looking for additional opinion on what heater to get

tbones_heater

Hi,
I was hoping to get some advice on if I should replace my conventional boiler with another conventional one or get a high efficiency condensing gas boiler. My contractor recommends a Lochinvar Noble fire tube boiler as the high efficiency one or I can get another regular conventional boiler, it's up to me. My gut kind of tells me a conventional boiler like I have would be more dependable but, I'm afraid I'm passing up the opportunity to get into the more high efficient boiler, maybe they are good machines and I would save some money on my gas bill and like it. I wanted to add that I live in Wisconsin and have baseboard emitters. (not sure if winter weather locations matter or not) I think I know when a high efficient boiler is running at higher temperatures in very cold or below zero temperatures it won't be doing much condensing and the efficiency will be somewhat lower.

There are probably tons of threads about this kind of question that have been asked by much more intelligent people than me, but if someone would steer me to them that might help me, otherwise I'll just keep poking around this site and see what I come up with.

This is a very helpful & nice site I see, cool stuff.

Thanks,

hot_rod

Pros and coins that only you can decide.

High efficiency is more $$ and more parts to fail. Conventional boilers are lower efficiency, maybe, and may require combustion air vents into the building, my biggest pet peeve.

Determine if your system has enough heat emitter to run a low supply temperatures. If you can run 140F or below at most of your heating season you get more benefit from a condensing type appliance.

Burner modulation is another attractive feature of mod con, and ability to program the control for many variables. Most have outdoor reset control built into the control, so you do get more bang for the extra cost.

Eastman

The Noble is a combi boiler. What generates your domestic hot water currently?

tbones_heater

Thanks Hot Rod! Great information,
I'll ask my contractor if he can calculate if I have enough fin tube in this house to be able to run at that lower temperature. I have a feeling the house is under radiated. My current boiler is always sent to 170 degrees and it heats well except when it gets to below zero, then I have to set it up to 185 or 190 degree range or it'll be cold in the house. That's a great question to ask my heating guy about.

Thanks again,

Eastman,
Right now I have a separate gas hot water heater, It's only me and one dog here. I don't think I would ever be using the hot water part of the combi boiler, unless I moved and someone else moved in here and wanted to use it.

Thanks for all your help guys!

Eastman

Combi boilers tend to be signifcantly oversized to meet on-demand hot water requirements. I don't understand why one would be specified if the combi functionality is not going to be used.

hot_rod

tbones_heater said:

Thanks Hot Rod! Great information,
I'll ask my contractor if he can calculate if I have enough fin tube in this house to be able to run at that lower temperature. I have a feeling the house is under radiated. My current boiler is always sent to 170 degrees and it heats well except when it gets to below zero, then I have to set it up to 185 or 190 degree range or it'll be cold in the house. That's a great question to ask my heating guy about.

Thanks again,

Eastman,
Right now I have a separate gas hot water heater, It's only me and one dog here. I don't think I would ever be using the hot water part of the combi boiler, unless I moved and someone else moved in here and wanted to use it.

Thanks for all your help guys!

Probably a good portion of your heating season could be at lower SWT. Doing some calculating could determine how often and how low you could run.

A load calc, determine emitter output at various SWTs.

Here are a few slides showing how condensing technology and ORD can help maximize condensing equipment on a fin tube application. Your heating requirements are probably a bit higher that this Boston example, data is available to estimate all this.

At the 160 SWT condition IF the load exceeds the SWT, most of the mod cons have a boost feature that would cover that higher SWT demand.

Plenty to think about, if you want to run it down this far.

This Condensing webinar, presented by Jody Samuell, now with Viessmann, is at the Caleffi You Tube station, to hear it all explained. 10- 2015 was the presentations.

tbones_heater

Thanks Hot Rod,
I'm going to print out those slides and check them out, I can see some of it and I can always ask an engineer I work with to help. I have heard about the load calculation, I'll ask my contractor, he did size and install my current boiler, so he probably knows some of these things about my situation or home.

For some reason all this high tech stuff is leaning me towards a high efficiency boiler - lol

thanks again

tbones_heater

Eastman said:
Combi boilers tend to be signifcantly oversized to meet on-demand hot water requirements. I don't understand why one would be specified if the combi functionality is not going to be used.

I don't know exactly why, except that if you wanted to use the on demand function at some point it's there. I think going that way still requires a small storage tank though and it may not be as good as a regular tank water heater? I don't know much about on demand water heaters, so far.

Thanks

SuperTech

You can have many of the same features with a conventional boiler, outdoor reset, boost, warm weather shut down etc. Just add the controls and then you will have the reliability, ease of service of a traditional boiler with some of the energy saving features of a mod con.
Mod cons are best used in high mass heating like radiant flooring or cast iron radiators.
You have to remember that higher AFUE isn't the only way that efficiency is measured, how your system uses the heat made by the boiler is the most important thing.

Zman

Eastman,
Right now I have a separate gas hot water heater, It's only me and one dog here. I don't think I would ever be using the hot water part of the combi boiler, unless I moved and someone else moved in here and wanted to use it.

Thanks for all your help guys!


Not sure why your contractor is suggesting a combi boiler if you are not going to use the DHW side. You would just need a Lochinvar knight.

If you post your house square footage, general insulation details and the lineal footage of baseboard heat, we can give you a little better advise.

If you have the means to do a heat loss calc, that would be ideal.

tbones_heater

Just wanted to say thanks to - Bob "hot rod" Rohr, Eastman, SuperTech and Zman for all your valuable information, it helped me out a lot in making my decision on what new boiler to get.

I decided to replace my Buderus G124X-25 with a Buderus GC144/4 with the Aquasmart control. (so much thinking to end up getting pretty much the same one I have) lol.

Now I just want to figure out my water situation and what water/ treatment to put in the new one. I've also decided to add a water meter too (watermeters.com) This new boiler isn't getting much if any of my super hard well water if I can help it.

I think I made the right choice and I ended up being "that guy" who likes the older school boilers, (with the Aqua Smart control)

Well Thanks for all your help.

T-Bone

Zman

Thanks for the follow up. Those are solid boilers.