View Full Version : Boiler Upgrade or Not if yes high eff or not
03-14-2010, 10:27 AM
We live in Upstate New York and the house we bought a year ago was a ranch built in 1956. It is L shape 3200 sq feet. It has 225 running feet of cast iron baseboard, heated oversized two car garage(blower unit) and an open basement to the garage. Well insulated house but with very large window areas through out the house.
The boiler is the original to the house (53 years old) American Standard 360000 btu input. It runs fine and the HVAC contractors (3) who we have had in for estimates to replace it say it is very well maintained and in good shape.
Domestic hot water heater is 2006 gas fired AO Smith 50 gallon unit.
My wife and I are both in our sixty's and retired so we are not going to be here most likely for the next 30 years. Though we plan to be here as long as our health and the good lord lets us be here.
Question are as follows:
Should we be replacing the boiler or continue to use it till we have a problem?
If we should replace it what should we replace it with and should it include indirect hot water heat?
Contractor one wants to put in HI Efficiency Boiler (Burderus GB142) and keep the current hot water heater.
Contractor two wants to put in HI Efficiency Boiler (Dunkirk Q95 m and indirect hot water)
Contractor three wants to put in an 85% efficent boiler, keep currnt hot water heater and add out side temp reset.
What is the right way to go given our age and the demographics of the house?
03-14-2010, 12:06 PM
A high efficiency modulating condensing will probably save you some money by from the lower temp you can use with your cast iron base board.
Did any of them do a load calc to see what size boiler your house needs?
Depends how old your water heater is as weather to replace it or not.
03-14-2010, 12:15 PM
The hot water heater is 4 years old but has 3 years of use. house was empty for a year.
The furnace is gas fired
Two of the contractors measured each of the rooms and cast iron base boards. They both recommended high eff units 70000 to 200000 btu modulating.
In 1956 houses were not insulated well.From your statement I would assume you had blown in insulation in the walls and added to the attic insulation.
I have to give you high marks for wanting to be prepared,sadly most folks wait till their equipment dies then make a panic judgement.
After reading your statement I would reccomend that you stand pat.If you go ahead with a new boiler it will be a heavy investment and recouping that investment in fuel saving will be a long road.
If after your evaluation you decide that you must upgrade I would say option one is the best course to take.
Another option would be to add outside reset to the existing boilerr you would see a saving with this and it would be a lot smaller investment which you might see a complete payback within 5 years.So that with rechecking your insulation is my best advice.
03-14-2010, 03:48 PM
Must be a bog unit heater in the garage. cause your cast iron baseboard isn't near 200,000
03-14-2010, 04:52 PM
After 53 years I think it's safe to say that your American Standard boiler is closer to the end than the beginning. While it is not necessary at this point to replace it, it sounds like it would be convenient for you and your wife to choose to replace it now. Does that sound better to you rather than waiting for the boiler to make that call in the middle of a cold winter's night and then scrambling for a contractor and available equipment?
As for the choices you've been offered, all could work well for you. Just depends on what you want.
90% boilers are more efficient but perhaps not as much as you think. Their efficiencies rise as the return water temperatures drop, such as for radiant floor heat systems. Sounds like you'll be running higher water temps with the cast-iron baseboard, so your efficiency won't be as high as advertised.
You'll get year-long use out of your new boiler if you also use it as the heat source for an indirect-fired water heater. You'll also get much more hot water out of the indirect water heater than you would out of a standard gas-fired water heater - perhaps more than you really need.
I also like the 90% boilers for their direct-venting: bringing combustion air directly to the unit and then venting the products of combustion directly to the outside through a factory and code approved venting system. With this setup you won't have to worry about combustion air like you do for an atmospheric vented boiler. No more worrying about the old masonry chimney and the problems they can have with condensation, blockage, and back-drafting. Using the indirect water heater wil eliminate the need for separate venting of the old water heater.
The federal tax credit on qualifying boilers is 30% of the installed price (up to $1500), so that will reduce the net price of a 90% boiler.
Talk to your contractor. He should be able to go into more detail than I could with these bullet points. Hope this helps.
03-14-2010, 04:56 PM
I would guess your boiler is 5 times over sized. Big waste of fuel. Rip it out the first sunny day and replace. A good 85% or mod/con is good with OD reset with either decision. One you know the heat loss and the connected load (radiation) it will be easier to answer this question. You do not have enough information now to answer. The blanket answer of using will save fuel is not untrue but may not be the best $$ investment due to life cycle costs. Again you need to know the heat loss and amount of radiation to determine water temperatures. The difference of operation between the two could be less than 5%.
For more heat loss info see link and click on heat loss menu and see FAQ
03-15-2010, 09:31 AM
To all we greatly appreciate the help. We will most likely replace the boiler as we plan some time each winter to visit family/grandchildren. We will have the freeze alarm installed and the house will be checked each day while we are gone.
We will feel more comfortable with the new boiler.
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