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Need new boiler and possibly water heater

Trigger Member Posts: 4
Our 22 year old boiler is needing some work. Several things wrong with it.

Talked to HVAC company today about replacing. Recommendation is Viessman 125000 Btu boiler. Cost is about 50% more than comparable American brand (Lennox). Up to 98% efficiency. O

Also have bid on stainless water tank that runs off boiler - brand is HTP. Current water heater is 22 year old as well - traditional tank type.

We have baseboard hot water heat. 3 zones. Current boiler has difficulty keeping up on extreme cold days (multiple days) but ok rest of time.

I've read lots of stuff online about the viessman. Looks like needs to be installed correctly. I'm looking for opinions on quality of this manufacturer and if it is worth additional money. As I said, I can do the math on efficiency differences. More interested in overall quality comparison. And ease of service.

Thanks much

Math is easy.


  • Tim McElwain
    Tim McElwain Member Posts: 4,588
    Did the HVAC company do a heat loss

    on the house? What kind of radiation do you have, is it all finned tube baseboard? What Model of Viessmann are they offering?
  • HomeOwner1
    HomeOwner1 Member Posts: 134
    Combi systems are also an option

    We have a combi in our home, does a nice job and is efficient.

    Triangle Tube, Navien, and others are out there. The hot water needs dictate the size of these units and see if your heating load falls into their efficient turn down area.

    Could potentially save you some money, save space and make things a bit more simply as far as installation goes.

    Calculating the heat loss is always a good idea to get an idea of what size unit your home really needs. We had a previous way oversized boiler which results in short and inefficient operation cycles.

    Good Luck.
  • Trigger
    Trigger Member Posts: 4

    We have fin tube radiant heat. Can't recall the model of boiler - he was quite confident the 125000 Btu size was correct. Pretty compact unit. Will check model when I get home.
  • SWEI
    SWEI Member Posts: 7,356
    Where are you located?

    and how large is the house?
  • Trigger
    Trigger Member Posts: 4
    House size

    Main floor is about 2400.

    Unfinished basement another 1600
  • Trigger
    Trigger Member Posts: 4

    The boiler model is one of the small wall mounted units. Not sure of the exact model number. But very compact, about 36" high and 20" wide.

    No sure if that helps.
  • SWEI
    SWEI Member Posts: 7,356
    edited October 2013
    He was

    "quite confident the 125000 Btu size was correct"

    ..and almost certainly wrong on that count.  125k firing rate on an 80% boiler would imply a load of about 42 BTUs per square foot.  How leaky is your house?  That same firing rate on a good mod/con would heat a load of 50 BTUs per square foot.

    Find a contractor who can do a proper heat loss calculation.
This discussion has been closed.