hoz53
Gold $$ Contributor
yeah i woildnt spend the $ myself on a split system hvac unit. id use some form of electric heater and a dehumidifier and give that a try like you said. shielded in the middle of a building it shouldnt get to hot in the summer.I've done a lot of these......owned 3, have one 30ft from my left elbow right now. I've had very good success using an oil-filled radiant heater (DeLonghi, Pelonis) for completely clean heat and a large enough dehumidifier (unit is about 18Wx22Tx8D) that it has a garden hose outlet (along with the collector pan. It's sometimes hard to find the hose bib on the unit)
I rotohammer an 1 1/8 hole diagonally down thru the footers into the free-draining fill near the footing drains and run a cut-off garden hose into the hole.
Turn it all on and walk away. NO rust on guns and stored paperwork is krinkly-dry.
I've also done a number of underground shooting ranges and a few "safe rooms" for hiding out in........these I've added a ventilation system to.
On my current one I just drilled a few more breather holes into the crawlspace area and have them plugged. If I'm ever required to spend time in the vault I'll pull the plugs. (Mine, and many I've done, is perty stealthed. could hide in it....)
My personal view is that penetrations need be tightly controlled as I'm concerned with oxygen seal in the event of house fire.