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Questions about baseboard hot water system installation

newguy101
newguy101 Member Posts: 22
edited March 2020 in THE MAIN WALL
Hi,

I live in Southeastern CT in a 2,500 sqft Colonial built in 1985 and heated by a combination of electric baseboards and a wood stove. My wife and I have lived in the house for 3 years. We love the wood stove, but not the work of cutting/splitting/stacking wood – at least not the amount of work it takes to support the stove for full-time heat. As a result, we are planning on upgrading our heating system.
I have considered a forced air system, a hydro air system, ductless minisplits, and a baseboard hot water system. We have settled on a baseboard hot water system with a propane boiler (natural gas is not available).

I have a few questions for you guys:

1. Most importantly – do any of you service Southeastern CT? I have met with a few contractors recently, and have been disappointed in some of the things they have told me, which seem verifiably false (hydro air apparently is the best system there is for allergies – much better than forced air, ductless minisplits don’t lose any efficiency as it gets colder). It feels like they are just telling me stuff they think I might want to hear, in order to sell me on the system they want to install. I have spent a few weeks reading stuff on these forums, and it seems like there are really knowledgeable people on here. So if any of you service SE CT, please let me know!

2. Can you give me a very rough estimate (+/- 5k) for what a baseboard hot water install should cost? I am willing to do any work possible myself to bring down the cost (e.g. removing the old electric baseboards, drywalling, etc). I am hoping for something in the range of $, but I’m not sure if that will be possible.

3. What is the best way to make a boiler work most efficiently in tandem with a wood stove? I roughly understand the idea of a modulating condensing boiler equipped with outdoor reset. If I understand correctly, when it is warmer, the outdoor reset tells the boiler to use lower temperature water, and that keeps the boiler in condensing mode. When it is warmer, the outdoor reset tells the boiler to use hotter water to make sure the house stays warm. Let’s say that my house needs 60k BTUs on a 20 degree day. Because it’s fairly cold out, the outdoor reset is going to tell the boiler to send pretty hot water to the system. And that will work out great if I don’t have the stove running, and if the system is well sized. However, if the stove is running and putting out say 30k BTUs, then the house will be warmer than the system thinks it should be, and so the return water will be warmer than expected. Is there a way for me to manually adjust the temperature curve based on whether or not I am running the stove? Does this question even make sense?

Comments

  • Jamie Hall
    Jamie Hall Member Posts: 23,160
    My own opinion -- and others will vary -- is that trying to get a mod/con to play nice with a wood stove is a very dubious proposition. Yes, you gain efficiency with a nicely set up mod/con with outdoor reset, but... as you have surmised, it doesn't know about the wood stove. Again my own opinion, but I think you would be much better served by getting a much simpler, easier to maintain, conventional cast iron hot water boiler -- and control it with a conventional, easy to maintain, thermostat. Lower first cost. Lower maintenance cost. Probably longer life. And the loss in efficiency is not that great -- 85% or so for the conventional, 94% if well set up for the mod/con.

    Price... we just don't talk about price on the Wall. It's much too variable, and not fair. Perhaps someone will PM you...

    On selecting the boiler and baseboard. Step one, step two, and step three are to calculate the actual heating load of your house. If you go here: https://www.slantfin.com/slantfin-heat-loss-calculator/ you will find, at the bottom of the window, the text "click here" and it will take you to the calculator. It's do it yourself, easy, and accurate. It will also give you the baseboard required for each room. Handy.

    Now... servicing southeast Connecticut. I honestly don't know of anyone on the Wall that does. Perhaps someone will know.
    Br. Jamie, osb
    Building superintendent/caretaker, 7200 sq. ft. historic house museum with dependencies in New England
  • EdTheHeaterMan
    EdTheHeaterMan Member Posts: 7,713
    edited March 2020
    Mod-cond boiler at the retail installed cost will take up most of your budget leaving very little to pay for the baseboard radiators.
    we don't usually talk prices on the WALL.

    If you select a standard 80-85% Cast iron boiler or steel boiler your cost will be lower leaving more for the baseboard.

    Oil heat may be less expensive to operate than Propane, but the more efficient (80 to 85%) oil boilers cost more upfront than the 80 to 85% gas boilers (on average).

    By using the SlantFin heat loss mentioned above you can get the proper baseboard needed for each room... just remember that you may not be able to have one continuous loop. You may need 2 or 3 loops (maximum of about 60 ft of fin per loop) see the following information http://media.blueridgecompany.com/documents/ZoningMadeEasy.pdf
    look at the last page for pipe sizing rules of thumb.

    Installing your own baseboard radiators will save big $$$. You just need to have a good design so you have a good outcome.

    As far as controlling the system with a wood stove and LP gas heat as a backup... the simplest way is to set your thermostat at 65° and let the wood stove heat the home to 70° or above, when the stove does not keep up the LP boiler will kick in.

    If you set up more than one zone, the zones furthest from the woodstove will need boiler heat sooner, the zones closest to the woodstove will operate less often.

    This is assuming the woodstove does not have a water jacket. If your woodstove makes hot water also, let me know and I can show you a control setup to integrate the woodstove hot water with the LP Boiler hot water to heat the baseboards.
    Edward F Young. Retired HVAC ContractorSpecialized in Residential Oil Burner and Hydronics
  • EBEBRATT-Ed
    EBEBRATT-Ed Member Posts: 15,452
    @newguy101

    Fortunately or unfortunately we don't talk price here. As @Jamie Hall mentioned an accurate heat loss is the first step. You contractor should do this but most don't so you should do your own even if only to check against you contractor.

    Your 60k heat loss guess is probably in the ball park.

    There has been and continues to be a big debate about mod cons versus cast iron boilers. Mod cons are great, nice and quiet, and the modulating fire is a big asset. They require yearly service by someone that really knows the equipment, parts are $$$ and sometimes not readily available. It would be common to wait 2-3 days for a blower motor or other part. Longevity has to do with water quality and if it is serviced on a regular basis.

    Cast iron is less expensive to install and the fire does not modulate. Service isn't needed as often, parts more available, and it's easier to find a tech who can service it.

    If you go mod con design your baseboard for 130 degree water

    Cast iron I would use 155 to keep the return water above 130 to prevent condensation.

    With a modcon you want the boiler to condense as much as possible and the water temp as low as possible.

    I assume you have electric for domestic hot water you can use a indirect hot water tank with either boiler.

    a mod con system will require more baseboard footage if you run with a lower water temp which you should do.

    I am old like @Jamie Hall so we lean in the cast iron direction.

    I don't know of any contractors down that way. What city are you in?



  • Alan Welch
    Alan Welch Member Posts: 266
    Have you considered the possibility of installing hydro air for the upper level and baseboard for the lower? Then you could have air conditioning upstairs where you need it most. I have a split level done that way, and the lower level stays fairly cool without ac ( especially since it is partially below grade) and some cooler air settles down as well. No need for window units, and might be less disruptive to install if you can install it in the attic.
    MikeL_2
  • SuperTech
    SuperTech Member Posts: 2,137
    I'm also someone who would rather see a cast iron boiler installed over a mod con. In my opinion reliability, longevity and ease of service trumps efficiency every time.
    I would also consider cast iron radiators or baseboards over fin tube baseboards. The boiler will cycle less often and the home will be more comfortable. Radiant flooring and panel radiators are also very attractive options. Mini splits are nice for efficiency, but I have found every brand of them seem to grow some sort of mold inside of them on the blower wheels. That can't be good for indoor air quality.
  • hot_rod
    hot_rod Member Posts: 22,018
    I'm old too, but I will take the other side of the discussion and points for considering a mod con.

    First as others have suggested a detailed heat loss. Then spend $$ to lower that heat load as much as possible. The could be as simple as 50 bucks worth of spray foam. A 1985 vintage would certainly have upgrade potential. The money spent tightening up your home will pay back for the life of the home.

    A blower door test would tell a story also, check to see if any incentives in your area help with these costs.

    www.dsireusa.org, click on your state for any incentive $$

    Then I would size the heat emitters to cover the load at 120° supply water on a design day!

    Now you have a future proofed system. IF a time comes and "they" force you to go fossil free you have an easy switch to a heat pump or other yet un-discovered technology perhaps.

    I would suggest this approach regardless of the heat source you chose, spend the bucks on the emitters that allow the lowest operating temperature.

    All mechanical systems should be checked yearly in my opinion, catch problems before they turn into bigger problems. Like an oil change in your vehicle.

    No question high tech, high efficiency equipment has more moving parts and potential for more to go wrong. Look under the hood of a new vehicle!

    I have owned and my customers also, 15- 20 year old mod cons that have not required expensive repairs, in my case 0 repairs in 15 years of run time.

    I have had a wood stove in every home I have built and lived in, it is an inter-active hobby, manual control is required to have it get along with a central heating system. Like feeding it fuel if nothing else :)

    Some thoughts here
    https://www.caleffi.com/sites/default/files/file/idronics_25_na.pdf
    Bob "hot rod" Rohr
    trainer for Caleffi NA
    Living the hydronic dream
    Grallert
  • newguy101
    newguy101 Member Posts: 22
    First of all, thanks everyone for the good and thoughtful advice. I will try to address everyone's responses.
  • newguy101
    newguy101 Member Posts: 22

    My own opinion -- and others will vary -- is that trying to get a mod/con to play nice with a wood stove is a very dubious proposition. Yes, you gain efficiency with a nicely set up mod/con with outdoor reset, but... as you have surmised, it doesn't know about the wood stove. Again my own opinion, but I think you would be much better served by getting a much simpler, easier to maintain, conventional cast iron hot water boiler -- and control it with a conventional, easy to maintain, thermostat. Lower first cost. Lower maintenance cost. Probably longer life. And the loss in efficiency is not that great -- 85% or so for the conventional, 94% if well set up for the mod/con.

    What you are saying makes sense to me. As a rule, I like things that are simple. Usually when a design results in a relatively small performance upgrade at the cost of simplicity, the tradeoff doesn't seem to be worth it.

    I was leaning towards mod/con only because the one contractor I have talked to so far that I liked (he was incredibly thorough, gave me long, detailed, insightful answers) only installs them.

  • newguy101
    newguy101 Member Posts: 22

    Price... we just don't talk about price on the Wall. It's much too variable, and not fair. Perhaps someone will PM you...

    I understand. Let me know if this question is out of bounds - I just got a quote for a mod con system (Viessman Vitodens 100 with outdoor reset) that was for $X. Can you give me an idea how much less than $X it would be for a conventional cast iron boiler?

    I am just wondering if the price is $1k or $5k different, on average. The price for the mod con system was out of my range.

  • newguy101
    newguy101 Member Posts: 22


    On selecting the boiler and baseboard. Step one, step two, and step three are to calculate the actual heating load of your house. If you go here: https://www.slantfin.com/slantfin-heat-loss-calculator/ you will find, at the bottom of the window, the text "click here" and it will take you to the calculator. It's do it yourself, easy, and accurate. It will also give you the baseboard required for each room. Handy.

    I will do this, thank you.

  • newguy101
    newguy101 Member Posts: 22


    Installing your own baseboard radiators will save big $$$. You just need to have a good design so you have a good outcome.

    How difficult is this? I have pretty average homeowner skills. Nothing special, but I am also not clueless. Would a contractor be willing to install a boiler if I had installed the radiators myself?

  • newguy101
    newguy101 Member Posts: 22


    As far as controlling the system with a wood stove and LP gas heat as a backup... the simplest way is to set your thermostat at 65° and let the wood stove heat the home to 70° or above, when the stove does not keep up the LP boiler will kick in.

    If you set up more than one zone, the zones furthest from the woodstove will need boiler heat sooner, the zones closest to the woodstove will operate less often.

    This is assuming the woodstove does not have a water jacket. If your woodstove makes hot water also, let me know and I can show you a control setup to integrate the woodstove hot water with the LP Boiler hot water to heat the baseboards.

    Thanks for the hot water baseboard/wood stove running tips.

    Unfortunately my stove does not make hot water.

  • newguy101
    newguy101 Member Posts: 22



    If you go mod con design your baseboard for 130 degree water

    Cast iron I would use 155 to keep the return water above 130 to prevent condensation.

    With a modcon you want the boiler to condense as much as possible and the water temp as low as possible.

    I assume you have electric for domestic hot water you can use a indirect hot water tank with either boiler.

    a mod con system will require more baseboard footage if you run with a lower water temp which you should do.

    I am old like @Jamie Hall so we lean in the cast iron direction.

    I don't know of any contractors down that way. What city are you in?

    Thanks for the tips on water temps.

    I currently have a propane fired heater for DHW.

    I live in East Lyme, CT

  • newguy101
    newguy101 Member Posts: 22

    Have you considered the possibility of installing hydro air for the upper level and baseboard for the lower? Then you could have air conditioning upstairs where you need it most. I have a split level done that way, and the lower level stays fairly cool without ac ( especially since it is partially below grade) and some cooler air settles down as well. No need for window units, and might be less disruptive to install if you can install it in the attic.

    I like the idea. Unfortunately I don't think I have the money.
  • DYI
    DYI Member Posts: 12
    The previous house I owned was heated primarily with a wood stove because the old forced-air NG furnace was terrible for comfort and expensive to operate. I installed a Triangle Tube combi boiler with Runtal radiant panels (sometimes referred to as baseboards depending on size and shape).

    To solve the problem of wood-to-radiant changeover, we installed a thermostatic valve (Danfoss in our case) on the panel in each room. When the wood stove was used the the valves on the panels in the warm rooms near the stove shut the flow of hot water to the panels. The rooms farthest from the stove continued to be heated with the radiant panels. It worked perfectly.
  • newguy101
    newguy101 Member Posts: 22
    hot_rod said:

    I'm old too, but I will take the other side of the discussion and points for considering a mod con.

    First as others have suggested a detailed heat loss. Then spend $$ to lower that heat load as much as possible. The could be as simple as 50 bucks worth of spray foam. A 1985 vintage would certainly have upgrade potential. The money spent tightening up your home will pay back for the life of the home.

    A blower door test would tell a story also, check to see if any incentives in your area help with these costs.

    www.dsireusa.org, click on your state for any incentive $$

    Then I would size the heat emitters to cover the load at 120° supply water on a design day!

    Now you have a future proofed system. IF a time comes and "they" force you to go fossil free you have an easy switch to a heat pump or other yet un-discovered technology perhaps.

    I would suggest this approach regardless of the heat source you chose, spend the bucks on the emitters that allow the lowest operating temperature.

    All mechanical systems should be checked yearly in my opinion, catch problems before they turn into bigger problems. Like an oil change in your vehicle.

    No question high tech, high efficiency equipment has more moving parts and potential for more to go wrong. Look under the hood of a new vehicle!

    I have owned and my customers also, 15- 20 year old mod cons that have not required expensive repairs, in my case 0 repairs in 15 years of run time.

    I have had a wood stove in every home I have built and lived in, it is an inter-active hobby, manual control is required to have it get along with a central heating system. Like feeding it fuel if nothing else :)

    Some thoughts here
    https://www.caleffi.com/sites/default/files/file/idronics_25_na.pdf

    Thank you for the tips. I got a energy survey when we moved into the house 3 years ago. A blower door test was included. The contractor who performed the test said that our house is apparently tight enough that if he made it any tighter, it would be too tight. This is consistent with my experience running the wood stove - we are able to use a single stove in one room of the house to heat the whole house, with reasonably consistent temperatures on the first floor at least, until it gets pretty cold out.


  • Brewbeer
    Brewbeer Member Posts: 616
    newguy101 said:


    Installing your own baseboard radiators will save big $$$. You just need to have a good design so you have a good outcome.

    How difficult is this? I have pretty average homeowner skills. Nothing special, but I am also not clueless. Would a contractor be willing to install a boiler if I had installed the radiators myself?

    I installed radiators and piping back to the boiler location, and retained a contractor (thanks @Charlie from wmass !) to install and commission the boiler. If you go this route, rinse every run, connect them together, pressurize with air, attach a gauge and valve and watch for leaks over time. If you can demonstrate your install holds air pressure over time, you can feel confident it will not leak water.
    Hydronics inspired homeowner with self-designed high efficiency low temperature baseboard system and professionally installed mod-con boiler with indirect DHW. My system design thread: http://forum.heatinghelp.com/discussion/154385
    System Photo: https://us.v-cdn.net/5021738/uploads/FileUpload/79/451e1f19a1e5b345e0951fbe1ff6ca.jpg
    newguy101
  • newguy101
    newguy101 Member Posts: 22
    Are there conventional boilers that can vent out a side wall instead of a chimney? My impression was that there were not, but if I read Sections 3a-3f of this manual correctly: https://www.weil-mclain.com/sites/default/files/field-file/CGi Series 3 Boiler Manual 1016 Web Version - Starting CP7531680.pdf

    it seems like there are conventional boilers which can vent out a side wall?
  • Charlie from wmass
    Charlie from wmass Member Posts: 4,318
    @newguy101 why would you want to?
    Cost is what you spend , value is what you get.

    cell # 413-841-6726
    https://heatinghelp.com/find-a-contractor/detail/charles-garrity-plumbing-and-heating
    mattmia2SuperTech
  • mattmia2
    mattmia2 Member Posts: 9,572
    There are ones that can or can have a power venter added. Not the greatest ideas if you already have a chimney available or can reasonably add a conventional vent out the roof.
  • HVACNUT
    HVACNUT Member Posts: 5,803
    > @newguy101 said:
    > Are there conventional boilers that can vent out a side wall instead of a chimney? My impression was that there were not, but if I read Sections 3a-3f of this manual correctly: https://www.weil-mclain.com/sites/default/files/field-file/CGi Series 3 Boiler Manual 1016 Web Version - Starting CP7531680.pdf
    >
    > it seems like there are conventional boilers which can vent out a side wall?

    Of course you can. Direct vent or power vent.
    I'm not a fan of power venting.
  • newguy101
    newguy101 Member Posts: 22
    edited March 2020

    @newguy101 why would you want to?

    Good question! I got a quote for a system installation with a mod con boiler (Viessman Vitodens) that was $. This is out of my range.

    I am hoping to be able to get something installed for ~$ because 1. That is the money I have budgeted for the project (for various reasons it would be hard to add to that budget for several years), and 2. As the cost gets into the $ range, it becomes pretty hard for me to justify.

    Based on my calculations (which of course are just a swag), a system with a 95% efficient boiler will save me $970-1880/yr, and an 85% efficient boiler would save me $790-1690/yr.
    A 95% efficient mod con that costs $ for the installation would take 15.5 yrs to pay off (using the average expected savings), although that doesn’t count any payments towards upkeep. My understanding is that I’ll have to spend a few hundred/yr for a cleaning.

    An 85% efficient boiler and system that costs $ (I got a verbal SWAG quote for this amount for a conventional boiler) , would take 13 years to pay off (using the average expected savings). This number also doesn’t include an estimate of costs for upkeep.

    In addition to a quicker payoff, my understanding is that the conventional boiler may not need cleaning as frequently, has fewer “high tech” parts that could break, and likely will last longer (no guarantee of course).

    The bottom-line though is that I don’t have $ to spend, and I want to add the system this year. If there was a massive difference in savings (e.g. if the mod con would save me twice as much per year), I would consider either financing the difference or waiting 2 years to save up the remainder. Since this isn’t the case, and since there is even the possibility that the mod con will cost me more due to equipment failure issues (not saying this is likely, but complexity does add risk), I am leaning pretty strongly towards a conventional boiler.
  • pecmsg
    pecmsg Member Posts: 4,775
    edited March 2020
    If your interested in Saving money on fuel usage then tighten the envelope. That $ unit now drops to $. that's a 30% savings right there!

    Run the heat loss #'s with the structure as is and again with better Best windows, doors, insulation. Simple things like weather striping, calking, sealing holes all add up.

    Then find a "Qualified" contractor that finances!
  • Erin Holohan Haskell
    Erin Holohan Haskell Member, Moderator, Administrator Posts: 2,276
    Please note that we can't discuss pricing on this forum (site rules) for a bunch of reasons - prices vary depending on job specifics and mentions of pricing could lead to illegal price fixing. We've removed all mentions of price here. Thank you!
    President
    HeatingHelp.com
  • newguy101
    newguy101 Member Posts: 22

    Please note that we can't discuss pricing on this forum (site rules) for a bunch of reasons - prices vary depending on job specifics and mentions of pricing could lead to illegal price fixing. We've removed all mentions of price here. Thank you!

    Sorry for breaking the rules! I will make sure to comply going forward.
    Erin Holohan Haskell
  • newguy101
    newguy101 Member Posts: 22
    Does anyone have any thoughts on the Weil-McClain AB-120C Combi boiler?

    I just got a quote for a system with this boiler. It seems like it has the same functionality as the Viessmann that I also got a quote on.
  • delta T
    delta T Member Posts: 884
    At the end of the day, what matters much, much more than brand, is the installation.

    Most modcons on the market today use the same few heat exchangers, the controls are different, but the guts of the boiler are by and large the same or at least close enough.

    What you need is a quality installation, sized correctly, piped according to the manual, and above all someone local to you that has repair parts. If you find an installer that has his or her preferred brand, it is likely because they have undergone factory training on that brand and have a local supplier that stocks repair parts for that brand.

    Please don't get hung up on internet reviews of boilers, it is very likely that whatever that person is dissatisfied with is either a poor installation, or lack of local repair parts.
    newguy101here_to_learn
  • mattmia2
    mattmia2 Member Posts: 9,572
    Some are aluminum. You need to be especualli y careful with water chemistry in those. If your water has a lot of chloride you need to make sure you pick components that are compatible or treat it with stainless.
    BillyO
  • newguy101
    newguy101 Member Posts: 22
    mattmia2 said:

    Some are aluminum. You need to be especualli y careful with water chemistry in those. If your water has a lot of chloride you need to make sure you pick components that are compatible or treat it with stainless.

    From what I have read online, the heat exchanger is a "single tube, large diameter, ASME certified 316L Stainless Steel heat exchanger".
  • newguy101
    newguy101 Member Posts: 22
    delta T said:

    At the end of the day, what matters much, much more than brand, is the installation.

    Most modcons on the market today use the same few heat exchangers, the controls are different, but the guts of the boiler are by and large the same or at least close enough.

    What you need is a quality installation, sized correctly, piped according to the manual, and above all someone local to you that has repair parts. If you find an installer that has his or her preferred brand, it is likely because they have undergone factory training on that brand and have a local supplier that stocks repair parts for that brand.

    Please don't get hung up on internet reviews of boilers, it is very likely that whatever that person is dissatisfied with is either a poor installation, or lack of local repair parts.

    Thanks for the tips. The guy who gave me this quote seemed very knowledgeable. I found him on Weil-McClain's website, so I think he has experience with the brand.

    I have no experience with hydronic systems, but I am a mechanical engineer and have been reading up on them in the past few weeks. I am going to try to design the system myself on the side, just to give myself peace of mind that the contractor is in the right ballpark.

    The only thing holding me back from accepting his quote right now is this stupid virus - it has kind of created some financial uncertainty for my family right now.
  • mattmia2
    mattmia2 Member Posts: 9,572
    If you want to read about hydronic theory, this is essentially a textbook in a series of articles:
    https://www.caleffi.com/usa/en-us/technical-magazine
    delta T