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Posted by Eric on January 13, 2005 at 07:37:31:
In Reply to: Re: Boiler Comparison posted by HeatPro on January 13, 2005 at 07:27:52:
** This makes sense. Thank you again. I will use the head load calculator link that you provided on another post to determine the proper size boiler to purchase, and be sure to have an annual service contract with the installer.
Regarding boiler sizing. after performing a head load calc., how much margin do I need to figure in? I have seen numbers ranging from 1.15 to 1.25. Does this take into account a tankless heater for domestic hot water needs? If, not, how would I figure this in.
Thank you.
: Efficiency ratings are published by GAMA every year so are public record. But, I know you don't really mean efficiecny which is a ratio of fuel in and heat out. What you want to know is EFFECTIVENESS - how comfortable you will be with low purchase cost and low fuel use. That will be determined by how well the installer put heat sources in your home and where. Almost every USA oil boiler today is rated between 84 and 87% AFUE, so there isn't much range of efficiency. As they last far longer than most people stay in their homes, their longevity is only an issue when they are not serviced to be kept to the design specifications. As most of the controls are made by three companies of each type, the part that might be considered is what they are made of, which is metal, designed to hold water - any other function is that of the controls. As long as the system doesn't leak to bring in oxygen with the water, they will last longer than you. The controls will be replaced when they fail; if you neglect them by saving on doing the yearly cleaning, adjusting, and combustion test, they fail sooner.