Article 1051186 of alt.home.repair: Path: news.misty.com!not-for-mail From: nicksanspam@ece.villanova.edu Newsgroups: alt.home.repair Subject: Re: Suggestions on heating detached garage - running gas? Furnace type? Date: 11 Oct 2008 19:18:14 -0400 Organization: Villanova University Lines: 20 Message-ID: References: <7b08b0af-daf4-4372-a0a0-1a07f634736b@t65g2000hsf.googlegroups.com> <948c4449-02b8-49b7-b7cd-ad461c0a07d4@h2g2000hsg.googlegroups.com> NNTP-Posting-Host: acadia.ece.villanova.edu X-Trace: max.inside.misty.com 1223767097 13519 153.104.44.130 (11 Oct 2008 23:18:17 GMT) X-Complaints-To: abuse@misty.com NNTP-Posting-Date: Sat, 11 Oct 2008 23:18:17 +0000 (UTC) Xref: news.misty.com alt.home.repair:1051186 hallerb@aol.com wrote: >DONT use a chimney, buy a high efficency furnace that PVC vents thru the wall There are at least 3 choices in the 20-30K Btu/h range, 1) a $2K condensing Mantis with 93% efficiency, 2) a $600? "high-efficiency" (80%?) direct vent heater (above), and 3) a $200 unvented heater with a dehumidifier or an $80 window AC inside the room with a $30 humidistat that runs it when the RH rises to 50%. With natural gas at $2/therm and electricity at 10 cents/kWh, 1) can make 100K Btu for $2/0.93 = $2.15, 2) costs $2/0.8 = $2.50, and 3) costs $2 for 89K of sensible heat plus 11K of latent heat, ie water vapor, which the AC converts to sensible heat with 11K/3 = 3667 Btu (1.07 kWh) of electricity, which adds another 3667 Btu to the room, so 3) can provide 92.7K Btu for $2.107, or 100/92.7x2.107 = $2.27 for 100K Btu, with no chimney nor thru- the-wall vent, at less initial cost, with welcome winter humidification. Nick