Water tank / Furnace questions (!)

[rrinker]

He's not the one looking to upgrade, Robert is. That's not the system he has.
Building-scale water circulation is what's used on many large commercial buildings. Also for high load cooling in computer rooms. I don't think water is as efficient as a phase-change heat transfer medium, but on a huge scale like something meant for the entire building, I'm sure it's better than giving everyone their own individual systems. Cpndos and apartment buildings in the US, at least the ones I've lived in, rarely have a whole building heating a cooling system, everyone is on their own, often with wall or window air conditions and electric baseboard heat.

--Randy

[Bob C]

Perhaps I missed something...is your home currently heated by a 'Radiant' water / steam system - or a 'Forced-Air' system ? A change-over from one to the other could be quite expensive due to the required distribution system changes necessary. What is the BTU(H) rating of the old system - the new one should produce a comparable output, no matter how it works. I have a radiant / water "boiler" (only heats the water to ~ 130 - 150 F) feeding baseboard radiators around the exterior walls. The boiler is ~96% efficient and, though my 1950s building is poorly insulated (walls are not insulated or 'wrapped' [visqueen / vapor barrier], the gas bills are reasonable. There is no ductwork - no central A/C. I also have a gas hot water tank - separate system. Your 'combi' system is unfamiliar to me, but whatever provides the heat will have to be able to constantly produce enough BTUs to warm the entire space. The systems I've heard of down here (west PA - not warm winters) are hybrid Heat-Pump / gas or electric, sized to heat the house, with an additional (separate circuit) for hot water supply. The main heat (heat-pump) is backed up for extreme weather by a gas or electric unit. What you seem to be describing seems more like something for Florida / southern US - but I may not be properly understanding. BTW; I believe "Ground-Coupled" heat pumps, properly installed, would likely work in Canada...but installation of the "Ground" circuit would be an expense, too. (Disclaimer: I AM NOT an HVAC professional...just a Rehab Addict / Holmes Inspection / - On Homes / - Makes It Right addict !). Bob C.