New boiler choices. What's the difference?

boilernewb

We are new to oil heat and moved into a 1,600 square ft, 1901 home in New England with a 20+ year oil boiler that will eventually need to be replaced.
We are have received some quotes for new oil boiler models, both from our oil company and a separate HVAC company.
We are trying to compare the following models for longevity, and return on investment.
Any thoughts, opinions or expert experience would be helpful.
Horror stories are welcome too!!

Well McLain WGO-2RD
Buderus G115WS/5
Dunkirk Excelsior EXB 4075

Jamie Hall

All good. But... make sure that you really are looking at the right size boiler. Did anyone do a heat loss study on your house? Before you specify a boiler for hot water heat, that is absolutely required.

boilernewb

We haven't had anyone do a heat loss study yet. We only moved in mid summer so we haven't spent a winter in the house to know. Who would we contact to conduct one?

Jamie Hall

The contractor whom you choose to install the boiler should do one as a matter of course. Some don't, and just replace what's there -- which is often an error. If they say they don't need to, find another contractor...

That said, it's very easy to do your own to double check. This website: https://www.slantfin.com/slantfin-heat-loss-calculator/ has an excellent program to do it which a lot of us like (either a smart phone app, if you're into such things, or at the bottom of the page there's a "click here" option to run it on a PC or Mac). It's a little conservative but on the whole quite accurate.

EBEBRATT-Ed

@boilernewb

And as we always say in this forum the installer is more important than the boiler.

All 3 boilers are ok in the right hands.

If it was my decision (and it's not) I would vote for the Weil Mclain or a Peerless. Simple and time proven.

Do you have natural gas available? What shape is your oil tank in?

The other item is to have your chimney inspected and possibly a liner installed by a certified chimney sweep.

And @Jamie Hall is correct about a heat loss. What provides your domestic hot water?

HVACNUT

What makes the domestic hot water?
The Weil McLain is rated at .7 GPH input. 
The Dunkirk is rated at .75 GPH input. 
The Buderus is rated at 1.00 GPH input. 
Unless there will be a large indirect water heater and you have very high domestic hot water needs, the Buderus is too big. The 3 section will be more than enough. 
For me, the WGO is off the table because it's a pin boiler and a 3 pass is a better design.
 

Ironman

As mentioned, the installer is 95% of the equation. Concentrate on finding a good one.

The Buderus is a better designed and made boiler, but the one quoted is way over-sized for your house. A G115/3 would be more than sufficient. The burner can be up-fired 10% if needed, but that’s doubtful.

I would cross that contractor off the list right now for quoting a boiler that’s twice the size that you need.

Check the contractor locator above for a pro in your area or post your locale  and we may be able to recommend someone.

boilernewb

Thanks for all the input so far.
To answer some questions,

Current boiler is a Smith Cast Iron 8 series S/W 4, GPH 1.10-1.25
The boiler does power the domestic hot water tank as well.
A natural gas line would cost a bunch to run to the house, according to local utility
Oil tank could be replaced, (that's what the oil company wants to tell me...) but no leaks yet.

STEVEusaPA

You'll never recover the cost of running a nat gas line. Like the others said, heat loss first.
Most likely the smallest triple pass boiler w/indirect is your best bet, or an Energy Kinetics is even better.
When they do replace the oil tank, get a double wall tank.
Please remove pricing on your last post.

boilernewb

Heat Loss Calculator estimated at least 49,000 BTU/HR Heat Loss at 5'F.
How do I factor this data into my decision?

Someone suggested switching to heat pumps and a furnace with the rising cost of heating oil, and adding solar to supplement the electricity needs, which might be tough with the shade.

Jamie Hall

boilernewb said:

Heat Loss Calculator estimated at least 49,000 BTU/HR Heat Loss at 5'F.
How do I factor this data into my decision?

Someone suggested switching to heat pumps and a furnace with the rising cost of heating oil, and adding solar to supplement the electricity needs, which might be tough with the shade.

Just to be certain, this is hot water heat, correct? Factoring the heat loss into your decision on a boiler is pretty simple. That's the output you need from the boiler. Period. The "at least" doesn't belong there.
That's the heat loss, give or take a few percent, of the structure, assuming you go the inputs to the calculation right. So, anything bigger is a waste of money and energy. Anything smaller won't work. So you try to get as close as you can to that number (you'll never hit it exactly, of course).

The domestic hot water load is not a factor.

That said, the smallest boiler you mention above is almost twice as big as you need. The largest that much worse.

Time for a rethink...

Robert_25

boilernewb said:

Heat Loss Calculator estimated at least 49,000 BTU/HR Heat Loss at 5'F.
How do I factor this data into my decision?

Someone suggested switching to heat pumps and a furnace with the rising cost of heating oil, and adding solar to supplement the electricity needs, which might be tough with the shade.

The smallest oil boilers available will be plenty big enough.

Heat pumps? What is your local electric rate?

Jamie Hall

I might add to my previous comment... your design temperature is 5 F? A heat pump is not an option for the coldest days, unless it is a ground source type.

Hot_water_fan

Someone suggested switching to heat pumps and a furnace with the rising cost of heating oil, and adding solar to supplement the electricity needs, which might be tough with the shade.

Heating oil is expensive, very likely a heat pump will be cheaper to operate. At $2.50/gallon, heat pump at $.12/kwh is about half the cost/btu. Solar can bring this number down even more. The rub is that you need ducts/ductless heads added, air-to-water heat pumps are not prevalent in the US yet. If you think you'll ever want AC, the incremental cost is negligible.

I might add to my previous comment... your design temperature is 5 F? A heat pump is not an option for the coldest days, unless it is a ground source type.

Skip ground source: way too expensive and barely more efficient. There are air source heat pumps that perform well into the negatives.

Hot_water_fan

Heat Loss Calculator estimated at least 49,000 BTU/HR Heat Loss at 5'F.
How do I factor this data into my decision?

I saw that you moved into the house, so this data might be hard to come by. Do you know how many gallons the boiler used last year? You can compare that usage to the weather (Heating Degree days) to determine the heat loss.

Ironman

A heat pump in a 120 year old house in NE? That’s the worst possible choice. It would never keep you comfortable even if you could get one with enough output.

The walls in that old place are like a large heat sync. You’d feel cold even if the room air temperature was 75*.

Dan has an article somewhere on here called “75* Cold” that explains this.

 I’ve personally got customers that have tried to go the forced air route against my advice in a house like yours only to contact me after it’s done and beg for a simple solution which doesn’t exist. 

You need to stick with your hydronic system and find ways to make it more efficient and also tighten the envelope of your house.

A new boiler with Out Door Reset (oil or gas) could easily save 30-40% in fuel if done right.

pecmsg

A heat pump in NE is not bad for the shoulder seasons. Once it gets around 25 - 30* time to switch to the back up heat. 

Converting to oil has no return on investment. 

Heat Load / Loss first. 

Remember you will be at design conditions 1% of the time. The other 99% that boiler is oversized. 

Hot_water_fan

If you’re ever considering AC, then a heat pump is extremely compelling. You’d get a 2-for-1 system that’s cheaper and cleaner than oil. Your house, while old, has a heat loss, well within the range of heat pumps, it’ll feel just fine. Don’t worry about the shoulder seasons, oil is so expensive it’ll be cheaper to just abandon it and go heat pump all the way down to design temperature. 

Jamie Hall

Got a challenge for you, good buddy @Hot_water_fan . You can PM me on it.. House I'm looking at has a design heat loss of 320,000 BTUh, reached for at least 7 days every year (real records). Design teno us -10 F, Current heat is oil fired steam, but ducting is possible in the basement. Probably not feasible for second floor. Maximum power available is 100 amps, 240 volt single phase AC (grid limited).

Comfort is subjective, of course, but based on previous experience with steam vs. hot air, I would expect to run about 5 degrees warmer with hot air, thus design heat output should be around 350,000 BTUh at design temp.

What's available? Any idea of cost?

boilernewb

It is hot water heat.

Electricity is about 0.242/ kw-hr
Heating Oil is about $2.59 gallon.


The house uses about 900 gallons annual.
Last Year.
Annual HDD:
5101 °F
Annual CDD:
818 °F

Robert_25

Hot_water_fan said:

If you’re ever considering AC, then a heat pump is extremely compelling. You’d get a 2-for-1 system that’s cheaper and cleaner than oil. Your house, while old, has a heat loss, well within the range of heat pumps, it’ll feel just fine. Don’t worry about the shoulder seasons, oil is so expensive it’ll be cheaper to just abandon it and go heat pump all the way down to design temperature. 

In theory that sounds good, but after my experience last winter I would not suggest heat pumps only to anyone in New England. We have a Minisplit system that works down to 5F or so, and for about a month last winter it was our only heat while I overhauled our hydronic system. It kept the house "warm", but the comfort level was not even close to the hydronic system. The basement felt like a meat locker, the walls and windows felt chilly if you sat next to them, and when it got below 20 degrees, the heat pump would regularly cycle into "defrost mode" and during that time...it felt chilly. It was like an old hot air system with a 5 degree swing.

Just my opinion, but heat pumps seem like a much better compliment to an oil system than a replacement.

Robert_25

boilernewb said:

It is hot water heat.

Electricity is about 0.242/ kw-hr
Heating Oil is about $2.59 gallon.


The house uses about 900 gallons annual.
Last Year.
Annual HDD:
5101 °F
Annual CDD:
818 °F

boilernewb said:

It is hot water heat.

Electricity is about 0.242/ kw-hr
Heating Oil is about $2.59 gallon.


The house uses about 900 gallons annual.
Last Year.
Annual HDD:
5101 °F
Annual CDD:
818 °F

With your (expensive) electricity rates, it will be tough for heat pumps to beat oil in cost of operation. Even propane would be worth considering, especially if you can further reduce your electrical usage with a propane stove, dryer, etc.

boilernewb

The electricity rate is 0.108 kw-hr for the supplier, it is the delivery charge that bumps the price up.

Hot_water_fan

The electricity rate is 0.108 kw-hr for the supplier, it is the delivery charge that bumps the price up

Solar looks great vs $.24/kWh!

Jamie Hall

Haven't answered my challenge, @Hot_water_fan !

Hot_water_fan

@Jamie Hall of course! You always get the fun projects. I’m always open to a hybrid setup. So two 4 ton ducted units for the first floor, probably only need 80 amps for that. To go all out, going from steam to water using a wood gasification boiler (maybe two!) would be fun. 

Jamie Hall

Hot_water_fan said:

@Jamie Hall of course! You always get the fun projects. I’m always open to a hybrid setup. So two 4 ton ducted units for the first floor, probably only need 80 amps for that. To go all out, going from steam to water using a wood gasification boiler (maybe two!) would be fun. 

Who makes a unit rated at 4 tons at -10F? I'll look at it...

JakeCK

Hot_water_fan said:

The electricity rate is 0.108 kw-hr for the supplier, it is the delivery charge that bumps the price up

Solar looks great vs $.24/kWh!

Just made a down payment on a 14kw dc solar system. 110% offset. Permits are pulled and interconnection has preliminary approval. Hoping to have it installed by the end of the month. Also comes with a service upgrade to 200amps. That has me salivating at the prospect of a 100amp sub in the garage. I'm pricing out insulation/tightening up the building envelope, and investigating replacing gas appliances with heat pump versions. I'm 99% sure the first thing I'll replace will be my 14 year old gas hot water tank. The beautiful thing is a hphw tank will help offset energy consumption from my dehumidifier for 8 months of the year, and ac usage for 4-5 months. 

Consider how bad this summer has been. It will only get worse. Even if our political leaders can't find the balls and political will to act, the international community will. Eventually action will be forced upon us. The days of cheap fossil fuels is going to come to a close real soon. One way or another. I'd rather be ahead of the curve then be caught with my pants around my ankles. 

There is more than one way to skin a cat. Something for the op to consider before he commits to anything. 

boilernewb

@JakeCK I have heard nightmare about people accepting a solar installations on their house and then being forced to do a roof replacement or the longevity of panels being limited... How does your home rate for solar?

JakeCK

If the roof is in such disrepair that it needs to be replaced... It needs to be replaced. I did have to replace the roof on my garage before hand but that wasn't a surprise. I knew that before I even called them, and it needed replaced regardless. Funny story about a family member that loathes spending money. The roof on his house needed replaced. He kept putting it off, patching, sealing, doing what ever he could to not replace it. Eventually the plaster upstairs collapsed right on to his daughters old bed. Luckily she wasn't living there anymore. Does the same kind of s*** with his cars.

But back to the solar panels, it all comes down to hiring a reputable company that installs quality equipment. Like anything else. I have been checking everything they have been telling me, so far I've been happy but they haven't actually been installed yet. I'll let you know. But I will say they seem to be erring on the conservative side of everything. Their estimates for solar generation have been a bit lower than what the online tools have shown for example. Maybe they have access to better shading information, maybe they just don't want to over promise and under deliver. But this is NOT cheap by any measure. I could have paid for a complete boiler and re-plumb of my whole house or installed geothermal for what I'm paying for this. Although the 22% federal credit does takes a bit of the sting off. ROI 12-15 years.

STEVEusaPA

I'd stick with the oil. The smallest triple pass with indirect, or the EK, like I mentioned earlier is the way to go.

Steamhead

Getting back to the original question- I'm familiar with the older Smith 8 series boilers (current ones are rebranded Peerless). They're built like tanks. So if that were my house, the first thing I'd try is down-firing the burner slightly. As long as the stack temperature is above 350° F or so, it should run fine without condensing.

These boilers also run very well with Carlin EZ-Gas burners. Again, as long as the stack temp is within spec, you're fine.

Neither of these should be attempted without the know-how and the use of a digital combustion analyzer.

STEVEusaPA

Downfiring slightly is probably awaste of time. Use slightly less fuel, and less efficient. Firing as recommended, clean heat exchanger, properly tuned is the 'best' you can do here.
Jim Davis has done a tremendous amount of research and teaching about the myths of under firing oil burners.