HW Boiler replacement

If Your Converting

To gas why are you not looking at a 95% AFUE boiler and taking adavantage of the $1,500 tax credit? You should also look into your local utility company and see if they are offering tax credits. My recommendation would be to do a little homework. I'm surprised this contractor did not make you aware of the Federal Tax Credit.

I am also an oil boiler installer, but not by preference, but because that is what we have here.
I do know that gas gives you a wider selection of boilers. Especially in condensing boilers and high AFUE boilers.
You are going to see a lot about AFUE ratings. I recommend you read up on that. It is the cause of much misinformation of actual fuel consumption. You can google Brookhaven Labs and afue. For example:

http://www.nora-oilheat.org/site20/uploads/NORA Policy r7.pdf



I don't feel that Weil McLain is a leader in efficient systems. I just looked at the website for the CGt-5 and it says it uses an in boiler tankless coil. That is obsolete. The new high efficiency systems use an indirect tank where the domestic hot water tank is another zone and the boiler water goes to the tank instead of running cold domestic water to the boiler. There are exceptions. For 30 years Energy Kinetics has been using a "side arm" hot water exchanger mounted outside the boiler which is more efficient and much easier maintenance than the boiler tankless coil. EK now also offers the indirect tank which is pretty standard now.

In addition to the more expensive high tech systems such as Viessmann, Lochinvar Knight etc, there are some basic simple, less expensive, yet effecient gas boilers like Laars Max and Burnham.

I don't feel that Weil McLain is a leader in efficient systems.

I do not know if they are a leader in efficient systems or not, but if I were looking at the W-M product line for an efficient oil boiler, I would not look at the CGt-5 (gas) boiler, that claims 81% AFUE, but at their Ultra-Oil (UO) series. They use an indirect DHW heater as a separate zone, they come with outdoor reset, claim over 86% AFUE.

If one is considering W-M gas boilers, likewise, I finally chose one of their Ultra-3 gas boilers that is mod|con and they claim an AFUE of 93% and up, depending on boiler return water temperature. It, too, supplies DHW with an indirect fired hot water tank, and has outdoor reset. They say you can get an AFUE of 98% it the return water is low enough. I just got one of these systems, at the end of May, so I cannot tell how it actually works in winter, but it supplies my DHW for about half the price of my former electric hot water heater, and the recovery rate is much faster than the electric one.

Since the largest area of my house is heated with in-slab radiant heat, I should get more than the 93% AFUE because the water that goes into the slab is only 120F on the coldest design day, so the return should be colder than that, and I expect a lot of condensing to go on. Similarly, I replaced the 3-feet long finned tube radiators upstairs with 14-feet long Slant/Fin, so I may be able to run those at 140F supply temperature to the first one. (They are in series, so the return should be low enough to condense also, at least most of the time.) I even get some condensation when the indirect water heater runs because that recovers so fast that the boiler does not even get up to the 180F set point before it has recovered.

It may be that other mod|con gas boilers are even more efficient, but after selecting my contractor, that is the boiler he recommends for high efficiency, and with which he has the most experience.