So, here I am envisioning a replacement for my forced-air wood furnace with oil backup for my 3,300 sf house in Maine, the system that has me up every 3 hours all night if the temperature drops below 10F or so. I've been considering a gasification boiler with storage, either a Garn or another boiler with external storage, and using this to drive radiant floor heating. Trouble is, that's a bit too big a chunk of time and money to commit for one year. Thus, I'm wondering how to split the project into two or more years. Would it be reasonable to get the boiler and storage in the first year and use a heat exchanger in the forced air plenum to supply heat while I go about installing radiant tubes? The problem with this, as I understand it, is that the heat exchanger must run at 140F or so, thus robbing me of much of the benefit of storage, as I'll only be able to draw the storage down from 180F to 140F and thus have to make fires frequently. Is there some better way to conceive of this? Some better way to install the new system over a couple of years?