Price sounds low. Got a model # of proposed boiler?

175,000 BTU for 2000 sq ft seems huge. How did he determine this size? Insulated? Abnormally high amount of windows?

What type of radiation? Baseboard? Big old radiators?

This is a hot water system, right (not steam)?

If you are interested in high efficiency, the boiler exhaust gases from a "high" (85%+) efficiency boiler shouldn't be vented into a masonry chimney, unless it is lined.

The 175K BTU gross input boiler sounds big. That's 140K BTU net at 80% efficiency. Even if you house has NO insulation, it seems too large. Insulation should be improved if possible before sizing the boiler. Smaller boilers generally = lower gas bills.

The price seems unbelievably low from New England standards. Get more quotes. Don't award the job to a contractor who doesn't do a heat loss calculation.

I have to agree with the above points. That recommended boiler size sounds way over sized. This would just be as bad or worse than the fuel usage you already have. The price also seems way too low. My 1,350 sq ft home, 25 years old, has a boiler that's 70k BTU.

My heating company technician said that grinding in a pump is the sound of a pump in its death throws. Definitely don't dilly-dally around.

RugCutter,

I will agree with the above too, but would like to know what is the current boiler input and output (BTUH Rating)? There sould be a name/data plate on the boiler. How often does it run on the coldest days? Does it cycle on and off on the coldest day or does it run continuosly?

Also the grinding could be a coupler (Spring type) between the motor and pump, if you have this type of pump. If the pump and motor are out of alignment, the couplers go out often. If you have a direct coupled pump, probably the bearings, like your service guy said.

You may be able to limp along through this winter, but 30 years is old in "Boiler Years".

Keep Warm,

Dan Martyn

The pump is making a grinding noise and he told you you were better off replacing the whole boiler? Why?
When I bought this house two winters ago it was the first house I ever owned with a boiler and hotwater radiant baseboards, size approx 2600 sq ft. The house is zoned into 5 loops. The boiler is original to our house built in 1957.
Not knowing the slightest thing about boilers I asked a few questions here and people were helpful explaining how they work etc. I then had a local long in business company come in to go over it with me and install an air bleed valve. I asked the lady at the office to only send me one of their guys who had been in this business for decades and knew all there was to know about older boilers fearing they'd send me some young guy LOL. I know it sounds strange but I wanted someone who knew his way around these old monsters. Anyways the guy who came around was an "old hand" with them and was supremely helpful in explaining everything about it to me so that I could understand it. He checked it all out, checked for carbon monoxide leakage , bled the system, installed the bleed valve etc. I asked him point blank if I should think about replacing it with a new unit and he said there's no point because it's quite possible my boiler may still outlive me.
As for it's efficiency it's probably not the most efficient but the tradeoff he said was that the unit itself radiates a lot of heat here into my finished basement/workshop, the toastiest part of the house in winter and all that heat does make it's way upstairs.
I check my monthly gas bill against my moms bill and the neighbors all who have similar houses and mid to high efficiency forced air furnaces and my gas bill is equal or lower and I keep the house around 71 to 72.
I'd get a second opinion if I were you.

As far as the sizing the first guy determined it based on what the existing boiler was (175,000 BTU). When I spoke to the company today another gentlemen offered to come to the house, and he did what I think was take data for a manual heat loss calculation. He essentially counted up the number and size of baseboard units in the basement, 1st floor rooms, and 2cd floor rooms.

So he arrived at the same line of thought, there may be potential that I could need a smaller boiler.

I asked him about replacing just the pump and he said it could be done, however if I wanted to replace the boiler later I couldn't re-use that same pump. That because the gasket seal would be broken and once you do that you can't reseal it. I essentially would need to get a new pump again.

Brands he offered were Peerless, Burnham, Crown. They use Peerless mostly.

I will know more when I talk to him tomorrow about his findings.

I kinda figured that was how he came up with 175,000 input. Counting up the fintube may come up with a smaller size, but is every room perfectly comfortable? An educated guess, I would think you should be around 80,000 to 96,000 for output (100,000 to 120,000 input), but without doing the calcs, who knows. A good rule of thumb would be 40 bth's per sq. ft. for newer construction, slightly more for older leaky contruction. If you had a pump replacement now, the reason you wouldn't reuse the pump is that, typically the new boiler comes with a pump. Pumps have flanged or threaded connections which can be gasketed or thread sealed, should be no reason you couldn't reuse a pump. When I had a boiler replacement in 2000, I got a Burnham, they have been in business for years, good reputation, and they make commercial boilers too. Very nice boiler. I would get a second and third estimate from other installers who base the new boiler size on a calculation. Otherwise as I mentioned before, know the operational history of the existing boiler can tell you if the current boiler is oversized. If the boiler cycles on and off during the coldest days in winter, it's oversized. A boiler should run nearly continuous on a design day (Lowest average temperature).

Stay warm!

Dan Martyn

Is it accurate to say that if my old boiler is only 55%-60%, then a new, smaller boiler that is 80%+ efficient will heat my home equally?

Since it works more to produce the same amount of heat, I thought that is my old boiler is a 175,000 BTU boiler.

Look back at my first post. The input and output ratings tell you exactly what the efficiency is (New), no guesswork. What model/series would your installer be providing? By providing a boiler which is oversized for the load, the boiler will "Short Cycle". The thermostat calls for heat, boiler turns on, house comes quickly up to temp, thermostat is satisfied and boiler shuts off. There is an inefficiency when the boiler turns on, it takes time to heat up the heat exchanger before the heat exchanger can heat up the water. You can reduce short cycling by sizing the boiler for the anticipated load, making the boiler run longer between cycles. I'd get at least one more estimate.

Dan Martyn

Here is a link that might be useful: Burnham Residential Boilers

A heat loss calculation is not the same as calculating the output of the radiators. A heat loss calculation involves determine the surface area of the floors, wall and ceiling areas inside the heated space that adjoin unheated space, and the r-value of those floors, walls and ceilings. The number of exterior doors, the number and size of windows, and the coldest temperature experienced are also used in doing the heat loss calculation.

On old boiler that is 175,000 BTUs input that is 60% efficient has a net usable output of 105,000 BTUs. The other 70,000 BTUs go up the chimney.

A new boiler that is say 125,000 BTUs input that is 85% efficient has a net usable output of about 106,000 BTUs, with only 20,000 BTUs going up the chimney.

If on the coldest day of the year your house only looses 50,000 BTUs/hr, then you dont want an 85% efficient 125,000 BTU boiler, because it produces twice as much heat as you need.

To the extent that it is possible, you want a boiler that is as close in output to your houseÂs heat loss on the coldest day of the year.

I was confused about what size I needed & wound up buying a Biasi boiler from a company right here in my backyard. The guys at www.houseneeds.com spent a lot of time on the phone with me to figure out what size I needed & made sure they didn't sell me anything I didn't need. I'd recommend checking them out.

So I spoke with the company this afternoon and he told me this. Based on his sizing, a 175,000BTU boiler is the right boiler to get. He also told me my current boiler is likely operating at 47 - 55% efficiency - the rest is going up the chimney.

There is a new tank that is needed with the new boiler, that wasn't included in the original estimate. So he quoted $4200.

The model is a Peerless - I believe an MI-6.

They offer a Burnham for $250 more and a Crown for $125 less. Warantees and service are the same for all three brands, so it doesn't sound like there is any advantage.

I asked him if it would have enough capacity if I chose to say, finish the basement and/or finish the attic. He suggested I could get a 195,000 BTU boiler to plan for future and they can set it up now to turn off one of the burners. Then turn on the extra one as I need to add capacity later. That would cost an extra $475 = so $4675 for the 195,000 BTU model.

So I'm not sure if I am miscalculating the size of my house and not describing it correctly on this forum. It's an 1896 farmhouse so I have no square footage from a builder - I just thought it was around 2000 sq ft.

I understand the energy needed for the multiple on/off cycles - thanks dan. Sounds like slamming on the accelerator and hitting the brakes when driving your car.

I did call another company to do an estimate Monday so we'll see where it goes when they size it as well.

Doesn't hurt to get several estimates, kinda like getting a second opinion from a doctor. The more input you have the better your decision will be. Do not disclose the other estimators prices, it's not fair to the original estimator.

Good Luck!

Dan Martyn

There's no need to contact a builder to get your square footage. If someone is going to do a heat loss calculation for you, all they have to do is measure the living space with a measuring tape and do the basic math. Then they tack on how well insulated and sealed your home is, the thickness of the walls, type of windows, any natural and mechanical ventilation, etc. The process of calculating the most accurate BTU loss can be nit-picky.

I find it odd that one person told you that 175,000 BTU is the right BTU rating to go for, and then tells you that the current unit is 47 ~ 55% efficient. (This can be 'sniff' tested, as well.) If the current boiler can only supply your home with half its rated BTU, it stands to reason that a new, more efficient unit can heat your house all the same with a lower BTU rating.

When my home was built in '82, it was supplied with a 140k BTU boiler for 1,350 sq ft. The new boiler is 70k BTU. Although we haven't reached a Design Day (-20°F), it has done a fine job of maintaining temperature. (Weil-McLain GV-3).

Ask these people who are doing boiler quotes about Outdoor Reset controls. These little gems sense the outdoor temperature and adjust the water temperature of your boiler accordingly. On a cold, Design day, the boiler would produce peak water temperature. As the outdoor temp warms, the boilers cools. All the while keeping your home warm yet reducing fuel cost.

There is no way your house needs a 175,000 BTU boiler. You need to have a proper heat loss calculation done to find out what is really needed. http://slantfin.com/heat-loss-software.html
download this and you can do the calculations yourself.

When boilers are oversized, they are rather inefficient. All the repeated starting and stopping results in alot of wasted heat. The proper sizing for a water boiler (or forced air furnace) is so that it runs constantly on the coldest day of the year while still being able to keep up with the inside setpoint.

As an example, my house is a 1890's farmhouse in SE WI (design of -4) with a 1964 addition/remodel. Walls have R13, ceiling has R19. Windows are decent wood framed double pane from 1964. I have 1600 sq ft downstairs, 1000 sq ft upstairs, and a 500 sq ft finished basement. Total of 3100 sq ft. The heat loss is just under 80,000 BTU, which works out to 25 BTU/sq ft.

With fuel prices going the way that they are, you really should consider a higher efficiency system. The best choice is a modulating/condensing boiler. They vent out the side wall (or through the roof) using 2" or 3" pvc pipe. These boilers will achieve up to 98% in a low water temp application. Even in systems that need higher water temperatures on design day can run lower water temperatures during the rest of the winter using Outdoor Reset as braytonak mentioned. This route will be more expensive to install, however, fuel bills will drop dramatically for years to come.

Peerless makes the Pinnacle mod/con, others are Lochinvar Knight (my favorite), Weil-Mclain Ultra as well as many others.

Michael

Our house has a similar situation. It's 1900 sf, built in the 1890's, has some blown in insulation in the walls (we only know this because we gutted the bathroom and found it - this room will have regular batt insulation in the walls and ceilings), has the original windows but triple track storms.

The old oil fired boiler is 199k BTU and our oil bills are completely heinous - we used about $650 worth of oil for the month of December. I can't imagine what our bills would have been for a house 50% larger. Just from a reality check standpoint, there is no way a house the size of ours requires the absolutely largest residential boiler available (there may be some slightly larger but in general, around 200k is as big as they get). Our old boiler does short cycle too, it's loud enough that you can hear it. Even in the dead of winter with single digits at night it cycles on and off. We are probably running somewhere in the 60-70% efficiency range also. Everyone who has quoted for us has universally said "WHOA that's a HUGE boiler for your house."

After evaluating all of our options, we are going with a modulating/condensing boiler at about half the capacity (maximum) and putting zones into our house. Right now when it is 68 downstairs, it's about 80 degrees in our bedroom - so at a minimum breaking the house down into different zones for upstairs and downstairs should also help - DH works at home during the day and there is no reason to throw all of that extra heat upstairs when no one is there in order to keep downstairs comfortable. For various reasons we are actually going with more zones than that (the way our system was originally piped makes it extremely easy - labor wise it would be just as much to combine them back into one zone as leave them split - and there is a big temperature difference between the various parts of the house we are splitting off) but you might want to check into whether it is possible given your current piping to separate your 2nd floor from your first into separate zones.

Between the zoning and the much more efficient boiler, we hope to slash our energy prices. It's NOT a cheap boiler (the cost of the boiler is more than the cost of your boiler + install) but with our old cast iron radiators with relatively cool return, the condensing part will work great, and with us zoning out our house, the modulating part should work great too (it operates at a much lower BTU if the demand isn't there). It also changes the temperature of the water sent out into the system based on the outside temperature, so if it's 50 degrees outside and we want to maintain say 70 inside, it's not necessarily moving 180-190 degree water through the system, so there is savings there too, especially in the shoulder months.

We are switching from oil to gas (it would cost us thousands to replace our oil tanks, the real reason we are replacing the boiler - the oil tanks are not long for this world and because there is no longer outside access to the basement it would be a huge job to get the old ones out in pieces and multiple small new ones in and we decided to put that money into a more energy efficient boiler rather than use the same old boiler and just get new oil tanks) so it will be interesting to see the difference in our energy bills.

Anyway it took a ton of research and a bunch of time looking at our system and figuring out what was going on to trace out the various loops we have, but I'm glad we put the time into it. We feel confident with the system we have chosen and hope our house will be far more comfortable and energy efficient for the years to come. Energy prices have nowhere to go but up, unfortunately. We are only planning to do this once so figured we'd do it right the first time. The first couple of contractors wanted to put in either a 200k btu boiler to replace the one we have or a 165kbtu boiler calculated by counting radiator fins. As I said before, some of our radiators have about 3x the capacity actually required for comfort in the room so it's kind of silly to oversize in this way because it's just easier to "replace in kind."