

Some older homes have no insulation at all in their outer walls; you can check the Yellow Pages under "Insulation" for a service that blows in cellulose; they remove an exterior shingle here & there & do all work from the outside, within a day.

Also check the windows for double pane or storm windows.

When the boiler installer comes over, he should do a HEAT LOSS CALCULATION, which measures how many heat btu's an hour are bleeding out of your home on a cold day.

He will then determine what size boiler to put in (anywhere from 50k btu/hr to over 100k btu/hr).

If you have more insulation, he can put in a smaller boiler & you'll burn less fuel every winter; the fuel saved will pay for the insulation cost very shortly.

You can do your own preliminary HLC at the sites below.

When it's time to get quotes on a new boiler, get at least 5 or 6 quotes from contractors & oil service dealers in your area; their choice of equipment & cost estimates will vary widely.

Get someone who is enthusiastic & seems interested in doing a good job.

I've concentrated on the cost & selection of the boiler & indirect HWH only in this post; this assumes your heat distribution system (radiators, baseboard, etc.) is ok & doesn't need any work or modification, which would entail a higher expense.

If you buy one of the high-efficiency boilers, the installer may want to install a stainless steel duct up your chimney; this is often necessary for older masonry chimneys & because of lower stack temperatures for newer boilers; this would be an added expense.

If your old boiler and nearby piping is completely covered with white material, this is probably asbestos insulation; additional hazmat costs are usually associated with removal & disposal of asbestos, which is seen as a hazardous material.

There have been many improvements in hydronics since the old boiler you have was installed, many of them over the years have been spurred by northern European heating engineers, particulary in Germany.

The reason for this is the much higher prices paid for Middle Eastern oil, that spurred innovation; these innovations have been incorporated into U.S. boilers now that energy is rising everywhere.

Hydronic boilers are 85% of the market in Europe, & remain only ~15% here, with forced hot air & natural gas still dominating the U.S. market, especially outside the Northeast.

Increasing popularity of hydronic radiant heat in the U.S., again due to European & U.S. equipment innovations & better heat efficiency has greatly widened adoption of hydronics.

If you must stick with #2 fuel oil, your options are still very good, though not as good as the more efficient natural gas-fired hot water boilers, which are up to 95% efficient.

Boiler efficiency is rated in AFUE percentage standards; thus, if a boiler has an AFUE of 85%, it burns 85% of its fuel to useable heat, and 15% is wasted, going up the chimney.

Generally, if a new boiler is 95% efficient, only 5% of the heat is going up the chimney & being wasted.

If your current boiler is 60 years old, that means that it is probably only 50% efficient, and 1/2 the fuel you burn is going right up the chimney.

This scenario is totally unacceptable with today's oil prices; even an entry level low-cost new $1200 cast iron oil-fired boiler would have you see a drop of 30% in fuel usage, simply because their design improvements allow them to burn fuel at about 82% efficiency.

The most efficient boilers these days are natural gas-fired condensing modulating boilers that have 95% efficiency; they no longer need a chimney, but vent their slightly acidic waste water down a 1 1/2 pvc sewer pipe drain.

If you install such a boiler, you should see a fuel usage drop of about 50%.

Since natural gas is a light fuel & contains a lot of hydrogen, it can be almost completely burned, producing water and few byproducts on condensation as it burns.

Most fuel oil sold in the U.S. contains a lot of sulfur, this has in the past prevented condensing boilers if they were oil-fired---but now Peerless Pinnacle and others have come out with effective stainless steel condensing boilers with 95% AFUE efficiency, just like gas-fired boilers.

Things are changing in Europe & the U.S. where low-sulfur fuel is now coming onto the market.

For oil-fired boilers you can begin with the least expensive $1200 85% efficient pin-type cast iron boiler that has been the staple of the industry for several decades.

Thus a $1200 boiler and a $700 indirect water heater =$1900 + $1000 for installation, valves, parts, labor to remove old & install new = ~$3k as a low ball base price for a new boiler.

Cast iron is used because it holds a lot of heat; these units weigh about 600 lbs; they rely on flue stack temps of ~600 degrees to carry the waste products of their combustion up the chimney

A step up would be to buy $3k or $4k boiler that has a more efficient design of its combustion chamber (3-pass design), which allows it to burn more of each gallon of fuel and lowers the stack temp to < 300 degrees, most of these are ~90% efficient & can tolerate lower boiler water temps, making them more efficient & capable of using radiant heat, also more efficient; outside reset is common (rather than a wall thermostat), also more efficient, so they burn much less oil each year.

You should see a fuel usage drop of ~40% if you install such a boiler.

Going up another step to a $7k or more boiler would be top of the line, such as Viessmann (German), Buderus (German), which has 95% efficiency; they make some oil-fired units in this class & don't use a chimney; they realize the highest savings in fuel; many of these units have stainless steel internal parts instead of cast iron.

You should see ~45%-50% fuel usage drop with such a boiler.

There are a wide number of efficient, domestic-made and foreign-made boilers available.

Among them I would recommend Viessmann, Buderus, Peerless, Utica, Burnham, Biasi, Dunkirk, Crown, Slantfin, Triangle Tube & others; see the pdf files for recommended Energy Star boilers that use less energy & have higher efficiencies of at least 85% AFUE.

On the indirect HWH I would recommend Triangle Tube, Crown, Burnham, Viessmann, Buderus, Amtrol Boilermate.

The most efficient indirects have a stainless steel inner tank (Triangle Tube & others).

There were some leak problems with Burnham over a year ago & some elastomeric seal leaks with Weil-McLain 2 years ago, on some models; I don't know if they've been completely cleared up.

Furnace Compare (below) has a review of some boilers.
Most of these mfgs. have been in business for many decades & have excellent products.

The site at Furnace Compare has warranty information on most above boilers; typically, a mfg will offer 1 year on parts and labor, & 5 to 10 years on the heat exchanger, but warranties vary widely.

Make sure you read all the warranty info on the particular boiler you intend to buy.

Each one of these mfgs usually produce all 3 types of boiler, the low-end cast iron, which is a tried & true design, the mid-range triple pass units, and the high-end condensing/modulating temp units.

Stay away from Sears-Kenmore, boiler manufacturing is a very specialized business by companies who do nothing else.

Basic pin-type cast iron section boilers have been assembled by U.S. & foreign foundaries for decades, they're not as efficient as the fancy condensing boilers these days, but the technology is tried & true; these units are tough, rarely leak & usually last for decades.

Also, each of these mfgs make oil-fired as well as gas-fired units & some propane-fired.

To see how boilers work, Google "troubleshooting a boiler" (with and without the quotes), "How boilers work", etc.

Also check out heatinghelp.com (The Wall) for more info; also doityourself.com (Plumbing/Heating/AC/Boilers), oiltechtalk.com (oil heat discussions).


Re: Hot Water Boiler Replacement---Need Education


Thanks for all the extremely helpful information.

Our house is a large (10 good-sized rooms) old federal in Maine. A lot of work has been done updating and making it more energy-efficient, though there is more that should be done. The walls are well insulated. The attic floor is insulated, though we need to increase that insulation as well as insulated the rest of the attic. All windows and doors are new and double-paned.

The oil-fired boiler feeds old cast-iron radiators in most of the house, except for two side rooms (separate zone) where the prior owner put in baseboard. We love the radiators, hate the baseboard. At some point, we might rip out the baseboard and put in a couple of refurbished cast-iron radiators or European radiators. Natural gas is not available in our area.

The radiators are in good working condition except for two rooms, where they are stuck in the "on" position. We need to fix that so that we can close off those rooms in the winter. Wondering whether it's worth it to install radiator thermostats on some of the radiators. Apparently they are used a lot in Europe, but not much here.

We've had 4 winters here and used about 1200 gallons each winter. The house is occupied all day, every day, so I think that's pretty good. We do take the edge off some of the time by using a wood stove.

The boiler tests at 84.7% efficiency, which is better than I would have expected. However, it has needed mid-winter emergency repairs twice that cost $200-$300 each time. It seems clear it needs to be replaced at the end of this heating season, if not before. Fortunately, we can afford a good system. We are penny pinchers by nature, though, so we wouldn't buy a premium system unless it was clearly superior and well worth the extra money. We would have to do some serious thinking about the leap from a $3-4k boiler to a $7k boiler. We do expect to live in this house for many years, so we would do the thinking.

Since we use fuel oil, it sounds like a condensing boiler is out of the question until low-sulfur fuel oil becomes readily available in the US. Correct?

Thanks again for all the education.

Re: Hot Water Boiler Replacement---Need Education

I certainly would love to see you keep the radiators, they give off a nice "fat" heat and have radiant aspects that are completely missing in baseboard.

It's hard to accept that the present boiler has that high an efficiency, but you can check it out in round about ways.

The biggest threat with a boiler of that vintage is that if it breaks down, the local distributor no longer stocks parts for it; & the original mfgr may have gone out of business.

The sites below will help you determine how much btu/hr output each of your radiators has, when all totaled up (assuming they didn't put too many rads in originally) they will give you the total btu/hr output.

Assuming 10' ceilings you can multiply the square footage of each room (including the boiler room) & total them up for total square footage & multiply by 40 or 50 to get a rough btu/hr heat loss calculation for the house.

If the total btu/hr is printed on the boiler (our you can get it from the internet or manufacturer), you can use that also as a comparison.

The heat loss sites will give you a more accurate calculation of how well your building is holding the heat the boiler is producing each hour in the winter.

The btu output of a radiator is roughly computed by assigning 170 btu/hr to each square ft., then multiplying by the number of rad sections.

Thus a 24 section radiator that is 1/2foot wide & 1.5' high = .5 X 1.5 =.75 sq.ft X 24 = 18 sq.ft. X 170 = 3060 btu/hr output for this rad.

I think you should run your situation by some of the boiler technicians at doityourself.com (Grady), and those at oiltechtalk.com, as well as at heatinghelp.com (The Wall).

If you can give them the total sq.footage of the house, the btu output of the rads & the possibly the btu/hr rating of the present boiler, they can give you a better idea of which way to go.

Low sulfur #2 should be available in your area with some dealers, but it usually costs .20 to .30 cents/gallon more.

Viessmann, Buderus & Monarch & some others have oil-fired condensing boilers available now, ask how reliable these units are; I think the Viessmann has a good reputation.

I think you can get below 800 gals/season.

If you have 12' ceilings, you might opt to drop them using sheetrock to 8', if this doesn't harm the appearance of the rooms.

This would be a big savings.

Aluminum reflectors are often placed behind each rad to deflect the radiant heat out into the room.

A low-cost globe valve rated at 200 degrees is often used on the "stuck on" radiators; they can be partially closed to cut down on room heat when not in use.

Also widely used now in the U.S. is the TRV (thermostatic radiator valve); these are more expensive than the globe, but are very handy.

Google "thermostatic radiator valve" to get the full story.

Present boilers & controls are designed to run at 180-200 degrees boiler water temp.

This is "old hat" & wastes a lot of energy; the move is toward lowering the boiler temp considerably & using outdoor reset.

Outdoor reset takes into consideration the reality that there are many "not so cold" days during the winter when the boiler temp doesn't have to be 180 degrees, so it automatically tells the boiler to lower the boiler temp to save fuel.

If you can get a condensing or 3 pass boiler, you can run the boiler temp at 130 degrees with more constant circulation.

This procedure is widely done these days in order to save energy.


Re: Hot Water Boiler Replacement---Need Education

Thanks for all the additional info. I had the boiler efficiency checked this year and last by two different techs and the result was the same, but I could still check it myself using the procedure you suggest.

Ceiling heights are not a problem. First floor heights are 9 feet and lowering them is out of the question because of the historic moldings. However, 2nd floor ceilings are only 7'2" if you can believe that. It certainly helps keep things warm in the bedrooms in the winter.

One way we lose some efficiency is that the thermostat for zone 1, which is 90% of the house, is in the main hallway. That hallway can be shut off, so that we could keep it and all the upstairs quite a bit colder than the downstairs rooms that are in use during the day. To do that we'll need to move the thermostat. We were thinking of getting a wireless thermostat, but haven't been able to find one locally as yet.

I was interested to hear that there is low-sulfur availability. I'll check into it around here, though my ability to do anything this season is limited since we have prepaid.

Many thanks.

Re: Hot Water Boiler Replacement---Need Education

Next, admit a best section of covering hanger & aberration it around; if you can apprehend it bouncing about the alveolate bank cavity, there is NO insulation in the wall. Some earlier homes accept no insulation at all in their alien walls; you can analysis the Yellow Pages beneath "Insulation" for a account that assault in cellulose; they abolish an exoteric bank actuality & there & do all plan from the outside, aural a day.


Re: Hot Water Boiler Replacement---Need Education

I am dumbfounded on that reply to a two year old post.:confused:

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