Replies

1. GBA Editor
   Martin Holladay|Nov 21, 2016 09:28am|#1

   Editor's note: Ann, I have moved your question from a different thread (where it didn't belong) to this new location (creating a new thread). All follow-up questions and comments on this topic should be posted on this page.

   I am also copying (below) Dana Dorsett's answer to your question.

   Dana wrote, "It all begins with a careful heat load calculation using aggressive (=assumptions that lower the load number) where ever that is reasonable. Since you will have a heating history on the place with the old system you can use the old system as a measuring instrument to establish a firm upper bound on the sizing. Getting the sizing right, not too small, but also not too large, is key to getting the most comfort and highest efficiency out of it. The methods for using the old heating system as a measuring instrument are outlined in some detail here:Out With The Old, In With The New.

   "If you have last winter's gas bills handy I can walk you through it on this forum.

   "BTW: If you're heating with a boiler, from both a net efficiency and hot water capacity point of view it's almost always better to heat your domestic hot water with an indirect-fired tank operated as the 'priority zone' off the boiler."

2. GBA Editor
   Martin Holladay|Nov 21, 2016 09:56am|#2

   Ann,
   You didn't describe what kind of heating system you want, but the brand names you listed are the brand names of boilers, implying that your house now has a hydronic (hot water) system, not a forced-air system.

   The more information you can give us, the better.

   If you don't have any ducts in your house, and you want air conditioning, those facts argue strongly in favor of ductless minisplits or ducted minisplits. Those units can provide space heating as well as air conditioning, so you may not need a boiler.