Convincing homeowner to switch?

James Day_2

I have a question for the hydronic gurus on the site.  Say you go on a job that has a oil forced hot air furnace that needs to be replaced.  Would you try and convince the homeowner to switch to hot water heating, or some variation of it.  If so what would be your main points for getting the homeowner to bite the bullet and spend the extra money to change over to hydronics.  What would be a realistic savings on a hot air to hot water conversion, whether it is oil hot air to oil hot water or oil hot air to natural gas water.    Just want to get some wisdom from you guys.   Thanks

Brad White

Subjectives and Objectives

From a purely energy-driven standpoint, heat is heat when comparing two systems delivered at the same overall efficiency and ability to adapt to changing loads (meaning modulation if done for one, is done for both).



A house with a heat loss of 50 MBH that is served by a modulating furnace and a modulating boiler will, thermally speaking, come out even. The parasitic losses of the furnace fan (say 1/4 HP or 200 Watts as your "delivery charge", is beat by a hydronic system with say, a P/S pump arrangement using, oh, 50 Watts each, or even less if ECM circulators.  But then you assume your radiation-side circulator runs all of the time when it is below a certain temperature outside. Your boiler circulator may or may not need to run all of the time.  So if you cycle your furnace fan off and on with a call for heat, you can break even on delivery (at the expense of some comfort).



With me here?



If there is a driving need for AC or filtration or humidification,

selling hydronics is a harder sell. The heating side, if the furnace is

top of the line in modulation of air flow and combustion and with good

duct distribution, will have a thin difference if any. A poor duct

distribution system seems to be the root of most air system discomfort.

Yes there are other factors, no question.



So, how would I make my case?



Comfort and the ability to more precisely deliver heat to a given space when I want it, where I want it, and not heat the rest of the house. OR, the ability if a single zone, to better adapt the temperature of the heating medium (be it air or water), to the load requirements at a given time. Air can do this as can water, but water gets the edge.



Are you selling radiant or baseboard? Now you are going to a different league. You lose the ability to compare appropriately.



If the air side is needed for AC, filtration or humidification, you can make the hybrid hydro-air case for possibly higher water efficiencies, ability to make HW and ability to branch out for more duct-coil zones. But then you no longer are comparing your father's air system.



So in summary, heat delivered to the same zoning at a given efficiency and appropriate distribution will have little difference to sell your clients in my opinion. Comfort and targeting the heat to more zones is the salable difference.