I boxed in my 1000 gallon horizontal tank installed in a corner of my shop. One side and one end of the tank are against outside walls. Insulation as follows: exterior walls 6" fiberglass + 2" foam board on the inside + 6" fiberglass between the foam and the tank. interior walls 6" fiberglass against the tank + 2" foam board + sheetrock. Top: 6" fiberglass against the tank + 2" foam board + removable wood panels which form a shelf so that I have storage on top of the tank. Floor: 2" foam under the concrete + 5" concrete + 2" foam board on top of the concrete + 6" fiberglass against the tank.
This old post shows standby heat loss from the tank over an operating period.
https://www.hearth.com/talk/threads/61892/
Notice that standby losses are higher with high tank temperatures and lower with lower tank temperatures. As mentioned in the post above, the standby losses really are not an issue because the tank is in my shop and much of the losses are going into the heated space.
I do not doubt that foam would insulate better. But my insulation is "good enough." My major concern was ability to access the tank for maintenance, ability to access temperature sensors, etc. with a secondary concern of the ability for me to insulate the tank easily and at low cost. The tank has been in place in my shop beginning with the 2010-2011 heating season, and I actually have never had to access the tank for any reason since installed.
This old post shows standby heat loss from the tank over an operating period.
https://www.hearth.com/talk/threads/61892/
Notice that standby losses are higher with high tank temperatures and lower with lower tank temperatures. As mentioned in the post above, the standby losses really are not an issue because the tank is in my shop and much of the losses are going into the heated space.
I do not doubt that foam would insulate better. But my insulation is "good enough." My major concern was ability to access the tank for maintenance, ability to access temperature sensors, etc. with a secondary concern of the ability for me to insulate the tank easily and at low cost. The tank has been in place in my shop beginning with the 2010-2011 heating season, and I actually have never had to access the tank for any reason since installed.
