LONG: Expected lifespan of a new condensing boiler?
We have to replace our failed Lennox CompleteHeat water heater that heats the entire house with 2 airhandler units and 3 zone in-floor radiant heating. The water heater also provided DHW. It was a 150K BTU unit which we think was over sized. We ran the water heater with 120F water temperature for years without any issues. We dropped the temp to give the failing Lennox increased life span :) The airhandler was fine at 120F even though the plumbers said it should be at 140F for comfort. (Never needed it)
The Lennox unit is dead. At this point, we have to decide how to replace this thing. When we initially got this, we were told that it would last 20 years. It lasted only 10 with multiple service calls.
We are being told that condensing boilers are replacement options and it will last 20 plus years. The reviews/articles I am reading from England (they have been used in Europe for decades) say that these boilers will last 10 to 15, not 20 years. I am inclined to go with shorter life expectancy, not the longer one being told by the local HVAC plumbers.
We have to use a side vent due to the house limitation. Chimney flue is not an option. I can't go with the cast iron conventional boiler at this point because of that.
are all viable options. Whatever we chose, the labor cost of rerouting plumbing will be about 3 days of labor with 2 guys working plus parts(pumps, expansion tanks etc) coming in at $6000 to $20,000 total bid.
My biggest concern is NOT energy efficiency since our energy bill is less than $1500 for the entire winter. (FWIW, the house is 68F or warmer with the gas fireplace running intermittantly and 2 1500W electric heaters placed in the house without any heat for about a week.)
My biggest concern is the longevity of the system with cost effective maintenance with the least initial up front investment. My analysis tells me that whatever system I go with, I will have a replacement cost in about 5 to 15 years, depending on the system. I will be extremely lucky to get beyond 15 years.
Those experts out theres, help me with the analysis.
There are couple contractors we elimated due to lack of 'good experience'. Everything I read tells me that the selection of contractors are more important than the selection of products.
How do you create a system so that when we swap out the boiler/heater next time, we minimize the labor cost?
Will the next system be a complete plumbing rebuld again?
What is a typical life span of a tankless water heater used to heat a house? (many are used in the city as such. Plumbers are saying 10 years. Is that true?) Are we really talking 5 years with a tankless?