HE Stainless Steel vs Cast iron Boiler

Bio

Which of the two would last longer?, whats their life expectancy given that they are properly maintain

Robert O'Brien

Here's

a 80+ year old CI gravity HW boiler still working but is it really doing anybody any favor? To answer your question,IMO CI will outlive SS but if SS lasts long enough to return the incremental cost difference,who cares?

Bio

Who cares??

The paying customer, who else. the ones that keep you in business, it was just a simple question and I was only looking for comparisons for a friend, you know pros/cons, who cares....

The Steam Whisperer (Formerly Boilerpro)

Besides the heat exchanger..

there's a few other things to consider.  I agree, cast iron will likely last at least 50% longer than SS. 

Also, to consider:

How much does it cost to maintain?

How often is the boiler going to need repairs?

When repairs are needed, will the parts likely be on hand?

How long will parts be available?

How much electricity does the SS heat exchanger boiler use versus the CI?



When you begin to consider all these other parasitic costs, a "high efficiency" boiler is not so efficient and will probably have much higher average operating costs than you might expect. 



My current high efficiency boiler running with a 50,000 btu/hr peak load uses about $30.00 of electricity a month and this boiler only requires a single pump.  My CI sectional boiler in another home with a similar heat loss is using  a whole lot less.  The whole home's elec bill is only about $35.00/month.  Both systems are using little 85 watt pumps, but the High efficiency boiler has a draft fan, condensate pump and lots of electronics that draw a bunch more power.

Energy Professionals have been trying to get electrical usage taken into account in government efficiency ratings since at least the early 90's  and have been unsuccessful.  Probably the main reason is the influence of the forced air  industry.  If electrical use is added to the efficiency equation, the efficiency rating of your typical 92% furnaces would drop about 7%.   Hot water boilers a point or two for CI, more for 90%+ models, and typical residential gas steam boilers would be virtually unaffected.

Robert O'Brien

Electrical consumption

A 95 watt pump running 24/7 uses 69 Kwh per month or $10.64 at the average Chicago rate of 15.3c per Kwh.