Non-Condensing Boiler Questions

[DorkyJen492]

My home's gas water boiler broke after 30 years (original) and am looking to replace it. I noticed that I have two options: condensing (+90% AFUE) and non-condensing (~80% AFUE) boiler. I am leaning towards getting a non-condensing boiler because:

• Non-condensing boiler is cheaper to purchase and install
• Non-condensing boiler is less complex (minimal computer technology, less parts) so therefore would be cheaper to maintain and have a longer life-span
• Condensing boiler will save ~20% on my gas bill (~$300 savings annually). Cost of condensing boiler and installation is ~$4500 more then a non-condensing boiler, which is a 15 year payback. I'm not confident that the condensing boiler will last that long.

My questions are:

1. My local Home Depot, Rona, and Lowe's doesn't sell non-condensing boilers. Will it be difficult to find parts to fix a non-condensing boiler within the next 30 years?
2. I turn the heat on for only 4 months of the year. Does this damage the boiler in any way as the system sits idle for most of the year?
3. What should I be looking for in between different non-condensing boiler? Are there certain features I should be looking for? Should I be looking for an stainless steel heat exchanger?

 

[Fitter30]

80% boiler are either cast iron or steel most have only a one stage burner thus no turn down. Boiler killer return water under 135* ,lack of water treatment and leaks adding fresh water.
Condensing boilers 95% efficient when return water is under 130*f 86% above 130*f. Turn down ratio 10-1 125,000 btu will modulate down to 12.5k. boiler piped with outside air will help with infiltration. Reset control will work with either boiler but a condensing will modulate down and track temperature change better. Boiler killer lack of water treatment and leaks adding fresh water.