View Full Version : Modulating/High Efficiency vs "old reliable"
02-04-2006, 12:35 PM
I have spent a lot of time trying to get educated enough to make an informed decision on a new heating system. Most of what I have learned is from this site, so I put my trust in you guys on this forum.
My questions are:
1) I have read several conflicting views about wheather or not a high effeciency/modulating boiler really saves much in fuel for a baseboard heating system becuase of high return temps do not allow for the condensing to happen, which is the primary savings. One of my contractors also seems to think with all the "moving parts" of the high effiecient boilers, there is more chance for problems. My system sounds like it will be consisting of 120' of baseboard, and a heating coil in the air handler. Is a high effieciency boiler the right thing here?
2) I have also read several posts about everyone's favorite brand name for boilers. Can I really go wrong with any of the following choices? 1) WM Ultra 2) Munchkin 3) Trinity TI 4) Burnham 5) Budures could we rank these by quality/price?
<<<< Can't give you info such as price, Forum Rules (http://hvac-talk.com/vbb/showthread.php?threadid=1241) but I'm sure the forum members will be along to help you on the rest of your questions. >>>>
[Edited by Mod2 on 02-04-2006 at 12:51 PM]
02-04-2006, 03:26 PM
If this is a completely new install, have the length of baseboard sized to whatever temperature you want. If there is enough baseboard in the room, you can run 120F water.
Baseboard at 180F puts out 600BTU per foot
Baseboard at 140F puts out 340BTU per foot
Baseboard at 120F puts out 220BTU per foot
When the baseboard system in my house was installed back in the 1960's, they way oversized the amount of baseboard. This turns out to be a very good thing now. On a 5F night, I can run 140F water, and still have the zone valves cycle occasionally. At temperatures above 25F (which account for the vast majority of the heating season) I can run 120F water.
I can't personally comment on the choices of boilers you mentioned, however, from what I have read, any of them would be a good choice. The key is to find an installer that has experience with them, and uses a combustion analyzer to assure that they are set up correctly.
02-04-2006, 03:31 PM
Forgot to include this:
So if that 120' of baseboard is sized for 180F water, you could put in 212' of baseboard and run 140F water.
02-04-2006, 06:41 PM
Don't forget that you only need the max temp when it is the coldest day of the year. When your heat loss is less, the supply temp can be less. The worst that will happen is that the boiler will become 80% but you will still save because it modulates.
02-04-2006, 06:59 PM
We have several Ultras on baseboard systems, they work great
Savings of approx, 28 to 32% on fuel consumption.
02-04-2006, 07:20 PM
One happy customer of ours with cast iron radiators reduced their annual average gas consumption from just under 1,700 Therms to just over 1,100 Therms without adjusting insulation or other weatherization. The water temps are adjusted to meet loads and outdoor temps due to the wonderful computerized controls available with modern condensing boilers. Yes, there are a lot more moving parts to consider. But if you are faithful at preventative maintenance, your concerns can be eased considerably.
I have found the biggest cost of boiler replacements usually involves having to reconfigure the near boiler piping. Condensing boilers require specific piping methods referred to as Primary/Secondary piping. I believe all hot water boilers, including cast iron types should be piped Primary/Secondary anyway, so that should not really be an issue. If your heat loads are small, then the savings of a condensing vs. quality cast iron boiler may be relatively minor. But, (just pulling numbers out of the air here) the entire concept of a boiler working away at say 20,000 Btus over a long haul and kicking up to 150,000 only when absolutely necessary vs. one that kicks on 'pedal to the metal' of 150,000 Btus off/on for short terms can improve overall comfort so much. Comfort is hard to measure subjectively anyway.
[Edited by Midwest on 02-04-2006 at 07:26 PM]
02-06-2006, 09:52 AM
Thanks again for all your information. I still am looking for some help on which boiler to go with.
You have convinved me to spend the extra and put in a high efficiencey modulating boiler.
About quesiton number 2. Any thoughts on which one to get, or would it just depend on which one my contractor services and uses more of?
02-06-2006, 12:30 PM
Piping is critical on these boilers. You must follow install instructions. This is why it's better to go with a brand your contractor has expierence installing a few.
02-07-2006, 02:55 PM
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