What's Wrong with Boilers?

Boilers: not the sexiest or most photogenic of topics. A boilermaker, on the other hand, can be entertaining... Nonetheless, I thought I’d share a boiler replacement experience to give an idea of potential costs and benefits.

A few years ago, we bought an early 70‘s triplex with the original boiler heating system still intact. This enormous-vintage-gas-burning-mass used a hydronic (water) pipe system to deliver heat via radiators.


I asked a HVAC friend to check out the unit to estimate lifetime and replacement options. Basically he said to hold my breath underwater. That prompted me to research cost-efficient replacement options. Indeed, less than 3 months after our discussion we received a call from a tenant about a loud thumping noise when the heat was turned on.

A service call and 3 estimates later we received similar recommendations; abandon the boiler and replace with a forced air system comprised of furnace, air conditioning and new ducts. Another suggested installing multiple electric heaters in each room. 

I was perplexed. All of my researched had indicated that the boiler system is one of the most efficient heating systems available. Abandon the entire distribution system with radiators too? Running all new ducts in an existing structure seemed crazy. Electric heat warranted consideration because we pay the natural gas and the tenants pay for electricity. However, with colder winters we couldn’t justify sticking tenants with enormous electricity bills only to see their monthly dissatisfaction grow into a burning desire to leave our units before the next winter.

Boilers can be very efficient in providing heat. New Energy Star models have fuel efficiency ratings up to 99%. The pipe distribution systems have lower rates of heat loss than air ducts found with furnaces. It didn’t make sense to install an entirely new heating system when all we needed to replace was the boiler unit itself.

So I began a search for boiler service companies in our region. Wow. For being an efficient and common choice for large commercial applications there are few companies specializing or even willing to work on residential boilers. Apparently, HVAC companies prefer furnaces and air conditioners with ductwork systems because it makes them more money. 

We found a boiler specialist to replace the 65% efficient boiler with a 98% efficient Energy Star boiler a quarter the size of the original. The total cost for installation was $8,000. I thought that was ridiculous too, but compared to the high bid for a forced air system with furnace and air conditioner of $24,000, I reconsidered my apprehension to the boiler bid. Winter was coming and the heater didn’t work. We needed a replacement. We estimated with various calculators that the energy savings over the old boiler would payback the investment in less than 10 years. In contrast, an efficient furnace and retrofit ducting would have taken at least 15 years to payoff.

Now, over 6 months after we installed the new high-efficiency boiler we can report mixed results. There has been 3 service calls to repair problems with the existing hydronic pipes (and couplers) to add close to another $1,000 in expenses. An unforeseen expense but understandable considering that the old things don’t like change. Hopefully the glitches in the system are all worked out. On the positive front the gas bills have decreased nearly $600 over 6 months when compared to the prior year. These savings are in-line with our expected return on investment. I’ll give another update 6 months from now. In the meantime, I’ll be researching sub-metering of gas lines to make each tenant aware of their usage.