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Looking for a sanity check regarding oil/propane hot water baseboard heat...

thomase00
thomase00 Member Posts: 21
My chimney is cracked and leaning, my wife and I think the 70's fireplace is ugly, and most masons say it would be better to tear down than rebuild because it is RICULOUSLY oversized. This means I'll need to replace my 34 year old Weil-McLain 566 boiler with a direct vent boiler, OR build a chimney chase for a new double wall steel chimney. Most new oil boilers (with a few exceptions to be noted) would need to be located 25' away from the current unit in order to vent out the leeward side of my house and away from the deck, but based on the estimates I have received so far, it seems that the new chimney route would be significantly more expensive.

Here is some info about the house:

2180 sqft colonial in New England with a 0F design day temperature. There is also a 320 sqft finished basement. 2x4 construction. Mixture of R19 and R30 fiberglass in 925 sqft attic. 330 sqft family room with vaulted ceiling over garage.

Currently have an oil tank and no access to natural gas

Planning to get at least a 120 gallon propane tank for cooking and new fireplace, even bigger if I convert to a propane boiler.

Current chimney is in garage 13' away from the basement where the boiler is, and the clay flue liner is in bad shape, AND my neighbor tore his chimney down years ago for similar reasons.

Blower door test shows 2735 CFM50. Using a really conservative LBL factor of 10, this approximates to a natural infiltration rate of 273CFM.

Weil-McLain 566 is down-fired to 1.0 GPH

I have 3 zones + a 4th for a MS-40 inidirect water heater.

Basement 320 sqft has 15' of baseboard
1st floor 1255 sqft has 76' of baseboard and K84 toekick heater
2nd floor has 925 sqft and 62' of baseboard

Slant-fin program and HVAC-Calc 4.0 both show a design-day loss of 45K BTU. I had to subtract out HVAC-Calc 4.0's estimated inflitration losses and replace with my own calculation based on 68F temperature difference and 273 CFM infiltration. This doesn't include the 320 sqft of basement, but that 15' of baseboard can only put out about 8K BTU max.

Fuel use vs. degree day calculation also shows about 45K heat loss. That's 216 gallons of oil used over a period in the winter with 1626 HDD, with an efficiency of 81%. This extraploates to 55K if you assume -15F outdoors. However, fuel use also accounts for DHW. I hardly ever heat the basement, although this many change if the kids want to hang out there when they get older. Basement walls are NOT insulated, but the finished side is mostly below grade.

I have collected multiple estimates, some for propane and some for oil. All except for one are in the same neighborhood price wise. The one outlier is LESS THAN HALF the cost of anyone else, and this includes burying a 500 gallon propane tank, running the gas line, and fixing my lawn. The owner of the company has been telling me things that fly in the face of everything else that I'm reading. I have an Electrical Engineering degree and I can do math. I kind of feel like I'm being gaslighted (no pun intended).

Some of the things he is saying are (paraphrased):
--------------------------------------------------
"Heat loss calculation is irrelevant after the fact because the baseboard is what it is. I MUST size the boiler to the existing baseboard assuming 520 BTU per foot AND add an extra 20K capacity on top for the indirect. If I go with anything smaller, it won't heat the house."
In other words, the baseboard IS the load. He flat out refuses to install anything smaller than a Bosch Greenstar 131 (propane). A few months ago, the same company wanted to replace my boiler with another oil burning Weil-McLain model WGO-4RD (1.0 GPH firing).

"You always want the boiler capacity to be more than your baseboard can put out because it will wear out faster if it has to run 24/7 to satisfy the thermostat. It's bad for the boiler if it needs to run 24/7 to satisfy worst case demand."

"He is 3rd generation in this family business and was installing systems at the age of 18 (maybe in his 50s now?). He went to school for this. Anyone who says I can go with a smaller boiler doesn't know what they are talking about, and frankly, is an idiot."
When I challenged him on adding capacity for the indirect, noting that it has priority and doesn't run at the same time as the other zones, he said it doesn't matter and that I don't know what I'm talking about. He might have a point if the house actually needed to max out the 90k baseboards with all 3 zones simultaneously in order to maintain temperature, but I'm pretty sure my baseboard is oversized.

"If he needed to do a heat loss calculation (but he doesn't), he'd assume -15F and high winds."
Reading between the lines during our conversation, it seems that in his experience, customer satisfaction correlates with how quickly the thermostat is satisfied. I guess you'll never have customers complaining that they are cold with this approach.

"No one can come close to his price because he installs 100s of systems a year. He has multiple install crews working every day. He doesn't need to make a lot on the install because he will sell me fuel. He owns all the equipment, real estate, and infrastructure and has thousands of fuel customers across 3 states."

"You need extra capacity in case you ever put on an extension."
I think it's unlikely that I'll ever do that, but if I did, it would probably be small and heated/cooled by a ductless mini-split.

"The Bosch is 95% efficient vs. my 81% current boiler, and outdoor reset will get me another 5% increase in efficiency."
I myself am skeptical that a mod-con would actually reach 95% efficiency with the amount of baseboard I have. I think it is oversized, but not enough to get the really low condensing return temperatures.

"He thinks I'd be crazy to go with anyone else at twice the price."

"Energy Kinetics boilers are great products, but you'll hate it when it needs service because repairs cost a FORTUNE." He had this response after I mentioned getting an estimate for an Energy Kinetics system.

----------------------------------

Am I crazy for questioning this guy? Maybe he thinks I won't be happy if I get a smaller boiler and find that the thermostat doesn't rise as quickly.

Everyone else I have talked to has agreed that I should size to my calculated load which is less than pretty much any boiler that I might install. Granted, they aren't doing the calculations themselves and have taken mine at face value, but most agree that 45K to 55K makes sense given the size of the house. If all 3 zones call at once, the supply temperature might settle at something lower than 180F, but I'll be still getting more than enough BTU to meet the demand. I don't need extra capacity for the indirect because it has priority. Even if the capacity of the boiler is less than the max BTU the indirect can accept, it still has much quicker recovery than a stand-alone gas or electric water heater.

I've leaning towards an oil-fired EK 90+ Resolute, primarily because the sidewall venting system allows for a 50' run, which means I don't have to relocate my whole setup. This would be using my existing MS-40 indirect though. I'm not sure what the disadvantages are vs. EK's indirect DHW tank.

Comments

  • Jamie Hall
    Jamie Hall Member Posts: 17,101
    If a deal sounds too good to be true -- it probably is.
    Br. Jamie, osb
    Building superintendent/caretaker, 7200 sq. ft. historic house museum with dependencies in New England
    kcopp
  • Zman
    Zman Member Posts: 6,993
    I don't doubt for a minute that he believes everything he says. His dad and granddad both said so.

    I am still trying to get my head around how the baseboard know what the heat loss for the house is. They just are not that smart.
    You will likely see an efficiency increase. It won't be because the new boiler is running at 95%, it will be because the old boiler was not really 81% and the new boiler is modulating to match the load.

    I would have serious reservations bout the guy and would only go with him if I saw some installations.

    I don't see any errors in your approach to this, you are just dealing with one of those guys that already has everything figured out.

    If you have not done the math on this yet, here is spreadsheet that will compare different fuels and efficiencies quickly.
    "If you can't explain it simply, you don't understand it well enough"
    Albert Einstein
  • thomase00
    thomase00 Member Posts: 21
    Assuming a propane system would be 95% efficient and that oil would be 86% efficient, propane has to be 73% the cost of oil per gallon. It isn't, but depending on the supplier, it might be close. Also, freeing up the space taken up by the oil tank, not having to worry about direct-venting oil, and getting a price break on propane use by other appliances (propane has usage-based pricing tiers) has some value.

    The problem is I know these efficiency numbers are not real world numbers, and I don't know how to go about derating these with any amount of accuracy in order to get to a REAL comparison.
  • thomase00
    thomase00 Member Posts: 21
    Is there any kernel of truth to the arguments he is making? I'm fascinated by how someone can get to a place where they are aggressively defending a position that defies logic and reason.

    Is it as simple as this?

    - Customers will NEVER complain about being cold.
    - If they have an existing system, they might complain if the new system doesn't satisfy the thermostat as quickly.
    - So what if the system cycles more? We will keep it running because the customer has purchased a service contract.
    - It's just not worth it to optimize this. For the piece of mind that comes with a service company that will send out an army of service techs during a blizzard, customers will gladly spend an extra few hundred bucks a year for fuel and not give it a second thought.
  • Wardo
    Wardo Member Posts: 8
    Your situation is similar to where I was some time ago. I went with a Triangle Tube combination boiler & it has worked well.

    A few questions:
    Are you going to stay with an indirect hot water tank due to high hot water demand? Do you have a large tub or multiple showers in use at the same time?
    What is the condition of your oil tank? Did any other bidders point out issues with your current tank, filter, or supply line? How does your homeowners insurance look at heating oil storage and how do they treat oil leak remediation claims?
    Have you factored in the cost of an annual oil furnace cleaning & tune up?

    Your low cost bidder doesn't sound very knowledgeable (or competent). Mod con boilers supply lower temp water over a longer period of time to achieve fuel savings. The bidders should all be aware of how to alter the outdoor reset curve (if possible).

    The Bosch unit mentioned above won't fire lower than 36K BTU. It may not be the best option. Did anyone quote a Navien brand unit? I have no interest in the brand - but Navien offers better turn down ratios - http://wholehousecombi.com. Local support for what I own is spotty. Keep in mind you are limited by what the local contractors offer.

    Let us know how attached to oil you are given that you are committed to a propane tank for cooking & the fireplace. You should at least consider the larger propane tank to keep your option open to use propane for heat/hot water.


  • gschallert
    gschallert Member Posts: 170
    According to the info you provided you have more emitter capacity (30-40%) than your estimated heat loss so a modcon would be well suited for that situation. The modulation + condensing for a large part of the season should get your fuel efficiency well into the 90's. If you are definitely planning on getting propane for cooking and fireplace it makes more sense to go with LP for heating and ditch the oil altogether rather than have two separate fuel sources.
    Bob Bona_4
  • thomase00
    thomase00 Member Posts: 21
    Yes, I have looked at Navien and it looks like the NHB-080 would work well since it modulates down to 8K BTU. I haven't found someone to give me an estimate yet though. I suspect it will be double the low-priced Bosch guy's estimate, NOT including the expense of the propane tank installation.

    What kind of delta-T drop should I expect with the amount of baseboard I have? Does this depend on the circulator flow rate, and if so, how is that determined? I currently have a Taco for each of the 4 zones, but I don't know what the GPM is (they have a range). I'd like to try an estimate how often it would actually run in condensing mode and what the efficiency would be.

    Regarding being attached to oil, my concern is that LP is more expensive per delivered BTU (although maybe only by 25%) and pricing is not transparent. The low price guy is claiming he'll lock me in at almost half the per-gallon cost of a neighbor I have talked to who has a different supplier (even though he owns the tank!). I don't like the idea of having a buried tank that someone else owns because they know I won't want to tear up my lawn and rip it out in order to get a better price from someone else. Another supplier wants to rent me 3 above ground 120 gallon tanks, but that might be an eyesore. Buying the tank adds up-front cost, makes me responsible for maintenance, and based on my neighbor's experience, won't necessarily help me on pricing unless I shop aggressively. I also have heard that some suppliers won't even fill a tank owned by the homeowner.

    All that being said, it would be nice to get a few more cubic feet of storage in the basement after the tank is removed. I wouldn't have to worry about replacing the oil tank in the future. As I already said, I assume I'd get a price break on propane used for other appliances. Also, ALL the new construction in the area has a buried propane tank, so it can't be that crazy of a choice to make. Then again, that might just be because the builder can get away without the expense of a chimney, the potential hassle of direct-venting oil, and he's not the one who will be paying for the fuel.
  • Steamhead
    Steamhead Member Posts: 14,842
    Remember, a chimney has no moving parts involved in exhausting combustion products. A sidewall-vented boiler does, and that means more service issues.

    Also, do you have enough clearance above the maximum recorded snow accumulation in your area so a sidewall vent won't get blocked in a blizzard, which is when you need it most?

    If that were my house, I'd stay with chimney venting. Sure, it might cost a bit more now, but you'll have less service headaches and costs later.
    All Steamed Up, Inc.
    Steam, Vapor & Hot-Water Heating Specialists
    Oil & Gas Burner Service
    Consulting
  • STEVEusaPA
    STEVEusaPA Member Posts: 5,315
    Maybe some of the chimney problems were from under firing your boiler.
    I'd forget the 3rd gen know it all, and find an experienced contractor, and I'd go with the EK.
    steve
  • Wardo
    Wardo Member Posts: 8
    Slant Fin shows base board heat transfer rates for varying water temps on their web site. An ACCA Manual J analysis will give you an idea of a room by room heat loss estimate, and you can divide the total zone heat loss by length of baseboard radiation to see what kind of BTU/foot you need. You can then see what temp supply water "should" work. Air Conditioning Contractors of America sells this literature. Heat loss calcs are an estimate.

    Contractors who size by rules of thumb, square footage, existing equipment capacity, or "x" years of experience are not helping you become efficient. These types of installers are looking for low hanging fruit (uninformed homeowners) to turn a quick buck. Good contractors won't give away the analysis at the quoting stage so the consumer can shop it around. This is just the way it is.

    Your installers should know how to play with the outdoor reset curve to adjust supply water temp. Its a Y = mX + B thing. Some reset curves might be more intricate now, but mine is straight line depreciation type math. For a double E, you should catch on fast.

    I have Grundfos pumps and they now offer smart pumps. I use simple manual 3 speed pumps set on Medium.

    I try for a 20F delta T between supply & return.

    My feeling is you should buy your own tank, and a tank large enough to supply heating & DHW boiler demand. Your challenge is finding a qualified contractor who knows the equipment to supply your DHW demand and to modulate low enough to heat in Fall & Spring.

    My contactor was a seasoned one man shop nearing retirement age but still engaged in the new offerings. Young guys with lots of overhead and large companies will be your high bidders. Ask electricians and other tradespeople for names. Supply houses are hit or miss. Try Navien's or Bosch tech line to see what contractors in your area are certified to install the product you need. They should be able to tell you who has taken the time to come to a tech seminar on the newer product.

    I still don't know what your domestic hot water demand is, so I can understand why a contactor may not devote excess time to your situation.

    As far as price, the units are all very similar. The primary / secondary piping is 1/2 days' work and 10-15 feet of copper. Find the list price of the boiler, double it, and that is your target installed with warranty price including applicable permit(s) not including removal of any old equipment. The propane tank and supply plumbing is another story - I have nothing to offer as I'm a natural gas burner.

    Good luck!
  • thomase00
    thomase00 Member Posts: 21
    edited June 2017
    Regarding my Bosch quote, I'm not questioning the maintenance service his company provides. I have a contract and they clean my old boiler every year, they fixed a failed aquastat on short notice (covered by the contract), and the techs are friendly and seem knowledgeable. They installed an indirect water heater years ago for a good price (although they didn't use a thermostatic mixing valve on the output). I've talked to one of his references and received copies of letters from other happy customers. They all praise the service but say nothing about the technical stuff.

    Should I send him a link to this article? The exchange quoted in this article sounds EXACTLY like my conversation with him (minus the steam stuff):

    https://heatinghelp.com/systems-help-center/dont-size-a-hot-water-boiler-by-measuring-the-radiators/

    On a different topic, how can manufacturers other than Navien get away with offering such low turndown ratios? Bosch is only 4:1, and the 79K unit is only 3:1! Are they trading the additional complexity of a high turndown ratio for efficiency losses due to cycling at the minimum firing rate? Are the cycling efficiency losses on gas/propane less severe than for oil such that you are not giving up much (although if so, why modulate at all)?
  • thomase00
    thomase00 Member Posts: 21
    I've looked at Slant-Fin baseboard ratings and it looks like 150F average temp will be enough to meet demand with a design day heat loss of 45K. For what its worth, working backwards, it looks like when the house was built, the baseboard was sized based on a 35 BTU per square foot rule-of-thumb. The basement baseboard equates to 25 BTU per square foot.

    My max hot water demand is 2 simultaneous showers at 1.75 GPM each, probably mixed down to about 105F at the shower (my indirect tank aquastat is currently set for 125F). I've done the math and arrived at 105K BTUH to sustain a 60F rise at 3.5 GPM indefinitely (8.333 BTU to heat one gallon by 1F). 70K BTUH may not allow 2 simultaneous endless showers, but it should be enough for 2 showers of reasonable length given my 40 gallon storage capacity. 1 endless shower shouldn't be a problem.
  • thomase00
    thomase00 Member Posts: 21
    I have 3' of clearance above the ground which should be fine regarding snow.

    I wouldn't consider a conventional oil power vent, but rather direct vent driven by the burner (Buderus and some others support this). I have a friend with a direct vent Buderus (not power vent) and he has no complaints.

    The EK system doesn't use a conventional power vent. Instead, it looks like there is a draft inducer fan attached right to the boiler itself. So, this is not exactly direct vent, but not a conventional power vent either. I guess it does have moving parts though...
  • thomase00
    thomase00 Member Posts: 21
    One other thing to consider for a mod-con system is that my K84 kickspace heater fan is controlled automatically and only turns on when the temp is 120F or above.
  • hot_rod
    hot_rod Member Posts: 15,037
    It fairly easy to find 10-1 turndown on LP boilers now, as well as ramp delay and other fine tuning functions. If you have multiple small zones these features will help reduce cycling.

    Any way to sleeve that chimney? I much prefer roof venting regardless of the fuel source. They make flexible plastic liners for gas fired equipment to sleeve masonry or B-vent flues..

    Fuel cost vary widely as you know, in my rural area, today, LP is $1.19. I own 3- 500 gallon tanks and have never had a problem with multiple providers filling them over the last 22 years.

    Direct bury 500 gallon tanks are the most common in new homes around here.

    As you mentioned LP can be used for cooking and clothes dryers, bar b cues, etc.

    An accurate load calc, and a design that indicates how low of supply water temperature is possible will help with your choices. Most non condensing equipment requires a 130° return temperature, if your system can run below that temperature for much of the heating season I think an LP mod con is a good choice.

    Keeping in mind most locations see design conditions (lowest outdoor temperature) a small percentage of the year, so modulating and low SWT may play a big part in low temperature equipment selection.
    Bob "hot rod" Rohr
    trainer for Caleffi NA
    Living the hydronic dream
    Bob Bona_4
  • thomase00
    thomase00 Member Posts: 21
    edited June 2017
    This whole thing is motivated by the fact that I want to tear down the chimney. I could go into a long story as to why it needs to come down, but masons that I trust agree this is the right thing to do.

    I could have a new stainless steel chimney with a framed chase for $7K, but this would need to be 7" diameter for the current boiler. If I keep the current over-sized boiler for now, when I eventually get a new boiler, it will most likely want a 6" chimney instead, so I'm getting a new boiler regardless (don't want to do a chimney twice). But why should I spend $$$ on a new boiler AND a new chimney if I can make direct vent work with a new boiler that I am going to need eventually anyway (the current one is 33 years old)? Moving a brand-new boiler setup to the other side of the basement to position it ideally for direct vent seems like a better and cheaper option than building a new chimney. EK boiler can vent 50' away and doesn't even need to be relocated.
  • EBEBRATT-Ed
    EBEBRATT-Ed Member Posts: 10,324
    Go propane. With a 45k heat loss and your firing 140K with oil. A mod con will match the load better and will solve the chimney problem.

    @Steamhead is right about checking your vent height versus the snowline

    And

    Run away from the guy with the lowest price he's an idiot
    Bob Bona_4Zman
  • thomase00
    thomase00 Member Posts: 21
    edited June 2017
    If I go with propane, should I buy or rent the tank? Low price guy says, "no one buys the tank because they rather not be responsible for maintenance. If you want to switch suppliers, the new supplier will buy out the tank."

    If I own and am responsible for maintenance, are there disadvantages to burying it? For example, I've read that I will be responsible for periodically replacing a sacrificial anode in order to prevent corrosion.
  • Zman
    Zman Member Posts: 6,993
    I own my own tank and have buried it. This gives me the advantage of being able to price shop without switching out the tank.
    I have had the seals redone once in 20 years, it was not very expensive.
    Over the long run, I have saved a lot of money that way.
    I would read the details in the rental agreement and make the decision that is best for you.

    The advantage of propane is that if natural gas is brought to your area, the conversion is usually easy. Natural gas is much cheaper than propane.

    Be sure that any new gas lines that are run inside the home are sized for natural gas. Sometimes you need to go up a size over propane because of the energy density of the fuel. Also be sure that the appliance you are buying can be converted.
    "If you can't explain it simply, you don't understand it well enough"
    Albert Einstein
  • thomase00
    thomase00 Member Posts: 21
    I probably won't ever get natural gas. I've pestered the gas company a few times, and although there are 2 different mains both about 1700' away in different directions, there are not enough houses in between to make a business case for it. The gas company says extending the main would have to be on my dime (and whatever neighbors who chip in).

    In one direction there are 5 houses plus the possibly impenetrable barrier of a road crossing over wetlands, stream, and cross drainage (this is probably why the main stopped where it did). In the other direction (the more probable one) there are 10 houses in between, spread out on 1 acre lots. The gas company says we would have to pay $120 per linear foot, which adds up to $200K just to have the main brought to the street in front of my house. Even if I could rally every single homeowner to chip in (I don't even know most of them), it would be split $20K each and that doesn't even include running the line from the street to the house.

    And it sounds like they have a 15 year moratorium on expansion while they work on upgrading existing infrastructure.