Please help me select the right boiler for a NG conversion. We (soon to be 4 people) live in the NE (Outside Philly) in a 50 yo two story brick colonial about 1400 sq ft. We currently have oil with a summer/winter hook up and have the radiators with the fins, not the cast iron ones.

I have three bids from BBB accredited contractors overall the prices are comparable at $11k for the high efficiency units with indirect hot water. All three have been in business for a very long time and my husband and I genuinely liked each one of them so the decision really boils down to the best most reliable equipment.

Contractor 1 - proposes to install one of three Utica boilers (range of 5k - 9k) - the MGB Series, UB-90-100 or the UB95M-200 (a modulating boiler). Both the UBs are condensing gas boilers, though I am unsure what the benefit of this is? I have one of three hot water options as well 2 Bradford Whites 40 or 50 gallons and then the Smart 30 which I see is from Triangle Tube that I keep hearing such great things about (range 700 - 1800).

Contractor 2 - proposes to install a Dunkirk Plus 90 (his other two were WMs and from what I have read, I'll stay far away!) This is not a modulating boiler. For HW he proposes either a WM indirect (11k) or a Bradford White 50 gallon (9700). This contractor specifies that a new chimney liner is additional. We already know we need a chimney liner and again from research we need a SS liner as opposed to aluminum when converting from oil to gas. This could end up adding another 1500k to the bid. But if the quality of the boiler is that superior, I'd still consider this guy doing the install.

Contractor 3 - proposes to install one of three Peerless boilers (range 7-11k) - the M1-04 Sprk-N, the PSCII04, or the PF-80-NG. It's unclear to me from the bid or the Peerless website if any of these are modulating. Boilers M1-04 Sprk-N & PSCII04 both propose the BW 40 gallon HW heater, the PF-80 is the Peerless 60 gallon indirect.

Here are some questions; does a smaller home with no zones really need the modulating? What benefit does it really bring? Is a high efficiency system compatible with the radiators we have (one other contractor told me no)? Does a small family benefit from an indirect hook up? IN terms of energy cost, since we have summer/winter hook up our furnace was always running, how often might the boiler run in the dead of summer to maintain its temp?

If there is anything else I'm missing or should consider, please do let me know. And many, many thanks!