18 or 30,000 BTU Furnace?

[vman11]

I bought a 8x18 Aluma Lite shell and am in the process of finishing it off. The walls, ceiling and floor will have +2 inches of spray foam.

Will a 18K btu forced air keep up, or will I need 30K?

I don't want the furnace to kick in and off constantly but I want it obviously to keep up. Looking for some first hand feedback.

[Boar]

I have a 20' V and upgraded frm a 20000 to. 30 cause the 20 couldnt keep up.. if that hlps. As much as u ice fish this is one case wher bigger is better.

[dirt292lv]

30k suburban force air

[Whopper Stopper]

Go 30,000 BTU

WS

[sportfish]

I upgraded from a 20k to the 30k on my ice castle 8x16 and now I can hear the tv when the furnice is on !

Last year the 20k took for ever to shut off , this winter it should be quick and quit