Dear Comfort Advisor,
I have an older boiler in my basement and I am considering replacement but the new boilers seem so complicated.
Dear Boiler Bob,
We have replaced and still service some really old boilers in our older homes and businesses around the valley. Some are as old as 80 years or more, but most fall into the 20-30 year old range. This fear of new technology is not uncommon, especially with boilers because they remained relatively unchanged for decades. Appling modern technology to boiler design plays a crucial role in improving efficiency, reliability, and safety. It may be difficult parting with your old warm cast iron friend in the basement, but the replacement model will impress you with substantial operating cost saving.
When considering replacement models, boilers fall into two different categories: high efficiency condensing models (90% AFUE efficient and above), and non-condensing models (85% AFUE efficient and below). The higher efficiency models produce condensate water when they operate, which extracts an additional 10% efficiency from the fuel you burn. Generally high efficiency models have been very popular because of the $1,500 federal tax credit, utility rebates, and lower operating costs. That is not to say that the standard efficiency units don’t have their place, but the incentives do help.
There are a number of factors beyond the boiler itself that need to be considered when replacements are planned. Older boilers typically have a large amount of water in the system and a lot of cast iron components. These boilers heat the water very slowly and not particularly efficiently. This is very different from most modern boilers which are considered “low mass”. This means they contain very little water and use stainless steel or lightweight alloy heat exchangers. Now, we heat a small amount of water very quickly. This allows much better control over the combustion process to maximize heat extraction.
The piping system differences can be considerable but easy to accomplish if the installation instructions are read and basic piping principles are applied. A “primary-secondary” piping connection is specified in most cases and insures consistant flow through the boiler. This usually requires installation on one more circulator, but it is often included with the boiler.
Another major advantage of new boiler technology is the sealed combustion systems on most models. While older boilers need to be positioned next to a chimney, most newer models will sidewall vent in PVC piping. The sealed combustion system is safer because it totally encloses the intake air to feed the burner and exhaust that vents outside. When weatherizing your home, sealing cracks and leaks is a primary focus. Tightening the home will often reduce the available combustion air. The sealed system eliminates this potential problem.
So in conclusion, do a little research on the subject and step into the next century. Your utility costs will be reduced and you can take advantage of the thousands of dollars in incentives before they run out. Certainly include some plans to weatherize your home while you are at it. AirWorks provides certified blower door tests to pinpoint leakage and help you further reduce your operating costs. Let my 30 years of boiler experience help you decide the best route to take to energy savings.