In fairness to all, we don't discuss pricing on the Wall. Thanks for your cooperation.
Converting 1 pipe steam with hot water coil, and baseboard,to forced hot water. Bsmt already has fhw baseboards I built using boiler water to circulate with a tempering valve. Worked fine but old boiler doing hot water is expensive. Plus I think it's way oversized.
Any I've been getting all sorts of heating guys telling me all different things like get two boilers it will be cheaper. Total home runs needed, don't use hepex. Monoflo, in and out on bottom no good.
Giving up and decided to plumb it myself and order a boiler and have the plumber come and do the finishing touches. Like the manifold, boiler and,pumps.
1. Had to get fhw radiators as mine were steam type. I got similar btu size on the assumption that my house was built in 1895 with no installation. And now has installation blown in, siding, double pane windows. I'm using the btu loss of the fhw radiator equals the btus now needed for this room. I also used a btu room calculator to prove my hypothesis. I'm also assuming that my boiler was installed in the 50's or has been replaced, but this was pre insulation . It is rated at 100k btu's so I believe this to be overkill for 1350 square feet with dhw. (Before finished bsmt of 800 square feet). Also this is a two family with two 100k boilers steam+dhw and I want to combine for one boiler. 2nd floor will be baseboard.
Used a couple of of programs and came up with an average of 1000sf = 24000 btu's in state of mass for a well insulated house. Both floors and bsmt = 3500 sq ft =84000 btu's.
Am I misunderstanding, bad at math, or what. How wrong am I????. Then the debate of btu upsizing for dhw . I would like to get a http contender 120 btu mod/con boiler. Which modulates between 44 to 120 btus. I think I'm factoring in everything. Please help all comers resent my questions, and just want to give me a huge price 30 to 40 k.
2. Pex and piping "......... I can repipe most of the radiators in copper if need be, or if you think it's better. I don't want to use the old steam pipe if I can repipe. I would like to run a single loop but can run home runs if I need to or if it's better ( keep the number of pumps down for electric savings). Can probably run split loop ( 3 3/4 feeds and 1 larger return.) Want to keep it simple no special tees and such. So questions are pex or copper. 3/4 or 11/4 pipe. Can I do bottom feed and return on radiators. And loop types. Boiler size, and dhw add on.
Thanks much for all your time and effort. Deadman switching.