# 3 - Reliability: Why a hydronic heating system is more reliable than forced air

The reliability of your heating system is something you may take for granted – until it's not working. But  hydronics has a long history of reliable service – even when neglected.

The traditional workhorse of hydronics is the cast-iron boiler. You know – like the one in grandma's basement that's been feeding those big 'ol cast iron radiators you used to put your mittens on after coming inside from a sledding excursion. It you go down there today you may find that same boiler just purring along some 30, 40 or 50 years later. With its massive cast-iron heat exchanger sections, it may still be some time before a leak forces her replacement. (I'm still talking about the boiler here!)

Compare that to the sheet-metal heat exchanger of a forced air furnace and there's not much debate. The heat exchanger of any heating equipment goes through thousands of heat-up and cool-down cycles in its lifetime. Each of these cycles starts to fatigue the metal and bring the furnace one step closer to failure. Compare 1/8" (at most) of a furnace sheet-metal heat exchanger to a 1/2" (or more) of cast iron and you begin to see why grandma's old boiler is still kicking while her neighbor, Myrtle, has had the furnace guys replace a couple of "slip unders" in the same amount of time.

Now, I'm not going to tell you that grandma's 40-year-old boiler is as efficient as a modern replacement boiler, but then she's probably thinking, "If it ain't broke, don't fix it", and, with proper maintenance, that can be good strategy.

But another way a hydronic heating system has it all over forced air is in the reliability of its distribution system. Over time, a furnace duct system can develop leaks and build dust and contaminants that blow throughout your home. A hydronic heating system has a network of pipe or tubing that distributes the heat throughout your home with the same reliability and efficiency today as it did the day it was installed. (I've seen systems installed in the 1920's and even earlier, still moving water from the boiler to the radiators.) The pipes can last this long because, after a few days, all of the oxygen is "boiled" out of the distribution water and it no longer has the capability to corrode the piping's internal walls. And leaking pipes just cry out "fix me!" while a leaking duct can go on leaking energy for years.

Many hydronic system owners also choose to heat their domestic hot water (for showers, clothes washing, etc.) with an indirect water heater. (I'll discuss the many advantages of an indirect water heater in a future installment of Heidronics.) It uses the boiler's capacity to heat hot water for domestic use in a separate tank. Many of these have a lifetime warranty and will be the last water heater you'll ever buy. Compare that to the 12 year national average life span of a traditional gas hot water heater. Now that's reliability!

Even though I've seen plenty of older hydronic systems continue to work for years without regular maintenance it's been my experience that any system will work longer (and more reliably) with scheduled, thorough maintenance performed by a competent service technician.

If you're considering hydronics for your home, be sure to ask the designer and installer what provisions they've included in the design and installation to maximize your new system's reliability.

Next week I'll talk about how versatile a hydronics system is – and how that compares to what a forced air system can (and can't) do.

Hydronically yours,

Wayne