A Tale of Woe Involving Boilers
The four pulse boilers in the Cross House. They heat water for the radiator system.
The previous owner, Bob, installed the boilers. I am gonna guess at least twenty-five years ago. So, I have old boilers. When I purchased the house in 2014, #3 and #4 (right) did not work. I was able to have #3 repaired but was told that #4 needed to be replaced. I asked how much? “$6500.”
“Do I really need a #4?”
“No.” I liked this answer and decided to ignore #4.
Recently though I noticed that #3 was also not working, which explained why the house could not be warmed as much as was possible a few years previously. I now realize that #3 likely did not work all this winter, and the previous winter.
Modern Air, which has worked on the Cross House since my purchase, came out to look at #3. It needed a service kit. “Which would not be cheap, and might not even be available.”
Today I received a repair quote. For like $700 they can order and install the service kit. “But the boiler may still not work”. Oh. Oh.
S0, spending $700 might prove a bad gamble. And even if it works I would still have 3 ever-aging boilers.
Another option would be to spend almost $19K and have boilers #3 and #4 replaced with one new one (NOTE: the labor rate will be significantly higher than the cost of a boiler.)
But this would mean that I would have one new fantastically expensive new boiler, and two old boilers. Which begs a question: If two boilers are now down how long before the other two die on me? This is THE question.
I also now understand that while 2 boilers will keep the house from freezing, I need a third boiler to keep the house warm on really cold days. Last week, when it was like -7, the inside temperature never topped 43, even though the thermostat was set at 55. A few years ago I was able to get the temperature up to 72.
Thus, I asked for a quote to replace all the boilers with new ones. The quote? About $35K. OK, that was painful to read. It seems though that spending $35K for all new boilers may be more prudent than spending almost $19K on one boiler, and keeping two elderly boilers in place.
With this in mind, I called the bank holding the mortgage on the Cross House and explained the situation. “Can I get the house refinanced to pay for new boilers?”
“We would need to get the house appraised and if the number comes in right, yes, we could do that.”
I felt a tiny bit better.
So, it seems the next step is to move forward with an appraisal. And, it is not bad outside right now, in the high 50s. Winter may, may be over. As such, I do not have to do anything now.
SIDEBAR: What I really lust for is a geothermal system. The quote? $150K. Thus, my lust dissapated.
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I understand that the poor function of the system is clearly due to the boilers, but is there a chance that there is corrosion in the pipes that might be affecting they system’s efficiency to a discernible extent? If so, then removing all of them for replacement might give you a good opportunity to give the system a thorough flushing.
I have a single large boiler for the whole house, (4700 sq feet) steam and it was $21k. If I were in your shoes I’d do it all at once. The newer ones are much more efficient too.
Yes, flush the whole thing out. we just did that in October and it cost a couple thousand but you would not believe the pails of mud that came out of the system. Now it warms up in about 20 minutes versus 45. Huge savings on gas.
Is there room for additional insulation in the building? Especially in the attic?
Isaac, there is thick layer of insulation in the attic floor.
How about air sealing? That made a huge difference on our (much smaller) home.
Ooof, ouch. The downside of owning a glorious, enormous Victorian mansion is that one has to heat and cool a glorious, enormous Victorian mansion, sigh.
Nicole, a classic What Price Beauty? situation!
I’ve seen worse. But yours ain’t no picnic!
I concur on flushing the system when you can. One massive High-Efficiency Boiler may do the trick, but given your building’s size and vulnerability, I would want a second backup boiler. Maybe alternate them every year to extend their lifespan.
This is a penny wise, pound foolish situation.
I think you are wise to replace all of them, (and flush the system), rather than do piecemeal and spit and bandaids to keep them limping along. You said it yourself, they’re at least 25 years old and that makes them old.
I am confident you can get the money from refinancing as you have made a lot of improvements to the house. Repairs and the addition of insulation, bathroom and kitchen. In addition, using the cash out of the refinance for the boilers increases the value of the home. If there is any left over it can be put towards finishing the kitchen. The Cross House is now habitable as it has a bedroom, bathroom, kitchen and heat. Sure there is more work to do but the value of the house has increased.
Keep in mind every year that passes the cost to replace those boilers increases. $6500 per boiler in 2014 and $8750 equivalent per boiler now. That actually isn’t that bad of an increase over 11 years. The new boilers will be more energy efficient so cost less to run. Between the new boilers and the new insulation your heating bill should go down, thus saving you money.
The rule of 12’s is always in play. Expect prices to double about every 12 years….more or less. Scary.
I don’t know why they have 4 boilers for your place. Was it because of the apartment-style set-up you had? Ditch that system.
And who wants to screw you out of 150K for geothermal? Do you have to dig 500 feet through granite for water? I put a high-end system in one of my rental houses (built in 1905) ten years ago. It uses groundwater for the heat transfer liquid. You do not need to pony up a bucket of cash for glycol or whatever overpriced water substitute they seem to be proposing. Drill two water wells, incoming and dump, and you’re set.
My system was $22K (17 net; see below), which included running an entire previously non-existent air handling system for the attic. Plus, we were able to tap into the water line coming to the house for water for the outside yards. Haven’t had an outside water bill for ten years — and I also use it for the properties I own on each side, so those two houses benefit from the free water as well. Happy tenants are good tenants. Who doesn’t like free water for their lawns?
And I finally started using the super-deheater in the summer, so the hot water heating bill on the geo house is practically zero during warm months when the cooling side is in use.
In addition, you do know there is still a tax credit for geosystems, don’t you? It’s pretty generous. On our installation, it was about a 30% tax credit. Our net cost for the entire system was $17K. I don’t think the 30 is still in place but it’s still decent and you can stretch that over a few years as I recall, to recop as much as possible.
You know, those boilers of yours look brand new compared to the single 1940 Honeywell we use in our 1888 Victorian. That will go away when we hook up geo on it next year, but replacement costs for the Honeywell, using a new model of the boiler, have never been estimated to be more than 15K. And that’s for heating 5000 square feet using a hot water radiator system that was installed in 1914. Our Honeywell is two feet wide, four feet long, and 3 feet high. It’s an early version of an on-demand system. No water is stored in the unit; it sits in the supply pipes and radiators until there is a call for heat. As it pumps through the cast-iron jacket around the flame plates, it heats up and goes to the radiators.
The geo setup will still feed the radiators but the gas boiler will be replaced by a geo unit that isn’t much larger than the Honeywell. And we will get air conditioning for the first time (geo gives you both heat and cool). Installing the a/c lines will be a snap due to the abundance of channels in the walls dating back to the coal-fired furnace days. Air conditioning supply will probably add 10K to the cost but that still brings us in well under 30 for the whole system in the house. Digging the wells and installing pumps and electric supply will be another 10-15, but 50K is a whole lot less than what you’re being quoted just for boilers to heat the place.
Hi, David!
I had four boilers because the house is so huge, almost 9,000 square feet.
The boilers would have rarely been ON at the same time. If it was, say 50-degrees outside, one boiler would turn on. Colder? Two boilers. Really cold? Three boilers. And then, as #4 would switch on, #1 would turn off. Thus, the boilers rotated in keeping the house warm, and diminished the “hours’ on each.
This all would have been way less costly than having one massive boiler.
I see the logic in that.
Too bad boilers don’t have the lifespan they used to. I’ve seen 120-year-old boilers chugging away and surprisingly efficient with the coal-to-gas conversions. The boiler in my house was 60 years old. It needed an eye on it, but it was very efficient.
I thought that might have something to do with it. Is it a steam or hot water system? And what is the BTU rating on each boiler?
You mentioned that this was all installed by the previous owner. It sounds like he was trying to use a modified zone system of some sort but I’m not sure how that could’ve worked as a whole-house system. As each boiler comes on, how does the system function as a unit? Are the boilers heating and reheating the same water?
Was there not a way to use one, maybe two, slightly larger boilers and get the same heat output?
The geo system in the house I wrote about has a two-step output. One is basically for the first floor, and Two is for the attic. In the cellar where the air-handler is, I have a damper on the large trunk duct that goes to the attic. No one is up there much because it isn’t technically a living space. The main use is as a nicely-finished work area, and the damper is open just a bit. But there is always some heat/cool on up there because all heat and a/c comes from a single source, the Heart of the Beast in the cellar, and so a little conditioned air goes up there when the One unit is on. We decided to not automate the damper control because the attic is just a bit warmer in summer and a bit cooler in winter naturally and we get more precise control by using personal comfort level as a gauge. We did insulate and air seal the attic using closed cell foam shot into the rafter bays, the gable ends, and such, but to date, I’ve not had to open that lever on the trunk duct to increase the airflow and trigger Step Two. The attic is comfortable enough to work in.
Effectively, then, only One runs in normal operation and Two would kick in only if I “asked” it to. I would then open the damper to the attic and thus increase the volume of air headed that way (along with its heat or a/c). So, One+Two adds heat/cool only because I would increase the amount of space I want to be fully conditioned.
The One+Two thing would be put into action only if it’s either very hot or cold and I feel I need a boost upstairs. The closed cell foam did a fantastic job for us; I can go up there on the coldest of days, like two weeks ago, and it’s comfortable without using Step Two. An intermediate thing I could do in winter before using Step Two would be to open the door from the kitchen to the attic. Warm air rises and it’s enough to add a few degrees in the attic.
A clarification.
I said your cost would be 50 to replace your boilers But it is instead 35, as you noted.
Replacing your boilers for 35 is about what I anticipate spending for a geo conversion at our Victorian. But I will have a much more efficient system than your gas boilers. And I will have a/c and free water in addition to that efficiency.
David, can you point me to any sites/info on doing geo? We have a single unit, gas fired McLean steam boiler. I have no clue how a geo system works to create 212 degree steam. I’m extremely curious.
Not David, but: my understanding is that geo can’t do the temps required for steam. Air to water heat pumps have the same issue. The latter can be two-phase, to get temps up to what a gas boiler hot water system would produce, but they can’t do 212.
Low temp radiant can be efficient and effective but you need enough surface area on the radiators.
Issac (below) is right: steam systems are more of a challenge compared to hot water ones like my Honeywell. But there are such geo systems, one of which is a hybrid. See if you can access these articles.
https://www.supplyht.com/articles/99139-combining-a-geothermal-heat-pump-with-a-boiler#:~:text=Geo%20%2B-,Although%20it's%20possible%20to%20size%20a%20geothermal%20heat%20pump%20to,heat%20pump%20with%20a%20boiler.
https://forum.heatinghelp.com/discussion/143621/can-a-geothermal-system-be-connected-to-a-steam-boiler
Even if the “solution” proved too costly or inefficient due to the particularities of steam, you could use a smaller scale geo set-up to provide heat just for household water (which is now done with gas, I guess?) and perhaps to supply conditioned air for parts of your property, like a basement washroom or workshop. Savings in those small ways might justify the use of geo for you.
I think having someone living in the house will also help with heating costs. It is another inducement to actually get moved in. Let me explain why. A decade or so ago, we experienced an ice storm here, that wiped out all the power poles for a 7 mile stretch. It took ten days to get the power back on. My much smaller Victorian never got below 45 degrees, even though it was in the minuses outside! Victorians have the lovely plaster walls that retain heat, but also they are designed to maximize sunshine in the winter. Those clever overhangs shade the house when the sun is high during summer, but during winter when the sun is lower in the sky, the sun pours in. But, you have to be there to open the drapes first thing in the morning, and close them at night. (I have a cat rescue, so I just have bare windows. So I didn’t even have the insulating value of drapes.)
Here’s a company I just came across that offers a variety of options for heat/air. Some very interesting systems!
https://www.waterfurnace.com/residential/
I would replace 3 and 4 with one boiler. My 83% efficient boiler in my old house was installed in the 1980’s and was still fine in 2023 when I moved.
I was told not to install one of the new small high efficiency boilers to a system with cast iron. I was told that crud in the pipes or radiators would likely block the water passages.
I do understand why they staged multiple boilers to give you better efficiency in the early and late parts of the season. I considered having an electric heat coil added to my central cooling to give me a little heat in the early and late parts of heating season.
I’m curious why folks think having more than one boiler is a good idea (unless the boilers are independent of each other and thus not in use when no one in a unit needs heat). Of course, no one has told us yet whether steam or hot water is the system they are using. A system that stores heated water versus one that heats water as it passes through may have different ways of solving the issue. But I’ve never heard of a house that used more than one boiler. for common heating.
What I mean is, if you heat water in one boiler and the house is still too cold and you fire up a second boiler, don’t you create a system that is inherently inefficient? Does Boiler #1 continue to heat water as Boiler Two kicks in? Has the water in #2 been unheated all this time? If Boiler #1 cools off as #2 is in action, won’t you need to reheat #1? How do the supplies of water in the two boilers mix to actually increase the heat output? On the other hand, with one boiler, ALL the water is heated and retains some heat all the time. When you get cold, you bump the temp and the whole tank gets extra heat, sure, but it also retains much of that extra heat and so needs less input on the next cycle to get the tank back to temp.
My hot water system stores its heated water in the system itself. No water sits in a tank at all. When the system calls for heat, the water in the pipes starts to circulate back to the jacket boiler. Since the water is already warmed, it doesn’t take long to get it up to peak again. After a few runs, the house gets warm as the pipes and radiators work together to put heat into the rooms. For an ancient system, it’s somewhat efficient. Most of the inefficiencies are due to the water heating process itself. The flame is quite large inside the jacket boiler when it is on and heating the water; I’m sure modern units are better at doing that.
Ross’ pipes are inside his walls as I recall, and so the heated pipes don’t do him much good. Both steam and hot water pipes can be out in the open, as it were. They aren’t unattractive but you can fancy things up with decorative screens if you want.
Can’t a system be sized for the entire house when it’s on full blast but be controlled by mixing valves that know how much heat you need/want at a given point? My hot water radiator system has a manifold that you can use to control flow to the separate parts of the house. You can also control output at the radiators by turning the knobs right on the radiators. The idea that the constant on-off of multiple boilers somehow makes everything more efficient? Not happening for me. What am I missing?
You’re ignoring the amount of gas at the burner to fire a large burner vs a smaller one. They’re set up in stages to accommodate the lesser demands of the season. They could be set in on zones if the piping allows. This provides some redundancy in case of a boiler issue. I’m not sure how much sense it makes, but I am friends with someone with a glorious pile or bricks, better than the Cross House, that has multiple boilers.
Thank you, Travis.
Yes, “multiple smaller boilers can be more efficient than one large boiler, especially in large properties or those with varying heat demands. A system with multiple boilers can modulate its output to match the actual heat requirement, improving the turndown ratio (the difference between the maximum and minimum heat output) and saving energy.”
How does the water move through the system? Do the tanks (I guess—I’m still waiting to hear if this is a steam or hot water system) serve as places where, when the second boiler starts up, hot and cold water mix and then go to the building? If so, doesn’t the net heat in the system drop while the cold second tank heats up? And the recovery time for #2 and subsequent boilers will increase due to that cold-hot mix, won’t it?
My main thought can be framed like this: if the entire system (equivalent to the 4 tanks combined) were heated at the same time, it would take a while for the water to come to a static state, right? Lotsa water, lotsa heat to get it warmed. All the water would have the same temp, whatever that was, when it did so.
But unless the system were shut down for a long period, there would be residual heat in that water throughout the system. Then, like with geothermal, there would be a smaller differential between actual heat and desired heat when the thermostat finally called for heat.
Wouldn’t heating this water a second, third, or fourth time become more efficient over time because you’re not starting from scratch with each boiler in its turn. Or would these two ways cancel each other out, so to speak?
If you have what amounts to cold pipes (not yet used in the multi-layer system), once you access that cold water and start to heat it with the second boiler, aren’t you essentially beginning with a cold tank into which you’ll need to dump heat so that the whole system is warm?
Hot water.
Dear David,
If it is, say, 50-degrees outside, I would have one boiler fire up to super-heat water. This small boiler would be vastly less costly than having one very large boiler having to super-heat water – the very definition of overkill.
If the temperature were to drop to, say, 30-degrees, a second boiler would come on, sharing super-heated water with boiler #1.
The boilers are designed to work together, not in isolation.
And so on.
I’m just happy you can work with Modern Air. Travis is such a good guy, and my parents’ radiator system hummed along with his help. I’ll be really interested to see what sort of system he recommends to replace your four-boiler extravaganza.