I use an unvented 30,000 BTU NG heater for supplemental heat in a not terribly airtight wooden house. The heater's low-oxygen sensor will shut down the heater at an O2 level equivalent to 4000' ASL, and there is also a tipover sensor shutoff. The room is centrally located in the house - A ceiling fan pushes heated air out an open interior door into the hallway, which has bedrooms at one end, & the kitchen & dining room at the other. There is a separate CO alarm (AC pwr + battery b/u) which also records peak CO level between resets. I keep the house HVAC thermostat set a few degrees lower than the supplemental heater - The effect is that the house is comfortable & the HVAC system (a heat pump) only runs in very cold weather. This setup paid for itself last winter, so I'm fairly pleased... "8) ... On 11/29/17, jim@jpes.com wrote: > > Don't want CO though do you? > > Regards, > > Jim > >> -------- Original Message -------- >> Subject: Re: [OT] Best garage heating option >> From: Sean Breheny >> Date: Wed, November 29, 2017 10:33 am >> To: "Microcontroller discussion list - Public." >> >> >> CO2 is heavier than air but CO is slightly lighter than air (1.145 g/cm^= 3 >> versus roughly 1.2 g/cm^3) >> >> >> On Tue, Nov 28, 2017 at 10:31 PM, Richard Pope >> wrote: >> >> > Allen, >> > Very true. With our tarp setup it was completely open at the >> > bottom >> > to insure that there was plenty of air for the heater and for us. Sinc= e >> > CO2 and CO are heavier than air they would fall out of the bottom of >> > the >> > tarps and protect us from being poisoned by them. This is slightly >> > different from a closed building where these can build up to toxic >> > levels very quickly. >> > Thanks, >> > rich! >> > >> > On 11/28/2017 9:16 PM, Allen Mulvey wrote: >> > > Much of the need for a "well ventilated area" is not so much >> > > for fear of CO but rather a need for fuel. In a well sealed >> > > environment you can burn off all your oxygen and asphyxiate >> > > yourself. >> > > >> > > Allen >> > > >> > > -----Original Message----- >> > > From: piclist-bounces@mit.edu >> > > [mailto:piclist-bounces@mit.edu] On Behalf Of >> > > mail@crcomp.net >> > > Sent: Tuesday, November 28, 2017 9:33 PM >> > > To: piclist@mit.edu >> > > Subject: Re: [OT] Best garage heating option >> > > >> > > RussellMc wrote: >> > >> On 28 November 2017 at 18:49, Gary Crowell >> > > >> > >> > >> > --- >> > This email has been checked for viruses by Avast antivirus software. >> > https://www.avast.com/antivirus >> > >> > -- >> > http://www.piclist.com/techref/piclist PIC/SX FAQ & list archive >> > View/change your membership options at >> > http://mailman.mit.edu/mailman/listinfo/piclist >> > >> -- >> http://www.piclist.com/techref/piclist PIC/SX FAQ & list archive >> View/change your membership options at >> http://mailman.mit.edu/mailman/listinfo/piclist > > -- > http://www.piclist.com/techref/piclist PIC/SX FAQ & list archive > View/change your membership options at > http://mailman.mit.edu/mailman/listinfo/piclist > --=20 http://www.piclist.com/techref/piclist PIC/SX FAQ & list archive View/change your membership options at http://mailman.mit.edu/mailman/listinfo/piclist .