Boiler/side arm replacement

Users who are viewing this thread


New Member
Reaction score
Fort Collins CO
My house has radiant floor heat and a large NG boiler as the heat source. DHW is generated by a side arm water tank.

House is now 20 years old. Everything still works fine. But I'm told boilers last about 15 years and I'm living on borrowed time.

Considering a pro-active boiler replacement.

There are several things I don't like about my current system. The boiler is the only source of heat in the house. If it fails, I could be in a dire situation if the weather is cold. My other major complaint is there is a single hot loop through the boiler. In the no heat season, this hot loop remains hot to service the side arm water tank. While there is no flow in the lower temp radiant heat loops, the entire copper distribution manifold is hot. I've applied some insulation to the pipes, but boiler room temps can still be pretty high in the summer.

My idea is to replace the conventional boiler with a high efficiency condensing boiler and the side arm water tank with a high efficiency standalone water heater. In the no heat season, all the radiant plumbing will remain cool. A standalone water tank will be warm, but a good quality tank will be well insulated and shouldn't leak much heat.

Haven't looked closely at the costs, but indirect water tanks aren't cheap. My guess is a smaller boiler and standalone conventional hot water tank won't be too much different in cost than a larger boiler and indirect water tank.

I've reduced the complexity of the boiler system, but added another appliance.

Hard to say how much heat I'm losing through the radiant heat distribution manifold in the no heat season. Hoping to reduce my gas bill of course.

Looking for general comments. Is this a good idea?

John Gayewski

In the Trades
Reaction score
I think you should wait until your boiler is good and dead. Your boiler now could last another 20 years it's hard to say. You could change some piping around and get a standalone water heater in the mean time. But your adding a lot of complexity with a new condensing boiler. If that's your heat source then I'd be more worried about that causing problems than your very simple boiler.

If the heat goes out most people put electric heaters where they need it until it's fixed.
Hey, wait a minute.

This is awkward, but...

It looks like you're using an ad blocker. We get it, but (1) can't live without ads, and (2) ad blockers can cause issues with videos and comments. If you'd like to support the site, please allow ads.

If any particular ad is your REASON for blocking ads, please let us know. We might be able to do something about it. Thanks.
I've Disabled AdBlock    No Thanks